Background and prediction of correct full-scale reproduction in wind tunnels as concerns gas dynamic parameters of hypervelocity atmospheric flights and scramjet combustion chamber conditions

The report analyzes possible schemes of aerodynamic rigs intended for reproducing gas dynamic parameters (velocity, density, pressure, and temperature) and chemical air composition as applied to the TAV trajectory with the indication of required stagnation parameters (P₀, T₀). Based on the calculation of physico-chemical processes taking place in nozzles of classical facilities it is inferred that the chemical air composition differs noticeably from the natural air composition even in solving the problem of producing and retaining the gas in the plenum chamber at ultrahigh temperatures and pressures (T₀⩾7000 K, P₀⩾4·10⁸ Pa). The analysis carried out reveals a distinct advantage of MHD-gas acceleration facilities in solving the stated problem. A set of equations of magnetogasdynamics and multitemperature physico-chemical kinetics which underlie the computation program is presented. The channels of energy transport from the electromagnetic field to the gas at different gas densities are considered. The program was compiled using the experimental data obtained in the TsAGI MHD-gas acceleration hypersonic wind tunnel. The report presents the calculated data on gas acceleration regimes in a wide spectrum of initial conditions and electrodynamic parameters. The consideration of nonequilibrium physico-chemical processes in the MHD-channel and in the secondary nozzle makes it possible to state that the nonequilibrium effects facilitate considerably the reproduction of a natural chemical air composition and a static temperature in the facility test section. The influence of alkali seeds on the induction time and hydrogen burning process in the scramjet combustion chamber is evaluated. Possible technical approaches to the realization of calculated versions of MHD-accelerators are analyzed