Simulation of the multiple-stage Roots dry vacuum pump

The multi-stage Roots vacuum pump is widely used in semiconductor production processes, due to its high integration and high energy efficiency. The simulation of its thermophysical process is facing the challenge of the crossflow regime and complex flow domain. This paper proposes a novel simulation path for the multi-stage Roots vacuum pump based on the chamber model. First, the working process of the multi-stage Roots pump is described and simplified, and the simulation path is proposed, which includes two steps: calculating the performance map of each stage Roots and then solving the intermediate pressure between each stage. Next, to obtain the performance map of each stage, the working process model for the single-stage Roots is established, which mainly considers the leakage flow influenced by the gas rarefaction and channel structures. Furthermore, the PSO optimization algorithm is employed to solve the intermediate pressure between each stage based on the calculated performance map. Finally, the above simulation procedure is verified by the prototype experiments under different inlet pressures. The gas pressure, power distribution, leakage process, and clearance sensitivity are further analyzed to reveal the working characteristics of multiple-stage Roots dry vacuum pumps. The findings of this study enhance the understanding of thermophysical processes in multi-stage Roots dry vacuum pumps and provide a foundation for advancing their design and performance.