微型燃气轮机回热器通道流动特性数值模拟

对C(WCross-aWvy)原表面几种不同导流段进、出口距离比(Li/Lo)的单周期通道流动特性进行数值模拟,在试验中无法观测到的信息,重点分析单通道不同区域段的压降情况。研究表明:对于进入换热板的每股流体无论进入哪个通道,经过整个换热板的总流程总是相等的,不同通道流动分布情况趋于一致,通道流动总压降最大相差不超过0.51%。空气在单通道内流动,压降较大值发生在入口导流区与波纹区过渡区,此处过渡段压降值约占整个通道总压降的20%,降低空气侧的压降必须更加合理地设计优化入口过渡区的结构。通过计算还发现,从第5个单元开始,流动分布不受入口段影响,压降亦不再受流动单元个数的影响而趋于恒定。

Numerical Simulation of Flow Behaviorr of Channels for Microturbine Recuperator

The flow behavior of the single cycling channels was numerically simulated at five cross-wavy primary surface guide with different ratios of inlet-distribution distance to outlet-distribution distance.The information not observed from the test was obtained.The pressure drop distribution was emphatically analyzed at the different sections.It is shown that the flow distance through the heat exchange plate is always equal at various channels.The fluid distribution of the different channel tend to consistency.The largest discrepancy of the channel total pressure drop do not exceed 0.51%.When the air flows in the single channel,the larger pressure drop appears not only in wavy heat-transfer section but also in inlet-transition section.The pressure drops in transition section is about 20% of the overall channel pressure drop.It is important that the configuration of inlet-transition section must be optimized to reduce the pressure drop of the air side.The numerical results reveal that the flow distribution and pressure drop approach steady and are not influenced after 5 wavy cells.