Numerical model and experimental verification of conjugation mechanism of transpiration cooling and non-uniform high-temperature flame

Transpiration cooling is a promising thermal protection strategy for aerospace flight due to its low coolant consumption and high efficiency. However, previous articles rarely investigated the conjugation between chemical reaction of combustion flame and transpiration cooling. Herein, we establish a new conjugated model for transpiration cooling under high-temperature flame based on the combination of extended Darcy equation, two-energy equation for convection in transpiration material, and the chemical kinetic model for oxyacetylene/air combustion. Results indicate that Drgpfa-simplified combustion model shows the error of 8.5 % from detailed mechanism model, smaller than the deviation of 24.3 % for Drgep simplified model. Nitrogen obtains higher cooling efficiency than air because part of oxygen in the air participates in the combustion reaction near the wall. The hot gas barely penetrates into the transpiration material with 10 % porosity, yet nearly penetrates into the entire porous materials with 30 % and 50 % porosities, thereby increasing the surface temperature to 560 °C and 510 °C, compared to only 400 °C for 10 % porosity. However, the pressure drop in lower porosity material is higher than that in larger porosity due to its lower permeability. The current findings have potential in geometric design of transpiration material and coolant selection for transpiration cooling.