RESEARCH ON THE AERO-HEATING AT THE SHARPENED LEADING EDGE BASED ON NONLINEAR COUPLED CONSTITUTIVE RELATIONS

The aerodynamic heating effect of a representative sharpened leading-edge model under hypersonic continuous/rarefied flow conditions is investigated through the integration of numerical simulation and wind tunnel testing methodologies in this study. Based on a three-dimensional finite volume framework, the sharpened leading-edge model is numerically analyzed using the nonlinear coupled constitutive relations (NCCR) model, facilitating the accurate representation of local rarefied non-equilibrium flow and surface heat flux. The performance of the NCCR model in describing the sharpened leading-edge is evaluated and corroborated in comparison with the experimental data. Under wind tunnel test conditions at an equivalent altitude of 33 km, it is observed that the discrepancy between the peak heat flux coefficient at the stagnation point computed by the NCCR model and the experimental data is a mere 1.81%. Moreover, the peak heat flux coefficient at the stagnation point obtained by the Fay-Riddell formula and the Navier-Stokes (NS) equations is within 5% according to the experimental value, the coefficient of heat flux at other locations on the surface is also well maintained from the experiment value, i.e., the deviations is within a range of 10%, which proves that the local rarefied gas effect near the sharpened leading-edge of the aircraft has a weak effect on aerodynamic heating. In contrast, at an equivalent altitude as high as 60 km, the effect of local rarefied gas near the sharpened leading-edge on aerodynamic heating is obvious, and the deviation between the coefficient of heat flux at the stagnation point with the help of the NS equations and the experimental data amounts to 33.31%. The deviation of the peak heat flux coefficient at the stagnation point calculated by the Fay-Riddell formula is 29.5% in terms of the experimental value. However, the variation in stagnation heat flux coefficient obtained from the NCCR model remains comparatively low at 11.77%. It shows the advantage of the NCCR model for solving rarefied nonequilibrium flows.