A simulation method for a liquid ring pump was developed using the moving particle semi-implicit (MPS) method [1]. The MPS method is a particle method that can simulate free-surface flows. Numerical methods can reduce product development costs by replacing experiments with simulations. Liquid ring pumps are used in steam turbine condensers, food vacuum packs, food processing, and as auxiliary pumps for large pumps. The components of a liquid ring pump include an eccentric impeller, air, and sealing water. The sealing water is rotated by the impeller and has an annular shape. Air flows through the inlet, and enters the space between the impeller blades. The air between the blades is carried to the outlets by the rotating blades, and compressed by the sealing water. Finally, compressed air flows out of the outlets. The developed method reproduces the above mechanism of liquid ring pumps on the basis of the MPS method. To represent the operating state of the liquid ring pump, we modeled the gas inlet and outlet, and the inflow and outflow of the sealing water. A two-dimensional simulation was adopted instead of a three-dimensional simulation to reduce computation time. The pressure and temperature of the gas were calculated on the basis of the equation of state, considering heat transfer. The effects of air on sealing water were considered in the pressure calculations. A liquid ring pump was numerically simulated using the developed method under various operating conditions. The simulation results for the shape of the water ring and pressure acting on the casing showed good agreement with the experimental results [2]. REFERENCES [1] S. Koshizuka and Y. Oka, “Moving-Particle Semi-Implicit Method for Fragmentation of Incompressible Fluid”. Nuclear Science and Engineering, 123-3, 421-434 (1996). [2] K. Shibata, T. Kaito, T. Takanashi and N. Yasuda, “Numerical simulation of liquid ring pump by a particle method”, 6-09, CMD2022 (2022) ACKNOWLEDGEMENT This work was supported by the Japan Society for the Promotion of Science (Grants-in-Aid for Scientific Research, Grant No. 23K04248).