Profile Design and Numerical Calculation of Instantaneous Flow Rate of a Gerotor Pump

Gerotor pump is a special kind of internal rotary pump, which contains a trochoid profile (commonly called as cycloid). Generation of trochoid is normally realized by external rolling method, namely a circle rotating on a fixed circle without slipping. This paper proposes derivative process of the trochoid profile by means of internal rolling method, which is that internal surface of a circle contacts with a fixed circle and rotates around it without slipping. Moreover the instantaneous flow rate can be obtained by numerically calculating the change ratio of area between the inner and outer rotors in the outlet region of the gerotor pump, which avoids to complicatedly derivative process.

凸舌油槽对摆线转子泵空化特性的影响

为了改善摆线转子泵的空化特性,提出一种增加极限进出油面积的凸舌油槽结构方案,建立摆线转子泵凸舌油槽结构模型,采用RNG k-ε湍流模型对不同工况下摆线转子泵的内部空化流动进行仿真模拟,分析摆线转子泵凸舌油槽结构在不同转速、不同转子位置时的空化特性,并对不同监测点的含气率及轴向含气率不均匀度进行分析,同时对不同旋转速度及不同进口压力条件下摆线转子泵的空化特性进行试验及对比分析。结果表明:凸舌油槽结构在3种转速下对空化均有所缓解,改善的空化位置主要位于靠近最大啮合容积处;高转速时凸舌油槽结构对转子区域内含气率改善最为明显,低转速下凸舌油槽结构对空化改善效果较小;空化沿轴向具有不均匀性,在进油侧最小齿间容积处、转子底部空化严重,而在较大的齿间容积处、转子中上部的空化更为严重。摆线转子泵的容积效率模拟值与试验值较为吻合,且变化趋势一致,不同进口压力下凸舌油槽的容积效率均高于原模型,凸舌油槽的空化特性优于原模型。