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Copy No.

NASA CR-152083

AN ANALYSIS OF THE ROTOR BLADE STRESSES OF THE THREE STAGE COMPRESSOR OF THE AMES

RESEARCH CENTER 11- BY 11-FOOT TRANSONIC WIND TUNNEL

by

NJules B. Dods, Jr.

Distribution of this report is provided in the interest of

information exchange. Responsibility for the contents

resides in-the author or organization that prepared it. .N78-

A ENAiALYSIS OF THE(NASA-CR-1520 8 3 )

STAGE COMPRESSORBLADE STRESSES OF THlE THRE 11-FOOT -0/OF-THE AMES RESEARCH CENTER 11- BYWIN Final EeportHC A0,,(Ramani licls_04787....TRASNsoIC . .... nG3/0 0ND TUNNEL

-- _Aeronautics R 14_pBCAO/M/2L - 078

Prepared under Contract No. NAS 2-9112

by

RAMAN AERONAUTICS RESEARCH AND ENGINEERING-, INC. Palo Alto, California, 94301

November 1977

https://ntrs.nasa.gov/search.jsp?R=19780009118 2020-06-12T20:29:18+00:00Z

TABLE OF CONTENTS

Page No.

SUMMARY .

INTRODUCTION . 1

NOMENCLATURE . . . . . . 3

MODEL AND WIND TUNNEL FACILITY . . . . 4

INSTRUMENTATION AND DATA ANALYSIS 4

Data Acquisition System . 4 Data Retrieval System 5

RESULTS AND DISCUSSION 5

Broadband or Oveiall Stresses 5 Power Spectral Analysis of Stresses 9

CONCLUSIONS AND RECOMMENDATIONS . . . . . . . 11

REFERENCES . . . 13

TABLE I . . . . 14

FIGURES 1 THROUGH 14 . 15

i

AN ANALYSIS OF THE ROTOR BLADE STRESSES OF THE THREE-STAGE COMPRESSOR OF THE AMES RESEARCH CENTER

11- by 11-FOOT TRANSONIC WIND TUNNEL

By Jules B. Dods, Jr.

Raman Aeronautics,Research and Engineering, Inc.

SUMMARY

An experimental investigation to determine the static and dynamic rotor

blade stresses of the 3-stage compressor of the Ames Research Center 11- by

11-Foot Transonic Wind Tunnel has been made. The data are presented in terms

of total blade stress, defined as the summation of the static and dynamic

stresses, for the complete operational range of compressor speeds and tunnel

total pressures. A power spectral analysis of selected portions of the data

was made to measure the modal frequencies of the blades and the manner in

which the frequencies varied with tunnel conditions. The phase angles and

coherences between various gage combinations are also presented. The maximum

total blade stress of 62.36 x 106 N/m2 (9045 psi) was measured on the third

stage blade at a distance of O.546 _(21 .5_inches)'outboard of the blade butt

for a tunnel total pressure of 220.12 x 103 N/m (65 in. Hg.). The static

stress accounts for 88.6-percent of the total, and the dynamic stress accounts

for the remaining 11.4-percent of the total stress. A band-pass frequency

analysis of the data indicated that the dynamic stresses are primarily due to

vibrations in the 1st bending mode. A series of recommendations are presented

to improve the results for any future experimental investigations of the rotor

blade stresses.

INTRODUCTION

The static and dynamic aerodynamic loads and the centrifugal loads

imposed upon the components of wind tunnel compressors result in rotor blade

stresses that vary considerably over the operational envelope of the wind

tunnel. Knowledge of the blade stresses is important in evaluating the oper

ational limits of the wind tunnel in terms of compressor speed and wind tunnel

otoal pressre mbiatlous.-- ItIaddition, the blade stresses must be known

in order to estimate the rotor blade fatigue life, and hence, the maximum

number of hours a given set of blades can be run. The consequence of a single

blade failure are catastrophic in terms of severe damage to the remaining

rotor and stator blades and to the wind tunnel, and in terms of the extensive

time required to replace the damaged parts. Thus, tests were initiated and

conducted by NASA personnel to determine the rotor blade stresses in the ;nd

and 3rd stages of the three-stage compressor of the Ames Research Center 11

by 11-Foot Transonic Wind Tunnel. The tests consisted of measurements of 15

strain gage outputs on two rotor blades for compressor speeds from 430 to

685 RPM and for tunnel total pressures from 16.93 x 103 N/m2 (5 in. Hg.) to

220.01 x 103 N/m2 (65 in. Hg.). The data were analyzed to determine the

total blade stresses, broadband (root-mean-square) dynamic stresses, and the

static stresses. In addition, the spectral characteristics of the dynamic

stresses were analyzed to determine the modal frequencies of the blade vibra

tions, the variation of these frequencies with compressor speed and tunnel

total pressure, the power spectral densities, and the phase angle and

coherences of various strain gage combinations.

The data analysis and preparation of the report were carried out at

Raman Aeronautic; Research and Engineering, Inc., Palo Alto, CA on contract

No NAS2-9112 from Ames Research Center.

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--

NOMENCLATURE

A constant = 3.65 in equation, f= AN (see figure 13)

C centrifugal force on blade, N (ib)

D drag on blade, N (ib)

f frequency, Hz

GS power spectral density of blade stress, (N/m )2/Hz [(ib/in2)2/Hz]

GsMf nondimensional power spectral density function of S(t), GsU/q2L) "- - - in2

K strain gage sensitivity, Nvolts/NIm _(ots/lb/in )

L lift on blade, N(lb) [also nondimensionalizing factor for G (f),

m(ft)]

>1' length of compressor blade, m (in)

M free stream Mach number in wind-tunnel test section

M modulus of gage signals, g

N 3-stage compressor speed, revolutions per minute

Pt, PT tunnel total pressure, N/m2 (in Hgo)

q wind tunnel dynamic pressure, nondimensionalizing factor for Gs(f)3

m 2)N/ 2(lb/ft

Q torque on blade, N-m (lb-ft) R resultant force on blade, N (ib)

total stress on blade, absolute value of S-MEAN and S-RMS, N/m2 (b/in2S-TOTAL

S-MEAN static stress on blade, N/m2 (lb/in2)

22b/inS-RMS dynamic stress on blade, N/m

2 (

S(t) time varying function of blade stress

T thrust on blade, N (ib)

U nondimensionalizing factor for Gs(f), m/sec (ft/sec)

U velocity approaching compressor blades, m/sec (ft/sec)c U rotational compressor velocity, m/sec (ft/sec)

UR resultant velocity on blade, m/sec (ft/sec)

X, Y generalized notation for gage signals, volts

a blade angle of attack, deg (see Fig. 2)

a blade angle (c-$), deg

y coherence between gage signals, [Mg2 /(GsX)(GsY)]

6angle between L and R vectors, deg

a phase angle between X, Y, deg (arctan quadrature-power/co-power)

*angle between resultant and rotational velocities, deg.

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~MODELAI WINDTUNNEIL FACILITY

The "model" of the present investigation consists of two strain gage

instrumented rotor blades installed in the three-stage compressor of the Ames

11- by li-Foot Transonic Wind Tunnel. A sectional side view of the compressor

showing the number and the arrangement of the entrance and exit vanes, and of

the stators and rotors is presented in figure 1. A force diagram for a typical

rotor blade is given in figure 2 for reference.

The general arrangement of the 11- by 11-Foot tunnel is given in figure

1.1.1 of reference 1 along with other detailed information. The tunnel is of

the closed-return variable density type having an adjustable nozzle with two

flexible walls and a slotted test section to permit transonic testing. The

Mach number range of the tunnel is from 0.7 to 1.4 and can be operated at unit

Reynolds numbers from 5.6 x 106 to 30.8 x 106/m (1.7 x 106 to 9.4 x 106/ft).

INSTRUMENTATION AND DATA ANALYSIS

Data Acquisition System

The locations of the strain gages on the 2nd and 3rd stage rotors of the

compressor are shown in figure 3(a) and the locations with respect to the

theoretical node points for the first four bending modes are given in figure

3(b). The output from each gage was amplified by an automatic gain-ranging

amplifier and recorded with a frequency range from DC to 2.5 kHz (7-1/2ipsy)

on a FM tape recorder (Ampex FR-1800, 32-channel). In the automatic mode each

amplifier adjusts its own gain step and is locked at that gain during the data

acquisition of that particular test point. A dc voltage analogous to the gain

is provided by each amplifier and is recorded on the tape recorder. A calibration

sine wave signal was also recorded on each tape recorder channel at the begin

ning of each discrete data point. A timing mechanism furnished timed relay

closures to accomplish a variety of tasks in the data acquisition procedure.

For example, a relay closure signaled the time code generator to start the tape

recorder. Other relays would control the auto-gain amplifiers to seek the proper

signal gain level ("reset" mode), to prevent further ranging of the gain once

the proper level was reached ("lock" mode), and to record the dc voltage levels

corresponding to the various gain steps ("interrogate" mode). In addition to

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recording the dynamic strain gage outputs, the static, or mean, strain gage

outputs were recorded on separate tape recorder channels in a dc mode.

Data Retrieval System

The data obtained on the magnetic tape during the wind tunnel test was

played back using the data "retrieval" system shown in figure 4. The data

recorded on the magnetic tapes were divided into four sets, two for the dynamic,

or ac mode, and two for the static (mean), or dc mode. Information from pre

vious tests had indicated the desirability of filtering the dynamic signals

beyond a frequency of 1 kHz. Accordingly, the low-pass filters shown on

Figure 4 were used to eliminate all frequencies above 1 kHz from the dynamic

measurement, and above 0.1 Hz (essentially zero) for the static measurements.

The resulting dynamic signals were then read by the root-mean-square (RMS)

modules and a digital voltmeter (DVM), while an interface scanner introduced

the results to the Hewlett-Packard 9830 computer. The static signals were

handled directly by the DVM/Scanner unit. The computer then processed the

signals and stored the final results on a cassette for printing and plotting.

To assist in an analysis of the relative "stress energies" of the various

bending modes, the low pass filters were replaced by the Krohn-Hite band-pass

filters, and portions of the data were rerun using band-pass frequencies set to

have a center frequency near the modal frequencies for the first four bending

modes. The data were run separately for each mode.

In addition to the data analysis for determining the overall blade stresses,.

selected portions of the data were analyzed to determine the power spectral

densities of the blade stresses using the system described by Lim and Cameron

in reference 2.

RESULTS AND DISCUSSION

Broadband or Overall Stresses

The blade stress data obtained from the wind tunnel test consisted of

outputs from 15 strain gages with variations in the tunnel total pressure from

16.93 x 103 N/m2 (5 in Hg) to 220.12 x 103 N/m2 (65 in Hg) and for compressor

speeds from 430 to 685 RPM. Although the data from all gages were analyzed,

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results are presented only for gages 4, 5, 6, 8, 11, and 12 through 16. The

data from gages 2, 3, 7, 9, and 10 are believed to be incorrect and, therefore,

are not presented. Two of these gages (7 and 9) were located on the camber

side of the blade, and thus no comparisons could be made of the stress differences

between the camber and the flat side of the blade. However, the remaining gages

were distributed quite well longitudinally along the blade and, therefore, it

is believed that a reasonably accurate assessment of the overall stresses could

be made. The gage indicating the highest stresses (No. 6) was located between

valid gages (5 and 11), and the gage indicating the next highest stress was the

one nearest the blade root (No. 12), which would be expected to respond more to

the first bending mode. (It will be shown later than the highest stresses were

found in the first bending mode).

