Design of multi-point meshing rotors and internal flow field characteristics of twin-screw pump
PAN Shiyang1, ZHAO Lizhuang1, LI Xueqin1, WANG Jun1*, ZHAO Sheng1, WANG Zengli1, GENG Maofei2
1. College of New Energy, China University of Petroleum(East China), Qingdao, Shandong 266580, China; 2. State Key Laboratory of Compressor Technology, Hefei General Machinery Research Institute Co., Ltd., Hefei, Anhui 230031, China
Abstract：In view of the problems of serious wear and large leakage in the meshing area of the screw rotor in the traditional twin-screw pumps, the meshing model of elliptic arc and its conjugate curve was established by engagement theory, a pair of screw rotors with transmission ratio of 2 to 3 was obtained, and multi-point meshing screw rotors were proposed. The computational fluid dynamics(CFD)method was used to calculate the internal flow characteristic of the proposed twin-screw pump, and the internal flow characteristics of the pump were studied. The results show that the proposed screw rotors can achieve three-point meshing in the shaft section, and multiple seals were formed on the twin-screw rotor profiles. The pressure distribution at the addendum of male screw rotor with V-shaped grooves is uniform, while the pressure distribution at the addendum of the female screw rotor with the traditional structure is stepped. The leakage rate of the circumferential meshing gap of the female screw rotor is 1.8 times that of the male screw rotor, which proves that the labyrinth-like seal formed by the edges of the male screw rotor with the V-shaped grooves and the casing can effectively reduce the leakage at the circumferential meshing gap and improve the sealing performance. The wear of the proposed twin-screw rotors was improved, and the novel screw rotors can effectively reduce the internal leakage of the twin-screw pump, which is of great significance for improving the high-pressure environment adaptability of the twin-screw pump.
