管内强化传热性能的熵产分析与性能评价

通过热力学第一、第二定律，对管内对流换热综合性能进行熵产分析和评价.建立了一种基于流动与传热过程熵增原理的统一分析方法，在等壁温边界条件下进行熵产分析.并以文献中内翅片管的强化传热作为应用，分别对相同流量、泵功、压降在等热负荷限制下进行强化传热性能评价.结果表明：对于给定的管道，量纲1熵产数只与流动Reynolds数和进口与壁面的温度差有关.利用该分析方法不仅可通过参数分析获得几种强化方式的能量综合利用效果，还可确定合理的流动工况参数、结构参数和合理的强化形式.

Entropy generation analysis and performance evaluation of heat transfer enhancement through internal flow

An analytical method based on the entropy generation theorem for fluid flow and heat transfer process was developed with the assumption of fully developed flow and constant wall temperature,and the method was used to obtain dimensionless entropy generation number, and performance evaluation criteria (PEC) of heat transfer enhancement were obtained with the constraints of identical mass flow, pump power and pressure drop respectively under fixed heat duty. The applications of these treatments were illustrated by the analysis of heat transfer and fluid friction characteristics of internally finned tubes from literature data.It was shown that the dimensionless entropy generation number depended exclusively on Reynolds number and wall-to-inlet temperature difference for a given duct or tube, and the method might help to identify inappropriate enhanced tubes or extended surfaces and assist engineers to design better heat transfer equipment with the criteria assessing the merits of augmentation techniques in connection with energy conservation and exergy destruction according to entropy generation analysis.