The basic data are presented in the form of total stress, mean (static)

stress, and root-mean-square (dynamic) stress for each operating condition.

The effect of tunnel total pressure on the stresses is shown in figure 5(a)

through (dd) throughout the compressor speed range. The effect of compressor

speed on, the stresses is shown in figure 6(a) through (u) throughout the tunnel

total pressure range. The longitudinal distribution of the blade stresses is

shown in figure 7(a) through (r) for various compressor speeds and tunnel total

pressures.

In general, the total blade stresses increase in a-fairly regular manner with

increasing compressor speed, and with increasing total pressure up to 152.39 x 103

N/m2 (45 in Hg). The data indicate that the compressor blades are probably

operating in a stalled condition at 220.12 x l03 N/rm2 (65 in Hg) and in general

the stresses tend to decrease at stall. Since it was recognized early in the

analysis that gage 6 had the largest stresses at 65 in Hg, the data were reread

numerous times during the course of the analysis to ensure reliability. The

results were consistent for all readings. Also, as will be shown later, the

ratios of mean to total stresses and RMS to total stresses for gage 6 are con

sistent with the other highly loaded gages. Therefore, it is believed that the

data from gage 6 are valid. Unfortunately, there are omissions in the available

data at 65 in Hg (N's from 570 to 630, and from 670 to 685), and in the total

pressure range between 152.39 x 103 N/m2 (45 in Hg) and 220.12 x 103 N/M2

(65 in Hg).

The maximum total stresses for each strain gage with their corresponding

tunnel operating condition are shown in the following table. The stresses are

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listed in descending order of magnitude. Also shown are the static (MEAN)

and dynamic (RMS) stresses and their percentages with respect to the total

stresses.

SITOTA;: ASf , Lercent Percent Gage PStAin N SN' S-M , S-RMS, S-HMSNo. Hg psi psi S-TOTAI- psi S-LOTAL

6 65 640 9045 8011 88.6 1034 11.4

12 45 685 6092 3216 52.8 2876 47.2

11 45 685 5381 2309 42.9 3072 57.1

5 65 640 4450 4000 89.9 450 10.1

4 45 685 4200 1670 39.8 2530 60.2

8 45 685 4108 1442 35.1 2666 64.9

13 45 680 3816 3053 80.0 763 20.0

15 45 685 3753 3008 80.1 745 19.9

14 45 685 3253 2377 73.1 876 26.9

The maximum total stress (gage 6) occurs on the 3rd stage blade at a distance

of 0.5461 m (21.5 in) outboard of the blade root (fig. 3(a)) for a total pressure

of 220.12 x 103 N/m2(65-iHg).As shown in figure 5(g), it is very likely that

the blade is operating in a stalled condition. The next largest total stress

occurs for gage 12, which is located nearest to the blade root 0.2413 m (9.5 in)

for a total pressure of 152.39 x 103 N/m2 (45 in Hg). As shown in figure 5(p)

the blade appears to be unstalled at this pressure. The third largest total stress

occurs for gage 11, the next nearest gage to the blade root 0.4445 m (17.5 in),

and also for a total pressure of 45 in Hg. This gage also indicates that the

blade is unstalled at this pressure. As shown in the above table, there appears

to be a large difference in the static and dynamic stress distribution between

a stalled and an unstalled blade. To illustrate this phenomena more fully, the

following table is presented showing the four most highly loaded gages for a

stalled and unstalled blade condition. In each case, blade stalling results in

a large reduction in the percentage of dynamic stress to total stress. This

result is somewhat unexpected since it might be presumed that the stalled blade

would have a more unsteady flow field, and thus larger rather than smaller

dynamic stresses.

Blade fPt' in S-TOTAL S-NEAKW Eercenc S-RMS, Percent,

Gage Condition Hg N psi psi qTTA psi -RMS

6 uristaliedo 45' -670f 7598 '9-95 65.7 2603. 34Z3' 6 -'stalled 65 640 9045 8011 88.6 1034 i4114

12 unstalled 45 685 6092 3216 52.8 2876 47.2 12 stalled 65 640 4190 3418 81.6 772 18.4 11 unstalled 45 685 5381 2309 42.9 3072 57.1 11 stalled 65 670 3001, 2599 86.6 402 13.4 5 unstalled 45 685 4233 1575 37.2 2658 62.8 5 stalled 65 640, 4450 4013 90.2 437 9.8

-7

http:N/m2(65-iHg).As

The "peaks" in the dynamic stresses that occur in the data, generally at

640N for the blades operating in a stalled condition (see fig. 5(1), (r),(u),

(aa) for example) are repeatable and occur for various gages and in both com

pressor stages. For these reasons it is believed that the peaks in the data

are valid even though the cause is unknown.

Comparisons between the maximum stress levels in the blades of the 2nd

and 3rd stages of the compressor are shown in the following table (from figure

5) for the blades in an unstalled condition. The data are for pairs of gages

in the two stages that are located at the same blade stations. The total

stresses in the 2nd stage blade are only 50 to 6's-percent of those of the 3rd

stage. As shown in the table, the lower total stresses in the second stage

blade are due mostly to lower dynamic stresses.

Percent, ercent, Percent Gkge Stage Pt3 in N -TOTAL, S-TOTAL-2 S-Mean S-1AXi 2 S-RMS S-RMS 2 -Hg psi S-TOTA 3 psi S-MEAN,3 psi S-RMS 3

6 3 45 670 7598 4995 2603

13 2 680 3816 50.2 3053 61.1 763 29.3

11 3 685 5381 2309 3072

14 2 685 3253 60.5 2377 100.3 876 28.5

12 3 685 6092 3216 2876

15 2 685 3753 61.6 3008 93.5 745 25.9

Comparisons were made of the data obtained from runs made by continuously

recording stress levels as the compressor speed was increased at a variable

rate (referred to as "sweep" data) with the constant speed data (referred to

as "discrete" point data). The results indicate that the sweep data were

considerably lower than the discrete point data by a factor of 2 to 2.5 in

most cases. The reason for these discrepancies is unknown. The sweep techni

que has been used previously in the measurement of other parameters (for

example, fluctuating pressures) with more reasonable results.

The dynamic blade stresses as a function of tunnel compressor speed are

given in figures 8(a) through (j) for a Pt of 152.39 Nrm2 (45 in Hg) and for

various band-pass frequencies in comparison with the normal data containing all

of the stress energy up to 1 kHz (low-pass). The band-pass frequencies were

chosen to include the resonant frequencies of the first four bending modes (see

figure 3(b)). These data indicate that for all gages the stress "energy" in

the ist bending mode (band pass from 30-90 Hz) is practically identical to that

obtained for the low-pass analysis. The stress "energy" for the other three

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modes is seen to be minimal. Thus, the dynamic blade stresses are primarily

due to vibration in the Ist bending mode. The band pass analysis for gage 6

did not show the above results. It indicates nearly zero stress in the 1st

mode and minimal stress in the other three modes. This indicates that the

observed result is due to a reading failure in the HP 9830 analysis equipment.

The result was not noticed in time to repeat the analysis on the lIP 9830.

However, a power spectral density analysis,of the data for gage 6 reconfirmed

the belief that the majority of the dynamic stress "energy" is also contained

in the first bending mode.

In order to indicate the importance of filtering out the data above 1 kHz,

the total blade stresses are presented in.figure 9--ith and-with6ut-the

"Dynamics" low-pass filter. The data are for a few representative gages and

operating conditions. The rather large differences in the stress levels illus

trate the importance of filtering the data. It is believed that the signals

beyond about the 4th bending mode (-700 Hz) are primarily "noise" and there

fore are not indicative of true blade stresses. The character of the noise

effects beyond 1 kHz will be discussed in the next section of the report.

Power Spectral Analysis of Stresses

The primary purpose of conducting a power spectral analysis of the blade

stress data was to measure the modal frequencies and to indicate the manner in

which the frequencies varied with compressor speed and with tunnel total pres

sure. A secondary purpose was to compare various gage combinations and to

measure their relative phase angles and coherences. At the beginning of the

analysis portion of the investigation it was believed that comparisons of the

phase angles and coherences would provide insight into the modal behavior of

the blade stresses. However, except for the 1st bending mode, little information

of ,substance was obtained. The reasons for this were twofold - one, the blade stresses were shown to be primarily due to first mode bending which tends to

mask any attempt to measure the higher mode phase angles and coherences; and

two, the failure of five of the strain gages, one of which was a torsional gage,

hampered the selection of gage combinations which would, through phase relation

ship, indidate t6Ysidnal and higher vibrational modes. These deficiencies,

however, are not too serious considering the primacy of the lt bending mode

stresses, and the low stresses near the leading edge as indicated by the one

operational torsional gage 8.

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The power spectral analysis consisted of measuring 918 individual power

spectral densities and cross-power spectral densities from which were obtained

modal frequencies, and phase angles and coherences between selected gages for

various test conditions. The results of the analysis are presented in figure

10(a) through (m) showing the variation of the modal frequencies, coherences,

and phase angles with compressor speed for various tunnel pressures. For

convenience, the same data are shown as a function of tunnel total pressure

in figure 11(a) through (i). In general, the modal frequencies agreed with

the values obtained from "bench" tests at zero RPM by NASA personnel. The

variations with either compressor speed or tunnel total pressure were minimal.

The 1st bending mode frequency varied from 42 Hz at N=470 to 62 at N=685.

Values of the coherence were generally near 1.0 for the 1st mode, and

decreased rapidly for the higher modes, and, depending on the gage combinations,

the phase angles tended to be 0' (in-phase) or 1800 out-of-phase. The coherence

tended to be higher at larger values of total pressure (compare figure 10(a)

and 10(d)). The signals from gages 4 and 5 (figure 10(a) through (e)) were

expected to be in-phase (80o). However,for the!,most part they were out-of

phase (Ol80o). An inspection of the signs of the signal (from the HP 9830

system analysis) indicated a sign reversal between these gages in the mean

values. Thus, it is probable that the phase angles shown should be changed by

1800. For gages 6 and 12 (figure 10(f) through 10(j)), the phase angle relation

ship should be correct as shown since the mean values have the proper signs.

The signals appear to be in-phase for the ist and 3rd modes and 1800 out-of

phase for the 2nd and 4th modes. Gages 6 and 11 (figure 10(k)) are in-phase

for the 1st, 2nd, and 3rd modes and 1800 out-of-phase for the 4th mode. The

second stage gages, 13, 14 and 15 are shown in figure 10(l) and (m). Gage com

binations 13, 14 and 14, 15 are in-phase except for the 2nd mode for the 14,

15 combinations. A summary of these phase angle relationships is given in

Table I.

The power spectral density analysis of the data also provided an indepen

dent check upon the broadband dynamic stresses measured by the HP 9830 system

by integrating the PSDs, and also by measuring the RMS signal strengths as the,

data were being transferred from the test magnetic tape to the "control loop"

of the hybrid system. In general, these values compared very well with those

measured by the HP 9830 system.

