Numerical Simulation of Chemical Non-equilibrium Flow for Ablative Flow Fields in Near Space
DOI:
https://doi.org/10.5890/JEAM.2023.09.002Abstract
A numerical method has been established and applied to compute the chemical non-equilibrium flow involving ablative chemical reaction and flow interference effect in near space, where the chemical non-equilibrium Navier-Stokes equation is solved by taking account of 23 species including the ablative products. The computational results of electron number density in plasma sheath for sphere-cone RAMC(Radio Attenuation Measurement C plan)-II are well compared with those of flight experiments. The reliability of the present method has been validated, and the varying feature of the electron number density with flight altitude has been revealed. The present numerical method is applied to compute the Teflon ablative flow field and flow interference in near space past sphere-cone body with different altitudes. It is indicated that the effect of ablative products on electron number density is mainly limited in the region of boundary layer while the phenomena of Teflon ablation are obvious at moderate and low altitudes. The decrease of temperature in the boundary layer is caused by the Teflon ablation which results in the increase of the number of negative ions. On the other hand, the number of chemical species F- increases continuously with the decrease of flight altitude resulted from the reaction between electron and electrophilic species of Teflon-air reactive mixtures. These factors cause the reduction of electron number density in the boundary layer, specially flow interference and characteristics around the wreckages generated by multiple disintegration of the Tiangong-type vehicle in expiration of service during off-orbit reentry.References
[1] Akey, N.D. (1971), Overview of RAM reentry measurements program, the entry plasma sheath and its effects on space vehicle electromagnetic systems, NASA Special Publication, 252, 19.
[2] Grantham, W.L. (1970), Flight results of a 25000-foot-per-second reentry experiment using microwave reflectometers to measure plasma electron density and standoff distance, (Vol. 6062). National Aeronautics and Space Administration.
[3] Hayes, D.T., Herskovitz, S.B., Lennon, J.F., and Foirier, J.L. (1974), An Ablation Technique for Enhancing Reentry Antenna Performance; Flight Test Results, Air Force Cambridge Research Laboratories, United States Air Force.
[4] Bhutta, B.A. and Lewis, C.H. (1991), A new technique for low-to-high altitude predictions of ablative hypersonic flowfields, AIAA, 91-1392.
[5] Bhutta, B.A. and Lewis, C.H. (1992), Low-to-high altitude predictions of three-dimensional ablative reentry flowfields, AIAA, 92-0366.
[6] Moretti, G. (1965), A new technique for the numerical analysis of nonequilibrium flows, AIAA, 3(2), 223-229.
[7] Dunn, M.G. and Kang, S. (1973), Theoretical and Experimental Studies of Reentry Plasmas (No. NASA-CR-2232), NASA.
[8] McBride, B.J., Zehe, M.J., and Gordon, S. (2002), NASA Glenn coefficients for calculating thermodynamic properties of individual species. NASA/TP-2002-211556.
[9] Gupta, R.N., Yos, J.M., and Thompson, R.A. (1989), A review of reaction rates and thermodynamic and transport properties for the 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K, NASA TM-101528.
[10] Qiao, Zh., Yang, A., and Zhu, B. (2003), Computation of the unsteady viscous flow about helicopter rotors in forward flight by a full implicit dual time method, AIAA Paper, 2003-4082.
[11] Kim, S.L. and Kim, I.A. (2003), Study on numerical characteristic of air chemistry and application of partially implicit method, AIAA Paper, 2003-6902.
[12] Shi, Y.Z., Zheng, Z.H., and Wu, Q.F. (1999), On chemical non-equilibrium vs flow over a Teflon ablative wall (in Chinese), Journal of National University of Defense Technology, 21(1), 1-3.
[13] Tang, J.R. and Peng, S.L. (2002), The effect of Teflon ablation on the electron density in viscous shock layer (in Chinese), Chinese Journal of Theoretical and Applied Mechanics, 34(6), 874-880.
[14] Evans, J.S. and Huber, P.W. (1963), Calculated radio attenuation due to plasma sheath on hypersonic blunt-nosed cone, NASA TND-2043.
[15] Schexnayder, C.J.J., Evans, J.S., and Huber, P.W. (1971), Comparison of theoretical and experimental electron density for RAM C flights, the entry plasma sheath and its effects on space vehicle electromagnetic systems, 1, NASA SP-252.
[16] Li, X.G., Yang, Y.G., Li, Z.H., and Pi, X.C. (2013), Design methods of the small size strain gauge balance, Journal of Experiments in Fluid Mechanics, 27, 78-82.
Article Metrics
Usage tracking begins September 1, 2026.