Performance of the vortex ventilator system based on capture velocity and capture efficiency

Abstract

The vortex ventilator (VV) is a new concept of a local exhaust ventilation system that uses a vortex flow to improve the directional capture ability and thus overcomes the critical defects of the general local exhaust ventilation (LEV) system. The LEV has a rapid decrease of the capture velocity with distance from the exhaust inlet, resulting in a very poor capture efficiency when contaminants are generated far away from the exhaust inlet. In this study, the capture characteristics of the VV are evaluated with respect to the capture efficiency as well as the capture velocity. Three-dimensional computational fluid dynamics simulations are performed together with experiments using the tracer gas method with SF6. Compared with simple suction, the VV gives more than nine times as large a capture velocity and thus has a capture efficiency of higher than 70%. The larger capture velocity and the higher capture efficiency of the VV guarantee a more flexible layout of the equipment in the working area.