Investigation on Aero-optical Effect in the Reaction Flow Field of DLR Combustor

摘要

The DLR supersonic combustor’s flow field is simulated to analyze theaero-optical effect in the supersonic combustion chamber. Steady twodimensionalReynolds-averaged Navier-stokes (RANS) simulation and SST𑘠− 𜔠turbulence model are applied to predict the shock structure andcombustion phenomenon inside the scramjet combustor. Eddy dissipationalong with finite rate chemistry model is used as a combustion model forsupersonic combustion. The aero-optical effect is analyzed by the geometryray-tracing method. Optical path difference (OPD) and its root-mean-squaredvalue (OPD_(rms) ) are the parameters that evaluate the magnitude of opticaldistortion in this paper. By changing the inlet Mach number, the strut width,H, and the injection slit width, S, the influence of the flow field structure onthe optical distortion in the combustion chamber is studied. Present resultsshow that, in cold flow, the optical distortion decreases with Mach numberand S, while climbs with the growth of H. Combustion will increase themagnitude of aero-optical distortion, and the more intense the combustion,the larger the distortion. The OPD_(rms) in reaction flow are 1.4% to 12.05%larger than those in cold flow. In reaction flow, the optical distortion decreaseswith Mach number and increases with H and S. Compared with the obliqueshock and the recirculation region, the distance between the two shear layershas a greater influence on OPD_(rms). The OPD_(rms) with the maximum H is10.27% larger than that with minimum H. Besides, this paper has a guidingsignificance for the correcti