Combustion, Explosion, and Shock Waves, Vol. 31, No. 3, 1995 NUMERICAL SIMULATION OF INVISCID FLOWS WITH HYDROGEN COMBUSTION BEHIND SHOCK WAVES AND IN DETONATION WAVES V. V. Vlasenko and V. A. Sabel'nikov UDC 530.46:662.3 A new numerical algorithm for simulation of nonequilibrium chemically reacting flows of an inviscid muIticomponent gas is described. Application of this algorithm to the numerical solution of several problems of air-hydrogen mixture combustion in oblique detonation waves is demonstrated. Numerical simulation of hypersonic flows of a real multicomponent gas with finite-rate chemical reactions is of both theoretical and practical interest. Extensive investigations to create an aerospace plane have been pursued in recent years. Here the development of a hydrogen-fueled hypersonic ramjet engine (scramjet engine) is a major problem. Nonequilibrium chemical processes occur in all elements of this engine: in an air inlet (air dissociation behind intense shock waves), in a nozzle (combustion product recombination), and, of course, in a combustor, where supersonic mixing and burning of the air-hydrogen mixture take place. The calculation of nonequilibrium hypersonic flows presents a number of severe difficulties. First of all, the dimensionality of the problem increases abruptly because one must monitor the concentrations of all the components of the reacting mixture. Then, the system of equations of chemical kinetics is of a rigid type, i.e., the physical phenomenon involves a few characteristic times differing from one another by a hundred times. The application of explicit numerical algorithms to the simulation of such processes is hardly possible because this requires a time step equal to the minimum characteristic time, whereas the use of implicit algorithms involves problems of inverting large-dimensionality systems of nonlinear equations and adequacy of a numerical solution. In view of the problem complexity it is expedient to begin with the development of efficient numerical methods for calculation of reacting flows of an inviscid gas. To solve this problem, one can use a reliable base, the well-developed numerical simulation of ideal inviscid gas flows. The main problems arising within the framework of the model of an inviscid reacting gas are related to the consideration of shock wave structures with heat release and, first of all, detonation waves. The combustion behind shock waves and in detonation waves can be used in scramjet combustors, while, as noted in [1, 2], an oblique-detonation-wave engine is more promising for flight Mach numbers Moo > 15. That is why the numerical simulation of inviscid reacting flows is of scientific and practical interest. Let us mention some problems that call for solution: the interaction of detonation waves in an air-hydrogen mixture with combustor wails, flame stabilization behind a shock wave, i.e., combustion process localization and its maintenance in different regimes (for instance, under the conditions of a nonpremixed combustible mixture, with changing wedge angle, etc.). The present paper is devoted to the development of an efficient numerical method for calculation of reacting inviscid gas flows and numerical solution of the above problems. Zhukovskii Central Aerodynamic Institute, Zhukovskii 140160. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 3, pp. 118-133, May-June, 1995. Original article submitted November 15, 1993. 376 0010-5082/95/3103-0376512.50 Plenum Publishing Corporation