Internal Flow in Vacuum Ejector Using Water Table

The purpose of this study elucidates a structure of internal flow in vacuum ejector. The vacuum ejector is used as a part of automatic conveyance systems, in which precision parts or foods are handled utilizing vacuum pressure from the ejector. So far, the vacuum ejector has been designed mostly by experience and the internal flow in vacuum ejector is not well analyzed. The flow field of ejector is so small that conventional measurements can not be employed and it is difficult to obtain the detailed information. Thus, the flow in the ejector is simulated on water table using hydraulic analogy. In this paper, to obtain optimum performance of the ejector, we examined the different ejector models with parameters, such as the nozzle width and the distance between nozzle and inlet of mixing chamber. As a result, it is shown that maximum performance is obtained for the ejector model with the nozzle width of 40mm, the mixing chamber width of 100mm and the port size of 40mm.