Numerical Research on Flow Characteristics of Vortex Stage in Dry High Vacuum Pump

AbstractWith the development of dry high vacuum pump, researches of pumping mechanism of vortex-stage are greatly concerned. This paper presents a horizontal dry high vacuum pump and establishes a numerical model of vortex stage. And then numerical simulation of flow is carried out with FLUENT software. Moreover, it studies how flow regions work on the internal flow and work performance of the vortex stage under various conditions, such as different number of blades and impeller with different blade rake. As a result, numerical simulation shows that there is a large impact on the pumping for different numbers of blades distributed on the impeller, the number of blades of single impeller should be obtained by combining with practical design sizes. In fact, this paper selects the best number of blades as forty-three by calculating and optimizing. In the mean time, there are three cases for the blade rake: pitched vanes, radial vanes and retroverted vanes. For each case, there are both longitudinal vortex and radial vortex existing in the impeller. Considering comprehensively, impeller with radial vanes is selected in the design after simulation and comparisons