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NASA CR-120802 PWA-4186
SINGLE-STAGE EVALUATION OF HIGHLY-LOADED HIGH-MACH-NUMBER COMPRESSOR STAGES
IV. DATA AND PERFORMANCE OF HUB-SLIT-SUCTION STATOR
November 1971
By G. D. Burger and G. Bogardus
Pratt & Whitney Aircraft Division United Aircraft Corporation
Prepared for National Aeronautics and Space Administration
NASA Lewis Research Center Contract NAS3-10482
L. Reid, Program Manager Fluid System Components Division
A. " NNOV197, ,
(ACCESSO
2(PAGES)
C3 (NASA CR OR TMX OR AD NUMBER)
THU
(CODE)
(CAIEGORY)
*--E~l-
https://ntrs.nasa.gov/search.jsp?R=19710028360 2020-06-25T13:30:32+00:00Z
Requests for copies of this report should be referred to:
National Aeronautics and Space Administration Scientific and Technical Information Facility P. 0. Box 33, College Park, Maryland 20740
1. Report No. 2 Government Accession No 3. Recipient's Catalog No
NASA CR-120802 1 4 Title and Subtitle 5 Report Date
SINGLE-STAGE EVALUATION OF HIGHLY-LOADED HIGH-MACH- 10 November 1971 NUMBER COMPRESSOR STAGES 6. Performing Organization Code IV. DATA AND PERFORMANCE OF HUB-SLIT-SUCTION STATOR
7- Author(s) 8 Performing Organization Report No
G. D. Burger and G. Bogardus PWA-4186 10. Work Unit No
9. Performing Organization Name and Address Pratt & Whitney Aircraft Division United Aircraft Corporation 11. Contract or Grant No
400 Main Street NAS 3-10482 East Hartford, Connecticut 06108 13. Type of Report and Period Covered
12 Sponsoring Agency Name and Address Contractor Report
14. Sponsoring Agency CodeNational Aeronautics and Space Administration Washington, D.C. 20546
6. Supplementary Notes
Program Manager, L. Reid, Fluid System Components Division, NASA-Lewis Research Center, Cleveland, Ohio
16. Abstract A single stage compressor with arotor tip speed of 1600 fps and 0.5 hub/tip ratio was used to
demonstrate the effects of boundary layer suction through slits at the intersection of the stator suction surface and the hub wall. No efficiency benefit was obtained at design speed; 1.5 percentage points improvement was obtained at part speed. Maximum design speed stage efficiency of 82.7 percent was obtained at a pressure ratio of 1.935. Accounting for rotor work on the flow bled through the stator hub slit decreases this efficiency 0.5 percent.
17 Key Words (Suggested by Author(s)) 12 Drstribution Statement
Boundary layer suction Unclassified - unlimited
Stator hub slit
19. Security Classif. lof this report) 20 Security Classif. (of this page) 21. No. of Pages
Unclassified Unclassified 133
*For sale by the National Technical Information Service, Springfield, Virginia 22151
22 Price*
3.00
PRECEDING PAGE BLANK NOT FILMED
FOREWORD
The work described herein was done under NASA Contract NAS3-10482 by Pratt & Whitney Aircraft Division of United Aircraft Corporation, East Hartford, Connecticut. Mr. L. Reid, NASA - Lewis Research Center, Fluid System Components Division, was Project Manager. The work was performed during the period 7 January 1971 through 4 March 1971.
?REiCMING PAGE BLANK NOT FILMED
TABLE OF CONTENTS
Page
Foreword iii List of Illustrations vi List of Tables viii
I. Summary I
II. Introduction 3
III. Apparatus and Procedures 4 A. Test Compressor 4 B. Instrumentation and Calibration 5 C. Test Procedure 5
1. Shakedown Test 5 2. Performance Test 6
D. Calculation Procedure 6
IV. Results and Discussion 7 A. Shakedown Test Results 7 B. Performance Test Results 7
1. Overall Performance 7 2. Blade-Element Data 9 3. Contour Plots of Stator Exit Traverse Data to
a. Total Pressure Ratio 10 b. Total Temperature Ratio 10 c. Air-Flow Angle 11 d. Static Pressure Ratio 11 e. Meridional Velocity 11
V. Remarks 12
References 13 Appendix 1 Performance Parameters 69 Appendix 2 Symbols 73 Appendix 3 Blade-Element and Overall Performance with Stator
Hub Slit Suction 77 Appendix 4 Blade-Element and Overall Performance without Stator
Hub Slit Suction 115 Distribution List 121
V
LIST OF ILLUSTRATIONS
Figure Title Page
I Cross Section of Test Compressor 14
2 Boundary Layer Suction Slits at Stator Hub 15
3 Assembled MCA Rotor 16
4 Schematic of Compressor Test Facility 16
5 Typical Instrumentation 17
6 Axial Station Number Designation and Location of Instrumentation 18
7 Circumferential Location of Instrumentation, Viewed from Rear 19
8 Oscillograph Trace of Typical Surge Cycle 20
9 Stage Overall Performance 21
10 Rotor Overall Performance 22
11 Effect of Stator Leading Edge Probe Blockage at Design Speed 22
12 Rotor Blade Element Performance with Stator Hub Slit Suction 23-31
13 Stator Blade Element Performance with Stator Hub Slit Suction 32-40
14 Effects of Stator Hub Slit Suction on Loss Coefficient 41-43
15 Effects of Stator Hub Slit Suction on Gapwise Distributions of Total Pressure, Temperature, and Efficiency, 70 Percent Speed 44-45
16 Effects of Stator Hub Slit Suction on Gapwise Distributions of Total Pressure, Temperature, and Efficiency, Design Speed 46-47
17 Efficiency Comparison of Free Stream Total Pressure versus
Free Stream Efficiency Calculation Methods 48
18 Total Pressure Ratio 49-52
19 Total Temperature Ratio 53-56
20 Absolute Air Angle 57-60
vi
LIST OF ILLUSTRATIONS (Cont'd)
Figure Title Page
21 Static Pressure Ratio 61-64
22 Meridional Velocity 65-68
vii
LIST OF TABLES
Number Title Page
1 Overall Performance Comparison with and without Slit Suction 1
2 MCA Rotor and Stator Design Parameters 4
3 Summary of Stall Weight Flows 8
4 Identification of Blade-Element and Overall Performance Table Headings 77
5 Blade Element and Overall Performance Design Data 78
6 Blade Element and Overall Performance with Stator Hub Slit Suction, 100 Percent of Design Speed, Points 1-8 79-86
7 Blade Element and Overall Performance with Stator Hub Slit Suction Free Stream Efficiency Method, 100 Percent of Design Speed, Points 1-5 87-91
8 Blade Element and Overall Performance with Stator Hub Slit Suction, 95 Percent of Design Speed, Points 1-3 92-94
9 Blade Element and Overall Performance with Stator Hub Slit Suction, 90 Percent of Design Speed, Points 1-6 95-100
10 Blade Element and Overall Performance with Stator Hub Slit Suction, 85 Percent of Design Speed, Points 1-3 101-103
11 Blade Element and Overall Performance with Stator Hub Slit Suction, 70 Percent of Design Speed, Points 1-5 104-108
12 Blade Element and Overall Performance with Stator Hub Slit Suction, 50 Percent of Design Speed, Points 1-5 109-113
13 Blade Element and Overall Performance without Stator Hub Slit Suction, 100 Percent of Design Speed, Points 1-3 114-116
14 Blade Element and Overall Performance without Stator Hub Slit Suction, 70 Percent of Design Speed, Points 1-3 117-119
viii
I. SUMMARY
A compressor stage with a rotor tip speed of 1600 ft/sec, high blade loadings, and boundary layer suction through a slit in the corner formed by the stator suction surface and the hub wall was tested. Both rotor and stator blades had multiple circular arc (MCA) airfoil sections. The stator chord angle was set 4 degrees more axial than design, to increase incidence for the purpose of evaluating the effect of slit suction on stator flow range.
