3IITh-303

TI'C FILE COPY

TECHNICAL REPORT BRL-TR-3098

BRLN TEMPERATURE AND OH CONCENTRATIONS

N IN A SOLID PROPELLANT FLAMEUSING ABSORPT71ON TECHNIQUES

JOHN A. VANDERHOFFANTHONY J. KOTLAR DTIC

SJUN 12 1990fAPRIL 1990 (?0

APPROVED FOR PUBLIC RELEAS DISTRIBUTION UNLIMED.

U.S. ARMY LABORATORY COMMAND

BALLISTIC RESEARCH LABORATORYABERDEEN PROVING GROUND, MARYLAND

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The findings of this report are not to be construed as an official Department of the Army position,unless so designated by other authorized documents.

The use of trade names or manufacturers' names in this report does not constitute indorsement ofany commercial product.

UNCLASSIFIEDREPORT DOCUMENTATION PAGE J

I OAW X& 070.01e

1. A4CY USI ONLY (-- i I. REPORT DATE 1. REPO -ATEs COwgjg

4. M AN SUBITUI April 1990 ITechnical L UO WMR4. T11L' AND SU--IILE L. FUDN NM~iS

Temperature and OH Concentrations in a Solid PropellantFlame Using Absorption Techniques 1LI61102AH43

& AUTNOR(S)

John A. VanderhoffAnthony J. Kotlar

7. PERFORMING ORGANIZATION NAME(S) AND ADOESS ES) 3. PERFORMING ORGANIZATIONREPORT NUMBER

S. SPONSORING; MONITORING AGENCY NAME(S) AND AOORESS(ES) Wo. SPONSOIRINGnI OITOWNG

Ballistic Research Laboratory AGENCY REPORT NUMBERATTN: SLCBR-DD-TAberdeen Proving Ground, MD 21005-5066 BRL-TR-3098

11. SUPPLEMENTARY NOTES

Accepted for presentation at the Army Science Conference, 12-15 Jun3 1990,

Durham, NC.

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Approved for public release;distribution unlimited.

IVABtSTRACT (maximum 200 wofRotationally resolved absorption spectroscopy in the A-X (0,0) vibrational band system of OH around

306.4 nm has been performed to determine the temperature and OH concentration in solid propellant

flames. OH is sufficiently well characterized that the spectra can be least squares fitted under a varietyof conditions. These conditions include the peculiarities of the experimental setup, instrument response

parameters and absorption baseline, as well as the temperature and OH concentration. The multi-parameter least squares fit of the spectra gives values and statistical uncertainties for temperature, OH

concentration, and other experimental design parameters. This technique has been applied to a nitraminepropellant flame burning in a windowed combustion vessel pressurized with 1.5 MPa nitrogen. Apropellant feed mechanism coupled to the combustion vessel extended the data taking time such thatgood quality OH absorption spectra could be obtained for this transient event. Here the light source was

an arc lamp and the detector a spectrometer with an intensified photodiode array.,, Experimental OH

spectral data have been fitted to temperatures ranging from about 2700 to 2000 K with a standarddeviation of about 120 K. Together with these temperatures, concentrations that range from about 640

to 250 ppm with a standard deviation of about 6% are also determined. These OH concentration values

are consistent with thermochemical equilibrium values for flame temperatures about 80 K below adiabaticand represent the first absolute determinations in a solid propellant flame environment.

4.'jSU4MICT TIlMI s I S. NUM BER OF P AUsAbsorption, Solid Propellant, Combustion, Temperature, 24Pressure, Flame, OH Concentration, HMX24, ) (" It M coot

I?. SICUNTY CLASWIATIO It $ICUN CASfW-"W if. SICUAY S: J K. LAATOOF ABSRACOF REPORT Of TINS PAU OF ABSTRACT

Unclassified Unclassified Unclassified UL

NISN 754001-20.5500 Standard Form 2"3 (Nov 2-O)UNCLASSIFIED '-0 ""

INTeNToNAL.Ly LEFr BUANK.

TABLE OF CONTENTS

PAGE

LIST OF FIGURES .................................. v

ACKNOWLEDGEMENT ................................ vii

1. INTRODUCTION .................................... 1

II. EXPERIM ENTAL .................................... 1

III. DATA ANALYSIS .................................... 3

IV . RESU LTS ......................................... 4

V. SUM M ARY ........................................ 7

REFERENCES ..................................... 9

A PPEN D IX ........................................ 11

DISTRIBUTION LIST ................................. 15

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iv

LIST OF FIGURES

FIGURE PAGE

1. The optical path for the absorption measurements of propellant burningwithin a pressurized combustion vessel ......................... 1

2. A sketch of the major components of the propellant feed mechanism . .. 3

3. An example OH absorption spectrum, taken in a CHSNO flame atatmospheric pressure ...................................... 4

4. Sample OH absorption data together with the least squares fit for anHMX1 propellant sample burning in 1.5 MPa nitrogen ............ 5

5. OH temperatures as a function of distance from the propellant surface . . 6

6. OH concentrations as a function of distance from the propellant surface 6

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vi

ACKNOWLEDGEMENT

We thank Dr. Tim Edwards of AFAL for supplying the HMX1 propellant used in this study.

vii

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viii

I. INTRODUCTION

Understanding a combustion event usually requires knowledge of the temperatures,species involved and their concentration profiles. Thermochemical equilibrium calculationswill produce final product species identity and concentration as well as adiabatic flametemperatures; however these results are not very event specific. Information about thedetailed chemical pathways from reactants to final products comes from studying thechemically active transient species. These species are generally present in small quantities(<1%) and exist primarily in a zone of small extent: the reaction zone.

