多管程布置微通道分液冷凝器的热力性能

Effect of Tube Pass Arrangement on the Thermodynamic Performance of Liquid-vapor Separation Microchannel Condenser

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 effeet 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%.