多管程布置微通道分液冷凝器的热力性能

摘要

分液式微通道冷凝器( LSMC)是一种新型的微通道平行流冷凝器。本文通过理论计算并实验验证了不同管程布置方案LSMC的管内换热系数和压力降,并采用惩罚因子( PF)对其综合性能进行评价。结果表明：管程数( NP)和每管程换热管数( TNPP)对平行流冷凝器的热力性能都有明显影响。在完全分液效果下,优化的4、5管程LSMC的换热系数分别比3管程LSMC提高了5.7％和13.8％,而4、5管程LSMC的压降也分别比3管程LSMC增大超过23.5％和138.7％。与此比较,LSMC的传热系数和压降在不同TNPP的变化较小,说明优化区间内管程数比每管程换热管数对LSMC单一的热力性能影响更大。此外,实现完全分液的LSMC比部分分液的LSMC热力综合性能好。与实验值比较,LSMC理论传热系数和压降的最大偏差分别为25.6％和20.8％。%Liquid-vapor separation microchannel condenser ( LSMC) is a novel microchannel condenser. This paper calculated heat transfer coefficient and pressure drop theoretically, and the theoretical results have been verified by experiments. Penalty factor ( PF) was employed to evaluate the thermodynamic performance of the LSMC. The results showed number of pass ( NP) and tube number per pass ( TNPP) have obvious effect on the thermodynamic performance. Under the condition of completely liquid-vapor separation, the 4-tube-pass and 5-tube-pass LSMC showed 5. 7% and 13. 8% higher heat transfer coefficient than 3-tube-pass LSMC separately. In addition, the pressure drop of 4-tube-pass and 5-tube-pass LSMC is also 23. 5% and 138. 7% more than 3-tube-pass LSMC separately. In contrast, the TNPP showed a less effect on the heat transfer coefficient and pressure drop. It showed that the NP had a larger effect on simplex perform-ance than the TNPP within the research scope. The thermodynamic performance for the LSMC with completely liquid-vapor separation was better than that with incompletely liquid-vapor separation. Compared with the experimental results, the theoretical heat transfer coefficient showed a maximum deviation of 25. 6% and the theoretical pressure drop showed a maximum deviation of 20. 8%.