The small concentrations of transient combustion species (radicals) renders the useof Raman techniques unattractive for concentration measurements. Non-linear techniquesare not considered since they are not simply related to concentration. Laser inducedfluorescence (LIF) and absorption have sufficient sensitivity for the detection of the radicalspecies. However, although LIF is a linear technique, it also is not simply related toconcentration because of the quenching effects on the excited state which are exacerbatedwith increasing pressure. Absorption is directly related to concentration and can provideuseful information under conditions where a line-of-sight measurement is meaningful.

This paper has a two-fold objective. First, an absorption technique is described whichcan simultaneously measure temperature and concentration profiles in time varying hostilecombustion environments. Second, the viability of this technique is demonstrated byobtaining temperature and OH concentration profiles from a solid propellant flame burningat elevated pressure. This absorption technique is a variation of the method described byLempert'. The present technique, however, has a different light source and detector whichallows the OH absorption spectrum to be obtained and analyzed in much more detail as wellas allowing different species to be studied with the same experimental setup. A descriptionof the absorption experiment and data analysis is given in the next two sections of thepaper.

II. EXPERIMENTAL

Many investigators have determined OH concentrations from the absorptions in the306.4 nm system using lamp light sources and a photomultiplier detector. The presentarrangement incorporates a high intensity mercury-xenon arc lamp light source but thedetector is an intensifiedphotodiode array which can be Photod,ode rray Mercury-xenonmuch more suitable for probing GaC lamptransient combustion processes. As Strand Burner

an indication of the sensitivity of CYL1 L2 L2 Lens

the experimental technique, 0 D..... .absorptions of 0.15% were readily

detectible in a steady state flame L Pinhole

environment. The optical path for Sampe

the absorption measurements of Fire 1 The light path for the optical absorption experiments. The glass

propellant burning within a filter (GF) was used to eliminate first order light when operating the

pressurized combustion vessel is spectrometer second order; the sample is either a premixed flame or

shown on Fig. 1. Two 20 cm focal pelat

1

length convex lenses (L2) focus and recollimate the light beam from the 1 kw mercury-xenon arc lamp and two apertures and a 0.15 mm pinhole confine the spatial extent toapproximately 0.15 mm in the burning direction. The aperture between the sample and thespectrometer minimizes collection of emission signal and the 10 cm focal length cylindricallens (CYLl) focusses the transmitted light onto the spectrometer entrance slit. Aperturesizes (A) between 0.5 and 1.0 mm were used to keep the emission signal levels to less than2% of the absorption signal. In actuality the aperture size was set from the results obtainedfrom a CH.JN20 flame, and it was assumed that the propellant would be similar in thisrespect. The spectrometer has a 0.3 m focal length and a 2400 groove per mm gratingwhich when operated second order gave a spectral resolution of about 0.03 nm with a 0.025mm entrance slit. This system allows a 6 nm band of light to be sampled at one time onthe intensified photodiode array. A uv transmitting black glass filter (Schott UG-11)eliminated first order light from entering the spectrometer. OH rotational absorptions ofinterest are much narrower than this 6 nm band; thus intensities of wavelengths whichundergo absorption, and nearby wavelengths which do not, can be recorded simultaneously.The system therefore provides a simple calibration of effective incident intensity in caseswhere continuous absorbers or scatterers inter,',%re.

Two combustion systems have been experimentally studied: a premixed CHJN20flame and a solid propellant flame. The solid propellant (HMX1)2 is composed of 73%cyclotetramethylenetetranitramine (HMX). The CHJN20 flame has been used primarily forcalibration and comparison purposes where a path length has been chosen similar to thepath length used for the propellant absorption studies. A burner consisting of many smallholes within a 0.4 cm diameter (the path length) was used to support this premixed flame.The top of the combustion vessel is removable and thus this flame can be placed at thesample location for experimentation. Long path lengths are traditionally desirable for tracespecies since, for small absorptions, the absorption increases linearly with path length.However, in these studies the overriding concern was to produce a horizontal burningpropellant surface, ie., a surface which is parallel to the direction of the arc lamp lightbeam. This condition could only be obtained for small cross sections. An HMX1 propellantgeometry which exhibited a reasonable cigarette fashion burn and was thus used, was astrand about 4 cm long with an octagonal cross section that measured 0.65 cm betweenopposing faces. The propellant strand was coated with a thin layer of fingernail polish toinhibit side burning.

