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DIRECT MEASUREMENT OF CONCENTRATION AT MIXING

IN THE HOT-SHOT FACILITY Goldfeld М.А., Starov А.V., Timofeev К.Yu.

Khristianovich Institute of Theoretical and Applied Mechanics

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Yang, M.L., Gu, S.J., Liu, G.E., Li, X.Y., "Trajectory with Diffusion Method for Predicting the Fuel Distribution in a Transverse Stream," AIAA Paper 83-0336, 1983.Shaikhutdinov, Z.G. and Klevanskii, V.M., "Penetration and Mixing of Liquid Injected into Supersonic Transverse Gas Stream" Izvestiya Vysshikh Uchebnykh Zavedenii Aviatsionnaya Tekhnika, Vol. 19, No. 1, 1976, pp. 99-108.Way J., Libby, P. Hot-wire probe for measuring velocity and concentration in helium-air jets mixture. AIAA J., 1970, Vol. 8, #3, pp. 976-978. Adler, D.A. A hot wire technique for continues measurement in unsteady concentration fields in binary gaseous mixture. J. Phis. 1972, Vol.5, pp.163-169.Brown, G., Rebollo, M. A small, fast-response probe to measure composition of a binary gas mixture. AIAA J., 1972, V.10, pp.649-652. Ahmed S., So R. M. Concentraion distribution in a model combustor. Experiments in Fluids, 1986, V. 4, #2, pp107-113. Ng, W. F., Kwok, F. T., and Ninneman, T. A. A Concentration Probe for the Study of Mixing in Supersonic Shear Flows, AIAA Paper 89-2459, July 1989. Ng, W. F., Epstein, A. A. High-frequency temperature and pressure probe for unsteady compressible flows. Review Sci. Instrumen., 1983, vol. 54, pp. 1678-1683.

Geometry of aspirating concentration probe

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Combustor model testing with kerosene fuel Injector Section

Attached pipeline operating mode

Test Parameters:

M= 2-3

P0= 10-50bars

T0= 1700-2500K0

1

2

3

4

5

6

0 20 40 60 80 100

min limit, M=2 max limit, M=2

min limit, M=2.5 max limit, M=2.5

P, bar

ms

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Combustor model testing with kerosene fuel at M=2

0

0.5

1

1.5

2

2.5

3

0 150 300 450 600 750 900

bottom, CI top, CI bottom, AR top, AR

0

1

2

3

4

5

0 150 300 450 600 750 900

10ms 25ms

45ms 75ms

Static pressure distribution along model xmm xmm

Phot/ Pcold Phot/ Pcold

Best variant of fuel injection: AR+NI Comparison of CI and AR

Flow visualization

Variants of fuel injections

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AIMS of investigations:

Determination of fuel mixing at supersonic velocities in channel

development of gas sampling system

tests in the hot-shot wind-tunnel with operating mode up to 100ms

determination of kerosene concentration in combustor sections at fuel supplying through aeroramp

determination of helium concentration at same conditions

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Gas sampling systemGas sampling system

Container for gas sample preservation with pressure gage

Sampling rake for gas probe

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Scheme of gas sampling Scheme of gas sampling systemsystem

1 – screw; 2 – nut; 3, 6 – piston; 4 – cylinder; 5 – connector; 7 – fixator;

8 – pirocartridge; 9 – sampling rake; 10 – packing ring.

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Concept of determination of kerosene Concept of determination of kerosene

quantityquantity

Flow visualization

Photo of installed sampling rake

The chemical analysis of samples mixture was carried out by means of gas chromatograph LHM-80МD. Accuracy of definition of concentration was less than 1%.

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Concentration distributionsConcentration distributions

Pt = 30атм, Tt= 2300K

ПоложениеОтносительная концентрация

ПоложениеОтносительная концентрация

ПоложениеОтносительная концентрация

11 1.294 21 1.055 31 0.932

12 1.271 22 1.320 32 1.178

13 0.181 23 0.386 33 0.915

Pt = 50атм, Tt= 2300K

Положение Относительная концентрация

11 1.051

12 1.535

13 0.403

Положение Параметры пускаОтносительная концентрация

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Pt = 50атм, Tt= 2300K 0.574

Pt = 30атм, Tt= 2300K 0.521

Pt = 30атм, Tt= 2000K 0.471

Таблица 1

Таблица 2 Таблица 3

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Concentration Concentration distributionsdistributions

Kerosene concentration distribution

Helium concentration distribution

Effect of flow parameters

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Developed gas sampling system allowed to obtaining the kerosene and helium distributions in combustor sections. Tests were carry out at M=3. It was investigated at conditions of hot-shot wind tunnel.

On the initial part of the channel in the region of a cavity the kerosene distribution on channel height is essentially non-uniformly. The difference of concentration reaches fivefold size. And in a cavity there is overrich mixture, and a poor mixture is in an opposite part of a flow. Further on length of the channel the kerosene portion in the bottom part of the channel increases, and above it decreases. Behind a cavity non-uniformity of the fuel concentration is decreased to 3.5 times differences on height. On distance of 217 mm from entrance kerosene is sufficiently uniformly distributed on cross-section of the channel with a difference no more than 25 %.

Change of parameters of an air flow has shown that the pressure increase at the channel entrance does not change qualitative distribution of kerosene on height (minimum of concentration in the bottom part of channel). There are only quantitative distinctions, in particular, fuel portion increasing in a flow core.

Measurements of concentration of helium have shown that in contrast to fuel with the big molecular weight, the helium portion in a flow core forms about 50 % from total amount of helium in the model channel. The increase of parameters of an air flow at the entrance leads to rather small (~20 %) growth of a helium size in the investigated section of the channel.

ConclusionsConclusions