Overall performance at design speed for data points with stator hub slit suction is compared to data without slit suction in Table 1. Two values of stage efficiency are given, the values in parenthesis were calculated using a procedure which accounts for the flow bled through the boundary layer suction slit. Comparison of data taken with and without slit suction showed that suction improved efficiency at maximum flow, part speed, but had little effect near stall. No significant increase in stage efficiency was obtained at design speed. Flow range from maximum flow to stall was not affected by slit suction. Slit suction reduced stator losses at 5, 10, and 15 percent span from the hub. Stator wakes were narrower and shallower with suction.
TABLE 1
OVERALL PERFORMANCE COMPARISON WITH AND WITHOUT SLIT SUCTION
(DESIGN SPEED)
Near-Stall Near-Stall Max Efficiency Max Efficiency Data Point Data Point
Data Point Data Point Without With Parameter Without Suction With Suction Suction Suction
Corrected Weight 181.03 179.58 173.09 173.58 Flow, lb/sec
Rotor Pressure 1.906 1.935 2.003 2.033 Ratio
Rotor Efficiency, 87.3 87.6 85.8 86.5 Percent
Stage Pressure 1.842 1.871 1.908 1.937 Ratio
Stage Efficiency, 82.3 82.7 79.2 79.9 Percent (82.2) (79.4)
Contour plots were prepared for pressure, temperature, velocity, and air angle at the statorexit instrumentation plane with stator hub slit-suction. Contour plots showed that stator losses were concentrated in corners where the stators intersected the endwalls, and'that these loss areas grew with increased back pressure. Increased back pressure caused more severe total pressure gradients in the wake region although wake width remained approximately constant.
No stress limits were encountered during the test program. Rotating stall surveys showed that abrupt stalls occurred at all speeds with indications of rotating stall initiating a surge cycle.
2
II. INTRODUCTION
Recent results from research compressors have shown that compressor rotors can be designed to operate with high aerodynamic blade loading and/or high inlet relative Mach number and still achieve good efficiency (85 to 94 percent) with acceptable stall margin (12 to 15 percent). However, there is a severe penalty on stage efficiency due to high stator losses. The major portion of the high loss region occurs in the vicinity of the stator end-walls. Therefore, no appreciable overall gains in stage performance can be made without reducing the level of losses in the stator end-wall regions. In addition to high stator losses, in many cases the stall free range of the compressor stage is limited by stator stall. Slit-suction is one type of endwall treatment that has shown some degree of success in reducing stator end-wall losses in cascades (Reference 2) and single stage compressors (Reference 3).
As part of Contract NAS3-10482, a stator end-wall treatment program was initiated to investigate the effectiveness of various types of end-wall treatments on reducing stator losses and increasing the stator stall free range of operation. The single stage compressor used in this investigation is the same as presented in Reference 1 with stator hub-slit-suction added. In order to evaluate the effect of end-wall treatment on stator range, the stator vanes were restaggered four degrees open (increased incidence) with respect to the design stagger. This compressor has a design rotor tip speed of 1600 ft/sec and demonstrated a rotor pressure ratio and efficiency of 2.0 and 89 percent respectively, and a stage pressure ratio and efficiency of 1.946 and 84.5 percent respectively.
The purpose of this report is to present the results of stator hub slit-suction applied to a high Mach number highly loaded single stage compressor.
3
III. APPARATUS AND PROCEDURE
A. Test Compressor
The compressor (Figure 1) is a highly-loaded, high-Mach-number, single stage with no inlet guide vanes, 30 MCA rotor blades and 44 MCA stator vanes. It is identical to the compressor of Reference 1 except for the addition of stator hub-slit-suction shown in Figure 2, and a stator restagger of four degrees to increase incidence so that the effects of slit suction on stator flow range could be evaluated. The rotor is the same one tested in Reference I except that blades tips were machined to remove results of tip abrasion, and leading edges were blended to remove nicks resulting from a bearing failure in a previous test. Extra material (0.030 inch) was added to the rotor shroud rub-strip to provide an acceptable blade tip clearance without changing the axial location of the rotor relative to the stator. Proximity measurements indicated that the rotor running clearance was 0.063 inch at design speed, compared with 0.050 inch in the test results reported in Reference 1. Rotor and stator design parameters are summarized in Table 2. The rotor assembly is shown in Figure 3. Complete design details are given in Reference 4.
TABLE 2
MCA ROTOR AND STATOR DESIGN PARAMETERS
Rotor - Stations 8 and 9
%Span Dia- 1 Dia 2 3*8 P*9 * 8ss 3*sh Solidity
5 (hub) 17.47 19.77 48.97 1.87 55.40 45.74 2.276 10 18.47 20.41 49.59 9.63 56.02 46.76 2.173 15 19.47 21.05 50.44 16.51 56.59 47.76 2.080 30 22.31 22.96 53.77 29.73 57.87 50.53 1.855 50 25.79 25.52 56.40 42.30 59.30 54.68 1.638 70 28.95 28.08 59.08 50.53 61.07 59.17 1.476 85 31.29 29.99 61.63 54.11 62.96 63.01 1.379 90 31.88 30.63 62.53 55.10 63.65 64.18 1.355 95 (tip) 32.50 31.27 63.21 55.84 64.14 64.96 1.332
Stator - Stations 10 and 11
%Span Dia- 1 Dia- 2 f3 10 3"11 3o10ss 13sh Solidity
5 (hub) 20.41 21.49 39.23 -16.41 42.15 34.47 2.010 10 21.01 21.96 38.27 -15.44 41.21 32.62 1.959 15 21.59 22.43 37.42 -14.89 40.36 30.94 1.911 30 23.31 23.90 35.44 -15.22 38.44 27.18 1.781 50 25.60 25.89 33.60 -16.04 36.72 24.01 1.632 70 27.82 27.90 32.45 -17.48 35.68 22.38 1.508 85 29.41 29.38 32.12 -19.91 35.44 22.82 1.430 90 29.91 29.86 32.15 -21.40 35.48 23.36 1.407 95 (tip) 30.38 30.29 32.33 -23.69 35.69 24.40 1.387
NOTE: Symbol definitions appear in Appendix 2.
