摘要
以热力学第二定律为基础讨论了理想的逆流、并流和错流型换热器的不可逆损失,并且提出采用熵产效率评价换热器的不可逆程度。重点考察了不同进口温度比、传热单元数(NTU)及流体的热流密度比对逆流、并流和错流型基本结构换热器的熵产数和熵产效率的影响,研究结果对换热器的结构优化、操作优化和节能应用的研究具有重要的现实指导意义。
Irreversibility of three basic-type flow heat exchangers of counter-flow, cocounter-flow and cross-flow was discussed on the basis of the Second Law. A new concept called entropy gener- ation effectiveness （EGE） which is same as heat transfer effectiveness is advanced,and the irreversibility of heat exchanger is evaluated by using EGE. Because of entropy generation number （EGN） and EGE as a function of enter temperature rate （0）, number of heat transfer units （NTU）,and heat density rate of the fluid （C） for the three basic types of heat exchanger,the effects of EGN and EGE also are emphatically discussed respectively. The study result has practical application for structure optimization, operation optimization and energy conservation.
出处
《石油化工设备》
CAS
2008年第1期16-20,共5页
Petro-Chemical Equipment
关键词
换热器
不可逆损失
熵产数
熵产效率
heat exchanger
irreversibility
entropy generation number
entropy generation effectiveness
