Transpiration cooling performances of oriented porous structures with lateral permeability under local block conditions

As a reusable thermal protection method, transpiration cooling technology is regarded as the most promising active thermal protection technology for hypersonic vehicles. The porous media which has oriented porous structure can achieve excellent cooling effects in transpiration cooling when local block occurs. However, it will cause excessive local pressure in pores, which brings uncertainty to the reliability of the thermal protection system. An oriented porous structure with pits based on the wood vessel structure is proposed for improving this problem in this paper. The effects of lateral penetration performance on the transpiration cooling characteristics of the oriented porous structures under local block conditions are investigated. The increase in lateral permeability can effectively release the internal pressure. As the lateral permeability increases, the maximum pressure inside pores decreases up to 60% compared to completely oriented porous structure. Moreover, new relationships that the maximum temperature location and the maximum stress location will change with the lateral permeability has been explored when local block appears. This work will provide an optimization scheme for design of porous media and improve the reliability of transpiration cooling in hypersonic vehicles.