板式换热器波纹通道的流动与传热机理

Flow and heat transfer mechanism of corrugated plate heat exchanger

采用Realizable k-ε湍流模型,针对一种人字形板间波纹通道的流动与传热机理进行了数值模拟研究。考察了不同Reynolds数湍流状态下波纹通道中沿壁面的平均以及局部表面特征数(Nu和f)的变化规律,揭示了流动与传热参数在波纹通道不同横向剖面的分布规律。结果表明在Re<7860时,凹壁面Nu更大;Re>7860时,凸壁面Nu更大;随着Re的增大凹壁面珚f大于凸壁面。凹壁面的Nu在近入口和近出口处存在两个峰值,并且在近出口处存在极大值;而凸壁面在近入口处存在一个极大值,在近出口处存在极小值。凹壁面的f在近出口处出现陡升现象,而凸壁面则在近入口处出现陡升。随着Re增大,剖线v和TKE增大,而T减小。另外,v、T和TKE在近凹壁面区域皆突然增大。

In this paper,the Realizable k-εturbulence model is used to simulate the flow and heat transfer mechanism of a corrugated channel.Considering various Re in turbulence regions,the variation of the averaged characteristic number on wall surface(Nuand f)and the local characteristic number along the wall surfaces of the corrugated channel are investigated.The distribution of internal flow and heat transfer parameters in different transverse sections is analyzed.The results show that when Re<7860,Nu of concave wall is larger;when Re>7860,Nuof convex wall is larger;while fon the convex wall is always larger than that on the concave wall.Nureached two peak values near entrance and exit of the convex wall,moreover,the maximum value in located near the exit.However,a maximum Nuis located near the entrance and a minimum is located near the exit for the concave wall.As for f,steep rising occurs near the exit of the convex wall,while steep rising appears near the entrance of the concave wall.With the increase of Re,vand TKEat all profiles also increase,while Tdecrease.In addition,v,Tand TKEall suddenly increase near the region of convex wall.