基于二维瞬态导热反问题方法测量气体射流冲击换热系数

摘要

Based on Levenber -Marquardt iteration method , a 2-D transient inverse heat conduction method was built .Combined with experimental method , the convective heat transfer coefficients on the surface of thick target plate were measured .By using RNG k-εturbulence model , a CFD mathemati-cal was built.The numerical and experimental results indicate that the 2 -D transient inverse heat conduction method can obtain the convective heat transfer coefficient accurately ;during the cooling of thick target plate , Nu number increases rapidly after the onset of air jet impinging , and reaches a plat-eau when the cooling time greater than 50s;the local Nu number determined by transient experimental method is greater than steady experimental result , which is caused by lateral heat conduction inside the thick target plate .%基于Levenber-Marquardt迭代法建立了二维瞬态导热反问题模型.结合实验,测定了厚规格材料表面射流冲击换热系数随着时间的变化规律.同时,采用RNG k-ε湍流模型建立了相应的CFD仿真模型.数值分析和实验结果表明:所建立的二维瞬态导热反问题模型能够准确计算表面换热系数;厚规格材料冷却过程中,冷却开始时,表面换热Nu数迅速上升.当冷却时间大于50 s时,Nu数逐步趋于平缓并维持不变;由于材料内部横向热流的影响,瞬态实验的局部Nu数高于稳态实验的局部Nu数.