Effect of hot fuel gas on a combinational opposing jet and platelet transpiration thermal protection system

•A combinational opposing jet and platelet transpiration TPS is investigated.•Gas generator similar to solid rocket engine is beneficial for saving the space and weight.•Hot fuel gas transpiration is ineffective for promoting cooling performance.•Hot fuel gas jet and low-temperature transpiration is effective for thermal protection.•A good cooling effect and high thermal protection efficiency can be obtained. A hot fuel gas from a gas generator is introduced as a coolant medium to the combinational opposing jet and platelet transpiration thermal protection system (TPS) to save the occupied space and weight of a coolant supply system. 3D Navier–Stokes equation and SST k-ω model with compressible correction are used to simulate the influence of hot fuel gas on combinational TPS. The hot fuel gas and low-temperature air are used as the coolant. Then, the flowfield and heat flux transfer are obtained. Detailed numerical results show that the hot fuel gas used in the opposing jet and transpiration does not have an evident effect on promoting thermal protection performance. Then, the hot fuel gas in the transpiration is replaced by the low-temperature air, and improved thermal protection performance is obtained. A good cooling effect and high thermal protection efficiency can be achieved with a small coolant with an acceptable intensity of hot fuel gas opposing jet and low-temperature transpiration.