Fluid-thermal coupled analysis of heat reduction by the opposing jet in hypersonic flows

摘要

As a type of active cooling approach, opposing jet in hypersonic flow keeps drawing scholars' eyes in recent years, due to its perfect heat and drag reduction performance. In order to well investigate the thermal interaction between the hypersonic flow and solid structure, the heat transfer of a two dimensional blunt leading edge with opposing jet configuration is studied numerically, using a fluid-thermal coupling strategy. The adopted Menter's k-ω (SST) turbulence model and the fluid-thermal coupling method is validated by the related experimental results respectively. The numerical results indicate that the heat flux distribution along the solid structure surface is strongly influenced by the thermal interaction between the flow and solid domain. For the case of PR = 0.037, the maximum heat flux at the shoulder region dropped rapidly from 0.78 to 0.45 MW/m~2 in the first 2 s, and to 0.096 MW/m~2 after 60 s, showing the necessary of the coupling strategy and an obvious thermal protection effect of the opposing jet. Due to cooling effect of the injection, fluid-thermal coupling procedure and heat conduction in the solid structure, the temperature distribution of the solid surface between the maximum temperature point and the tail end presents more and more uniform, as the heating time goes. When the PR increased from 0.037 to 0.074, the maximum temperature in the solid structure decreased by about 300 K after 60 s' heating, and raised more slowly during the coupling procedure, which thus would indicate a smaller thermal shock.