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--

A series of representative power spectra, for the most highly stressed

gages (6, 11, and 12) is shown in figures 12(a) through (h). The spectra are

for a total pressure of 152.39 x 103 N/m2 (45 in Hg) and for various compressor

speeds, and were analyzed for frequencies up to 20'kHz in order to measure the

noise peaks previously mentioned for the regions above 1 kHz. (The majority of

the power spectra were, of course, limited to 1 kHz to correspond to the 1 kHz

limits used with the HP 9830 system.) The plotted data appear to end at from

3 to 5 k{z instead of 20 kHz. The reason for this is that the spectral values

are less than the lowest decade shown, and since the plots are limited to 5

decades, the values do not appear. They are, however, included in the overall

integrations.

As previously discussed in the section of the report concerning the band

pass analysis (figure 8), these power spectra show that the peaks for gage 6

compare closely in frequency and amplitude with those for gages 11 and 12, con

firming the statement made in a previous section of the report that the majority

of the stress "energy" for gage 6 was in the ist bending mode.

The frequencies of the noise spectral peaks above 1 kHz are presented in

figure 13 as a function of compressor speed. These frequencies can be approxi

mated by the equation f= 3.65 N. It has been conjectured by NASA personnel that

the strain gages act as miniature RF antennas and pick up the peaks from being

rotated in an enclosed electromagnetic environment. In any event, these peaks

must be considered as being noise because their amplitudes are about two orders

of magnitude greater than the 4th bending mode peaks at f 700 Hz (see figure 12)

and, therefore, it would be unrealistic to believe that the peaks could be caused

by higher modal vibrations of the blades. Thus, for the present analysis, the

noise spectra is defined as that.portion of the power spectra having frequencies

>1 kHz. The effect of filtering out the noise spectra upon the dynamic stresses

is illustrated for gages 6, 11, and 12 in figure 14. It is recommended that the

above definition of the noife be retained for any further tests to determine

blade stresses.

CONCLUSIONS AND RECONMENDATIONS

An analysis of tests conducted to determine the rotor blade stresses of

the 3-stage compressor of the Ames Research Center 11- by 11-Foot Transonic

Wind Tunnel has resulted in presentations of the blade total stresses, the

static stresses, and the dynamic stresses over the operating range of compressor

speeds and tunnel total pressures. A power spectral analysis of selected

portions of the data was made to measure the modal frequencies of the rotor

blades and the manner in which the frequencies varied with tunnel conditions.

The phase angles and coherences between various gage combinations are also

presented. The analysis has resulted in the following conclusions and recom

mendations.

1. The maximum total blade stress of 62.36 x 106 N/m2 (9045 psi) occurs

on the third stage blade at a distance of 0.5461 m (21.5 inches) out

=board of the blade root for a Pt 220.12 x 103 N/m2 (65 in Hg). The

static stress accounts for 88.6 percent of the total, and the dynamic

stress accounts for the remaining 11.4 percent of the total.

2. The data indicate that the compressor blades are operating in a

=stalled condition at Pt 220.12 x 103 N/m2 (65 in Hg) and mostly in

= an unstalled condifion at Pt 152.39 x 103 N/m (45 in Hg).

3. Unexpectedly, blade stalling results in lower dynamic stresses. For

example, for the most highly stressed gage No. 6, the ratio of

dynamic stresses to total stresses is 34.3 percent for the unstalled

blade, and only 11.4 percent for the stalled blade.

4. The total stresses in the 2nd stage rotor blade are only 50 to 60

percent of the stresses in the 3rd stage rotor blade.

5. A band-pass frequency analysis of the data indicated that the dynamic

stresses are primarily due to vibrations in the 1st bending mode.

6. The variations of the modal frequencies with either compressor speed

or tunnel total pressure were minimal. The measured lst bending

mode frequencies varied from 42 Hz at N=470 to 62 Hz at N=685.

7. Values of the coherence for various gage combinations were generally

near 1.0 for the 1st bending mode, and decreased rapidly for the

higher modes. The phase angles tended to be 0' (in-phase) or 1800

(out-of-phase) in the first mode. The primacy of the ist bending

mode stresses tended to mask the measurements of the higher mode

phase angles and coherences.

The following recommendations are given for any further experimental blade

stress investigations:

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http:Pt152.39http:Pt220.12http:Pt220.12

(a) Locate strain gages nearer to thd Toot of the blade- afdadditional

gages near gage 6 to more clearly determineatle maximum stresses.

(b) Provide more strain gages on the camber side of the blade, since there is

some evidence from previous tests that the stresses may exceed somewhat

the values on the flat side of the blade.

(c) In general, provide more redundancy of strain gages, or investigate pro

cedures to prevent gage failures. For the present investigation, failure

of one of the torsional gages precluded the measurement of possibly higher

stresses near the blade trailing edge. For wide blades, vibration in the

torsional mode may induce relatively high longitudinal stresses. However,

the one operational torsional gage 8 did not indicate very high stresses

near the leading edge.

(d) Because of the considerably lower stresses measured on the 2nd stage

blade, eliminate the gages in the 2nd stage, unless significant changes

are made to the compressor configuration.

(e) Conduct the tests for several values of tunnel total pressures between 45

in Hg and 65 in Hg to determine more definitely the pressures and compressor

speeds for blade stall.

(f) Eliminate tests at the lower compressor speeds and at the lower tunnel

total pressures.

(g) Establish definite strain gage signs by pushing on the blade. This pro

cedure will result in more confidence in phase-angle relationships.

(h) Investigate the possibility of strut, stator, and/or rotor redesign in

order to avoid responses of the rotor blades to the forced oscillation

frequencies of the present compressor configuration.

REFERENCES

1. Anon: Research Facilities Summary. Wind Tunnels - Subsonic, Transonic,

and Supersonic. Vol. II - NASA-Ames Research Center, Moffett Field, CA,

December 1965.

2. Lim, R. S.; and Cameron, W. D.: Power and Cioss-Power Spectrum Analysis

by Hybrid Computers. NASA TM X-1324, 1966.

-13

TABLE I.- SUMMARY OF PHASE ANGLES

Gages 4, 5

Ptin Hg ist Mode 2nd Mode 3rd Mode 4th Mode

10 1800 - 1800 00 180 J

20 1800 , 1800 00 1800

30 1800 1800 Erratic 1800

45 1800 1800 Erratic 1800

65 1800 1800 Erratic 1800

Gages 6, 12

10 00 1800(mostly) 00 0*f180 0Erratic

20 00 1800 00 1800

30 00 1800 00 1800

45 00 1800 00 1800

65 00 1800 00 1800

Gages 6, 11

I J45 00 00 0a 1800 Gages 13, 14 (2nd Stage)

4 5 00 00 00 1 00 ,180 0@ N 0620, 630

Gages 14, 15 (2nd Stage)

5 00 1800 00 00L

Probably see Discussion in TextS;

-14

NOTE: ALL DIMENSIONS ARE IN

METERS (FT INCHES) NO. OF NO. OF NO. OF EXIT STATOR ENTRANCE

VANES VANES VANES

60 58 34 34 54 ~FLOW

V Is fill V STRUT CLOCKWISELOOKING 52 52 52 DOWNSTREAM

NO. OF ROTOR BLADES

o uc

S+I

v STAGE NO'S.

3 2 1

1-10.3 442 (33'-11141)

Figure I.- Sectional side view of the Ames 11- by 11-Foot TWT 3-stage compressor.

DIRECTION OF

ROTOR ROTATION

NI

CENTRIFUGAL FORCE, C

IS PERPENDICULAR TO T

T AND Q PLANE ROTATION

BLADE REFERENCE

SLINE

Ut)

Figure 2.- Force diagram for typical rotor blade0

NOTE: ALL DIMENSIONS ARE

IN METERS (INCHES)

0.1254 1.0541 (41.50)

(4.938)

I LEADING EDGE r ,o508 (2.00)

°[] [1] (9 __[13° o1 2 GAGE NO. C) -tlS12 (7) 11 13

0.116 (4.0

0.012.OO 10.0 )

-' - - -

NOTES 0.3810 (15.00)

1. GAGES ARE ON FLAT, OR THRUST 04318 (17.00)

SIDE OF BLADE, EXCEPT NO'S (7) -,----'. 636 (18.25)

AND (9) ARE ON CAMBER SIDE. 0.5080 (2000)" 2. GAGES 2 THROUGH

STAGE BLADE NO. 12 ARE ON 3rd-069(2.) 620. GAGES [13], -069(200"

[14], AND [15] ARE ON 2nd STAGE -.7366 (29.00)-

BLADE NO. 676. GAGE 16 (NOT 0.8128 (32.00) SHOWN) IS A DUMMY GAGE.

(a) Blade and gage dimensions.

Figure 3- Location of the strain gages on the rotor blades of the Ames 11- by 11-Foot

TWT 3-stage compressor.

http:0.012.OO

NOTE: ALL DIMENSIONS ARE IN METERS (INCHES)

1= 1.0541 (41.60)

0.8128 (32.00)

0.7366 (29.00)

0.6096 (24.00)

0.5080 (20.00)

- 0.4636 (18.25) -

O. 7.0 -GAGE 713.831

• -.----.38 0 5.2287 -9 9(021.0)

isnd MODE

04 522828.5

0.5228 0.8.582

0.1391

-- --- 5.48) 3rd MODE

0- 26.64)---.677

-18-Z.3753 (14.78)__--061

II I .0991 ---: : -- F-4th MODE

b)Gage locations with respect to the theoretical mode points.

Figure ,3°- Concluded.

http:�-.----.38

TIME

CODE

0 MONI1TOR] E DATA CH. 11-18

GPANRA

OSCLLOCOP MODULES]

SET 1ODD CH. 1-15 " 8 "DYNAMIC" MODEL 6364a DVM/SCANNER

acFILTERS LOW PASS SET 2MODE1 k Hz

ODD CH. 17-29(BTEWRH

FR 1900SET 4

FMAPE EVEN CH. 18-30 (BUTTERWORTH)80 OMPTE

NOTE: THESE FILTERS WERE

REPLACED BY KROHN-HITE MODEL

3350 FILTERS FOR THE BAND-PASS

OPERATIONS

OSCILLOSCOPE OSCILLOSCOPE

Figure 4.- Block diagram of data retrieval system.

--

6X10 3 07

4X ERGE# H

5 Pt

IN. HG. N/m2XtO 3

3- 1 5 16.93

2 7.5 25.40 7

4 3 10 33.86 4 15 50.80

5 20 67.73

6 30 101.59

7 45 152.39

N 3 8 65 220.12

22 2

0 0 . ' 400 440 480 520 560 600 640 680 720

N, RPM

(a) Total stress; gage 4; 3rd stage0

Figure 5.- Effect of compressor speed on the blade stresses as a function of tunnel total

pressure.