A partial diagram of the windowed combustion vessel is shown in cross section onFig. 1. This vessel is made from stainless steel with two pairs of opposing windows andprovides an environment to burn propellants at an elevated pressure. An exit orifice in thevessel allows a purge gas to be flowed at rates typically about four times the propellantgasification rate. A video camera (not shown) provides a photographic record of eachpropellant burn. This record provides the burning rate of the propellant as well as visualinformation on the "flatness" of burn. Further details of the combustion vessel can be foundelsewhere.3 ,

4

Propellant burning in this experiment is a transient process since the burning surfaceregresses with time. This limits the amount of time that data can be taken depending onthe amount of spatial resolution desired. The first studies of OH in a propellant producedmarginally acceptable data and thus a propellant feed mechanism was incorporated into the

2

experiment to expand the data acquisitiontime. A sketch of the feed mechanism is IGNITON WI ___ __ M

shown on Fig. 2. This mechanism is more ,,OL AT

rudimentary than previous feedmechanism , in several respects. First, SWAM

the feed mechanism is not enclosed in the S ,L M

pressure vessel, but rather couples inlinear motion by a drive shaft sealed with TR

a plastic ferrule swage. Second, the driveshaft is unidirectional during theexperiment with the feed rate and traveldistance having been programmed into the - 2 A sketch of the mqor components of the propellant

speed control. Instead of maintaining an feed mchanism and asemated. components that are trinred atoptical feedback control, the feed rate is various time. during the course of an experimental ru.

set to be some large fraction of thepropellant burn rate. For the experiments reported here the speed controller wasprogrammed to drive the translator at a linear rate of 1.00 mm/s. The apparent burn rate,as viewed by a video camera, was measured as 0.27 mm/s which means the actual burn rateof HMX1 in a combustion vessel pressurized to 1.5 MPa nitrogen is 1.27 mm/s.

The following sequence of events occur for a typical propellant burn experiment. Thecombustion vessel is pressurized to 1.5 MPa nitrogen and the video recording system isactivated. A master switch engages the power to heat the ignition wire and also starts thetime sequencer. After preset delays the time sequencer starts the propellant feed andtriggers the photodiode array control. The apertured light from the arc lamp is terminatedby the propellant strand at the beginning of each experiment and the initial passage of thislight to the detector indicates when the propellant surface is in the sampling region. Thephotodiode array repetitively scans and resets many times while storing each scan intobuffer memory. The total data accumulation time as well as the time for each scan can bevaried over a wide range. Total data accumulation times were major fractions of the totalpropellant burn time, ranging from 15 to 20 seconds.

III. DATA ANALYSIS

In this section working equations are presented which are used to extracttemperatures and absolute concentrations from experimental absorption spectra. Thedevelopment and detailed discussions of these equations can be found elsewhere. 7,' Basedon the differential absorption law for a parallel beam of light of frequency L, traveling inthe +x direction through a medium with absorption coefficient k(v),

-dI = I kM.) dx ,

the intensity of the incident beam, IL (assumed to be constant), is attenuated along a path

of length I according to

I = I exp[-Ik(p)] .

Assuming a Boltzmann distribution the transmitted intensity of a group of lines is given by

3

I(v) = L exp{ -(hvi /c) [NT/Q(T)] [ . Bj gj exp(-Ej /kT) Pj(v)] ,

where h is Planck's constant, c is the speed of light, k is the Boltzmann constant, T is theabsolute temperature, B, is the absolute Einstein coefficient of absorption for the jthtransition in energy density units, gj is the degeneracy of the jth sublevel and E, its energy.NT is the total number density, Q(T) is the partition function which is evaluated using astandard closed form expression, and Pj is the transition lineshape. For conditions wherethe light source and spectrometer bandwidth is much larger than the width of a typicalabsorption line, an instrument function, S(v,v), centered at &,. and normalized to unit areais introduced to give

I, S(vvo)IG') dv,

where I, is the integrated light transmitted.

The Einstein coefficients for OH are from Dimpfl and KinseyO and the transitionfrequencies are from Dieke and Crosswhite'0 . 126 transitions of the A-X (0,0) band areincluded in the calculation, although typically only 90 are used for the range of data selectedfor analysis. Other molecule specific parameters are from Huber and Herzberg". Amultiparameter, nonlinear, I ist squares program with interactive graphics running on a386/25MHz PC was used to fit the data. Since the width of the instrument function, takento be Lorentzian, is larger than the transition linewidth, and in order to reduce computationtime, the transition lineshape was approximated as a delta-function, thereby reducing theabove integral to a sum. Using this model, the time to fit a spectrum was 10 minutes orless. Further details about the fitting procedure are found in the Appendix.

IV. RESULTS

Previously, OH concentrationsfor an HMX propellant have beencomputed from peak absorptions of "--

the Q2 bandhead in the A-X (0,0)vibrational band system for OH. 094

There the experimental data were not 092

sufficiently resolved for thedetermination of temperature and -0-0 . •thus it was necessary to construct atemperature profile by other means4. oMOnly for a CHSN 2O flame were thedata of sufficient quality to calculate 0."

a temperature from a Boltzmannplot4. We report here simultaneous 3077 0 301 309 3092 30 95 ,0,

temperature and concentrationdeterminations for both a steady WAVELENGTH /

Figure S Absorption spectrum of the A-X (0,0) band system of OHstate CH./N2O flame and a solid taken I mm above the burner surface of a premixed CH.NO flame. (a)propellant flame. An example OH is the data and the solid line is the least squares fit.