4
The suction slit design was based on data reported in References 2 and 3 which showed that end-wall-region cascade losses were reduced significantly by extracting small amounts of flow through a slit at the intersection of the wall and blade suction surface. These data showed that most of the attainable benefit was obtained by extracting the corner flow passing through the area common to the boundary layer displacement thickness growth on the vane surface and the wall.
The stator hub slit extends from 15 to 85 percent chord and is .025 inch wide. Design flow rate through the slits is 0.30 percent of compressor design flow. Slit suction design details are given in Reference 4.
Suction for stator hub slits was provided by test facility exhaust pumps. The stator hub slit suction plenum is evacuated using four hollow struts just upstream, and in line with the rear bearing support struts. Suction flow through these struts is measured using a common calibrated flow measuring orifice (Figure 4). Other facility hardware was the same as described in Reference 1.
B. Instrumentation and Calibration
Static pressure in the plenum beneath the suction slits was measured by three pressure taps, and the plenum temperature was measured by three bare-wire thermocouples. Slit-suction flow rate was measured by a 3.297 inch sharp-edge orifice (Figure 4) within an estimated accuracy of ± .03 lb/sec flow. Hot film probes are used to detect rotating stall. Other instrumentation is described in Reference 1. Typical instrumentation is shown in Figure 5. Axial and circumferential locations of instrumentation are shown in Figures 6 and 7, respectively.
C. Test Procedure
All testing was conducted with uniform inlet flow. Stator hub slit suction was used for all tests unless otherwise noted.
1. Shakedown Test
Shakedown tests were conducted to establish the mechanical integrity of the compressor and to locate critical stress boundaries which could limit the operating range. Vibratory stresses were recorded during accelerations and decelerations from 50 to 105 percent of design speed with open throttle, part-throttle, and near stall throttle settings. All fixed instrumentation and wake rake traverse data were recorded at the beginning and end of each constant throttle acceleration to provide three data points at 50 percent and at 100 percent speed. At design speed, one performance data point was acquired which included traverse data at all stations to verify the hub-slit-suction flow rate and demonstrate the operation of data acquisition and reduction systems.
Rotating stall surveys were conducted at 50, 70, 85, 90, 95, and 100 percent of design speed. Velocity fluctuations at the rotor inlet were indicated by a hot film
5
probe with three sensors located at 25, 50, and 85 percents of span from the hub (Figure 5f). Readings from this probe along with selected rotor and stator strain gages, a speed signal, and a stator leading edge static pressure were recorded simultaneously as the throttle was closed from wide open to stall. Several surge pulses were recorded for each stall-transient survey.
2. Performance Test
Performance data with stator hub slit suction were obtained at 50, 70, 85, 90, 95, and 100 percent of design speed for a total of 30 points.' In addition stall flows were measured for all speeds. Traverse data were taken at nine diameters at the rotor-inlet and stator-exit for 26 of the data points. For the remaining four data points, boundary layer surveys were conducted at fifteen radial positions for all probes. Stator-inlet probes were traversed for these four points, in addition to the rotor inlet and stator exit probes. One combination probe (shown in Figure 5c), at the stator exit was tangentially traversed across a stator blade gap at fifteen radial locations to supplement the wake rake data. Three of the boundary layer survey points were acquired at design speed, part throttle, peak efficiency, and near stall. The fourth point was acquired at 70 percent speed, near stall flow.
Six additional performance data points, three at 70 and three at 100 percent of design speed were taken, without stator hub-slit-suction to isolate the effects of suction on performance. All radial traverse data were obtained for these six performance points including stator inlet traverses. Stall flow was measured at 100 percent speed without slit suction.
D. Calculation Procedure
The calculation procedure was the same as discussed in Reference 1 for uniform inlet flow conditions with an additional adjusted efficiency calculation which accounts for the stator hub-slit-suction flow.
Adjusted efficiency was defined as the ratio (ideal work/actual work) where ideal work was calculated for only the flow which reached the compressor exit, and actual work as the sum of work done on the bleed flow in addition to work done on compressor exit flow. The actual work term does not account for the work required by the facility exhausters. The equation of this adjusted adiabatic efficiency is given in Appendix 1. Adjusted efficiency values are tabulated for each data point in Appendix 3.
For the boundary layer survey points, overall performance and blade element calculations were made using the wake rake data and contour plots of various stator aerodynamic parameters were generated from combination probe measurements. Velocities were calculated from combination probe measurements of total and static pressure, total temperature, and air angle in the following manner: 1) Measurements of total and static pressure were used, with a probe calibration, to determine Mach numbers; 2) Total temperature measurements were corrected for Mach number and pressure level effects and used with Mach number to calculate absolute velocities; 3) Measured air angles were corrected for Mach number effects and used to resolve meridional and tangential velocity components.
6
IV. RESULTS AND DISCUSSION
A. Shakedown Test Results
Levels of vibratory stresses on the blades and vanes were recorded during accelerations and decelerations between 50 and 105 percent of design speed with wide open throttle, and near stall throttle settings. All observed blade and vane vibratory stress levels were within acceptable limits.
Surge occurred at all speeds. This was determined from continuous recordings of signals from a three-sensor hot film probe at the rotor inlet, from strain gages, and from static pressures located along the flow-path walls. At high speeds, these measurements showed large fluctuations in velocity simultaneous with high vibratory stresses in rotor and stator blades, and static pressure variations. Periodic fluctuations in velocity indicated that rotating stall occurred at the beginning of the surge cycle.
An oscillograph trace at 90 percent speed (Figure 8) shows a representative velocity pattern for all stalls. Velocities at midspan and hub decreased at surge whereas tip velocities increased. The period of the surge-pulse was approximately 0.13 seconds. The recovery period between surge pulses varied with speed, ranging from 1.05 seconds at design speed down to 0.11 seconds at 50 percent speed. At 50 percent speed, static pressure variation, velocity fluctuations, and vibratory stresses were small.
As flow was reduced at a given speed, rotor and stator vibratory stresses increased sinmultaneously, so that it was not clear which blade row stalled first.
B. Performance Test Results
1. Overall Performance
Overall performance of the rotor and stage with and without stator hub-slit-suction is presented in Figures 9 and 10. The stall line was established by extrapolating the characteristic speed lines to measured stall airflows, shown as slashed symbols on the figures. Stall flows are tabulated in Table 3. A maximum stage efficiency of 82.7 percent was achieved at design speed with slit suction at a pressure ratio of 1.871 and a corrected weight flow of 179.6 lb/sec. This efficiency drops to 82.2 percent when it is adjusted for the work done by the rotor on the hub-slit-suction flow. The same peak efficiency was recorded without slit suction. Efficiencies which have been adjusted to account for suction flow are shown in the upper efficiency scale in Figure 9. Rotor efficiency for the same data point with slit suction is 87.6 percent at a pressure ratio of 1.935. This rotor'efficiency is 1.5 percentage.points lower than the maximum rotor efficiency obtained at design. speed in the test of Reference 1. The difference may be attributed to any or all of the five changes in apparatus between this test and that of Reference 1; i.e. (1) increased rotor tip clearance, (2) decreased rotor inlet annulus area due to rotor tip fill, (3) the restaggered stator, (4) blended out nicks in slightly damaged rotor blades (Figure 3), and (5) upstream effects of stator hub slit suction.
