非对称翅片管换热器传热和阻力特性的数值分析

摘要

A three-dimensional model of asymmetric finned tube heat exchanger was established on the basis of COMSOL software,so as to implement numerical study on the flow and heat transfer performance on the air side,then compare it with plain finned tube heat exchanger,and finally to further analyze the effects of inclined angle on the performance of the asymmetric finned tube heat exchanger under different Reynolds numbers.Results show that,compared with plain finned tube heat exchanger,the heat transfer factor of asymmetric heat exchanger is 13.95％ higher on average when the Reynolds number varies in 3 239-9 700.The larger the Reynolds number is,the lower the friction factor would be,with an average reduction of 4.80 ％,and the reducing trend enhances under high Reynolds numbers.Taking MJF as the evaluation criteria and keeping other structural parameters unchanged,the MJF reaches the maximum at β=30°,when optimum comprehensive performance of the heat exchanger is obtained.%基于COMSOL软件建立了一种非对称翅片管换热器的三维模型,对空气侧的流动和传热特性进行了数值研究,与平直翅片管换热器进行对比,并进一步分析了不同雷诺数下交错角β对非对称翅片管换热器性能的影响.结果表明:在Re为3 239～9 700内,与平直翅片管换热器相比,非对称翅片管换热器的传热因子增大,平均增大量为13.95％,阻力因子减小,且随着Re增大其减小效果更加明显,平均减小量为4.80％;以MJF作为评价标准,且其他结构参数不变时,β=30°时MJF最大,换热器的综合性能最好.