6XlO3 07

4X 5RSE# H

5Pt

3" IN. HG. N/m2X10 3

1 5 16.93

4- 2 7.5 25.40

3 10 33.86

Fn 4 15 50.80

CL 5 20 67.73

ft 6 30 101.59

(M z 7 45 152.39

65 220.122. < - 8

NH w

2- 7. 7

"

0. 0400 440 480 520 560 600 640 680 720

N, RPM (b) Static stress; gage 4; 3rd stage0

Figure 5.- Continued0

6XiO 37 4XI0

5-

3"P

IN. HG. N/m2XlO 3

4- 1 5 16.93

2 7.5 25.40

3 10 33.B6

4 15 50.80

5 20 67.7304

- 3 6 30 101.59

7 45 152.39

" 8 65 220.12Z7

2

400 440 480 520 560 660 640 680 720

N, RPM

(c) Dynamic stress; gage 4; 3rd stage0

Figure 5.- Continued.

7 6X1O3

4X10 EREE# E

5' Pt____

IN. HG. N/m2XI0 3

3 1 5 16.93 7 2 7.5 25.40 a

4-3 4 1015

33.86 50.80 /

5 20 67.73 6 30 101.59

c 78165 45 152.391220.12

2

0 0. 400 440 480 520 560 600 640 680 720

N, RPM (d) Total stress; gage 5; 3rd stage0


6X10 37 4XI0

EREE# E

5-- Pt

IN. HG. N/m2XIO 3

3- 1 5 16.93

2 7.5 25.40

4 3 10 33.86 .&

4 15 50.80

n 5 20 67.73 /

6 30 101.59

7 45 152.39

zz

C,) 2,

0- 0 400 440 480 520 560 600 640 680 720

N, RPM

Ce) Static stress; gage 5; 3rd stage0


5

6X10 3

4XI0 7 rX0 GR6E# E

Pt

IN. HG. N/m2Xl0 33" 1 5 16.93

4" 2 7.5 25.40

3 10 33.86

4 15 50.80

E0, 5 20 67.73

CL 6 30 101.59

('. - 7 45 152.39

65 220.12 jE2 Q 8

(I) 2

400 440 480 520 560 600 640 680 720

N, RPM

(f) Dynamtc stress; gage 5; 3rd stage.


8X10 7 ERGE# G

7"

6-

E4 04

IOXIO 3

6-o

Pt IN. HG. N/m

2Xl0 3

1 5 16.93 2 7.5 25.40 3 10 33.86 4 15 50.80

5 20 67.73 6 30 101.59 7 45 152.39 8 65 220.12

aB //

7

7

7

7

' <

(gCotlsres:gg sae ar

0F 0C 400 440 480 520 560

N. RPM 600 640 680 720

(g) Total stress;

Figure 5e.

gage 6; 3rd

Continued.

stage0

8XI0 7 GAGE# G

7- IOXIO 3 Pt IN. HG. N/m

2X10 3

1 5 16.93

6- 2 7.5 25.40

3 10 33.86 a

4 15 50.80

5 20 67.73

5 6 30 101.59

7 45 152.39

8 65 220.12E4 '6

Z 4-- 4087 w

Cm W 3~47 7

U-tl

5

t0 0 400 440 480 520 560 600 640 680 720

N, RPM

(h) Static stress; gage 6; 3rd stage0


8Xl0 7

7- IOXIO 3 Pt

8

5

S7E46

1 2 3 4 5 6

8

IN. HG.

5 7.5

10 15 20 30 45 65

N/m2X10 3

16.93 25.40 33.86 50.80 67.73

101.59 152.39 220.12

3--cr '4

2'

2 2 -

400 440 480 520 560 N, RPM

600 640 680 720

(i) Dynamic stress; gage 6; 3rd stage0


4X107 6X0

5-

3

Pt ERE# 6

N

3 -

4

IN. HG.

1 5 2 7.5 3 10 45 1520 6 30 7 45 8 65

N/m2XlO 3

16.93 25.40 33.86 50.8067.737

101.59 152.39 220.12

z0 0

2 -

I j ,I

0 01 400 440 480 520 560 600 640

N, RPM (j) Total stress; gage 8; 3rd stage0

Figure 5°-- Continued,

680 720

7 4XI0

6XiO3

ERBE* B

5 Pt 3 IN. HG. N/m2XlO 3

(j Z

41 2 3 4 5 677 8

5 7.5

10 15 20 3045 65

16.93 25.40 33.86 50.80 67.73

101.59152.39 220.12

2-

o

400 440 480 520 560 600 640 N, RPM

(k) Static stress; gage 8; 3rd stage.


680 72

6Xi0 3

rGR5E# B

5

Pt

IN. HG. N/M2XO 33 1 5 16.93

4 2 7.5 25.40

3 10 33.86

4 15 50.80

(.1 5 20 67.73

- 6 30 101.59

2. -t 7 45 152.39

8 65 220.12 1Eu 3

z (I)

2--

Ai0 0 400 440 480 520 560 600 640 680 720

N, RPM

(1) Dynamic stress; gage 8; 3rd stage0


4X10 7 6Xl0 3

5-- Pt 7

\5

3 4-

C_

58

1 2 3 4 5 6 7

IN. HG.

5 7.5

10 15 20 30 45 6

N/m2XO 3

16.93 25.40 33.86 50.80 67.73

101.59 152.39 220.12

7

Iz

U,,

0

2-3

:

0 0400 440 480 520 560

N, RPM 600 640

(m) Total stress;

Figure 5.

gage 11; 3rd stage0

Continued.

680 720

7 6X10 3

4XI0 GRGE# I I

5-- Pt

C'%J

3

F CL

4"

"

1 2 3 4 5 6 7 8

IN. HG.

5 7,5

10 15 20 30 45 65

N/m2X10 3

16.93 25.40 33.86 50.80 67.73

101.59 152.39 220.12

C~j

E212 z

Il 7 I0 n 2-

400 440 480 520 560 600 640 680 720 N, RPM

(n) Static stress; gage 11; 3r stage..

Figure 5., Continued.

5

6X10 37 4XI0

BREE# I I

Pt

3" IN. HG. N/m2X1O3

1 5 16.93

4 2 7.5 25.40 3 10 33.86 4 15 50.80

Fl) 5 20 67.73

al 6 30 101.59

( 7 45 152.39 7 Er -- 8 65 220.127

2--G 62O

a8 .- A a fil Jauu 400 440 480 520 560 600 640 680 720

N, RPM (o) Dynamic stress; gage 11; 3rd stage0

Figure 5°- Continued.

8Xl0 7

5RE# 12

7 IOXiO 3 Pt

IN. HG. N/m2Xl0 3

6 1 5 16.93

2 7.5 25.408-- 3 10 33.86 4 15 50.80

5 5 20 67.73

6 30 101.59

7 45 152.39

c'J 8 1 65 220.12 7

Iz j

30 1 68.-Li) 14 I

0 0 400 440 480 520 560 600 640 680 720

N, RPM

(p) Total stress; gage 12; 3rd stage0


4X 07

6X10 3

GRGE# 12

5 Pt

(

3-4

0-30 z1

1 2 3 4 5 7

IN. HG.

5 7.5

10 15 20 45 65

N/m2 X10 3

16.93 25.40 33.86 50.80 67.73

101.59152.39

220.12

,

E

z

2

-L 04

400 440 480 520 560 N, RPM

600 640

(q) Static stress;

Figure 5°

gage 12; 3rd stage0

Continued0

680 720

4X 07

6X10 3

EHGE# 12

3"

2

5

4"

E5 0.

U) 3 c

1 2 3 4 5 6 7

8

Pt

IN. HG. N/m2X10 3

5 16.93 7.5 25.40

10 33.86 15 50.80 20 67.73 30 101.59 45 152.39

65 220.12

73

7

I• 2

400 440 480 520 560 N, RPM

600 640 680 720

(r) Dynamic stress; gage 12; 3rd


stage,,

7 4XI0

6X10 3

EREE# 13

C1

5

4

1 2 3

5 6 7 8

Pt

IN. HG. N/m2Xl0 3

5 16.93 7.5 25.40

10 33.86 15 50.80 20 67.73 30 101.59 45 152.39

165 220.12 7

7

Iz 0I

I

400 440 480 520 560 600 640 680 720

N, RPM

(s) Total stress; gage 13; 2nd stage,

Figure 5.- Continuedo

4X0 7 6X GRGEt 13

5 Pt

IN. HG. N/m2 XlO

3" 1 5 16.93

4 2 3

7.5 10

25.40 33.86

4 15 50.80 5 20 67.73 6 30 101.59 7 45 152.39

04f

z3

zNN RPM N,,P

(t) Static stress; gage 13; 2nd stage.


7 4XI0

6XIO 3

GREE# 13

5-Pt

3' IN. HG. N/m2X10 3

NM

2

4-

W3

1 2 3 4 5 6 7 8

5 7.5

10 15 20 30 45 65

16.93 25.40 33.86 50.80 67.73

101.59 152.39 220.12

Z

U) 2

7

400 440 480 520 560 N, RPM

600 640

(u) Dynamic stress; gage 13; 2nd stage,


680 720

4X10 7 6X10 3

EiRGE# I14

5-- Pt

3 1 2 3 4 5 6

IN. HG.

5 7.5

10 15 20 30

N/m2XI0 3

16.93 25.40 33.86 50.80 67.73

101.59

z 0

Z" a 2-

Ir

I

400 440 480 520 560 N, RPM

600 640 680 720

(v) Total stress; gage 14; 2nd stage0


7 6XlO3

4XI0 SRSE# IN

5. ~Pt

3" IN.HG. N/m2X10 3

4 1 2 5 7.5 16.93 25.40

3 10 33.86 4 15 50.80 5 20 67.73

96 30 101.59

N% z 7 45 152.39

3-- 8 65 220.12

I

2,

I

400 440 480 520 560 600 640 N, RPM

(w) Static stress; gage 14; 2nd stage0


680 720

36XlO

7

4X0 EFIE* I4

5-

Pt

3" IN. HG. N/mX103

1 5 16.93

4" 2 7.5 25.40

3 10 33.86

4 15 50.80

5 20 67.73

6 30 101.59

(M 7 45 152.39

2" 8 65 220.12

2

440 480 520 560 600 640 680 720

N, RPM

(x) Dynamic stress; gage 14; 2nd stage0

Figure-5.,- Continued.

34XlO7 6X0 SHED IS

' Pt5

IN. HG. N/m2Xl0 3

3- 1 5 16.93

2 7.5 25.40

4 3 10 33.864 15 50.80

5 20 67.7376 30 101.590. 7 45 152.39

-j 8 65 220.12

< -0

4,, 0 440 480 520 560 600 640 (680 720

N. RPM

(Y) Total stress; gage 15; 2nd stage.

Figure 5.- Continued,

4X 07

6XlO 3

EREtE IS

5 Pt IN. HG. N/m2XI0

3

W 0

4

ft

1 2 3 4 5 6 7 8

5 7.5

10 15 20 30 45 65

16.93 25.40 33.86 50.80 67.73

101.59 152.39 220.12

EE2z

-

L I '

0*

400

II

440 480 520 560 600 640 N, RPM

(z) Static stress; gage,15; 2nd stage.


I

680

I

720

4X107 6X0 3

SRHE# I

5" Pt

IN. HG. N/m2X1O 3

3 1 2 5 7.5 16.93 25.40

4 3 10 33.86 4 15 50.80 5 20 67.73 6 30 101.59 7 45 152.39

1 8 65 220.12

2

I

I

0 0 400 440 480 520 560 600 640 680 720

N, RPM

(aa) Dynamic stress; gage 15; 2nd stage.


