An experimental and theoretical study of a jet-pump refrigeration system designed using a new two-dimensional model for the entrainment region of the ejector

摘要

The performance of an ejector refrigeration cycle is investigated both theoretically and experimentally. By applying the equations for the conservation of mass, energy, and momentum as well as that for the exergy balance, for each component in the cycle, a new two-dimensional thermodynamic model is developed. The influence of flow viscosity is taken into account by assuming a two-dimensional flow near the ejector inner wall. Results indicate that the cycle coefficient of performance decreases with increasing generator temperature and the second law efficiency increases with increasing evaporator temperature and/or decreasing generator temperature. It is found that the maximum relative error occurred in calculating the entrainment ratio is 7.52%. Exergy analysis revealed that the ejector has almost the highest contribution in the total exergy destruction. In addition, increasing the evaporator temperature from 2 to 15.5℃ results in a decrease in ejector exergy destruction by up to 8%.