Prediction study of geometric optimization for an ejector nozzle with coupled flow-heat transfer method

In order to optimize geometric design for the flaps of an ejector nozzle, coupled computation investigations on flow field and solid temperature filed of the nozzle were conducted and presented in this paper. Finite volume method is employed to solve flow Navier-Stokes equations. For the calculation of convective fluxes, numerical dissipation in shear layer and total enthalpy non-conservation passing strong shock can be eliminated with the help of modified Roe scheme while the resolution of shock wave and entropy condition are satisfied. Diffusive fluxes are evaluated by central differencing scheme which can dispel possible odd-and-even decoupling modes. Time-stepping is executed using LUSGS implicit method with multigrid acceleration. Diffusive equation of solid temperature field is discretized applying central difference method of two order accuracy. Based on the prediction results, it can be concluded that short length relative to the baseline length for the second and the third flaps should be given priority as regards the geometric optimization of the nozzle flaps.