6X10 3

7

4X10 EREE# 1R

5Pt

3" IN. HG. N/m2X1O 3

1 5 16.93

4" 2 7.5 25.40

3 10 33.86

4 15 50.80

0. 5 20 67.73

6 30 101.59

7 45 152.39

65 220.122- x3-8 -4

2-I

0. 0 400 440 480 520 560 600 640 680 720

N, RPM

(bb) Total stress; gage 16; dummy.


exio37 4XI0

SHEE# IS

Pt5--

IN. HG. N/m2 X10 3

1 5 16.93

2 7.5 25.40

4 3 10 33.86

4 15 50.80

5 20 67.73

6 30 101.59

7 45 152.39

8 65 220.12z

00 (i,I

2-

I

720400 440 480 520 560 600 640 680

N, RPM "

(cc) Static stress; gage 16; dummy9


4XI0 7

6xIO3

ESEE4 I1E

5-Pt

04

N,

3

4

Fn

2- Q 3" 2

(I) 2

1 2 3 4 5 6 7 8

IN.HG.

5 7.5

10 15 20 30 45 65

N/m2XO 3

16.93 25.40 33.86 50.80 67.73

101.59 152.39 220.12

I

404 440 480 520 560 60 640 680 720 N, RPM

(dd) Dynamic stress; gage 16; dummy0

Figure 5°: Concluded.

3 7 6X104X10

SHEEt 4

34

0 o ¢0 AL +

RPM 490 550

600 640 660 685

0

UC,

2"

0

0 I

0 o 20 II

30 4 PT, IN. HG.

50 III

60 70

0 40 80 120 N/m 2

160 200 240X10 3

(a) Total stress; gage 4; 3rd stage0

Figure 6,- Effect of compressor speed on the blade stresses as a function of tunnel total

7 4X0

5REE# 4

RPM

03

490 550

4 o 600

640 4 660 + 685

Nz

z

2-

II

0 10 20 30 40 50 60 70

III PT IN. HG. I I

0 40 80 120 160 200 240X10 3

N/m 2 (b) Static stress; gage 4; 3rd stage0


4X0 7 GXIO

EGFIE# 4

3

5.

4

0 a o A L +

RPM 490 550

600 640 660 685

I

I

-

0 I

I

M

0o 2M

040

to 20

II

80

30 40 P1, IN. HG.

I 120

N/rn2

50

160

60

II 200

70

240X10 3

(c) Dynamic stress; gage 4; 3rd stage,


8Xl0 7

N4

7

6

5

IOXIO3

8

cn

RPM 0 490o3 550 0600 A 640

N 660 + 685

3E1" 4

2-

I C,)

2

0 oo

II

20 30 40 P'r IN. HG.I

50

II

60 70

0 40 80 120 N/m 2

160 200 240XI0 3

(d) Total stress; gage 6; 3rd stage0

Figure 60- Continued0

8X0

7

6

5

7

IOXiO 3

8

0 E 0 A i. +

RPM 490 550 600 640 660 685

EGEt E

z

iIn

2

2

04 0 10 20 30 40 50 60 70

II I PT IN. HG.I I 0 40 80 120 160 200 240X10 3

N/m 2

(e) Static stress; gage 6; 3rd stage.


GXI O 4 X 0

7

E3REE* E;

5 RPM

0 490

3, 0 o>

550 600

4 640 fK 660

zo) + 685

2 2"

IW

0 0 0 20 30 40 50 60 70

I I PT IN. HG. I I

0 40 80 120 ISO 200 240X10 N/M2

(f) Dynamic stress; gage 6; 3rd stage0


I

7

4XI0

EREEt 11 5 RPM

0 490

3' 33 < 550600 4--/ S640 660

% C') 2

I

0 0 10 20 30 40 50 60 70

III PT, IN. HG. III

0 40 80 120 N/M2

160 200 240X103

(g) Total stress; gage 11; 3rd stage.


4X0 7

GE#~~E 1 1

3 -

0

5

4--

RPM o 490 0 550

0 600640 I. 660

+ 685

N

I

II

0I

0

0

I

t0 I

40

I I !

20 30 40 50 PT, IN. HG.I I I

80 120 160 N/m 2

(h) Static stress; gage 11; 3rd stage0


I

60

200

I

70

240X10

4X0 7 6 1xi

3

IBRIlE# II

5' RPM o 490

3" 13 0

550 600

.A 640 4 i,

+ 660 685

Co 2 z

I

I I

0 -

0 10 20 30 40 50 60 70

II PT IN.HG.I I I

40 80 120 160 200 240X10 3

N/m2

Ci) Dynamic stress; gage 11; 3rd stage.


3

7 6104X0

EREE# 12

RPM

5, 0 490

3 5506o00

0640-3-x 660

+ 6854"

(I) C3--

I

II

it.J I t l ]I I f

30 40 50 60 7o0 1o 20

PT, IN. HG.

II IIIII

0 40 80 120 160 200 240X10 3

N/m 2

(j) Total stress; gag'e 12; 3rd stage.


3 7 6 xr 4XI0

13FIIE# 1:2

RPM

90550

o 600 A 640 4-L+ 660

4 + 685

CL

('U

2,

II

0 I0 20 30 40 50 60 70 PT, IN.HG.

II I 3 0 40 80 120 160 200 240X10 3

N/m 2

(k) Static stress; gage 12; 3rd stage.


ex1 o34X 0

7

SREE* 12

RPM O3

490 0550

o 600 4- 640660

685

I

II

0 10 I

0 I0 0 I8040

PT, IN. HG.I120 f 70 40 80 120 160 200 240X10 3

N/m 2

(1) Dynamic stress; gage 12; 3rd stage.


4X0 7 6 103

ERSE# 13

3

5"

4" 4--+

oO 0 A L

RPM 490550 600 640 660685

cq~

z I

2

0 10 20 30 40 50 60 70 PT IN. HG.

0 40 80 120 160 200 240X10 3

N/m 2

(m) Total stress; gage 13; 2nd stage0

Figure 6,- Continued0

3

4 XI 0 7 6x10

EREE# 13

5. RPM

3 0 490 O 550

4- A 600 640

x 660 + 685

d

2 Zf

0 t0 20 30 40 50 60 70 PT IN.HG.

0 40 80 120 160 200 24OX 3

N/m 2

(n) Static stress; gage 13; 2nd stage.


--

10 4XI0 7

ro

ERIE- 13

5

RPM

0 490

3 - 550

o 6004-- A640 660b

+ 685

C(3_

z 2-

('

a0-

20 30 40 50 60 70000 PT IN. HG.

I I I IIII

0 40 80 120 160 200 240X10 3

N/M 2

(o) Dynamic stress; gage 13; 2nd stage.


4X0

7

1REE I4

5

4

3

RPM

0 490 0 550 0600 A 640 th. 660 + 685

0_

z

E20 II

I0 30 40 507

0

0

1O

I

40

20 30 40 5'0 PT, IN. HG.

I I

80 120 160 N/m2

(p) Total stress; gage 14; 2nd stage0


60

I

200

70

240X10 3

6X10 3 4X0 7 SEEtb IH

CL

Z

5

4 -

31

3D 0 o-A

+

RPM

490 550 600 640 660 685

z

0\C I ,

I

00

L

0

10

40

20 30 40 50 PT IN. HG.

I I

80 120 160 N/M2

(q) Static stress,; gage 14.; 2nd stage0


60

II

200

70

240X10 3

7 4X0

EIREE# I4

5. RPM

3 0 E

490 550

44- 0600A 640 I 660 + 685

2,

0

0 10 20 30 40 50 60 70 PT, IN. HG.

040 80 120 160 200 240XIO 3 N/m 2

(r) Dynamic stress;4gage 14; 22d stage


--

6 i4X10 7 3

IEFIEE* IS

5 RPM 0 49o

S0 o 550

600

4 A t

640 660

+ 685

E

0 0 I0 20 30 40 607 ' 70 PT IN. HG.

120 160 200 240X103040 80 N/m2

(s) Total stress; gage 15; 2nd stage.

Figure 6,- Conti'nuedo

4X0 7 6X10 3

ERI3E# IE 5,-

RPM

3" 0 13

490 550

4o A

600 640

N. 660 (1) + 685

Oj f .L

z

0 10 20 30 40 50 60, 70 PT IN. HG.

I I II I

0 40 80 120 160 200 240X!0 3

N/m 2

(t) Static stress; gage 15;' 2nd stage0

Figure 6,- Continued.

7 ex10 3 4XI0

EREE* IE

5 RPM

3 0 490 O3 550

4 o A 600 640 rs, 660 + 685

0_

z (I

* 0-

I

I

0 10 20 30 40 50 60 70 I I PT IN.HG.I II

40 80 120 160 200 240X10 3 N/m 2

Cu) Dynamic stress; gage 25; 2nd stage.

Figure 6.- Concluded.

8X107

7-- lOXIO 3

RPM

0 685

6' 0 680655

6408--

b 620

5 610

570

490

z I -DISTANCE

304

H 0 1.0541 m

2 2

0 8 16 24 32 40 48

DISTANCE FROM TIP, IN. 1.0541 rI I I I I

0 .2 .4 .6 .8 1.0 1.2 DISTANCE FROM TIP, m = N/m 2(a) To'tal stress; pt 3,3.86X10 3 (10 in. H'g); 3rd stage.l

Figure 7.- Effect of compressor speed on the longitudinal distribution of blade stresses

for various tunnel total pressures.

8XI0 7

WU

7-

5 -

IOXlO 3 RPM

0 685

E 680< 655 A640620

610 570

490 rn 450

'C w 4 DISTANCE

2 2 0 1.0541 m

oI 24

,

0 8 16 24 32 40 48

I DISTANCEI FROMI TIP, IN. 1.0541I

0 .2 .4 DISTANCE

.6 FROM

.8 TIP, m

1.0 1.2

(b)Static stress; pt 33.86Xi0 3 N/m 2 (10 in. Hg);

IFIGURE 7. -CONTINUED.

3rd stage.

7 6X0 3 4X0

5-RPM

0 685 ] 6803- 655A- 6404-620

13 610

ciQ f570530

J' aa

? 490

('n 450

z Uf)

2- DISTANCE

1.0541 m0

0c~QFN~, ffn%~~jQQ0o~

0 8 16 24 32 40 48 DISTANCE FROM TIP, IN. 1.0541 mI I I I I I I

0 .2 .4 .6 .8 1.0 1.2 DISTANCE FROM TIP, m

Cc) Dynamic stress; Pt = 33°86X103 N/m 2 (10 in0 Hg); 3rd stage.


