Generation method for a novel Roots rotor profile to improve performance of dry multi-stage vacuum pumps

Multi-stage vacuum pumps are commonly used to increase pump efficiency, and several kinds of Roots rotor profiles have been proposed. However, the lack of design flexibility for rotor profiles means they may be unable to meet the requirements for different stages. This paper proposes a mathematical model and method to generate a novel rotor profile for multi-stage "IVEC" type Roots vacuum pumps. Two geometric performance indices, the area utilization ratio and the meshing gap area, are used to evaluate different types of rotor profiles. A practical experiment compares the performance of an existing benchmark vacuum pump to one with IVEC rotors. Numerical and experimental results demonstrate the superiority of the proposed IVEC Roots rotor profile.