A Study On Calculation Method Of Vacuum System Components Gas Flow Simulation Based On FLUENT

In the altitude test facility vacuum system design and pumping calculation, it needs accurate calculation of gas flow in the vacuum components In order to better guide the production design. But for the complex structure components such as butterfly valves and the heat exchangers, it can not be calculated with the theoretical formula. FLUENT is a very broad application of fluid dynamics simulation software which has been applied widely. Study on the method of vacuum system components gas flow simulation with FLUENT software and use FLUENT software to simulate gas flow in vacuum, thus adding a computer aided design method.This paper based on the theoretical derivation of medium and low vacuum gas flow law, found a more intuitionistic method of flow pattern decision. And this paper further simulated a variety of common shaped pipes based on the determination of the permission pressure lower limit by using FLUENT software, and we compared the results with the empirical and theoretical formula, they are in good agreement.Thus it proved the feasibility of using FLUENT software to simulate the medium and low vacuum gas flow. The applicable flow patterns include turbulent flow, laminar flow and transitional flow between turbulent and laminar flow, and the transitional flow is defined as the viscous flow in the traditional vacuum field. On this basis, discussed using the method of user defined function, which makes the FLUENT software can simulate the pumping process of vacuum pump. The results show that using this method to the pumping process simulation is feasible.With the improvement of the process level of vacuum application technology and the reinforcement of the complexity of vacuum equipment, the demand for vacuum control valve in vacuum system is more and more. In contrast, the production supply and successful application of vacuum control valve lag far behind the demand, which is largely attributed to the poor understanding of manufacturers and users about the operating characteristics of the control valve.Aiming at the butterfly control valve which is widely used in vacuum system, this paper simulated the internal gas flow and found the quantitative relationships between the opening angle and the flux and the flow resistance by means of CFD commercial software FLUENT, and all of these can provide a theoretical basis for the development, design and application of the vacuum butterfly control valve.This paper also simulated the shell-side gas flow field of the shell and tube heat exchanger and got the mass flow of the two different conditions and calculated the magnitude of their flow conductance which provided a basis for accurate calculation of the vacuum system design.