Numerical investigation on regeneration-transpiration combined cooling of cavity structure in scramjet engine

As a key component in the scramjet engine, the cavity plays a role in promoting the mixing of fuel and oxidant, but it also faces the problem of high temperature damage. Because it is difficult to meet the thermal protection requirements of higher Mach number by only using pure regenerative cooling to cool the cavity, this paper studies the cooling effect of regeneration-transpiration combined cooling on the cavity. The results show that the wall temperature and the fluid temperature gradient near the inclined wall are significantly reduced under the combined cooling. The convective thermal insulation ability on the surface of porous media is particularly prominent, which is an important reason for the effectiveness of combined cooling. Increasing the split ratio reduces the wall temperature, but the pressure difference between the internal and external porous media becomes larger, which leads to higher requirements for the supply device, and the uniformity of the regenerative cooling heat sink utilization is also reduced. Increasing the incoming Mach number and reducing back-tilt angle can both promote the coolant penetration, resulting in an increase in the convective thermal resistance intensity.