Influence of Inlet Pressure on Performance of Vacuum “Generator”: A Simulation Study

The flow field in the lab-built device, called vacuum “generator” and designed by modifying an ejector, was mathematically modeled and numerically simulated with Fluent software.The influence of the inlet-pressure on the entrainment rate, axial distributions of pressure/velocity, and the lowest pressure obtained was investigated.The simulated results show that the inlet-pressure has a major impact.For example, under the port-closed transient condition, there is a critical inlet-pressure;at the vacuum port, an optimized inlet pressure results in the lowest pressure, whereas an inlet-pressure higher than the critical one causes a periodic pressure fluctuation.Moreover, in steady-state isobaric mixing hypothesis, an optimized inlet pressure maximizes the entrainment flow and entrainment rate.We suggest that the simulated results be of some technological interest in design and application of the vacuum “generator.”