遷臨界 CO₂ 二相流エジェクタサイクルにおけるノズル出口断面積の影響

抄録

Characteristics of two phase ejector cycle using CO₂ as refrigerant was investigated by experiment and cycle simulation. Results of the experiment and the cycle simulation with proper efficiencies have a good agreement. Cycle performance and ejector efficiency was shown by the cycle simulation with a change of the ejector nozzle cross-section area. The ejector cycle has higher performance than a conventional CO₂ cycle, which using expansion valve, in all given conditions in the cycle simulation results. An entrainment ratio and pressure recovery which influence on an ejector efficiency was shown. The results shows different tendency for gas cooler outlet temperature 30 ℃ and 40℃. The nozzle diameter condition which took the maximum ejector efficiency was indicated for each gas cooler outlet pressure and temperature. Moreover an exergy loss of the driving nozzle, the suction nozzle, mixing section and diffuser was calculated. The exergy loss at mixing section and diffuser was higher than other parts. The tendency of these exergy loss affect strongly for the whole ejector performance.