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General calculation model of effective volume utilization coefficient for rotor pumps |
LI Yulong*, ZANG Yong, ZHAO Yan, LI Xiurong |
School of Mechanical and Electrical Engineering, Suqian College, Suqian, Jiangsu 223800, China |
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Abstract To construct a general model suitable for calculating volume utilization coefficient(VUC)of all kinds of external meshing rotor pump, first, for one type of rotor with wide-top which could reduce radial leakage, the general profile structure and profile equation with change in instantaneous center radius were given; secondly, based on a rotor pair with exactly the same structure and size, and the geometric relationship of the rotor pair in minimum clearance position, the accurate calculation formula of conjugated cross-section area and VUC with instantaneous center radius was derived step by step; finally, the cycloid rotor was used as an example for verification and analysis. The results show that effective cross-section area has two parts: inherent cross-section area of rotor itself and minimum clea-rance additional cross-section area of rotor pair. It can also be divided into smaller dynamic conjugated cross-section area affected only by instantaneous center radius and larger static pitch circle cross-section area. Lobe number, initial normal angle and addendum angle are three independent parameters which affect effective VUC. The larger the lobe number, the smaller the effective VUC is; the larger the initial normal angle, the larger the effective VUC is;the larger the addendum angle, the smaller the effective VUC is. The addendum angle has a little effect on the effective VUC, which is beneficial to reduce radial leakage. The general calculation model of effective VUC can provide theoretical basis for further research on rotor pumps.
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Received: 24 August 2019
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