客车余热回收系统用尾气换热器性能研究

Study on the performance of tail gas heat exchangers for waste heat recovery system of the passenger car

以翅片管式尾气换热器为研究对象,采用CFD方法对其性能进行了数值模拟,得到了换热器内温度场、速度场、压力场等细观信息,同时还考察了不同进口雷诺数和不同翅片管结构参数对换热器传热性能的影响。结果表明:进口雷诺数的增大,会导致尾气换热器传热性能有所提升;翅片间距为2.0~3.5 mm时,换热器的传热性能随着翅片间距的增大而逐渐下降,间距为2.0 mm时传热性能较好;翅片高度为6.0~8.4 mm时,换热器的传热性能随着翅片高度的增大而逐渐增强,高度为8.4 mm时传热性能较好;翅片厚度为0.3~0.9 mm时,换热器的传热性能随着翅片厚度的增大而逐渐下降,厚度为0.3 mm时传热性能较好。该研究结果为后续翅片管式尾气换热器传热性能的研究提供了参考。

Taking the finned tube tail gas heat exchanger as the research object,its performance is numerically simulated by CFD method,and the meso information such as temperature field,velocity field and pressure field in the heat exchanger are obtained.At the same time,the effects of different inlet Reynolds numbers and different finned tube structural parameters on the heat transfer performance of the heat exchanger are also investigated.The results show that the heat transfer performance of tail gas heat exchanger increases gradually with the increase of inlet Reynolds number.When the fin spacing is 2.0~3.5 mm,the heat transfer performance decreases gradually with the increase of fin spacing,and works best when the fin spacing is 2.0 mm.When the fin height is 6.0~8.4 mm,the heat transfer performance increases gradually with the increase of the fin height,and works best when the fin height is 8.4 mm.When the fin thickness is 0.3~0.9 mm,the heat transfer performance decreases gradually with the increase of the fin thickness,and works best when the fin thickness is 0.3 mm.The research results provide a reference for the subsequent research on the heat transfer performance of finned tube tail gas heat exchanger.