通道截面形状对碳氢燃料流量分配的影响

Effect of channel cross sectional shape on flow distribution of hydrocarbon fuel

关注超燃冲压发动机冷却通道截面形状对碳氢燃料流量分配的影响,以平行四边形通道为例和矩形通道进行对比,对并联通道中碳氢燃料流动换热过程进行了三维数值建模。结果表明:不同高宽比下,平行四边形通道相比矩形通道具有更大流固间换热面积,因而在流量分配和冷却效果方面都优于矩形通道,加热面壁温峰值降幅最大可达226K。通道倾角对流量分配也有重要影响,大通道倾角能实现更合理的流量分配和冷却效果;倾角从105°增加到150°时,加热面壁温峰值降低了287K。在非理想分汇流布置(以U型分汇流布置为例)和非均匀热流条件下验证了平行四边形通道设计,说明了此设计的实用价值。研究结果对超燃冲压发动机冷却通道设计有一定参考意义。

The effect of cooling channel cross sectional shape on the flow distribution of hydrocarbon fuel in SCRamjet was researched.Parallelogram shape cooling channel was taken as an example to compare with rectangular channel.3-D modelling of the flow and heat transfer of hydrocarbon fuel in multiple cooling channels under supercritical pressure was done.Under different channel aspect ratios,the parallelogram channel was better both in flow distribution and cooling effect because of the larger heat exchange area.The maximum heated wall temperature fell 226 Kat most.Then the angle of the parallelogram channel was also important.Larger angle design led to larger heat exchange area and improved the flow distribution and cooling effect.The maximum heated wall temperature fell 287 K when the channel angle increased from 105°to 150°.The effect of practical headers was also taken into consideration.The parallelogram channel design was validated under the joint influence of U-type headers and non-uniform thermal boundary condition,showing good application value.The results of this work offer possible solution to the cooling channel design of SCRamjet.