考虑热进口段时管内对流换热过程的热力学分析

Thermodynamic Analysis of Forced Convective Heat Transfer Through a Duct Including Thermal Entrance Region

利用热力学第二定律，分别在壁面热流恒定和壁面温度恒定两种情况下，在考虑热进口段时对管内对流换热过程进行了热力学分析。引入了熵产强度和无因次熵产强度两个概念，并给出了有关计算式；讨论了壁面热流、壁面温度及流动阻力对无因次熵产强度的影响。

Based on the second law of thermodynamics, irreversible analysis of forced convective heat transfer through a duct including thermal entrance region is made on the condition of constant wall heat flux and constant wall temperature respectively. The general expressions are derived by introducing the concepts of entropy generation density and nondimensional entropy generation density. The effects of the heat flux, wall temperature and flow resistance on the nondimensional entropy generation density have been discussed. The theoretical analysis and conclusions provide basis for the optimal design of heat exchangers.