4

absorption spectrum, taken in a CH4 /N20 flame at atmospheric pressure, is shown in Fig.3. The absorption path length for this flame was 0.4 cm and one second was required toobtain the data. All of the absorptions observed experimentally on Fig. 3 are accounted forby the fitting program. Thus there is reasonable confidence that the discrete absorptionsover the wavelength range from 307.7 to 310.1 nm are due solely to OH. A value of 2367K has been determined for the temperature of this small premixed flame. All least squaresfitted values and the standard deviations are given in Table 1. This value is in goodagreement with prior determinations 4 of temperature for this flame which gave 2360 K and2304 K obtained from Boltzmann plots of peak rotational values for OH emission andabsorption, respectively. The adiabatic flame temperature for a stoichiometric CHdN 20 flameis 2922 K; however, this flame was strongly burner stabilized and, as has been found withother burner stabilized flames1, can have substantial heat loss to the burner head. Althoughthe purpose of using a small steady state flame was only for setting up for propellantmeasurements, the absolute concentration determination for OH agrees well with publishedtrends. That is, the fitted value of 3.9x10 s molecules/cc is about 1.7 times larger than thethermochemical equilibrium value13 and is very similar (1.5 times) to the peak concentrationof OH 12 reported for a stoichiometric CH4/N20 flame operating at atmospheric pressure.

Sample OH absorption data together with the least squares fit for an HMX1propellant sample burning in 1.5 MPa nitrogen are shown on Fig.4. The fitted values forthe spectrum of Fig. 4 and for eight other spectra at different positions from the propellantsurface are tabulated in Table 1. It was necessary to accumulate data for timescorresponding to movement of thepropellant surface in order to obtainstatistically reasonable data; hence 096-

the propellant spectrum of Fig. 4 isan average over 0.4 mm. Here again 094

for the propellant case all of theprominent features over the 092

wavelength range from 307.9 to310.3 nm have been accounted for 090 .with the OH fitting program.Temperatures and OH concentrationswith their standard deviations havebeen tabulated in Table 1 and are 0 1

plotted on Figs. 5 and 6. The 307.9 3082 8. 091 094 3097 310,0 31o3

temperature rise from the propellant WAVELENGTH / nsurface to the final flame Figure 4 Same a Fig. 3 except here the sample in an IIX1 propellant

temperature occurs within 0.4 mm of burni in 1.5 MPa N, from 0.4 to 0.9 mm above the propeHant swface,the propellant surface. Within the corresponding to a data acquisition time of 1.6 seonds.

statistical uncertainty of the data thefitted temperature reaches theadiabatic flame temperature. It also appears from Fig. 5 that the temperature is slightlydropping with increasing distance from the propellant surface. These temperaturemeasurements can be directly compared with the recent results obtained by Stufflebeam andEckbreth14 . Using a CARS technique they have measured temperatures in HMX1 propellantsburning in 2.31 MPa helium. Values ranging from 2600 K at 2.4 mm from the propellantsurface to 1900 K at 12 mm from the surface were observed. The present data are in

5

excellent agreement with Table I Temperature and OH concentration values and standard deviationm obtained

these published results. from fitting OH absorption spectra.

OH concentrationsas a function of distancefrom the propellant surface System Distance Tenperature OH Concentration

are shown on Fig. 6. A 16rise in OH concentration MM K 10 moLecules/cc

can be observed at CH / N 0 1 2356(124) 3.9(0.2)

distances less than about 1 4 2mm from the propellant 0- 0.4 2739(281) 1.50.2)surface and theconcentration decreases 0.4 - 0.9 2512(015) 2.5(0.1)

further from the propellant 0.9 - 1.8 2690(116) 2.8(0.2)

surface due to cooling ofthe flame. Together with 1.8- 2.7 2540(103) 2.7(0.1)these data are dashed lines x 2.7 3.6 2479014) 2.20.1)which represent calculatedOH concentrations 3.6 - 4.5 2704(131) 2.2(0.1)

assuming thermochemical 4. 5.4 203(103) 1.6(0.1)equilibrium. The threeconcentrations computed 5.4 - 6.3 2290107) 1.7(0.1)

are for temperatures of 6.3 - 7.2 j 2437(176) 1.2(0.1)

2617 (adiabatic), 2500 and2400 K. Thus it is seenfrom Fig. 6 that the OHconcentrations computedfrom fitting OH absorption spectra fall in a thermochemical equilibrium concentration rangefrom slightly above 2500 K to about 2400 K. Although the standard deviation in the OHconcentration determinations do not allow for concentrations high enough to satisfy anadiabatic flame temperature, the total error in the OH concentration determination isestimated to be a factor of two. This additional uncertainty comes from the path length and

3100

2900 ............ ..........-- -- - Ll- - --.....

27T - T

T-2500 x

0 1 2 3 4 5 6 7 0 1 2 3

Noitonce from Prapellont Surface / mm D(stoce from Prolalont Surfoe / -m

FJgure 5 Temperature a a function of distance from the Figure 6 Concentration as a function of distance from thepropellant surface for an HMXI1 propellant burning in 1.5 propellant surface corresponding to the temperatures inMPa nitrogen. (a) represent the temperature data which Fig. 5.is tabulated in Table 1.

6

lineshape variables which affect the concentration determination much more than thetemperature. A factor of two uncertainty in experimental OH concentration does includethe computed OH equilibrium concentrations appropriate for the adiabatic flametemperature. There is no known direct comparisons for absolute OH concentrationsmeasured in a solid propellant flame except for some of our previous work 4 using only apeak absorption of the Q, bandhead at 309 nm. Here concentrations for OH in HMX1burning in 1.5 MPa nitrogen were about a factor of two smaller than those presented here.The difference in these results is primarily the result of using a Lorentzian instrumentfunction for the present study, rather than the triangular function previously used.

