Flow Field Analysis And Performance Study Of Rotary Vane-Roots Pump

With the development of vacuum industry,the working pressure that vacuum application departments used becomes wider and wider.One type of vacuum pump is not completely applicable,according to different working pressure or different requires,we must use different type of vacuum pumps to make a vacuum pump unit,and the most commonly used unit is rotary vane-roots vacuum pump unit.Rotary vane-roots vacuum pump unit although in some extent solve the problem that single vacuum pump does not apply for a variety of conditions,at the same time,there are also some shortcomings,for example large volume occupied and many components used,so there will be a new concept of composite rotary vane-roots pump.Based on the rotary vane-roots pump entity model,we choose the composite pump internal flow field analysis and performance study as the main research direction.We simulate the flow field of roots working chamber,rotary vane working chamber,air inlet and air outlet ofthe rotary vane-roots pump by using computational fluid dynamics software fluent,and then we analyze the simulation results and discuss the pumping performance of rotary vane-roots pump.First,according to the structure parameters and 3D solid model of the rotary vane-roots pump,we establish the numerical simulation model of the composite pump cavity,connection parts and the inlet and outlet by using modeling software CAD and SolidWorks,and then we simplify the model.Secondly,according to the characteristics of the model,we use meshing software Gambit to model the unstructured meshes,due to the rotors in the pump chamber always rotate,in the simulation,the dynamic mesh method is used.The dynamic mesh method is realized by C language program which we calls for at any time by the UDF function of the software Fluent,and through the program we control the movement of the rotary vane and other parts,and realize the grid constantly updated by the grid reconstruction method.According to the actual working conditions of the composite pump,the pre-condition of the model is set up,and the simulation results of the flow field of the composite pump are obtained by using FLUENT software.Finally,according to the results of the numerical simulation,through the FLUENT software processing functions,we detailed analyze the flow process of the internal flow field,pressure field and temperature field distribution and changes of the rotary vane-roots pump,and then we study the pumping gas properties,and the simulation results and actual pumping speed were compared,and at last we discuss different pump temperature influence on the properties of the composite pump,and then draw the conclusion.