一项评价污垢对换热器传热性能影响的指标

以热力学第二定律为基础 ,提出了一项评价污垢对换热器传热性能影响的指标———单位传热量的熵增率 ,讨论了洁净状态下的传热单元数Ntuo、冷热流体热容率比R、冗余面积a等参数对换热器在考虑污垢时的传热性能的影响 ,并把不同流型换热器的评价结果进行了比较

A Criterion for Evaluating the Effect of Foul on the Heat Transfer of Heat Ex changers

Based on the second law of thermodynamic,a criterion for evaluating the effect of foul on the heat transfer of heat exchangers——the entropy generation increment rate of per unit heat transfer flux,was proposed,the effects of various parameters,such as heat transfer unit number ( N tuo ) in a clean condition,heat capacity rate ratio of cold and heat fluids ( R ),and superfluous area( a ) on the heat transfer of heat exchangers were discussed when the foul was considered,and a comparison of the estimation results of heat exchangers with various flow patterns was made.