Profile Design And Numerical Analysis On Air-cooled Roots Vacuum Pump

The air-cooled Roots vacuum pump has the advantages of simple structure and reliable run, and widely used in large space simulator, turbine balancing devices, and chemical industry. The profile of air-cooled Roots vacuum pump in domestic is double-folium cycloidal profiles. It has the shortcomings of noise and lower efficiency. Also we can't measure the internal flow with experimental tools because of the structure of the pump. With the development of the CFD, simulating the internal flow of the pump is an effective research method.Based on the experience of former researchers, this article investigates the rotor's profile of air-cooled Roots vacuum pump with mesh theory. Simulates the internal turbulent flow of the rotor of double/triple/quadruple-folium cycloidal profiles with FLUENT, and get internal velocity distribution and pressure distribution in different working conditions and to analyze the internal flow rule of the air-cooled Roots vacuum pump.The main work done is:1. With the mesh theory and working principle and working process of air-cooled Roots pump, the theoretical and actual cycloidal profile equations of double/triple/quadruple-folium rotors are set up.2. Set up the volumetric coefficient of utilizationλformula for the above profiles,and plot the curves of relationship of the c(Rm/R) and volumetric coefficient of utilizationλ.3. Make model with Unigraphics NX and Autocad for the air-cooled Roots vacuum pump from manufacture. Set up the flow field model, generate the computational grid and set the boundary conditions and conditions of regional characteristics with gambit. 4. Simulate unsteady internal flow of the air-cooled Roots vacuum pump with triple-folium cycloidal rotors in FLUENT and analyze the result in details, which helps optimal design of air-cooled Roots vacuum pumps.