7
TABLE 3
SUMMARY OF STALL WEIGHT FLOWS
Percent With Stator Design Speed Hub-Slit-Suction
50 74.2
70 109.8
85 138.8
90 150.2
95 161.3
100 173.3
Maximum adjusted stage efficiency with stator hub-slit-suction was 85.8 percent and occurred at 50 percent of design speed. For 70, 85, 90,and 95 percent design speed the maximum adjusted stage efficiency was approximately 84.5 percent. Anet adjusted stage efficiency benefit of 1.5 percent was obtained with hub-slitsuction at 70 percent speed for the maximum flow condition, but no effect was seen at other speeds.
The lower pressure ratio seen near stall at design speed without stator hub-slitsuction (Figure 9) is probably due to blockage effects caused by stator leading edge transverse probes. These probes were not traversed during hub-slit-suction tests except for the boundary layer points. Evidence of traverse probe blockage at design speed is shown in Figure 11. Spanwise profiles of pressure ratio for two points with slit suction and no stator leading edge probes are compared to two points with stator leading edge probes, one with slit suction and one without slit suction. Spanwise pressure ratios agree well for the two points which include stator leading edge probe traverses except at the root where slit suction improvement is expected. These same points show a lower pressure in the tip region when compared to the points without stator leading edge probe traverses. This probe blockage effect on pressure ratio was not seen at 70 percent speed, where the stator inlet Mach number did not exceed 0.76.
Overall stator recovery (P /P10 ) listed for points with and without slit suction in Poo
Appendices 3 and 4 as O) gives a direct measure of the effect of stator hub-slit-LOCAL
suction. Slit suction increased stator recovery for the peak efficiency point at design speed from .968 to .974. It must be remembered that this recovery increase with suction is gained at the expense of approximately a half percent in stage efficiency to account for the work done on the bleed flow.
8
Rotor performance for this test differed considerably from that achieved in the test of Reference 1. Maximum efficiency at design speed was 1.5 percentage points lower for this test as mentioned previously while pressure ratio was generally lower except near stall. At lower speeds, pressure ratios were slightly higher for this test at higher flows although near stall values were the same. Efficiency values were 0 to 5 percentage points higher at lower speeds for this test. Gains were largest at maximum flow points with no significant change near stall. Part of the difference may be due to measured wake rake total pressure readings which showed one rake consistently higher than the other although no reason could be found to dispute the data.
2. Blade Element Performance
Blade element total pressure loss coefficient, diffusion factor, and deviation versus incidence angle are presented for both rotor and stator in Figures 12 and 13 for the performance test with slit suction. These data are tabulated in Appendix 3. Although overall performance benefits obtained by the addition of stator hubslit-suction were small, suction did reduce losses at 5, 10, and 15 percent of span from the hub for both 70 and 100 percent speeds. Figure 14 presents plots of stator blade element diffusion factor and total pressure loss coefficient versus incidence angle at these three spans for test points with and without slit suction. At 5 percent span from the hub, slit suction reduced the losses over the entire incidence range for 70 and 100 percent design speed. At 70 percent design speed the losses were reduced approximately 23 percent at the near stall incidence angle and 50 percent at the maximum flow incidence angle. At 100 percent design speed the losses were reduced approximately 18 percent at the near stall incidence angle and 29 percent at the maximum flow incidence angle. This effect diminishes outward from the hub until the effects are insignificant outboard of 15 percent span from the hub. Complete blade-element performance data for points without stator hub-slit-suction are tabulated in Appendix 4.
Gapwise distributions of stator exit total pressure, temperature, and adiabatic efficiency clearly show a narrower and shallower wake with slit suction. Figure 15 presents distribution at 5 percent span from the hub for open throttle and near stall data points at 70 percent speed showing that the effect of suction is much stronger at the maximum flow condition than at the near stall point. At design speed (Figure 16) the effect is of the same magnitude as at 70 percent speed near stall regardless of throttle setting. Slit suction effects on the total pressure and temperature wake distributions disappear above 15 percent of span from the hub. The increase in temperature in the wake region without suction may be caused by a redistribution of flow through the stator as a result of higher stator hub losses causing the stator to operate at a higher inlet pressure in the hub region. This would back pressure the rotor hub causing an increase in energy at the rotor hub. Another explanation is that enough high temperature air is being bled through the stator slits with suction to cause a lower temperature reading at the hub. The temperature ratio of the flow in the suction slit plenum is approximately .01 higher than the temperature ratio at 5 percent span from the hub at design speed.
9
This is the magnitude of the change seen in gapwise pressure profiles between suction and non-suction data points.
Rotor performance was calculated using stator-exit free-stream total pressure obtained from the peak wake rake reading at each radial location. Design speed data were also reduced using the stator-exit free-stream efficiency method, as discussed in Reference 1, to determine rotor performance. Figure 17 shows the rotor overall efficiency comparison for the two methods at design speed and shows the spanwise efficiency distribution for the peak efficiency point at design speed. Blade-element performance of thetrotor and stator at design speed, using the freestream efficiency method is given in Table 7, Appendix 3. The free-stream efficiency method gave lower rotor hub efficiencies which resulted in slightly lower overall rotor efficiency for the same stage efficiency.
3. Contour Plots of Stator Exit Traverse Data
Tangential traverses were made at the stator exit for part throttle, maximum efficiency, and near stall points at design speed and at near stall for 90 percent speed with stator hub-slit-suction. Measurements of total and static pressure, total temperature, and absolute air angle were obtained at 4.3, 5.8, 7.0, 9.7, 12.2, 15, 30, 50, 74, 90, 94, 97, 98, and 99.5 percentages of passage height from the hub. A fifteenth radial position was intended closer to the inner case but was not obtained due to an incorrect probe. depth setting. - Tangential spacing gave 15 readings across a stator gap at 90 percent span and 11 readings at 4.3 percent span. These measurements were used to calculate velocity vectors, and to construct contour plots showing patterns of P/Pinlet, T/TinletI airflow angle, and Vm /\/0-7 at the stator-exit instrumentation plane. These contours are shown in Figures 18 through 22.
a. Total Pressure Ratio
Low pressure areas in the vicinity of the stator hub suction surface no longer exist as they did in Reference 5, possibly as a result of slit suction. Lowpressure areas in the tip region are still present.
Areas of strong gapwise gradients exist near both walls, Figure 18, and progress toward midspan as back-pressure is increased. At midspan the wake width increases slightly and the pressure gradient in the wake region becomes stronger with increased back-pressure. High pressure regions near the intersection of the stator pressure surface and the hub wall may be due to rotor wake flow migration to the stator pressure surface, as explained in Reference 6. Rotor work changes, due to locally high back-pressure ahead of the stator, may also cause gapwise total pressure variations in addition to stator losses.
b. Total Temperature Ratio
Total temperature plots (Figure 19) show endwall gradients similar to the total pressure plots, indicating that rotor-wake separation or rotor back
10
PRATT & WHITNEY AIRCRAFT
pressure patterns cause gapwise variations in both parameters. Both hub and tip endwall regions have a .03 to .04 drop in temperature ratio from the stator pressure to suction surface at design speed regardless of back-pressure. Matching total pressure and temperature profiles led to the free stream efficiency method for calculating stator-inlet average total pressure, Reference I No consistent temperaturepattern is seen at midspan but gapwise gradients tend to occur in the wake region.