V. SUMMARY

Temperature and OH concentration profiles have been obtained for a solid propellantburning at elevated pressure using a sensitive absorption technique together with leastsquares fitting of a number of rotationally resolved lines. The rather coarse spatialresolution of 0.4 mm compromised the ability to observe the initial rise in temperature andOH concentration however, because OH varies slowly in comparison to many other radicalspecies (after this initial rise), it is believed that the rest of the profile is adequatelyrepresented. Both the temperature and concentrations obtained are consistent with thissolid propellant flame burning at its adiabatic flame temperature, and an OH concentrationin thermochemical equilibrium.

7

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REFERENCES

1. Lempert, W. R.: Microwave Resonance Lamp Absorption Technique for Measuring Temperatureand OH Number Density in Combustion Environments, Combust. Flame, 73, 89 (1988).

2. Edwards, J. T.: Solid Propellant Flame Spectroscopy, AFAL-TR-88-076, 1988.3. Vanderhoff, J. A.: Spectral Studies of Propellant Combustion: Experimental Details and

Emission Results for M-30 Propellant, BRL-MR-3714, 1988.4. Vanderhoff, J. A.: Spectral Studies of Solid Propellant Combustion II. Emission and Absorption

Results for M-30 and HMX1 Propellants, BRL-TR-3055, 1989.5. Rekers, R. G. and Villars, D. S.: Flame Zone Spectroscopy of Solid Propellants, Rev. Sci.

Instrum., 25, 424 (1954).6. Edwards, T. J., Weaver, D. P., Adams, R., Hulsizer, S., and Campbell, D. H.: High-

Pressure Combustor for the Spectroscopic Study of Solid Propellant Combustion Chemistr, Rev.Sci. Intrum., 56, 2131 (1985).

7. Mitchell, A. C. G. and Zemansky, M. W.: Resonance Radiation and Excited Atoms,Cambridge University Press, 1971.

8. Lucht, R. P., Peterson, R. C. and Laurendeau, N. M.: Fundamentals of AbsorptionSpectroscopy for Selected Diatomic Flame Radicals, PURDU-CL-78-06, 1978.

9. Dimpfl, W. L. and Kinsey, J. L.: Radiative Lifetimes of OH (A22) and Einstein Coefficientsfor the A-X System of OH and OD, J. Quant. Spec. Radiat. Transfer, 21, 233 (1979).

10. Dieke, G. AND Crosswhite, H.: The Ultraviolet Bands of OH: Fundamental Data, J. Quant.Spec. Radiat. Transfer, 2, 97, (1963).

11. Huber, K. P., and Herzberg, G.: Molecular Spectra and Molecular Structure. IV. Constantsof Diatomic Molecules, Van Nostrand Reinhold Company, 1979.

12. Anderson, W. R., Decker, L. J., and Kotlar, A. J.: Temperature Profile of a StoichiometricCHJN 20 Flame from Laser Excited Fluorescence Measurements on OH, Combust. Flame, 48,163 (1982).

13. Svehla, R. A. and McBride, B. J.: Fortran IV Computer Program for Calculation ofThermodynamic and Transport Properties of Complex Chemical Systems, NASA-TND-7056,1973.

14. Stufflebeam, J. H. and Eckbreth, A. C.: CARS Measurements of High Pressure SolidPropellant Combustion, Combust. Sci. Technol., 66, 163, (1989).

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APPENDIX

Comparison using delta-function or Voigt lineshapes for fitting OH experimental spectra.

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12

APPENDIX

Comparison using delta-function or Voigt lineshapes for fitting OH experimental spectra.

In order to verify the validity of using the delta-function approximation for the transitionlineshapes, a typical flame spectrum was fitted using both the delta-function and a Voigtlineshape for the transitions. The comparison of the parameters that were determined orfixed in the fit is given in Table 2. The parameters in Table 2 with standard deviations(±1a) are those that were allowed to float during the fit. Seven parameters were fitted

T"bl 2 Comparison obtained from fitting a typical flame spectrum using either a Voigt or a delta-fuinctiontransition lineshape.

VOIGT LINESHAPE DELTA-FUNCTION LINESHAPE

FINAL STANDARD FINAL STANDARDNAME VALUE DEVIATION VALUE DEVIATION DIFFERENCE

TEMP 2220.86343 90.74400 2262.57580 92.97000 1.8782%NTOT 3.91337E+16 1.50E+15 3.73733E+16 1.51E+15 -4.4986%RCH 550.113341 0.04223 550.82424 0.04242 -0.0017%RLAM 3089.80000 3089.80000INC 0.07514 3.624E-5 0.07514 3.669E-5 0.0009%SLIT 0.26855 0.00110 0.28312 0.00441 5.4253%LGTH 0.40000 0.40000AD 0.96647 0.00164 0.96616 0.00165 -0.0323%Al -1.43822E-5 2.900E-6 -1.45467E-5 2.943E-6 1.1438%TAU 0.17963 0.01727 N/ARERR 1.OO0OOE-4 N/ASTD 0.00502 0.00508XNIN 3077.33927 3077.33941 0.0000%XMAX 310.4.01394 3104.01528 0.0000%

time -4-8 hrs. -1 min.

