Rotor profile improvement by optimizing meshing curve for helical roots blowers in HFCV application

Abstract

This paper introduced a novel design and optimization method of the Roots profile to enhance the performance of helical Roots blowers in Hydrogen Fuel Cell Vehicle applications. The proposed profile was generated based on defined meshing curves, and thus the shape of meshing curves can be explicitly optimized. First, the mathematical models for Roots profile generation based on meshing curves were presented. Next, the influence of the shape of meshing curves on the geometric performance of Roots rotors was investigated, and the meshing curve was further optimized using a genetic algorithm. Finally, the CFD method was employed to identify the specific performance enhancement brought by the optimized Roots profile. Results showed that the proposed profile design method could flexibly adjust the shape of meshing curves so as to intuitively control the spatial leakage channels formed by helical rotors. The optimized profile boosted the volumetric and adiabatic efficiency of the Roots blower up to 2.87%, and 1.89%, respectively, compared to the original one. The leakage analysis indicated that the performance improvement was attributed to the reduction of the leakage rate caused by the blow-hole and contact line. The conclusions obtained could effectively support the development of high-efficiency helical Roots blowers.