液体再循环方式引射制冷系统性能研究

Study on the Performance of Ejection Refrigeration System with Liquid Recirculation

本文提出一种采用引射器作为节流装置的液体再循环制冷系统,将气液分离器设置在蒸发器之后,利用高压制冷剂与气液分离器中液态制冷剂的压力差来引射液体,在不借助额外能量的条件下使蒸发器形成超倍供液,以改善系统性能。搭建了系统实验台,对该系统的引射比及系统性能的变化规律进行变工况实验研究,并与两相流引射方式进行对比。结果表明:在蒸发温度为-13^-6℃及冷凝温度为36~42℃两种工况下,采用引射器液体再循环方式的制冷量比两相流引射方式的制冷量提高了24.6%~45.9%,系统COP最大可提高14%;而当蒸发温度低于-13℃及冷凝温度高于42℃两种工况下,系统COP略有降低。同时发现,引射器进出口压差是影响液体再循环制冷系统中引射比的主要因素。

A liquid recirculating refrigeration system,with ejector as a throttling device,was proposed in this paper.Furthermore,a gas-liquid separator was set after the evaporator in the system.By using the pressure difference between high-pressure refrigerant and liquid refrigerant in the vapor-liquid separator to inject the liquid,the evaporator can form a super-feeding without consuming additional energy,which can improve the cooling capacity of the system.An experimental bench of the system was set up to conduct experimental studies on the changing conditions of the system′s ejection ratio and system performance,and they were compared with that obtained via the two phase flow injection method.The experimental results indicated that under the two conditions of evaporation temperature in the range of-13℃to-6℃and condensation temperature in the range of 36-42℃,the cooling capacity of the ejector liquid recirculation method is 24.6%-45.9%higher than that of the two phase flow injection method,and the maximum COP of the system increases by 14%,while the COP of the system slightly decreases when the evaporation temperature is lower than-13℃and the condensation temperature exceeds 42℃.At the same time,it was determined that the pressure difference between the ejector inlet and outlet was the main factor that affected the ejection ratio of the liquid recirculating refrigeration system.