换热管传热过程的熵产分析

基于热力学第一、二定律对换热管由管内到管外的传热过程进行了熵产分析，以管内流体为基准引入了无因次熵产数并得到其计算式；讨论了管内流体雷诺数、管内外流雷诺数比值、无因次入口换热温差及无因次特征尺寸等参数对换热管传热过程不可逆性能的影响。结果表明，存在一最佳的管内流体雷诺数使无因次熵产数最小；无因次熵产数值随管外与管内流体雷诺数的比值的增大而单调递增，随无因次入口换热温差和无因次特征尺寸的增大亦近似成线性增大。结果和方法对进一步完善基本对流换热过程的热力学评价具有一定的意义，同时为换热管双侧强化传热时性能的评价提供理论基础。

Entropy Generation Analysis of Heat Transfer Process through a Duct

Based on the first and the second laws of thermodynamic, the entropy generation of heat transfer process from the inside to the outside through a duct is analyzed. A dimensionless entropy generation number based on the fluid of inside duct is introduced and an analytical expression for the dimensionless entropy generation number is obtained. The effect of some dimensionless parameters on the irreversibility performance of heat transfer process through a duct is discussed. The results show that an optimal Reynolds number of fluid inside duct is found to make dimensionless entropy generation number minimum , the dimensionless entropy generation number increases with the increment of the ratio of the Reynolds number of inside and outside duct fluids, dimensionless inlet temperature difference and dimensionless characteristic geometric dimension. The results from this paper provide a reference for the thermodynamic performance evaluation on the basic heat transfer process through a duct and enhancement in double sides of duct.