Thermal protection performance of a low pressure short penetration mode in opposing jet and its application

摘要

An experiment about the flow mode of opposing jet is performed in a supersonic quiet tunnel, and a Nanoparticle-based plaser scattering method(NPLS) is used to acquire the shock wave information. A stable short penetration mode (SPM) in low jet pressure is observed in experiment aside from the traditional unstable long penetration mode (LPM) and high-pressure stable SPM. Hence, the flow mode of the opposing jet presents three kinds structures as the increasing jet pressure: low-pressure stable SPM, unstable LPM and high-pressure stable SPM. Then, numerical analysis about the flow-field and surface heat transfer on the opposing jet is conducted. The low-pressure SPM in hypersonic flow is also acquired in numerical results. Comparing to the unstable LPM, the low-pressure SPM has better cooling efficiency than the unstable LPM with smaller coolant gas. Nevertheless, the low-pressure SPM is not suitable for opposing jet TPS than the high-pressure SPM because its intensity is not strong enough to provide available thermal protection performance. The low-pressure SPM can be introduced to the combinational opposing jet and platelet transpiration TPS which the cooling efficiency in reattachment region is strengthened by transpiration coolant so the intensity of the opposing jet can be reduced to save coolant mass. The numerical results indicate that opposing jet and platelet transpiration combinational TPS with low-pressure SPM mode can realise better cooling effect and high efficiency than the traditional high-pressure opposing jet TPS.