外啮合齿轮泵流量特性影响因素分析

为研究外啮合齿轮泵重要参数对流量脉动系数的影响,通过理论推导获得流量脉动系数计算公式,分析齿数、压力角对流量脉动系数的影响;采用边界型函数和动网格技术,并结合k-ε湍流模型对不同参数条件下的齿轮泵进行非定常模拟,分析负载压力、径向间隙对流量脉动系数的影响.结果表明,增大齿数和压力角均会减小齿轮泵流量脉动系数,有利于提高齿轮泵的流量特性.另外,增大齿数与增大压力角对提高齿轮泵的流量特性效果较为接近;齿轮泵的流量脉动系数也会随着负载压力及齿轮径向间隙的增大而减小,在设计中适当增大负载压力及齿轮径向间隙,可以改善出口流量特征的质量;过大的负载压力和齿轮轴向间隙会导致齿轮泵容积效率下降,在设计过程中应当引起足够重视.

Analysis of influence factors on flow rate characteristics in gear pump

In order to research the important influence factors of the coefficient of the flow rate pulsation φ on the external gear pump, the analytic way of deducing and simulation was adopted. By deducing the formulation of the coefficient of flow rate pulsation, the relationship between gear number, press angle and φ were analyzed. A numerical simulation of the transient flow field of the gear pump was performed by using the moving boundary condition and dynamic mesh method with k-ε turbulent model, and the relationships among the loading pressure,the clearance and the φ were achieved. The result shows that the coefficient of flow rate pulsation will decrease with the increasing of the gear number z or the pressure angle α. It is good for improving the flow rate characteristic of the gear pump. Furthermore, the gear number makes a very similar function in improving the flow characteristics with the pressure angle′s function. On the other hand, the coefficient of the flow rate pulsation will also decrease with the loading pressure p or the clearance δ increasing. The exaggerated loading pressure and clearance δ will lead to the volumetric efficiency decreasing, and this characteristics should be attached great importance in pump design procedure.