基于OpenCFD-Comb的高焓湍流边界层气体注入的直接数值模拟OA

Cooling-gas injection is crucial to the thermal protection of hypersonic vehicles.As a commonly used coolant,air contains N2 and O2,which exhibit different chemical reactivities under temperature conditions where N2 dissociation is not yet significant.Understanding their behavior in high-enthalpy turbulent boundary layers is of practical importance for vehicle thermal management under realistic flight conditions.Using OpenCFD-Comb,an open-source high-order solver for chemically reacting turbulence developed by our group,direct numerical simulations are performed to investigate species evolution and turbulence-chemistry interactions in a Mach 10 high-enthalpy turbulent boundary layer over a flat plate,with O2 injected through a slit in the fully turbulent region.Pure O2 is injected at the free-stream temperature with a blowing ratio of 0.001.Results show that the injection creates a localized oxygen-rich zone downstream,leading to a non-monotonic O2 distribution and significantly enhanced production of atomic oxygen.Mass-fraction fluctuations of O2 and N2 are amplified,while those of N and NO are weakened.The injection strengthens chemical reactions involving O2,O and NO,but has limited effect on the relatively inactive N2 and N.Compared with species fluctuations,turbulence-chemistry coupling is more sensitive to temperature fluctuations.