C. Air-Flow Angle
Gapwise variations in air-flow angle were measured in the wake region at all spans (Figure 20). Studies have shown that the small (±10 degrees) angle variations indicated by the probe at midspan and hub can be attributed primarily to the large total pressure gradients in the wake region because sidehole pressures on a wedge probe tend to turn it in the direction of the higher total pressure. Steeper angle variations in the tip endwall region indicate a vortex formation downstream of the intersection of the wall and stator blade.
d. Static Pressure Ratio
Gapwise gradients of static pressure were weak (Figure 21) although showing a wake pattern similar to the total pressure wake. Measured static rise across the wake is probably all due to the total pressure gradient forcing the probe to yaw and measure part of the velocity head with the side holes. Pressure increased with radius probably as a result of streamline curvature as the upstream hub convergence blends into a constant diameter wall.
e. Meridional Velocity
Meridional velocity contours (Figure 22) follow the patterns of the total pressure contours because static pressure variations are relatively small, and air angle does not vary enough to have a significant effect. Increasing backpressure enlarges the comer stall region near the tip but does not appear to thicken the wall boundary layer.
11
V. REMARKS
Stator hub-slit-suction caused a reduction in hub losses for this test out to 15 percent span from the hub, maximum effect occurring at 5 percent span from the hub. These local benefits were not enough to influence the total stator losses appreciably so that overall stage efficiency benefits were slight. No adjusted efficiency benefit was seen at design speed, while the maximum benefit was 1.5 percentage points at 70 percent speed, maximum flow conditions. Similar loss reductions were seen during the test of Reference 3 with slit suction although the influence reached to 30 percent span from the hub. Stator hub recovery had more effect on the efficiency of the compressor in the test of Reference 3 than in this test so that the overall benefit was about 1.5 percent in unadjusted stage efficiency at design speed.
No stall line improvement was seen with slit suction in this test where results from hot film probes and strain gauges were inconclusive as to which blade now stalled first. It is believed that the stage stall isinitiated by rotor stall even though the stator was restaggered four degrees open (4 degree increase in stator incidence angle).
The results of this test and those of References 3 and 7 show that hub-slit-suction effects are local and only benefit overall performance when the stator hub has very high losses. These local effects may be quite significant, however, in high bypass ratio engines where most of the flow into the engine comes from the high loss fan hub region.
12
REFERENCES
1. Sulam, D. H., Keenan, M. J., and Flynn, J. T., Single-Stage EvaluationofHighly-Loaded, High-Mach-NumberCompressorStages, Dataand Performan~eReport,MultipleCircular-ArcRotor,NASA CR-72694, PWA-3772, 1970.
2. Peacock, R. E., Flow Controlin the Comers of Cascades,A. R. C. 27291, October 1965.
3. Harley, K. G., and burdsall, E. A., High-LoadingLow-Speed Fan Study, Dataand PerformanceReport, Unslotted Blades and Vanes, NASA CR-72667,,PWA-3653, 1969.
4. Monsarrat, N., Keenan, M. J., and Tramm, P. C., DesignReport, Single-S tage Evaluation ofHighly-Loaded,High-Mach-NumberCompressorStages, NASA CR-77562, PWA-3546, 1969.
5. Burger, G. D., and Keenan, M. J., Single-Stage EvaluationofHighly Loaded, High-Mach-Number CompressorStages, Dataand PerformanceReport,Tandem Rotor,NASA CR-72772, PWA-3954, 1971.
6. Keerebrock, J. L. and Mikolajczak, A. A., Intra-StatorTransportofRotor Wakes and Its Effect on CompressorPerformance,American Society of Mechanical Engineers, Paper No. 70-GT-39, 1970.
7. Harley, K. G., Harris, J., and Burdsall, E. A., High-LoadingLow-Speed FanStudy, Data andPerformanceReport, Slotted Blades and Vanes and Rotor Tip Treatment,CR72895, PWA-3899.
13
MAIN RIG SUPPORT ROLLER BEARING TO DRIVE ENGINE CASE
DRIVE SHAFT TO DRIVE ENGINE GEARBOX
THRUSTS
ONT BEARING---,
SPPORT 30 ROTOR --BLADES
VANES
4 STATOR HUB SLIT PLENUM MANIFOLDS
Figure 1 Cross Section of Test Compressor
STATOR OUTER CASE
STATOR INNER
SLTBLE AIRFLOWO.01T"WIDE
Figure 2 Boundary Layer Suction Slits at Stator Hub (XPN-16602)
15
Figure 3 Assembled MCA Rotor (XPN 16597)
VALVE (24 INCH DIA) -'- a I-r - - VALVE (12 INCH DIA)
CALIBRATED ORIFICE
VALVE 16FT DIAlDRIVE ENGINE
EXHAUST STACK
COMPRESSOR TO EXIHAUSTERSDISCHARGE EXHAUSTr HUB.SLIT.SUCTION STCK FLOW SUPPLY
"J - 42-INCH DIA PIPE, BYPASS PIPE BYP SS IPEPILENU MACH" A R 7 FEET LONG
90)INCH DIA C FCAIBRATEDNOZZLE
FLOW STRAIGHTENER SCREEN
TURBINE DRIVE ENGINE GEARBOX TES COMPRESSR
TOROIDAL COLLECTOR
Figure 4 Schematic of Compressor Test Facility
16
XP-99889 XPN-1815 (a) (b)
RADIAL TRAVERSABLE TOTAL PRESSURE
RAKE RAKE TEMPERATURE
\
XP-1928S XP-99893 (f)
HOT TRAVERSABLE FILM DISK PROBE PROBE
(e)
XP-99886 XPN-660 (C) (d)
TOTAL COMBINATION PRESSURE PROBE RAKE
XP-19286
Figure 5 Typical Instrumentation
17
STATION NO. 0
STATION NO. 1
-24
NO. 1.1 -20
-16 NO. 2
-12 NO. 3
-b NO. 4
U)
X -4 C-z NO. 5
0-NO. 6
CPLANE LU,-I NO. 7
wROTOR.7 - NO.8 a
Xc 8IC
NO. 9
12 - NO: 1
NO. 11S C - T NO. 12
16 -o> -o NO. 1STATOR
NO 13.1 NO. 1420 r
C 9
24 'O.N 15
28
12 16 20 24 28 32 36 38
DIAMETER - INCHES
PLENUM CHAMBER SCREEN
INSTRUMENTATION PLANE
INSTRUMENTATION
ROTOR LEADING EDGE(SLANT STATION)
ROTOR TRAILING EDGE (SLANTSTATION)STATOR LEADING EDGE
TRAILING EDGE
INSTRUMENTATION PLANE
INSTRUMENTATION PLANE
Figure 6 Axial Station Number Designation and Location of Instrumentation
18
O °
21.7 ° 0
4 62.8e6
87
. 7
STATION NO. STATION 10 SYMBOLS
STAIo PO.WAL1STTIC
332.296.5.2 °
282.270--
341.67 ° 24.5e
069.97
7.53 o 85.920
56.4
85,92 °
0*
30 0
60
*
"
TT FIXED TEMPERATURE RAKE
DISK TRA VERSE PROBE
PTWAKE RAKE
PT FIXED WAKE
D ISRA E R
26&"920
2505°0', 2.9
-
21045ISU0204 .5 16 .33,
102,270
152.37 °
12
COMBINATION PROBE
HOT FILM MASS FLOW SENSOR
PsTT SUCTION
PLENUM
STATION 12 STATION 13.1 STATION 16
Figure 7 Circumferential Location of Instrumentation, Viewed from Rear
SURGE CYCLE
SURGE PULSE
> w
PERIOD OF ROTATING STALL
-I >
>w
LwUJ -
I STATIC PRESSURE 'ONE PER
0.01 SEC. DIRECTION OF INCREASING TIME
Figure 8 Oscillograph Trace of Typical Surge Cycle
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.6..... . . . ...
