A Study on the Performance of a Two-Stage Ejector-Diffuser System

The objective of present study is to come up with an efficient method for better utilization of the discharged momentum of an ejector-diffuser system. The introduction of a two-stage ejector-diffuser system can be a favourable configuration to utilize the remaining momentum of the mixed flow and increase the energy utilization rate considerably. In the present study, the flow phenomenon inside a two-stage ejector-diffuser system has been critically predicted by means of the numerical approach using Reynolds averaged Navier?Stokes (RANS) equations. A CFD method has been applied to solve the compressible RANS equations governing an axi-symmetric supersonic ejectordiffuser flow. A fully implicit finite volume scheme was applied to the governing equations, with a two-equation k-w turbulence model. The numerical were validated with existing experimental data. Detailed flow physics and their contributions on ejector performance were detected to compare both single-stage and two-stage ejectors. The ratio of mass flux was introduced to explore the performance improvement of the two-stage ejector-diffuser system. Initial results of mass flux ratio are declaring the benefit of the two-stage configuration on ejector performance.