Numerical Analysis Of Chemical Non-equilibrium Flow In Nozzle/afterbody Of An Airbreathing Hypersonic Vehicle

Nozzle/afterbody is an important part of the airbreathing hypersonic vehicle which produces thethrust, the lift, and the moment, and the flow in the nozzle is complicated. The effect of thenon-equilibrium flow and non-uniform flow on the thrust, the lift, and the moment has beeninvestigated. Numerical analysis was firstly undertaken considering the effect of the chemicalnon-equilibrium flow. The basic scheme which contains seven reactions and thirteen elements forfinite rate hydrogen-oxygen reaction chemistry was used. The effect of nozzle freezing,‘kineticafter-burning’ and the oxygen atom concentration on the burning position has been analyzed. And，thenumerical results closely match the experimental results from Stalker R. J. So the numerical methodsused are feasible. Based on the chemical non-equilibrium analysis, the non-uniform flow conditionswere adopted for further numerical simulation. The non-uniform conditions were deduced by totalmomentum conservation and total mass conservation. The flow field parameters and the aerodynamiccoefficients were obtained at a series of non-uniform flow conditions. The contrast between thenon-uniform and uniform entrance cases show that the position of the thrust loss is near the entrance,however on the middle and the back of the nozzle surface the pressure distributions are almost thesame. The distribution of the thrust coefficient, the lift coefficient and the moment coefficient may bevaluable to control thrust losses on nozzle/afterbody.