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CORRECTED HEIGHT FLOW -Wvu71 67 LB/E1. . . . . . . . . . . . .. ........ .. . ... . . .:. ....... .
1- ,1.:,Figure 10 Rotor.. .Overall.. Performance. .. .. ..1. ... . . o .. ,... . .2.0..
Cl) ...... .... ::o:::CORR. FLOW RATE LES/SEC: o... ..................... ... .... ........ ,..,.....,,........... ........ ,..,..........,.o,,•. ....°.o..... ........................... o...o......,.o.,......... o
6/) 0 10 2, o o5o6o0o . 0 . 0 HUB 10 , ., . ,.P. . 177.0 6 0 70 70 90 100 0 9 0 40Po TIP
F u 0oo.oco.°o,,ooo0,StatorLe0ading E P c a esIoooo0oIoo0ooff of0 e 0gno0eHUBECTD PERCENTLWSPAN LS/E TIP
Figue11Effetro Stto Leadin Ede PoeBlocageatDsgSpe
2........ o ..... ................................. •.•.....................................22 ....... " " '" " " " , "o' .' o "O R F O A EL SS C
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i ] . .... . .. -18
........16S14 . ....o..... .. i ' : ....... ! ........ .. ..
)_ l: :.- : :. . : ! ]"" . - - 5%SP-AN ""
%oDESIGN SPEED MACH NO. RANGE
100 .938-966 6 95 .885-.922
90 .828 -- 869 85 .782-.818
X 70 .624-.6644 i 50 .436 - .467
2 .. . . . ... .. . . s . . . .2 : . . . .
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- .-0.1 . - - - - . . .
-2 0 2 4 6 8 10
INCIDENCE ANGLE, SUCTION SUR'FACE, Is, DEGREES
Figure 12a Rotor Blade Element Performance With Stator Hub Slit Suction, 5Percent Span From Hub
23
18
16 . .. ....... ... ".. ..... .....
c 14 -'...... . ". ... . .... .. ................. ... ... .
o 12
10J
10% SPAN """% DESIGN
0 8 .. . SPEED MACH NO. RANGE
SO 100 .988-1.016 O 6 -" . - - 8 95 .933-.970
> 90 .874-.914
4 -• - - 0
X 8570
.824-.860.659 -.698 ..
S . . . 50 .462 .492 ....................... .... ............................ ............ ........ ..
2 : 06 . -..
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03 0A
L.-. :... .. '
od, 0 l±Ja ,......... : ..... .:. .... .
-0.1 -2 0 2 4 6 8 10
INCIDENCE ANGLE, SUCTION SURFACE, IS,DEGREES
Figure 12b Rotor Blade Element Performance With Stator Hub Slit Suction, 10 Percent Span From Hub
24
20
18
16 Cn
cc0 14 ,"... .. .X - - : ..... .:...x- - . . . " . . .. .. ... .
w 12
.. ...... ...... .. ... .... .... ... ..... ..................................
Ct 101 - . 15% SPAN O .. . ...... . % DESIGN
SPEED MACH NO. RANGE;:--' 8 :
5°'LU . I............. . - " ' ' -'
w . . 0 100 1.034-1.063
95 .977-1.0136 "-6 90 .915- .954
. . 86 .863- .897 4.X> 70 .691-730
: 50 .484-.514 .. . .. ... .... .... ..... ... . ..........;....... .. ........... . .
21
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LU0 . 0.1
U-Lu0
0 1
. .. ... ... ... .. ... ... ... .. .... . ...... .... . ....... .... ........
-0.1 6 8 10-2 0 2 4
INCIDENCE ANGLE, SUCTION SURFACE, Is, DEGREES
Figure 12c Rotor Blade Element Performance With Stator Hub Slit Suction, 15 Percent Span From Hub
25
--- - --- -
20 ."... ......... ..*.... .. ."...... ........
30% SPAN 18 %DESIGN
... .. SPEED MACH NO. RANGE ..... ....
16 100 1.153-1.189 u .... .... ........ 95 1.090 - 1.131
- .90 1.021 -1.062 OL 14 0 85 .963-.999 o ... . X 70 .774-.812
o : 50 .543-571
0.. .. ..* eLc 10
.,
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6
4
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IL
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--)0.1.
-2 0 2 4 6 8 10
INCIDENCE ANGLE, SUCTION SURFACE, Is, DEGREES
Figure 12d Rotor Blade Element Performance With Stator Hub Slit Suction, 30 Percent Span From Hub
26
20 '
18 ' S:..... "'""..... :" '." .......' " .... --- ""50% "--D E IG SPAN
* .%%DESIGN
16 " SPEED MACH NO. RANGE
LU 14 100 1.285-1.3315 1e.95 1.215 -1.262
U ... ............... 90 1.139-1.186 . .: 85 1.076 -1.114
12 "'X 70 .866- .904 S... ........... 50 .608-.636
Z210 -.
.... .
8--x
>~
4
21
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U
--0 . ..:. .. e.- :
. . . . .
-2 0 2 4 6 8 10
INCIDENCE ANGLE, SUCTION SURFACE, Is,DEGREES
Figure 12e Rotor Blade Element Performance With Stator Hub Slit Suction, 50 Percent Span From Hub
27
20
18
16
. .
..... ...... .. .......... .... . i i : :
... ....... 70% SPAN ,........vi............... 7 PA ....... .... . . "' " " " --
%DESIGN
SPEED MACH NO. RANGE wi ...-- ..... .. . . :. . .. .. .. . ..i--...... ... .
VD 14 . .... 100 1.406 -1.448w 96 1.329- 1.373 .. ".".-........ ----..... -" .......... 901 45- 1.291:.......... ....... .:--........-- -.
090 1.245-2185 1.178- 1.214
12 , '"X 70 .949- .984 ...........- .-- .................... 50 .668- .694 ......0°:............................... .... .!:i... ...
_0 8 .. . .
B I> . .... . ...... .. .......... ..
4. 4 " : [ :. [ :. . .