8X10 7

RPM

0 6856 0] 680

r655

640

8" 620

600

5--0Q 570

Q530

490

E 4 6 - 450 Z- DISTANCE

3 - 0 1.0541 m

14

0 8 16 24 32 40 48

DISTANCE FROM TIP, IN. 1.0541

0 .2 .4 .6 .8 .0 1.2

DISTANCE FROM TIP, m' 2(d) Total stress; Pt = 67.73X10 3 N/m (20 in. Hg); 3rd stage0


8Xl0 7

7-- IOXIO 3

5

C~NL

6'0[ 0

82 5Lr

0

RPM

685680 >655

640 620 600570 530 490

450

z LU DISTANCE

3'4 0 1.0541 m

2

0 8 16 24 32 40 48

I I DISTANCEI FROM TIP, IN.I 1.0541 m


3 N/m 2(e) Static stress; Pt = 67.73X10 (20 in. Hg); 3rd stage.


4XI0 7 GXIOP RPM

0 685 El 680

640L 620 r 6003- - 570 Q 5304 - 490

fl 450

cm~

z c O - DISTANCE20

0 1.0541 m

II0-0 I , I I

0 8 16 24 32 40 48

DISTANCE FROM TIP, IN. 1.0541 m I I I I I 0 .2 .4 .6 .8 1.0 1.2

DISTANCE FROM TIP, m (f) Dynamic stress; pt = 67,73XI0 3 N/m 2 (20 in0 Hg); 3rd stage.


8XI0 7

7 IOXIc 3

RPM

0 685

6- 680

655

8' 640

620

5-- 600

5 570

- Q 530

(\)j 490 DISTANCE

E 4 a6 L 450z 0 1.0541 m

3-0

(I,2.

I-I0 I

0 8 16 24 32 40 48

DISTANCE FROM TIP, IN. 1.0541 rI I I


M 2(g) Total stress; pt = 101,59Xi0 3 N/r (30 in. Hg); 3rd stage.


8XI0O

7- IOXIO 3

RPM

0 685

6- [] 6808' < 655

8-- 640

8U. 620

L 600

570

530

4~6W 490

z -J '4 DISTANCE3, 4

(/) 0 1.0541 m

2

0 8 16 24 32 40 48

DISTANCE FROM TIP, IN. 1.0541 mI I I I


(h) Static stress; pt = 101.59X103 N/m 2 (30 in0 Hg); 3rd stage.


4X107 6XIU"

RPM

5-- 00 685680

& 655

3 5" 640620

6003

C]570

490

0 450

Cu

z X

DISTANCE

14C)

2. 0 1.0541 m

0 I I I I I

0 8 16 24 32 40 48

DISTANCE FROM TIP, IN. 1,0541 m

I II I I

0 .2 .4 .6 .8 1.0 1.2

DISTANCE FROM TIP, m

(i) Dynamic stress; pt = 101.59X10 3 N/m 2 (30 i'n. Hg); 3rd stage.


8XiO7

7 IOXIO 3

RPM

6856 0ro -- 680655

640

DISTANCE5 6205- 600

Ql 570

Q 530 0104

N U) C>490

E4 -6 n 40

3-0 4

000

0I I I I

8 16 24 32 40 4800

DISTANCE FROM TIP, IN. 1,0541m

.2 .4 .6 .8 1.0 1.20 DISTANCE FROM TIP, m

(j) Total stress; Pt = 152°39Xi03 N/m 2 (45 inoHg); 3rd stage.

Figure 7,.- Continued.

8XI0 7

7- IOXIO 3 RPM o 685 o] 680

6 - 655 640

r 6008 L6205570 Q 530

490 c'. c 450

Z DISTANCE

Ld

3 o 40 1.0541 m 4-

22

I J

0 1 II0 8 16 24 32 40 48 DISTANCE FROM TIP, IN. 1.0541I I I I I


3 m 2(k) Static stress; Pt = 152°39XI0 N/r (45 in. Hg); 3rd stage0


6X103

4X1O7

3 4.

RPM o 685 0I 6802655

640 620 600

o 570 530 490450

4 - 0 1.0541 m

z

2-

EITA3--IN G FROM .o4

0

0 II8 16 DISTANCE

24 FROM

I32 TIP, IN.

40 1.0541m

I48


= 3 N/m 2(1) Dynamic stress; Pt 152.39X10 (45 in. Hg); 3rd stage0


8XIOf

7- IOXtO3

RPM

6 0 6700660

650

5630 5-570o 530l4 W6 N

8XI0 7

N

E

7-

6

IOXIO 3

8 5

Cd CL"- '450

Z

RPM

0 6700l 660206606sg

640

U 6305 570o 530 0 490

OISTANU

3 0 1.0541 mn

2-

0

0

(n) Static

8 116 24 32 DISTANCE FROM TIP,

.2 .4 .6 .8 DISTANCE FROM TIP,

stress; pt = 220°i2Xi03 fl/ m 2 (65 in.

-Figure 7.- Continued.

40 IN. 1.0541

1.0 m Hg); 3rd stage.

48

1.2

4X10 6XI037

RPM

5 0 670

n 660

I650

6403-- 630

4 570L4- C) 530

Q 490

J 450

z n - DISTANCE

0 1.0541 m

0 I I 1

0 8 16 24 32 40 48

DISTANCE FROM TIP, IN. 1.0541I I I I I I I

0 .2 4 .6 .,8 1.0 1.2

DISTANCE FROM TIP, m

N/m2 (o) Dynamic stress; Pt = 220.12X103 (65 in0 Hg); 3rd stage,


8Xl0 7

7- IOXiO 3 RPM

0 685 6 - 680

655640 620

5 _570

530 NE'4 () 045o09490n-6

I %J- 6 -n 5 DISTANCE

I 0 1.0541 m3 o 430

2

2

I -

0 8 16 24 :32 40 48 DISTANCE FROM TIP, IN. 1.0541 m

I II I I I 0 .2 .4 .6 .8 1.0 1.2

DISTANCE FROM TIP, m Cp) Total stress; pt = 152.39X10 3 N/m2 (45 in0 Hg); 2nd stage0


8XI0 7

7- iOXIO3 RPM

0 6856-- 680655

8- 2640 620

5 L 600 f570

Q 530 _

N I)

4X 07

5'

RPM

0 685 0 680655

640 U& 620

600570

Us)

Q4' o

530 490 450

N.E2 _o_._ L

DISTANCCI1.041 DmSTANC

E

I I

0 8 16 24 32 40 48

DISTANCE i

FROM TIP, I I

IN. 1.0541 z li

m


(r) Dynamic stress; Pt = 152.39X10 3 N/m 2 (45 in. Hg); 2nd stage.


7 6X10 3

4XI0 RGEt H

5 0 LOW PASS, 1000 Hz CUT OFF BAND PASS, Iz

3"I 30 90 115 - 235

4-A 280 - 470

(.,. 550 - 1000

z =0

2

0 0-M 400 440 480 520 560 600 640 680 720

N,RPM Ca) Gage 4; 3rd stage,

Figdte 8.- Distribution of the' dynamic blade stresses in various band pass frequenc ranes as a fundtion of compressot speed at a tunnel total pressute of 152.39X10

N/m (45 in. Hg).

6X10 37 4X0

5

3 4

0_

0

[1

4XI0 7 6 103

1RIEE# S

,

3-

C-i. ( CL

5-

4

0 LOW PASS, 1000 Hz CUT OFF

BAND PASS, Hz

30 - 90

0 115 - 235

A& 280 - 470

550 - 1000

'2--

I

400 440 480 520 560 600 N, RPM

(c) Gage 6; 3rd stage0

Figure 8o Continued.

640 680 720

6Xl0 3

EREEt B

5 0 LOW PASS, 1000 Hz CUT OFF BAND PASS, Hz

3 0 30 - 90 4 < 115 - 235

A 280 - 470 K 550 - 1000

a_ ('4

E2

2-

I

I

0 0400 440 480 520 560 600 640 680 720

N, RPM (d) Gage 8; 3rd stage.


4X 07

6x103

1FIE# II

3

5

4-

0 LOW PASS, 1000 Hz CUT OFF

BAND PASS, Iz [ 30 90

115 - 235 A 280 - 470 Ix 550 - 1000

2- W --

I

2

0 400 440 480 520 560 600 N, RPM

(e) Gage 11; 3rd stage.


640 680 720

7

4XI0

6X'0 3

ERUE* 12

(.

5

4'

0

ElI 0 A

LOW PASS, 1000 Hz CUT OFF

BAND PASS, Hz

30 - 90

115 -235

280 - 470

550 - 1000

I Z

2-

I I

0 04 400 440 480 520 560 600

N, RPM (f) Gage 12; 3rd stage.

Figure 8.- Continued;.

640 680 720

4XlO7 6X0 3

16RGE# 13

3

2

5

4-

Q

A L

LOW PASS, 1000 Hz CUT OFF

BAND PASS, Hz

30 90

115 -235

280 - 470

550 - 1000

I

2.

400 440 480 520 560 600

N, RPM (g) Gage 13; 2nd stage,

Figure 8.- Continued.,

640 680 720

,r _6XI0 3

1E1I0Et IH

5" 0 LOW PASS, 1000 Hz CUT OFF

BAND PASS, Hz

3 [] 30 - 90 K4"115 - 235 A% 280 - 470 3'. 550 - 1000

%22

I

,-II 0 . -

400 440 480 520 560 600 640 680 720 N, RPM

(h) Gage 14; 2nd stage.


4XlO7 6X0 3

II3H6E#

5 0 LOW PASS, 1000 Hz CUT OFF

BAND PASS, Hz

3 30 - 90

4 0 A%

115 280

- 235 - 470

Cl) L 550 - 1000

2iz 03

0 :05

400 440 480 520 560 600 640 680 720

N, RPM (i) Gage 15; 2nd stage.


6X103

!ERBE* l4XI0 7

3

5

4

0

11 (

L

LOW PASS, 1000 Hz

BAND PASS, Hz

30 - 90

115 - 235

280 - 470

550 - 1000

CUT OFF

0i

2-

I

0 0 400 440 480 520 560 600

N, RPM (j) Gage 16; dummy gage.

Figure 8.- Concluded,

640 680 720

6XI0 3

EREE# 2

5 IN.PT'

1 5 3-- 2 7.5

3 10 4- 4 is

5 20

6 30

n 7 45

.J 8 65

to I FILTER OUT

2--

I

-2___ ER IN

0 0 , , -- I

400 440 480 520 560 600 640 680 720

N, RPM

N/m2 (a) Gage 2; pt = 25°40X103 (7.5 in0 Hg).

Figure 9.- Effect of a low pass filter with a cut-off frequency of 1 kHz on the total_

blade stresses for various gages and tunnel total pressures.

4XlO7 6X0 3

GRBE# 2

5

4

1 2 3 4 5 6 7 8

PT' IN.

5 7.5

10 15 20 3045 65

H 0 i If-FILTER OUT 4

2" q

II

A -FILTER IN

0 000400 440 480 520 560 600 640

4 680 720

N, RPM (b) Gage 2; Pt = 50,80XI03 N/m2 (15 i n, Hg),


8XI0 7

1REE# 2

7 IOXIO 3 1

PT, IN. 5

2 7.5

3 10

5 8

5 6 7 8

20 30 45 65

2

E 4 - 6- FILTER OUT B z 3-0

4-4 FILTER INI (r)

2,

2

0- 0-400 440 480 520 560 600 640 680 720

N, RPM (c) Gage 2; p s-'33,86 and220.12X103 N/m2 (10 and 65 in0 Hg).


4X107 6XI0 3

ESE H

5 PT, IN.

1 5

2 7.5

3 10

4 15

5 20

57 3045

8 65

H ~ I

Z0 I r-FILTER OUT

U)

2 2

I

FILTER IN

0 0 400 440 480 520 560 600 640 680 720

N, RPM (d) Gage 4; Pt = 25.40XI0 3 N/m 2 (7.5 in. Hg).

