EFFECT OF INFLOW CONDITIONS ON UNDER-EXPANDED SUPERSONIC JETS

Year 2012, Volume: 4 Issue: 1, 17 - 30, 01.03.2012

M.M. Ashraful Alam Toshiaki Setoguchi

Abstract

The present work involves numerical simulations to investigate the effect of inflow
condition on aerodynamic and shock characteristics of under-expanded turbulent jets
from sonic nozzle. The TVD finite volume method was carried out and two equation k-ε
turbulence model was used to model the turbulent stresses of the compressible flows in
the present simulations. The jet pressure ratio was settled from 1.893 to 6.0 for
generating perfectly expanded to moderately high under-expanded jets. The pressure and
Mach number distributions on jet axis, and the flowfield structure was visualized by
density distributions. The potential core and supersonic flow lengths were also
measured to make a quantitative investigation on the jet structure. The effect of inflow
condition at nozzle inlet was found to be pronounced resulting in the sonic line moved
upstream of the nozzle throat. Moreover, numerically predicted results were compared
with the experimental data to validate the present numerical code.

Keywords

Compressible flow, numerical analysis, potential core, shock wave, supersonic flow lengths

References

• [1] D’anbrosio, D., DeSocio, L.M. and Gaffuri, G., Physical and Numerical Experiments on an Under-Expanded Jet. Meccanica, 34, 267–280, 1999.
• [2] Love, E.S., Grigsby, C.E., Lee, L.P. and Woodling, M.J., Experimental and theoretical studies of axisymmetric free jets. NASA TR R-6, 1959.
• [3] Frauenberger, J.H. and Forister, J.G., The axial decay and radial spread of a supersonic jet exhausting into air at rest. Aeronaut. Q., 12, 131-149, 1961.
• [4] Addy, A.L., Effects of axisymmetric sonic nozzle geometry on Mach disk characteristics. AIAA J., 19(1), 121-122, 1981.
• [5] Kashitani, M., Miyazato, Y., Masuda, M. and Matsuo, K., Numerical and experimental investigations of supersonic jets from sootblower nozzle. JSME Intl. J., Series B, 41(2), 375-380, 1998.
• [6] Katanoda, H., Miyazato, Y., Masuda, M. and Matsuo, K., Pitot pressures of correctly-expanded and under-expanded free jets from axisymmetric supersonic nozzles. Shock Waves, 10, 95-101, 2000.
• [7] Kashitani, M., Yamaguchi, Y., Miyazato, Y., Masuda, M. and Matsuo, K., Mean-flow properties on high and low Reynolds number ideally
• expanded supersonic jets. AIAA-2001-1053, 2001. [8] Villermaux, E. and Rehab, H., Mixing in Coaxial Jets. J. Fluid Mech., 425, 161–185, 2000.
• [9] Sheeran, W. and Dosanjh, D., Observations on Jet Flows from a TwoDimensional, Under-expanded, Sonic Nozzle. AIAA J., 6(3), 540–542, 1968.
• [10] Chang, I.S. and Chow, W.L., Mach Disk from Under-expanded Axisymmetric Nozzle Flow. AIAA J., 12(8), 1079-1082, 1974.
• [11] Kim, H.D. and Shin, H.S., Numerical Study on Under-Expanded Jets through a Supersonic Nozzle (Part 2). J. Korea Society of Mech. Eng., Series B, 20(6), 1994-2004, 1996.
• [12] Kim, H.D. and Lee, J.S., An Experimental Study on Supersonic Jet Issuing from Gas Atomizing Nozzle (Part 1). J. Korea Society of Mech. Eng., Series B, 20(2), 677-709, 1996.
• [13] Mate, B., Graur, I.A., Elizarova, T., Chirokov, I., Tejeda, G., Fernandez, J.M. and Montero, S., Experimental and Numerical Investigation of an Axisymmetric Supersonic Jet. J. Fluid Mech., 426, 177-197, 2001.
• [14] Abbett, M., Mach Disk in Under-expanded Exhaust Plumes. AIAA J., 9(3), 512-514, 1971.
• [15] Davidor, W. and Penner, S.S., Shock Stand-off Distance and Mach Disk Diameters in Under-expanded Sonic Jets. AIAA J., 9(8), 1651- 1652, 1971.
• [16] Eastman, D.W. and Radtke, L.P., Location of the Normal Shock Wave in the Exhaust Plume of a Jet. AIAA J., 1(4), 918-919, 1963.
• [17] Crist, S. Sherman, P.M. and Glass, D.R., Study of the Highly Underexpanded Sonic Jet. AIAA J., 4(1), 68-71, 1966.
• [18] Launder, B.E. and Spalding, D.B., Lectures in Mathematical Models of Turbulence, Academic Press, London, England, 1972.
• [19] Launder, B.E. and Spalding, D.B., The Numerical Computation of Turbulent Flows. Comp. Meth. Appl. Mech. Eng., 3, 269-289, 1974.
• [20] Roe, P.L., Approximate Riemann solvers, parameter vectors, and difference schemes. J. Comput. Phys., 43, 357-372, 1981.
• [21] van Leer, B., Towards the ultimate conservative difference scheme V. A second order sequel to Godunov's method. J. Comput. Phys., 32, 101-136, 1981.
• [22] Pandya, S.A., Venkateswaran, S. and Pulliam, T.H., Implementation of dual-time procedures in overflow. Technical Report AIAA-2003-
• [23] Turkel, E. and Vatsa, V.N., Choice of variables and preconditioning for time dependent problems. Technical Report AIAA-2003-3692, 16th AIAA Comp. Fluid Dyn. Conf., Orlando, Florida, June 2003.
• [24] Kweon, Y.H., Miyazato, Y., Aoki, T., Kim, H.D. and Setoguchi, T., Experimental investigation of nozzle exit reflector effect on supersonic jet. Shock Waves, 15, 229-239, 2006.