Gas ejector modeling for design and analysis

摘要

A generalized ejector model was successfully developed for gas ejector design andperformance analysis. Previous 1-D analytical models can be derived from this newcomprehensive model as particular cases. For the first time, this model shows therelationship between the cosntant-pressure and constant-area 1-D ejector models. Thenew model extends existing models and provides a high level of confidence in theunderstanding of ejector mechanics. ?Off-design? operating conditions, such as theshock occurring in the primary stream, are included in the generalized ejector model.Additionally, this model has been applied to two-phase systems including the gas-liquidejector designed for a Proton Exchange Membrane (PEM) fuel cell system.The equations of the constant-pressure and constant-area models were verified. Aparametric study was performed on these widely adopted 1-D analytical ejector models.FLUENT, commercially available Computational Fluid Dynamics (CFD) software, wasused to model gas ejectors. To validate the CFD simulation, the numerical predictions were compared to test data and good agreement was found between them. Based on thisbenchmark, FLUENT was applied to design ejectors with optimal geometryconfigurations.