Numerical Simulation Study Of Flow Field And Thermal Field In Dry Scroll Vacuum Pump

Dry scroll pump with clean oil-free,small size,wide operating pressure range,vibration,noise and other advantages,widely used in semiconductor manufacturing,biopharmaceuticals and other industries need clean vacuum.In actual conditions,dry scroll vacuum pump may face harsh pumping complex environments,such as corrosive gases,the gas containing dust particles,and the suction pressure and temperature changes.Therefore,the study of flow characteristics of the fluid within the scroll pump and the fixed scroll heat distribution and thermal deformation is significant.This paper mainly studies for dry scroll vacuum pump CFD and numerical heat transfer simulation.According to the existing pumping mechanism,the establishment of three-dimensional model of the internal flow area and the fixed scroll,using ANSYS-ICEM software for convection fluid domain and solid domain mesh,simulate the pump flow field,thermal field and exhaust side of the fixed scroll internal temperature distribution and other parameters using the transient simulation method,the results of the analysis are compared with experimental data,and verify the reliability of numerical simulation methods.Firstly,based on CFD method and dynamics mesh method,the transient flow simulation model of dry scroll vacuum pump was established.Numerical calculation was carried out under three kinds of working conditions which inlet pressure is 1 kPa and 10 kPa.Simulation results are in line with the results of experiment or theoretical calculation on the whole.The maximum error of pumping speed between the simulation and the experiment is about-5.71%.Further analysis of the gas within the pump during compression ratio,pressure variation and flow characteristics of temperature distribution and other trends.Secondly,the numerical model of wall temperatur for adiabatic,293.15K and 338.15K three kinds of different thermodynamic boundary are calculated.The effects of the boundary conditions on the pumping speed,torque and power are analyzed,and the flow characteristics of the pressure distribution or the thermal field distribution under different thermal boundary conditions are also analyzed.Thermal boundary conditions on the pumping speed significantly affected,little effect on the compression power of the pump chamber temperature,pressure distribution trend and flow trend is almost no influence,but the overall pressure,temperature heating conditions affect the corresponding increase or decrease.Finally,a dry scroll vacuum pump bidirectional liquid-thermal coupling simulation model with an exhaust side of the fixed scroll was established,achieve a two-way coupling numerical calculations.Analyzes the fixed scroll internal heat distribution and thermal deformation,Scroll to the heart of the overall temperature distribution is increased,the temperature along the scroll wrap angle expand gradually increased in the negative direction.Fixed scroll therrmal deformation in the radial direction increases with the radius,the position of the maximum deformation occurs around the fixed scroll,and to provide a theoretical basis for further study of the theory and design of dry scroll vacuum pump.