21
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L.03
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0 0
-0.1 0 2 4 6 8 10
INCIDENCE ANGLE, SUCTION SURFACE, Is,DEGREES
Figure 12f Rotor Blade Element Performance With Stator Hub Slit Suction, 70 Percent
Span From Hub
28
. .20. . . .. .. . . . . . . . .... .. . .....
18 ............. . . . 85% SPAN...
* . %%DESIGN 16 - SPEED MACH NO. RANGE
... ..... ..... . ",.. .. ;"I...-:C./.... ; CoL 14 o 100 1.491 - 1.524
1 95 1.409 - 1.447 ... .. ........ 90 1.319 -1.363
o12 8b 1.248 -1.2812ol X 70 1.005-1.040 " ... .. . 50 .708- .733
;2 10z
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04
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0.21 f*
130.
-0.12
-2 0 2 4 6810 INCIDENCE ANGLE, SUCTION SURFACE, Is, DEGREES
Figure 12g Rotor Blade Element Performance With Stator Hub Slit Suction, 85 Percent Span From Hub
29
1. . . .. ,- + .... +.. +. . .•...... ..... . . ... ... . . ......... . . .. .. . . . + . •. . . +
...... 90% SPAN %DESIGN166 : . . MACH NO. RANGE-SPEED
Lii
o 100 1.517-1.547O 14 ii a 95 1.433 - 1.470 a 90 1.342 -1.385
85 1.270 - 1.302 u 2 X 70 1.023 -1.057
-. . 50 .721-.746
00 . . . ..S. . .
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-2 0 2 4 6 8 10
INCIDENCE ANGLE, SUCTION SURFACE, Is, DEGREES
Figure 12h Rotor Blade Element Performance With Stator Hub Slit Suction, 90 Percent Span From Hub
30
20
18 - .-. . - "95% SPAN % DESIGN
SPEED MACH NO. RANGE 03 1616 ....... . .-. +. ... . - .. - ........ " W . .. *o 100 1.541- 1.570 ... .
:. 95 1.457 -1.491 w o 14 "-. .. . . . . . . . . -.. . 9085 1.364-1.4061.290 1.322
o X 70 1.040- 1.072 u -.J
12 , : , : ,:r-,_
[3 5. 733-.757
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____
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: * I .%DESIGN- - MACH NO. RANGE -":-1SPEED: . 2C -t--j I :.-
--. ! . L -_{__ .... " ....... _ __ 1w0 .892 950 __..... 2 0 0 95 869 - 26"18 . - ' :
85 .802-.873 16 X 70 309-.759 -
... ....... 50 .484-.547
--~--14
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1
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32 ..................
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1/ :SPAN - ___" _% DESIGN
w -_SPEED MACH NO. RANGE
--CD:----- --
16 - 100 866-10
0 95 .842- 887:....... 4 " 90 .302-854 85 .771- 831
"X 70 .316-.728 L6 14
. I .50 .462-522
0 . - ------------- -:....... ..... < ----. .-.... > 10
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6 -14 -12 -10 - -2 0 2 4 6 8 10 12 14 16
INCIDENCE ANGLE, SUCTION SURFACE, is,DEGREES
Figure 13b Stator Blade Element Performance With Stator Hub Slit Suction, 10 Percent Span From Hub
33
- - - -
22
20 ---- --
10i] : [ ] 15% SPAN
" , . . . ... - %DESIGN 4-- SPEED MACH NO. RANGE
lii . ... ;. . ..,... . . -. { 1 : : -. o[ 100 .832- 888
1 0 95 806-.858s9 .773-820
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I : I :t- :
16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 t6
INCIDENCE ANGLE, SUCTION SURFACE, is, DEGREES
Figure 13c Stator Blade Element Performance With Stator Hub Slit Suction, 15 Percent Span From Hub
34
-------- --
---
22 - -- . 30% SPAN
" % DESIGN
20... ..... --.- -- .:A------ --- t------ MACH NO. RANGE-.SPEED
o 100 .754- 823 18 --------- e 95 .71S- 799
90 684 -. 766 S. -"... 85 .659-.738
c9 1 8...-- - - -...-- - - ... X 70 330-628 ----------- - - - - - 50 AO0- 448
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INCIDENCE ANGLE, SUCTION SURFACE, is,DEGREES
Figure 13d Stator Blade Element Performance With Stator Hub Slit Suction, 30 Percent Span From Hub
35
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INCIDENCE ANGLE, SUCTION SURFACE, is, DEGREES
Figure 13f Stator Blade Element Performance With Stator Hub Slit Suction, 70 Percent Span From Hub
37
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INCIDENCE ANGLE,SUCTION SURFACE, i.DEGREES
Figure 13g Stator Blade Element Performance With Stator Hub Slit Suction, 85 Percent Span From Hub
38
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INCIDENCE ANGLE, SUCTION SURFACE, i., DEGREES
Figure 13h Stator Blade Element Performance With Stator Hub Slit Suction, 90 Percent Span From Hub
39
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INCIDENCE ANGLE, SUCTION SURFACE, is,DEGREES
Figure 13i Stator Blade Element Performance With Stator Hub Slit Suction, 95 Percent Span From Hub
40
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INCIDENCE ANGLE, SUCTION SURFACE, i., DEGREES
Figre 14a Effects of Stator Hub Slit Suction, 5 Percent Span from the Hub -Stator Blade Element Performance
41
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INCIDENCE ANGLE, SUCTION SURFACE,* is, DEGREES
Figure 14b Effects of Stator Hub Slit Suction, 10 Percent Span from the Hub -Stator Blade Element Performance
42
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INCIDENCE ANGLE, SUCTION SURFACE, is,DEGREES
Figure 14c Effects of Stator Hub Slit Suction, 15 Percent Span from the Hub -
Stator Blade Element Performance
43
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50 60 70 80 90 00 10 20 30 40 50
PERCENT GAP
Figre I15a Effcts of Stator Hub Slit Suction on Gapwise Distibutions of TotalPressure, Temperature, and Effciency, 5% Spa, 70%Speed, Maximum Flow
44
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PERCENT GAP
Figure 16a Effects of Stator Hub Slit Suction on Gapwise Distibuions of Total Pressure, Temperature, and Efficiency, 5% Span, Design Speed, Maximum Flow
46
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PERCENT GAP
Figure 16b Effects of Stator Hub Slit Suction on Gapwise Distributions of Total Pressure, Temperature, and Effciency, 5% Span, Design Speed, Near Stal
