延伸冲击孔冲击冷却流动与换热特性的数值研究

In order to investigate the effects of the impingement hole extended length on the cooling perfor⁃ mance of the impingement cooling system，the effects of three impingement jet Reynolds numbers and five im⁃ pingement hole extended lengths on the flow and heat transfer characteristics in the impingement cavity were ana⁃ lyzed by numerical simulation. The changes of distributions of Nusselt number，pressure，central cross-section velocity and the resulting overall thermal perform were given in detail. The results show that the extended jet hole can effectively prevent the deflection of crossflow to the impingement jet. The extended impingement hole made the jet outlet closer to the wall，and the flow velocity was higher when it reached the target surface，which obvi⁃ ously improved the average Nusselt number on the target surface，and the heat transfer coefficient distribution of the whole target surface is more uniform. The cooling performance of impingement cooling increased with the in⁃ crease of jet Reynolds number and the extended length of the jet hole. Compared with the traditional jet impinge⁃ ment configuration（baseline），when the impingement hole extended length is 2.5 times the length of impinge⁃ ment hole diameter，the average Nusselt number of target surface increases by more than 15%. But the penalty was higher pressure loss. In term of comprehensive heat transfer performance，there was an optimal range of ex⁃ tended length，which made the impingement cooling system have the highest comprehensive heat transfer perfor⁃ mance. In this study，the best extended length is 2.5 times the length of impingement hole diameter.