Figure 9. Continued.

4XlO7 6XI0 3

LREE# H

3

. 2 --N O3

5"

4"

3-.

2 2 3 4 5 6 7 8

PT' IN.

5 7.5 10 15 20 30 45 65

C/) 2

. FILTER IN

0 0,400 440 480 520 ,,,560 600 640 680 720

(e) Gage 4; Pt

N, RPM = 50°80X10 3 N/m 2 (15 in. Hg).


8X10 7 ERiE# H

7

6-

IOXIc 3

8-

58

2 3

45 6 7

PT IN.

7.5 10

1520 30 45

65

Iz

3-0

I) -

-FILTER OUT

22

FILTER IN-=

00 640 680 720400 440 480 520 560 600 N, RPM

(f) Gage 4; pt = 33°86 and 220o12Xi03 N/m2 (10 and 65 in0 Hg).


4X107 6XI0 3

1REE# I I

PT' IN.5 ' 1 5 2 7.5

3 103" 15

4- 5 20

6 30

7 45

8 65

E2-2ITE U2.#2 CD 0z

2-2

I

I I0 400 440 480 520 560 600 640 680 720

N, RPM (g) Gage 11; pt = 25°40XI0 3 N/m 2 (7.5 in0 Hg).

cq, n0 - Cnn+ ir.eoi

7 6XIO4X10

BRIE# I1

S PT IN.

2 7.5 3 10

3 4 15 5 20

4 6 7

30 45

8 65 4

CML Z - o02/iFILTER OU

2-

I-FILTER IN

0 0xII 400 440 480 520 560 600 640 680 720

N, RPM

(h) Gage 11; pt = 50.80X103 N/m2 (15 in. Hg).

Fiaure 9.- Continued0

8Xl0 7

IRE# II

7-- IOX103 PT IN.

1 5

6 2 7.5

3 10

8 4 15

5 20

6 30

5 7 45

8 65

N%

FILTER OUTH4 U)

2

2-FILTER IN

0O-0 - I 6 720

400 440 480 520 560 600 640 680 720 N, RPM

3

(i) Gage 11; Pt = 33°86 and 220,12X10 N/m

2 (10 and 65 in0 Hg).


6XlO 3

4X10 7 EX0 EHIBE* 12

PT' IN.51 5 2 7.5

3 10

3- 4 15 5 20

4" 6 30

7 45 8 65

E21 CDD

2.

I

0 01 400 440 480 520 560 600 640 680 720

N, RPM (j) Gage 12; pt : 25.40X10 3 N/m 2 (7.5 in. Hg).


07 6X10 3

4X EREE* 12

5--PT, IN.

2 7.5 4 3 10 4 15

4 5 20 FILTER OUT 6 30 7 45 8 65

z 0

2- -FILTER IN

I H 0 .

I

400 440 480 520 560 600 640 680 72 N, RPM

(k) Gage 12; Pt = 50.80X10 3 N/m 2 (15 in. Hg).


8X'0 7

GREE# 12

7-- IOXl 3 PT, IN.

1 5

6 84

2 3

7.5 1015

5 20

5 B 6 7

30 45

8 65

CN

Z FILTER OUT

3 0 FILTER OUT

2

2 FILTER IN FILTER IN

0 0 400 440 480 520 560 600 640 680 720

N, RPM (1) Gage 12; Pt = 33.86 and 220.12X10 3 N/m2 (10 and 65 in. Hg).

Figure 9.- Concluded0

800 -IIIGHER NUMBER GAGEFLAGGED IF DIFFERENT

700 A - A -

N~ d

600- .85ED

0 0IIC 400 - -- o Zo 440 480 520 560 600 640 680

o"N, RPM30 0 A0

200- 0160I

100, 80-Ht

440 480 520 560 600 640 680 a 440 480 520 560 600 640 680 N,RPM N,RPM

=(a) Gages 4,5; pt 33,86X103 N/m 2 (10 in. Hg).

Figre 0.-Variation of the frequency, phase angle, and coherence with compressor

spee forthe first four bending modes of the blade for various gage combinations

and tunne total pressures. "-, _"

800

700 A A A

600 i0 1MODE 0 0

1st 2nd

- 500 pl4th

0 ,

"

D400 440 480 520 560 600 640 680

P7- N, RPM

H4300

a)

V) 100 o 80

00 _ 080

440 480 520 560 600 N, RPM

640 680 S 440 480 520 560 600 N, RPM

640 680

(b) Gages 4,5; pt = 67.73X10 3 N/m 2 (20 in. Hg).


800

700 A A-A-4 7000

600600 -MD

NA4thr500-

BENDING

o 1st O 2nd o 3rd

~ Q W)-' o04

8

w40C 0

300t-300 _

200

N-D

0

,

800

700 " -AAA

600

N5 0 0 oc~~~~~

>1)

ol A

BENDOING -MODEo

I End

4th.4

60)

L

8

0

-

I !tI

a400=> .

300o 4-7

. 0 440 480 520 560 600

N,RPM 640 680

200 C

160

100 0 80

0 440 480

I

520 I I I

560 600 N, RPM

I

640

i

680

I I.

cC

I

440

I0!

480

I

520

I I

560 600 N, RPM

I

640

I

680

(d) Gages 4,5; pt = 152.39XI0 3 N/M 2 (45 in0 Hg).


800

700A A EAIAi-

BEllIDING

600 0 2nd 3rd 4th

8

-500 o 4

400

=o3-

300 4-:

200

0

440

ci)

O160

480 520 560 600 N, RPM

640 680

100

0 440 480

I 520

I I 560 600 N, RPM

I 640

I i 680

080 0)

-.c 0

cC 440 480 520 560 600 N,RPM

640 680

(e) Gages 4,5; Pt = 220.12X103 N/m2 (65 in. Hg).


800

700 A-

600 6 0 -MODE BEUOING 0 8 o 1st C

2nd

N4th-5004 o 3rd -c

0 .4

w3400 6440 010

480 520 560 600 640 680 HHw N, RPM

P-t300

200 160

100 .3 80

0 I 00 I I I I I I .. 0 '

440 480 520 560 600 640 680 ciS 440 480 520 560 600 640 680 N, RPM N, RPM

(f) Gages 6,12"; pt = 33°86X10 3 N/M 2 (10 in. Hg).

Figure 10,.- Continued..

800

700 - A A

N

600

500

BENDINGI lODE

o 1st o 2nd

0 3rdA 4th

(3)

-

o0

.8

4

-400

H

430014

6 0

6

A0 440 480 520 560 600

N, RPM 640 680

200

O0 U) -. 1

o80

0

440 480

I

520

I

Figurn

I I II

560 600 640 680 N, RPM

(g) Gages 6,12; Pt

F

=

0. Conine)

I. 0 ,O

cC 440 480

67°73X103 N/mn2

I

520 560 600 N, RPM

(20 in. Hg).

640 680

Figure 10o- Continued0

Soo

700-

N

600

5

6 0 -MODE

o0o0 A

EErIDIG

t 2nd 3rd 4th

o .8 (

a 0

.4.4

co

(D400

4 300

001 - > 440 480 520 560 600 N RPM

640 680

200 -0

. 160 0I -

100 I0

0

440

-

480

I

520

I I I

560 600 N, RPM

, I

640

I

680

i

80 U) 0 o 0

C

ca3 440 480

I

520

I I ,n¢ itt

560 600 640 N,RPM

680

(h) Gages 6,12; pt = 101°59XI0 3 N/m 2 (30 in0 Hg),


800

700

600)600BEND MODEING Q)C .

0 1st G] 2nd

N - 500 -

A 4th .4

400•-0 , 6o 4

4 0 440 480 520 560 600 640 680

SN, RPM

3000 [

200 -160 a)

100 0 80 (I)

0 II I I0 I 0 - -440 480 520 560 600 640 680 6 440 480 520 560 600 640 680

N, RPM N,RPM

(i) Gages 6,12; Pt = 152.39X10 3 N/m 2 (45 i-no Hg).


800

700 A A

N

600

500

0 E]

BENDIUG MODE 1st 2nd 3rd 4th

o c 0

0

.8

.4

H c)

C-)

a)400

o-N,

o300

-

o

6 o -

01 440 480 520 560 600

RPM 640 680

200 160

1O0 () 80

0 440 480 520 560 600

N,RPM 640 680

0 iz 440 480 520 560 600

N,RPM 640 680

(,j) Gages 6,12; Pt = 220,12XI0 3 N/m2


(65 in. Hg).

800

700

600

N"T500

0

BENDING

2nd 3rd(1)4th

C)

.o

.8

4 .

H-

D400

.300

0 440 480 520 560 600

N,RPM 640 680

200 N..

0)

0C

- 60 0

-

440 480 520 560 600 N, RPM

640 680 c6 440 480 520 560 600 N,RPM

640 680

(k) Gages 6,11; pt 152°39XI0 3 N/m 2 (45 in. Hg).


800

700

600 ,-BENOING 0 8

070

0 0 o 3ro o 0

520 0 A 4h 3ldl 4406 46440 480 520 560 600 640 680

300- C-) N, RPM

C)(D 200 .160

100 0 80

-0 1 1 1 1 1i a 0 1 440 480 520 560 600 640 680 ai 440 480 520 560 600 640 680

N, RPM N, RPM

(1) Gages 13914; Pt = 152°39X10 3 N/m 2 (45 in. Hg,).

Figure 1,0.- Continued.

800

700a

600 - BENDING NODE (~CC.) 8 0 2nid -

N 4th ' - 4 -500 .

0 400

0 440 480 520 560 600 640 680

a7" N, RPM

300 4--

200 a) - 10

100 CD0 80

g gppgcC~0 U)0

440 480 520 560 600 640 680 3 440 480 520 560 600 640 680 N,RPM N,RPM

(m) Gages 14,15; pt = 152,39Xi0 3 N/m 2 (45 in0 Hg).

Figure 10,- Concluded0

800

700--- --- 4th: HODE

600 0

H, RPM 490

N~ []0

550600

r500 L 660

4001

300

4

200

200

2nd MODE

100

42 1st MODE

I I II I I I0 1 10 -20 30 40 50 60 70

PT IN. HG.I I I I !

40 80 120 160 200 240X10 3 N/m 2

(a)Fodal frequencies for gages 4,5,6,12.

Figure 11.- Variation of the frequency, phase angle, and coherence

for the first four bendi'ng modes of the blade with tunnel total

pressure for various gage combinations and compressor speeds.

-124

-c

a)k o .8 c- N, RPM

c0 .4

(3) Q0 490C0 550'0 600

640 o 660~685

0 i I I I I m I I

0)

(D

-160

080 0)

C/)

QC 10 20 30 40 50 60 70 PT, IN.HG.

III I I

40 80 120 160 200 240X10 3

N/m2

(b) 1st mode 0 and y for gages 4,5.

Figure 11o- Continued.

-125

--

S.8C N, RPM () ,0 490(.t 0F 55010 600

A- 640

0 .4 u 660,o~ ~ 685

SI I I I II

0'

cj

0 80 -10

10 20 30 40 50 60 70PT, IN. HG. III I I I

80 120 160 200 240X10 3

40 N/M2

Cc) 2nd Mode 6 and y for gages 4,5o


-126

N, RPM E

O .

