Model development and numerical procedure for detailed ejector analysis and design

The main purpose of this work was to develop a mathematical model and computer programs for ejector studies in refrigeration cycles. Version A of the program was written for optimal ejector design while Version B, with more built-in flexibility, was intended for simulation. The study is a one-dimensional analysis of compressible refrigerant flow, based on a forward marching technique of solution for the conservation equations. Refrigerant properties were evaluated using NIST [NIST Standard Reference Database 23, NIST Thermodynamics and Transport Properties of Refrigerants and Refrigerant Mixtures, 1998, REFPROP, Version 6.01] subroutines for equations of state solutions. The approach assesses the flow locally and provides the flexibility of returning upstream for correcting adjustments. Model validation against the R141b data of Huang et al. [Int. J. Refrig. 22 (1999) 354] has shown very good agreement under all conditions. Analysis with refrigerant R142b was performed for typical refrigeration conditions. The entrainment ratio ω, the compression ratio P6/P2 and geometric parameters such as diameters and axial dimensions were used to assess performance. Local distributions of pressure, temperature and Mach number were obtained for typical conditions and the mixing chamber was found to greatly impact operation and performance, by controlling the shock wave occurrence and intensity.