The parameter ines used in fth fitn program are retained in thes table: TEMP. temperature (K); NTOT, total number density(molecmlcc); RICH, reference ctwinell corresponding to RLAM, reference wavelength (A); INC, wavelength icrement per channel(A); SLIT. intrumeri fwiction FWHM (A); LGTH. absorption pathenth (cm): AO and Al. ortart and firt order baseine coefficients;TAU, Lorentzian FWHM (cm 1); RERR. relative error of the numerical integration. STD. standard deviation of t ft., XMIN and XMAXmnum end maximum wavelength (A) of the fitted portion of t spectnrum. The approxim~ate time for one Iteration of the ft a also

using the delta-function lineshape; an additional parameter, the Lorentzian linewidth of theVoigt profile, TAU, was also fitted when a Voigt lineshape was used for the transitions. Ofthe seven common parameters fitted in both cases, the two of primary interest are thetemperature, TEMIP, and the total number density, NTOT. The other five parameters arerelated to the particular conditions under which the experiment was performed. The largestdifferences are associated with those parameters most closely dependent on the value of thetransition linewidth, L~e. the width of the instrument function (SLIT) and the total numberdensity. The differences in these parameters obtained using the computationally lessdemanding delta-function lineshape as opposed to the more accurate Voigt lineshape are ca.5% and -4% respectively. A single temperature is obtained from the fit using the Voigtprofile since both the rotational temperature, and the translational temperature which

13

determines the Doppler width in the Voigt profile, are assumed to be the same value; also,the pressure broadened (Lorentzian) linewidth is assumed to be the same for all therotational lines. The approximate time of a least squares iteration for each model is alsogive in Table 2. Since typically 5-10 iterations are needed to refine a fit, the desirabilityof using the delta-function model for routine data analysis is apparent.

14

No of No ofCpjm Qxzan do Organization

Office of the Secretary of Defense 1 DirectorOUSD(A) US Army Aviation ResearchDirector, Live Fire Testing and Technology ActivityATTN: James F. O'Bryon Ames Research CenterWashington. DC 20301-3110 Moffett Field, CA 94035-1099

2 Administrator 1 CommanderDefense Technical Info Center US Army Missile CommandATIN: DTIC-DDA ATTN: AMSMI-RD-CS-R (DOC)Cameron Station Redstone Arsenal, AL 35898-5010Alexandria, VA 22304-6145

1 CommanderHQDA (SARD-TR) US Army Tank-Automotive CommandWASH DC 20310-0001 ATTN: AMSTA-TSL (Technical Library)

Warren, MI 48397-5000CommanderUS Army Materiel Command I DirectorATTN: AMCDRA-ST US Army TRADOC Analysis Command5001 Eisenhower Avenue AITN: ATAA-SLAlexandria, VA 22333-0001 White Sands Missile Range, NM 88002-5502

Commander (Cl--. only) 1 CommandantUS Army Laboratory Command US Army Infantry SchoolATTN: AMSLC-DL ATTN: ATSH-CD (Security Mgr.)Adelphi, MD 20783-1145 Fort Benning, GA 31905-5660

2 Commander (0RL& ouly) I CommandantUS Army, ARDEC US Army Infantry SchoolATTN: SMCAR-IMI-I ATTN: ATSH-CD-CSO-ORPicatinny Arsenal, NJ 07806-5000 Fort Benning, GA 31905-5660

2 Commander I Air Force Armament LaboratoryUS Army, ARDEC ATTN: AFATL/DLODLATTN: SMCAR-TDC Eglin AFB, FL 32542-5000Picatinny Arsenal, NJ 07806-5000

Aberdeen Proving GroundDirectorBenet Weapons Laboratory 2 Dir, USAMSAAUS Army, ARDEC ATTN: AMXSY-DATTN: SMCAR-CCB-TL AMXSY-MP, H. CohenWatervliet, NY 12189-4050 1 Cdr, USATECOM

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and Chemical Command SMCCR-MUATTN: SMCAR-ESP-L SMCCR-MSIRock Island, IL 61299-5000 1 Dir, VLAMO

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15

No. of No. of

Copes Organization Coies Orzanization

4 Commander 2 CommanderUS Army Research Office Naval Surface Warfare Center

ATTN: R. Ghirardelli ATTN: R. Bernecker, R-13

D. Mann G.B. Wilmot, R-16R. Singleton Silver Spring, MD 20902-5000

R. ShawP.O. Box 12211 5 CommanderResearch Triangle Park, NC Naval Research Laboratory

27709-2211 ATTN: M.C. LinJ. McDonald

2 Commander E. OranArmament RD&E Center J. ShnurUS Army AMCCOM RJ. Doyle, Code 6110

ATTN: SMCAR-AEE-B, Washington, DC 20375D.S. Downs

SMCAR-AEE, 1 Commanding Officer

J.A. Lannon Naval Underwater Systems

Picatinny Arsenal, NJ 07806-5000 Center Weapons Dept.ATTN: R.S. Lazar/Code 36301

Commander Newport, RI 02840Armament RD&E CenterUS Army AMCCOM 2 Commander

ATTIN: SMCAR-AEE-BR, Naval Weapons Center

L Harris ATTN: T.Boggs, Code 388Picatinny Arsenal, NJ 07806-5000 T. Parr, Code 3895

