微通道分离式热管换热特征的模拟研究

为了研究充液率和运行参数对微通道分离式热管性能的影响,建立了微通道分离式热管的稳态换热模型,并验证了模型的准确性,模拟和实验结果最大相对误差为7.9%.基于该模型分析了充液率、风量以及蒸发器和冷凝器之间高度差对制冷剂侧换热系数、空气侧压降、换热量和能效比等参数的影响.计算得出系统最佳充液率范围为80.2%~105.6%,相应的换热量为3.75~3.90kW.制冷剂侧换热系数随着充液率的增加先增大后减小,系统压力随充液率增加而增大;同时当蒸发器侧风量由1 500m~3/h增加至5 000m~3/h时,系统换热量和EER分别增加了100.1%和92.5%;蒸发器和冷凝器高度差为2.4m的分离式热管比高度差为1.2m的分离式热管的平均换热量提高了9.18%.研究结果对微通道分离式热管的节能设计和运行控制有一定的参考价值.

Numerical Investigation on Thermal Characteristics of Micro-channel Separate Heat Pipe

In order to study the effect of liquid filling rate and operating parameters on the performance of micro-channel separate heat pipe (MCSHP),the steady state heat transfer model of MCSSHP was established. Compared with experimental data,the maximum relative error of this model is 7.9%. Based on the model,the effects of refrigerant filling rate,airflow rate and height difference between evaporator and condenser on refrigerant side heat transfer coefficient,pressure drop,heat transfer rate and energy efficiency ratio (EER) were analyzed. The results showed that the optimal refrigerant filling rate of this system was about 80.2%~105.6%,and the corresponding maximum heat transfer rate was 3.75~3.90 kW. With the increase of the refrigerant filling rate,the heat transfer coefficient at the refrigerant side increased first and then decreased,and the system pressure increased with the increase of the refrigerant filling rate. Meanwhile,when the airflow rate at the evaporator side increased from 1 500 m3/h to 5 000 m3/h,the heat transfer rate and EER increased by 100.1% and 92.5%,respectively. When the height difference between evaporator and condenser increased from 1.2 m to 2.4 m,the average heat transfer rate of the MCSHP increased by 9.18%. The research results are valuable for the energy-saving design and operation control of MCSHP.