麻面管耦合换热的多目标优化研究

Multi-objective optimization study on coupling heat transfer of pitted tube

为通过优化换热元件达到提高管壳式换热器综合传热效果的目的,提出了一种新式麻面管,并采用三维数值模拟方法,以油侧努塞尔数Nu、阻力系数f、综合换热性能指标PEC为目标函数,研究了凹坑直径d、凹坑深度h、圆周凹坑个数N与轴向坑距p对麻面管传热与流动特性的影响。结果表明:表面凹坑对麻面管的传热与阻力均起到正面效果,使麻面管的综合传热性能明显优于光管;在研究范围内,基于响应面法对Nu值、f值与PEC值进行分析,可得单因子轴向坑距与凹坑深度的显著性较高,且显著性最高的交互因子均为轴向坑距与凹坑深度,最低的交互因子均为凹坑直径与圆周凹坑个数;系统最优参数组合为Re=1 144,d=2.2 mm、h=1.1 mm、N=12、p=10 mm,对应的Nu=209.95、f=1.08、PEC=1.6。

In order to improve the heat transfer effect of the shell-and-tube heat exchanger by optimizing the heat exchange tube,a new type of pitted tube was proposed,and three-dimensional numerical simulations were conducted for the pitted tube to investigate the influence of different pit diameter d,pit depth h,circular pit number N and axial pit distance p on heat transfer and flow characteristics by taking Nusserl number Nu on the oil side,drag coefficient f and comprehensive heat transfer performance index PEC as objective functions.The results show that the pits have positive effects on the heat transfer and resistance of the pitted tube,and the comprehensive heat transfer performance of the pitted tube is obviously better than that of the smooth tube.Within the scope of the study,Nu,f a nd PEC values are analyzed based on the response surface method,and the single factor axial pit distance and pit depth are both more significant,the interaction factors with the highest significance are all axial pit distance and pit depth,and the interaction factors with the lowest significance are all pit diameter and circular pit number.The optimal structure in this study is that Re=1 144,d=2.2 mm,h=1.1 mm,N=12,and p=10 mm with corresponding Nu=209.95,f=1.08,and PEC=1.6.