China Lake, CA 93555-6001

2 CommanderUS Army Missile Command 1 SuperintendentAMTN: AMSMI-RK, D.J. Ifshin Naval Postgraduate School

W. Wharton Dept. of Aeronautics

Redstone Arsenal, AL 35898 ATTN: D.W. NetzerMonterey, CA 93940

CommanderUS Army Missile Command 4 ALLSCF

ATMN: AMSMI-RKA, A.R. Maykut ATTN: R. Corley

Redstone Arsenal, AL 35898-5249 R. GeislerJ. Levine

Office of Naval Research Edwards AFB, CA 93523-5000

Department of the NavyATTN: R.S. Miller, Code 432 1 AL'MKPB800 N. Quincy Street ATTN: B. Goshgarian

Arlington, VA 22217 Edwards AFB, CA 93523-5000

Commander 1 AFOSR

Naval Air Systems Command ATN: J.M. Tishkoff

ATN: J. Ramnarace, Boiling Air Force Base

AIR-54111C Washington, DC 20332Washington, DC 20360 1 OSD/SDIO/UST

Commander ATTN: L CavenyNaval Surface Warfare Center Pentagon

AIMN: J.L East, Jr., G-23 Washington, DC 20301-7100Dahlgren, VA 22448-5000

16

No. of No. ofOrganization Copies Organization

Commandant 1 AVCO Everett ResearchUSAFAS Laboratory DivisionATTN: ATSF-TSM-CN ATTN: D. SticklerFort Sill, OK 73503-5600 2385 Revere Beach Parkway

Everett, MA 02149FJ. Seiler

ATTN: SA Shackleford 1 Battelle Memorial InstituteUSAF Academy, CO 80840.6528 Tactical Technology Center

ATITN: J. HugginsUniversity of Dayton Research Institute 505 King AvenueATTN: D. Campbell Columbus, OH 43201ALPAPEdwards AFB, CA 93523 1 Cohen Professional Service!

ATITN: N.S. CohenNASA 141 Channing StreetLangley Research Center Redlands, CA 92373Langley StationATITN: G.B. Northam/MS 168 1 Exxon Research & Eng. Co.Hampton, VA 23365 ATTN: A. Dean

Route 22E4 National Bureau of Standards Annandale, NJ 08801

ATTN: J. HastieM. Jacox I Ford Aerospace andT. Kashiwagi Communications Corp.H. Semerjian DIVAD Division

US Department of Commerce Div. Hq., IrvineWashington, DC 20234 ATTN: D. Williams

Main Street & Ford RoadAerojet Solid Propulsion Co. Newport Beach, CA 92663ATTN: P. MicheliSacramento, GA 95813 1 General Applied Science

Laboratories, Inc.Applied Combustion Technology, Inc. 77 Raynor AvenueATTN: A.M. Varney Ronkonkama, NY 11779-6649P.O. Box 17885Orlando, FL 32860 1 General Electric Armament

& Electrical Systems2 Applied Mechanics Reviews ATTN: MJ. Bulman

The American Society of Lakeside AvenueMechanical Engineers Burlington, VT 05401

ATTN: R.E. WhiteA.B. Wenzel I General Electric Ordnance

345 E. 47th Street SystemsNew York, NY 10017 ATITN: J. Mandzy

100 Plastics AvenueAtlantic Research Corp. Pittsfield, MA 01203ATTN: M.K. King5390 Cherokee Avenue 2 General Motors Rsch LabsAlexandria, VA 22314 Physics Department

ATTN: T. SloanAtlantic Research Corp. R. TeetsATTN: R.H.W. Waesche Warren, MI 480907511 Wellington RoadGainesville, VA 22065

17

No. of No. ofOrganization Covies Organization

2 Hercules, Inc. I Olin CorporationAllegheny Ballistics Lab. Smokeless Powder OperationsATN: W.B. Walkup ATTN: V. McDonald

E.A. You-' P.O. Box 222P.O. Box 210 St. Marks, FL 32355Rocket Center, WV 26726

I Paul Gough Associates, Inc.

Honeywell, Inc. ATTN: P.S. GoughGovernment and Aerospace 1048 South Street

Products Portsmouth, NH 03801-5423ATTN: D.E. Broden/

MS MN5O-2000 2 Princeton Combustion600 2nd Street NE Research Laboratories, Inc.Hopkins, MN 55343 ATTN: M. Summerfield

N.A. Messina

Honeywell, Inc. 475 US Highway OneATTN: R.E. Tompkins Monmouth Junction, NJ 08852

MN38-330010400 Yellow Circle Drive 1 Hughes Aircraft CompanyMinnetonka, MN 5534., ATTN: T.E. Ward

8433 Fallbrook AvenueIBM Corporation Canoga Park, CA 91303ATTN: A.C. TamResearch Division 1 Rockwell International Corp.5600 Cottle Road Rocketdyne DivisionSan Jose, CA 95193 ATTN: J.E. Flanagan/HB02

6633 Canoga Avenue

lI T Research Institute Canoga Park, CA 91304ATTN: R.F. Remaly10 West 35th Street 4 Sandia National LaboratoriesChicago, IL 60616 Division 8354

ATTN: R. Cattolica

2 Director S. JohnstonLawrence Livermore P. Mattem

National Laboratory D. StephensonATTN: C. Westbrook Livermore, CA 94550

M. CostantinoP.O. Box 808 1 Science Applications, Inc.Livermore, CA 94550 ATTN: R.B. Edelman

23146 Cumorah CrestLockheed Missiles & Space Co. Woodland Hills, CA 91364ATTN: George Lo3251 Hanover Street 3 SRI InternationalDept. 52-35/B204/2 ATTN: G. SmithPalo Alto, CA 94304 D. Crosley

D. GoldenLos Alamos National Lab 333 Ravenswood AvenueATTN: B. Nichols Menlo Park, CA 94025

T7, MS-B284P.O. Box 1663 1 Stevens Institute of Tech.Los Alamos, NM 87545 Davidson Laboratory

ATTN: R. McAlevy, III

National Science Foundation Hoboken, NJ 07030ATTN: A.B. HarveyWashington, DC 20550

18

No. of No. ofConies Organization Conies Organization

Thiokol Corporation 1 California Institute ofElkton Division TechnologyATTN: S.F. Palopoli ATTN: F.E.C. Culick/P.O. Box 241 MC 301-46Elkton, MD 21921 204 Karman Lab.

