Impact of Mesh Resolution and Temperature Effects in Jet Ejector CFD Calculations

Abstract

Featured Application: Jet ejector refrigeration cycles. Recent advancements in computational and experimental techniques have deepened the understanding of ejector dynamics. Working maps, which depict the relationship between operating conditions and the performance metrics of entrainment and pressure, are commonly used in defining the ejectors’ performances and designs and enhancing their operational flexibility. This paper investigates the sensitivity of a jet ejector to variations in the inlet temperatures, with a focus on how changes in these temperatures affect its performance and Mach number distribution. Using high resolution CFD (computational fluid dynamics) simulations, this study maps ejector behavior by using the ideal gas approximation, marks Mach number scene responses to those changes, and is aimed at optimizing it to work with refrigeration systems using commercial fluid R1234yf/2,3,3,3-Tetrafluoropropene. The findings provide valuable insight into operational conditions for jet ejectors. The analysis revealed little dependence on the changes in inlet temperatures, therefore expanding the design working conditions by at least +20% of the temperature at each of the inlets. This study also analyzes the small deviations in ejector behavior due to temperature variations at the inlets. It contributes to the development of sustainable refrigeration systems, as it broadens the operational temperature range and enhances practical applications in this field, as this information is difficult to find in commercial databases.