0 4

~0

-)

c:

a) 1670

IN

20-

P-I,

0

G

5 0 7

10

40

t

20 30 40 50 60 PTI IN. HG.!I

80 120 160 200

N/m2

(d) 3rd mode e and y for gages 4,5.


70

240X10 3

-127

0 90 - 0 50.410

0

0 0 A ': 660

E' 685

- ,60*= _0

80 U)

a0 : 1

40 1I

20

80

30 40 PT, IN. HG.

i

120

50

ii1

160

60

200

70

240Xi03

N/m2

(e) 4th mode 6 and y for gages 4,5.

Figure ll.- Continued.

-128

o .8 Q)

L.- a 4901 C.) 0] 550

t .4 o60010 .4 6401 ts.660J

U 685S

0 I I I I I I

-160 C

0 80

c

,; tO 20 30 40 50 60 70

I I PT IN. HG. I 1

40 80 120 160 200 240X10 3

N/m 2

(f) 1st mode e and y for gages 6,12.

Figure 11 Continued.

-129

rN, RPM

640O0 4.660 8685

0

f) _ 1601

0

00 20 30 40 50 60 70

40 80 PT IN. HG.

120 160 200 240XI0

N/m2

(g) 2nd mode 0 and y for gages 6,12,

Figure ll- Continued,°

-130

0 A(-

NH,RPM

60 0 490 160 550 __. 0 600

A 640 {_ [ 660

o- 685

UD -131

0

C6 o1 20 30 40 50 60 70 PT, IN. HG.

40 80 120 160 200 240X103

N/m 2

(h) 3rd mode 8 and y for gages 6,12.

Figure 1l- Continued.

o.8

0 .4

0i

160

oQ)h

1

II

40

2 00 607660

20 30 40 50 60 70PT IN. HG. I I I

80 120 160 200 240X10 3

N/m2

(i) 4th mode e and y for gages 6,12.

Figure 11.- Concluded0

-132

I I 1 11 1I 1 1 1 1 1 I I MI l I II 1 I I 1I 1 1 1 I11 I QXIO +02 1oXIO +03 t.OXIO+ 0 I OXIO-04 I.OXIO-C5

GAGE

0IOXID 4 12

132

0

II - I I-ilI- l l I I I.0xlve

I~i .0XO-0oi"iYa1I 0x0I0 0 I I~ oIIII I[1 1 0 Ixo tIII

cdi u to20ka la It T

I In I m 1 n I JLI }I

I I II IT II , I I I I I1 I I

I.XO01I t II IfCl I I I K; 1 1 II XI-10IOX10*0IX°0 XO0IXI041I O0 copeso blXadeO fo frqunce 0 pt X--- ko atova

compressor speeds; pt = 152.39X103 N/r (45 in. Hg).

-133

12

I I 1 111111 1 1 1111111 I 1 1111111 I I 1111111 05 +01 +02 +03 +04

I OXIO I-OX10 I OXIO I OX10 I OXlO

GAGE

0l11 +0

I OXI

- 4+

1 ,, ,, iil

tnlmY l I, WilllllIII o 0

O f I OXIO 11 11 1

-1-4

x

502 3 1 oxur+0OX1+Iaxir+ 1nX1oflIO000IOX1a0 '0 f', frequency, Hz

[b) N = , 0.83.550; Mw4


-134

I .OXIO .O055I o* I

OX1O 0 1 1 1111 1 I OX10* 02 1 1 1111 1111 DX1 + 0 3

i tit ll

1 1 I OXl

tttl

+014

1 1 IIIIIII OX10

GAGE0 69

+ 05

-IT

0~0

I p I I I

C)

CD 0I

I XaI I XIO 3 I fIIII I

Iunx , e H

Ic)IN = 6 0 iMii 0 MG ,9,1l.OXlO + 0 1

I Illlll0 ° x1T]

+ 0 0 0 + 0 2 + 0 3 + 0 4 + 05

l.OX1O I OXlO l.OXlO 1 OxlO 1 OXlO I.OXlO

f, frequency, Hz

=Cc) N 600; Mw = 0.98°


-135

S I I OXio+O1

I 1111111i I OXIO+ 02

I i 11111l11 IOX10+03

I 11111111l I'OX*0 +04

I I I II liii I-OX1O +05

-- GAGE

011

I OXIO+05 X12

I x 1120

-jjL I OXICl 03 II III

C/)

0~0

I OXiD+02

I

I OXI0O00 I 0XI0+01

0oc 00

0 0

x

IOX0I002 I XI0 3

f', frequency, Hz

(d) N = 640; MW 1.14,


I OXIO04 IxioOI

-136

I

I I I 1111111 I I 1 1111111 I I IIIIIII I I 1lll1 ll 01 +0 05 OXIO +04 0 6 0XIO 1.OXiO+02 I OX I OXW

OXIO

IaIIIwos GAGE -- 0 6

)(X12

CD0 ' 01

,, 0~0

0o

9°X 4M I Ilo

0OXO0

DO I 0 I IXO IXO0 I I OX00 I OXll+0I.X I.OII

(e)N =,660l-- ll 1.22.;Mw

Fiur 12,-+ ConiudFigure, 1 . o ninued.

'"' '"r137" ° '"137-I

ORIGIN~AL DAPE h 88

I [[1 1 1 lii11i1 1 1 i i 11i1111111+0 1 I OX1O+02 I OX1O +03 I OXIO +04 I OXlO+05 +06 I.OXlOI OXlO

- ,i IGAGE

-- 0 6

)K12

+ 0 5 I 10XO

0

I OX10w0

c-a

(- -i- l- - i l 00 i ° CDC

0 1

CDC

00 . M I) K I rlI II u - I I I I I I I I I II

+03 0I OXlO

I iliii0t Iil; 00)°!00TA

02 0 3 04 OXio+00 I oxio 0' i oxo 1xo IOXI Ij0

f, frequency, Hz

(f) N = 670; M.E 1.25,


-138

I OIOXI0+O8

I.OXIO +02

0+ I OX1O 0 1

-

I.OX IO+0

ll

-

I OXIO 03 I.OX I

+04 I.OXIO + 05

GAGE

0 6 011

X12

I-°XlD+°03

0 0!

I I x

OX1O+02•• O

f, reqenc, H

X x

J 1 . -11

C\1$

f, frqeny ,H,

(9 8; MW 1.26.


-139 --()T

I I ii iI Il I I I l IM i

0 30 2 0 1 I.OXIOI OXIOSI.OX1I O W O

c111

I I[ [ l ] I I [ [ 1

xF

0~0

+ 0 ! I.OXIO

I.XOX +21I 0 ;X0l Illl 0IO III OxIv

....... frequency, Hz

(h 8 ;,. . 7

IaiH IM I I Ioixii + 0 5 OXIO

0 1 XIO

, ,-[GAGE

I I I

0 O +

~ ~ ~Figure 12-Cnldd

F2 Co [ 1 i I ] ] I[[ ) II 1 4 0

CC

-10

0

25X10 2 0

OGG24

23

22

2 1 - A= 3.65, WHERE

. 2 0 - f=AN C(SYMBOLS- MEASURED

C, 19- fVs FROM FIG. 12) r1

160

15 I I I I I I

440 480 520 560 600 640 680 720

N, RPM ,Figure 13,- Variation of the frequency of the noise peaks observed at frequencies above

m 2I kHz with compressor speed; Pt = 152 0 39XI03 N/ (45 in. Hg).

6X10 3 4XI0 7

FROM Gs(f))o f < 1 k Hz (INTEGRATED 5- f < 20 k Hz (INTEGRATED FROM Gs(f))

f < I k Hz (HP-9830 SYSTEM)

A f < 20 k Hz (HYBRID SYSTEM-LOOP)

3

4

C/)

2. 2 I

0 000-,Ja 400 440 480 520 560 600 640 680 720

N, RPM (a) Gage 6.

Figure 14.- Variation of the dynamic blade stresses with compressor speed illustrating the

effect of noise peaks at frequencies above l1 kHz; p. 1'52.39XI0 3 N/rm2 (45 in. Hg).,

7

4XI0

0 f < 1 k Hz

5" 0l f < 20 k Hz O f < I k Hz A f < 20 K Hz

34

(II

2

400 440 480 520 560 600 N, RPM

(b) Gage 11.


(INTEGRATED FROM GS(f))

(INTEGRATED FROM Gs(f))

(HP-9830 SYSTEM)

(HYBRID SYSTEM-LOOP)

640 680 720

eXlO3 7

4XI0

0 f < I k Hz (INTEGRATED FROM Gs(f))

5 Li f < 20 k Hz (INTEGRATED FROM Gs(f))

Q' f < 1 k Hz (HP-9830 SYSTEM) 3 f < 20 k Hz (HYBRID SYSTEM-LOOP)

5-4 .

CM.. . -.

2

0-1

0 0 ,

400 440 480 520 560 600 640 680 720

N, RPM Ccl Gage 12.


I Report No -152083 2 Government Accession No 3 Redipent's Catalog No NASA CR-15 8

1

4 Title and Subtitle 5 Report Cafe "An Analysis of the Rotor Blade Stresses of the November, 1977

Three Stage Compressor of the Ames Research Center 6 Performing Organization Code

11- by 11-Foot Transonic Wind Tunnel"

7 Author(s) 8 Performing Organization Report No

Jules B. Dods, Jr. 10 Work Unit No

9 Performing Organization Name and Address

Raman Aeronautics.Research and Engineering, Inc. 11 Contract or Grant No

Palo Alto, CA 94301 NAS 2-9112

13 Type of Report and Period Covered 12 Sponsoring Agency Name and Address Final Report National Aeronautics & Space Administration 14 Sponsoring Agency Code Washington, D. C. 20546

15 Supplementary Notes

16 Abstract The static and dynamic rotor blade stresses of the 3-stage cbmpressor of

the Ames Research Center 11- by 11-Foot Transonic Wind Tunnel were measured

over the operational range of the tnd t~nnel. A maximum total blade stress (static plus dynamic) of 62.36 x 10 N/mZ (9045 psi) occurs on the third stage blade at a distance of 0.5461 m (21.5 in) outboard from the root of the blade for a tunnel total pressure of 220.12 x 103 N/m2 (65 in Hg). The static stress accounts for 88.6- percent of the total stress, and the dynamic stress accounts for the remaining 11.4-percent of the total stress.

A band-pass frequency analysis of the data indicated that the dynamic

stresses are primarily due to vibrations in the first bending mode.

17 Key Words (Suggested by Author(s)) 18 Distribution Statement Rotor Blade Stresses Static Stresses UNCLASSIFIED - UNLIMITED Dynamic Stresses Transonic Wind Tunnels

19 Security Classif (of this report) 20 Security Classif (of this page) 21 No of Pages 22 Price*

UNCLASSIFIED UNCLASSIFIED

*Forsalebythe National Technical Information Service, Springfield, Virginia22161

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AN ANALYSIS OF THE ROTOR BLADE STRESSES OF THE THREE … · 2013-08-31 · AN ANALYSIS OF THE ROTOR BLADE STRESSES OF THE THREE-STAGE COMPRESSOR OF THE AMES RESEARCH CENTER 11- by