Pasadena, CA 91125

Morton Thiokol, Inc.

Huntsville Division 1 University of California,ATTN: J. Deur BerkeleyHuntsville, AL 35807-7501 Mechanical Engineenng Dept.

ATTN: J. Daily3 Thiokol Corporation Berkeley, CA 94720

Wasatch DivisionATTN: SJ. Bennett 1 University of CaliforniaP.O. Box 524 Los Alamos Scientific Lab.Brigham City, UT 84302 P.O. Box 1663, Mail Stop B216

Los Alamos, NM 87545United TechnologiesATN: A.C. Eckbreth 1 University of California,East Hartford, CT 06108 San Diego

A'ITN: F.A. Williams

3 United Technologies Corp. AMES, B010Chemical Systems Division La Jolla, CA 92093ATTN: R.S. Brown

T.D. Myers (2 copies) 2 University of California,P.O. Box :9028 Santa BarbaraSan Jose, CA 95151.9028 Quantum Institute

ATTN: K. SchofieldUniversal Propulsion Company M. SteinbergATTN: HJ. McSpadden Santa Barbara, CA 93106Black Canyon Stage 1Box 1140 2 University of SouthernPhoenix, AZ 85029 California

Dept. of Chemistry

Veritay Technology, Inc. ATTN: S. BensonATTN: E.B. Fisher C. Wittig4845 Millersport Highway Los Angeles, CA 90007P.O. Box 305East Amherst, NY 14051-0305 1 Case Western Reserve Univ.

Div. of Aerospace SciencesBrigham Young University ATTN: J. TienDept. of Chemical Engineering Cleveland, OH 44135ATTN: M.W. BecksteadProvo, UT 84601 1 Cornell University

Department of ChemistryCalifornia Institute of Tech. ATTN: T.A. CoolJet Propulsion Laboratory Baker LaboratoryATTN: L. Strand/MS 512/102 Ithaca, NY 148534800 Oak Grove DrivePasadena, CA 91009 1 University of Delaware

ATTN: T. BrillChemistry DepartmentNewark, DE 19711

19

No. of No. ofopies Organization Qooes Oranization

University of Florida I Polytechnic Institute of NYDept. of Chemistry Graduate CenterATTN: J. Winefordner ATTN: S. LedermanGainesville, FL 32611 Route 110

Farmingdale, NY 117353 Georgia Institute of

Technology 2 Princeton UniversitySchool of Aerospace Forrestal Campus Library

Engineering ATTN: K. BrezinskyATTN: E. Price I. Glassman

W.C. Strahle P.O. Box 710B.T. Zinn Princeton, NJ 08540

Atlanta, GA 303321 Purdue University

University of Illinois School of AeronauticsDept. of Mech. Eng. and AstronauticsATTN: H. Krier ATTN: J.R. Osborn144MEB, 1206 W. Green St. Grissom HallUrbana, IL 61801 West Lafayette, IN 47906

Johns Hopkins University/APL I Purdue UniversityChemical Propulsion Department of Chemistry

Information Agency ATT1N: E. GrantATTN: T.W. Christian West Lafayette, IN 47906Johns Hopkins RoadLaurel, MD 20707 2 Purdue University

School of MechanicalUniversity of Michigan EngineeringGas Dynamics Lab ATN: N.M. LaurendeauAerospace Engineering Bldg. S.N.B. MurthyATIN: G.M. Faeth TSPC Chaffee HallAnn Arbor, MI 48109-2140 West Lafayette, IN 47906

University of Minnesota 1 Rensselaer Polytechnic Inst.Dept. of Mechanical Dept. of Chemical Engineering

Engineering AT7N: A. FontijnATTN: E. Fletcher Troy, NY 12181Minneapolis, MN 55455

1 Stanford University3 Pennsylvania State University Dept. of Mechanical

Applied Research Laboratory EngineeringATrN: K.K. Kuo A1TN: R. Hanson

H. Palmer Stanford, CA 94305M. Micci

University Park, PA 16802 1 University of TexasDept. of Chemistry

Pennsylvania State University ATIN: W. GardinerDept. of Mechanical Engineering Austin, TX 78712ATTN: V. YangUniversity Park, PA 16802 1 University of Utah

Dept. of Chemical EngineeringATTN: G. FlandroSalt Lake City, UT 84112

20

No. of No. ofConies Orianization Conie Organization

I Virginia PolytechnicInstitute andState University

ATN: JA. SchetzBlacksburg, VA 24061

1 Freedman AssociatesATIN: E. Freedman2411 Diana RoadBaltimore, MD 21209.1525

21

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22

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I. BRL Report Number BRL-TR-3098 Date of Report APRIL 1990

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