两段式喷嘴对CO2两相流引射制冷系统性能的影响

Effects of dual- throat nozzle on performance of CO_2 two- phase ejector refrigeration system

文章对采用两段式喷嘴的引射器及其两相流引射制冷系统在不同工况、不同几何尺寸条件下进行了实验研究。实验结果表明,在实验工况固定的条件下,采用两段式喷嘴的CO_2两相流引射制冷系统的COP随引射器第一喉部直径的增大而增大,引射比随第一喉部直径的增大而减小;系统COP和引射比随引射器中间连接直径的增大而减小。对于固定几何尺寸的引射器,系统COP随气冷器出口压力的升高而增大,引射比随气冷器出口压力的升高先减小后增大,在9MPa时引射比最小。与传统的CO_2制冷系统相比,采用两段式喷嘴的CO2两相流引射制冷系统的COP在不同工况的条件下均高于传统系统的COP,最大可提高约15%。

The performance of a two - phase ejector refrigeration cycle （TPERC） system with a dual - serial - throat nozzle ejector was studied experimentally under different working conditions and different geometric sizes of the nozzles. The experimental results indicate that under a fixed working condition, the COP of TPERC system increases and the entrainment ratio of the ejector decreases with the increase of the cross - sectional throat diameter of the first throat. The COP and the entrainment ratio decrease with the increase of the intermediate connection diameter in TPERC system. Under the fixed geometric size of the nozzle, the system COP increases with the increase of the gas cooler outlet pressure, the entrainment ratio firstly increases and then decreases with the increases of the gas cooler outlet pressure, the entrainment ratio of the ejector achieves the minimum as the gas cooler outlet pressure is about 9MPa. Compared with the traditional CO2 refrigeration system, the COP of the TPERC system is higher than the traditional CO2 refrigeration system under different working conditions and the maximum increase is up to 15%.