Investigation of the Effect of Top-End Pressure on Rotor Axial Pressure in a Gas Centrifuge Machine Using the DSMC Method

In centrifuge machines, the study of gas dynamics is of critical importance not only within the rotor but also in the surrounding external region. To reduce both pressure and frictional power losses in the space around the rotor, molecular pumps are employed. Given the direct interaction between the pressure in the top-end region and that within the rotor, understanding their mutual influence is essential for optimal machine design. Predicting the wall pressure of the rotor during the gas feed process, along with defining acceptable ranges for variations in operational and geometrical parameters that affect rotor axis pressure, is vital for maintaining stable pressure in the top-end region. These considerations underscore the importance of assessing how top-end pressure is influenced by rotor axis pressure. However, despite its significance for designers, direct measurement of rotor axis pressure faces substantial technical challenges. In this study, to establish the relationship between top-end pressure and rotor axis pressure, the gas flow within the entire external space of the rotor, as well as part of its internal region, was simulated using the Direct Simulation Monte Carlo (DSMC) method. Simulation results reveal that the pressure distribution inside and outside the rotor depends on the type of gas. Moreover, a correlation was derived showing that a 2.5-fold increase in top-end pressure results in a 70% rise in rotor axis pressure, while a tenfold increase in top-end pressure leads to an approximately threefold increase in rotor axis pressure.