Design of cylindrical mixing chamber ejector according to performance analyses

A design method for cylindrical mixing chamber ejector according to performance analyses is proposed based on the real gas properties. Compared with the experimental data, the entrainment ratio and critical back pressure calculated by the proposed method have errors within ±17% and ±6%, respectively. Ejectors with common characteristic sizes using steam, ammonia, R290 and R134a as working fluids are analyzed by this method. Consequently, design curves and regressive expressions are provided to describe the relations between entrainment ratios, ejector area ratios and expansion and compression ratios, as well as the relations between nozzle area ratios and expansion ratios. The expressions of nozzle throat areas are regressed for steam ejectors at 75-130 °C, as well as for ammonia, R290 and R134a ejectors at 75-95 °C. The design curves and regressive expressions provided by this paper can be used to design ejectors with cylindrical mixing chamber accurately and conveniently.