两相喷射器增压的二级压缩制冷系统性能分析

Analysis on Performance of Two-Stage Compression Refrigeration System Pressurized With Two-Phase Ejector

建立一维等面积两相喷射器热力学模型,改进传统的二级压缩系统,提出一种喷射器增压的二级压缩制冷系统.以R1234yf为制冷剂,采用能量分析模型,研究不同设计工况下喷射器的性能.结果表明:当蒸发温度升高时,系统的性能系数(COP)和喷射系数增大,喷射器升压比减小;当冷凝温度升高时,COP和喷射系数减小,喷射器升压比增大;当蒸发温度为0℃,冷凝温度为50℃时,COP随着中间温度的升高先增大后减小,且存在一个最优中间温度,系统性能提高率可达10%以上.

A one-dimension constant area mixing two-phase ejector thermodynamic model was established,and a type of two-stage compression refrigeration system pressurized with ejector was proposed to improved the traditional two-stage compression refrigeration system.Using R1234yf as the refrigerant,a thermodynamic model was used to study the performance of the ejector in different design conditions.The results show that with the increase of evaporating temperature,the coefficient of performance(COP)and the entrainment ratio both increase,while the pressure lift ratio of the ejector decreases.When the condensation temperature increases,COP and the entrainment ratio decrease,and the pressure lift ratio of the ejector increases.When the evaporating temperature and condensation temperature are 0℃and 50℃,respectively,the COP increases first and then drops down with the increase of intermediate temperature.In addition,there exists an optimal intermediate temperature,and the system performance improvement rate can reach up to more than 10%.