47
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PERCENT SPAN
Figre 17 Efficiency Comparison of Free-Stream Toal Pressure versus FreeStream
Efficiency Calculation Methods
48
*
PRESSURE SURFACE
SUCTION SURFACE
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Figure 18a
/
Total Pressure Ratio (P1 3 /P0 ), 100 Percent Flow Rate
HUB
Speed, 181.5 Pounds Per Second
49
4 PRESSURE SUCTION SURFACE SURFACE
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Figure 18b Total Pressure Ratio (P 13 /P0 ), 100 Percent Span, 180.7 Pounds Per Second Flow Rate
50
t PRESSUR> SUCTION SURFACE) SURFACE
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Figure 18c Total Pressure Ratio (PI 0 Flow Rate
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1.90
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51
i PRESSURE SUCTION SURFACE SURFACE
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0
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Figure 18d Total Pressure Ratio (P1 3 /P0 ), 90 Percent Speed, 153.96 Pounds Per Second Flow Rate
52
PRESSURE SUCTION SURFACE SURFACE
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11.220 _9 ' ! -171! 24 o 1.220
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Figure 19a Total Temperature Ratio (TI 3 /T0 ), 100 Percent Speed, 181.5 Pounds Per Second Flow Rate
53
PRESSURE SUCTION SURFACE SURFACE
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Figure 19b, Total Temperature Ratio (T1 3 /T 0 ), 100 Percent Speed, 180.7 Pounds Per Second Flow Rate
54
PRESSURE SUCTION SURFACE SURFACE
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a
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Total Temperature Ratio (TI 3 /T0 ), 100 Percent Speed, 175.0 Pounds Per Second Flow Rate
55
PRESSURE SUCTION SURFACE SURFACE
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Figure 19d Total Temperature Ratio (T 13 /T 0 ), 90 Percent Speed, 153.96 Pounds Per Second Flow Rate
56
PRESSURE SUCTION SURFACE SURFACE
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20
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L)O
-6 -6
12.20 -
16.14 LHU //
12.20
-6 6 -4- -6
HUB
Figure 20a Absolute Air Angle, Degrees (90-3 13), 100 Percent Speed, 181.5 Pounds Per Second Flow Rate
57
NPRESSURE SUCTION
9944
SURFACE
1
SURFACE
TIP
89.40
73.88
2lL 52.01
I-6
94.3!.-
12.18 12
-8
0-6
31.55
12.3-8
9.6 -6
-4
Figure 20b
58
Absolute Air Angle, Degrees (90 -913), Second Flow Rate
10
HUB
Percent Speed, 180.7 Pounds Per
PRESSURE SUCTION SURFACE SURFACE
99.48 TIP
94.42
a-Co
z 52.o8
C--8 w
-5
-10 -8 1.14
12.22:
9-70
HUB
Figure 20c Absolute Air Angle, Degrees (90 -913), 100 Percent Speed, 175.0 Pounds Per Second Flow Rate
59
PRESSURE SURFACE
SUCTION SURFACE
TIP
--
-8,
w-91.07
INI
Figure 20d
60
1-2.19
=:98
-HUB
Absolute Air Angle, Degrees (90 -/1) Second Flow Rate
-10
90 Percent Speed, 153.96 Pounds Per
* PRESSURE) SUCTION SURFACE SURFACE
99.4o TIP
73.99
2 LU
U
52.08
- 1.20
31.57
-1.15
12.20
9.70
HUB
Figure 21a Static Pressure Ratio (P 13 /P0 ), 100 Percent Speed, 181.5 Pounds Per Second Flow Rate
61
PRESSURE SURFACE
SUCTION SURFACE
89.40 1.4o
73.88
cC
z .3
52.01
31-5
16.og
12.18 1.25 1.29.61
X.0
.0
HUB
Figure 21b Static Pressure Ratio (PI3/P0 ), 100 Percent Speed, 180.7 Pounds Per Second Flow Rate
62
PRESSURE SUCTION SURFACE SURFACE
1.50
944
89.4
I
LU __52.080
0.,
1.45
-12.21 1.4
9.70 6.6
HUB
Figure 21c Static Pressure Ratio (P1 3 /P0 ), 100 Percent Speed, 175.0 Pounds Per Second Flow Rate
63
http:LU__52.08
PRESSURE i) SUCTION SURFACE SURFACE
9_9' TIP
1.35
73.98
z 520 F- 52.07
0 w
wJC.,
31.56
1.30
16.13
12.19
6.98
1, 36 .25 125
HUB
Figure 21d Static Pressure Ratio (P13/P0), 90 Percent Speed, 153.96 Pounds Per Second Flow Rate
64
PRESSURE SURFACE
SUCTION SURFACE
9.4 - 4oo
TIP
8. 4o 0 1 M_5000
Cooo
2 44
89.4
70052.08 z
LHU
9.70
Figure 22a Meridional Velocity, Ft/Sec (Vml3), 100 Percent Speed, 181.5 Pounds Per Second Flow Rate 65
PRESSURE SUCTION SURFACE SURFACE
q -44TIP
/--- oo
89.40O
-- 00
73.88
700
z
~52.0O1
LU 0.
7800
4--(
16.01
12.18
9.61
HUB
Figure 22b Meridional Velocity, Ft/Sec (Vml3), 100 Percent Speed, 180.7 Pounds Per Second Flow Rate
66
PRESSURE SUCTION SURFACE SURFACE
200 a__8N TIP
-500
I-Lu
- 2.08
0. L) ' / oo o60
070
86oo
12.21
6. 6 9.900
HUB
Figure 22c Meridional Velocity, Ft/Sec (V.1 3 ), 100 Percent Speed, 175.0 Pounds Per Second Flow Rate
67
PRESSURE SUCTION SURFACE SURFACE
.300
Iz 52.07
a..:
79.70
Figure 22d Meridional Velocity, Pt/Sec (Vml3), 90 Percent Speed, 153.96 Pounds Per
Second Flow Rate 68
APPENDIX 1
PERFORMANCE PARAMETERS
a) Relative total temperature T'8 =t 8 [i+ 7- 1 (V)2]T1 1+ Y2 1 (M' 8) 2](rotor (oo nin)
T' 9 =T18 + [cwr8) 2 2 8(wrj9)2 (rotor out)
b) Incidence angle based on mean
in =/'8 -#"8
tm =010 -*10
camber line
(rotor)
(stator)
c) Deviation
80= - 0 (rotor)
IQ= 0l! - 0*11 (stator)
d) Diffusion factor V' 9
D 1 V' 8Vr
D=1- V11110
+
+
r9V9 -r8V 8
969 8V8 (r 8+r 9 ) cV' 8V -r V a
10 V0 10 riri 11 (r1 0, + rll) aV 1 0
(rotor)
(stator)
e) Loss coefficient
PE8 [T'8 --
P9 (rotor)
j = 1I0 11I
P11(stator)
0 P1 0
69
f) Loss parameter
cOCos (9 (rotor) 2 a
Cos flu (stator) 2or
g) Polytropic efficiency
y1in 9 S [ P7 j
1) p -
1 7Pin T9] (rotor)
y1In I[Pill1
2) "p = tl 17 (stator)
h) Adiabatic efficiency
[P9 " -1
ad= [7J 1 (rotor)
L T12 -1
nad = ] (stage)
70
W12[P7 12
ad= adjusted W
[]
1 2
I + W16 T16- 1
(stage)
) Wake blockage factor
Z AV P A
n AV
avg
where n is number of tangential traverse
points equally spaced across a stator gap and PAy avg is calculated from mass flow averaged values of P, p, and T at that radius
71/72
APPENDIX 2
SYMBOLS
A - area, ft2
Aan - annulus area, ft2
Af - frontal area, ft2
c chord lengt
Recommended