叶轮口环结构对离心泵性能及流场的影响

Influences of impeller ring structure on performance and flow field of centrifugal pump

为了揭示叶轮口环间隙及结构型式对离心泵性能的影响,以IS80-65-160离心泵为模型载体,采用RNG k-ε湍流模型,对不同叶轮口环间隙及口环结构型式下的离心泵内部流场进行数值模拟,分析叶轮口环间隙对离心泵的效率、压力场和速度场的影响规律;研究3种环状结构型式的叶轮口环对离心泵性能的影响机制。研究结果表明:叶轮口环间隙的变化改变了离心泵内部流场的流动状态,影响其前、后泵腔处的压力分布,间隙内部的速度发生明显变化;锯齿形口环泄漏量最多可减少16.2%,容积效率提高,轴向力降低,锯齿形叶轮口环结构可提升离心泵2%的水力效率;流经两环状结构空腔的流体,过流面积增加,产生剧烈旋涡,并进行能量耗散,阻止了流体压力能的恢复,分散了经密封齿隙高速射出的流体的动能,间隙内部流体的速度梯度和压力梯度增大,湍动状态加剧,流动阻力增加。

In order to study the impeller ring clearance and structural change effects on the performance of centrifugal pump, based on IS80-65-160 centrifugal pump, internal flow field for different impeller ring clearances and structures were numerically simulated through RNG k-ε turbulence model. The influences on efficiency, pressure field and velocity field were analyzed, and three kinds of impeller ring structures effect on the centrifugal pump were researched. The results show that impeller ring clearances changed the internal flow field of centrifugal pump and affected the pressure distribution of pump cavity. Among the three kinds of annularity structures, rectangle and serrated impeller ring can reduce leakage,（at most reduced by 16.2%）, improve volumetric efficiency, balance action of axial thrust. Hydraulic efficiency increases by 2% after the change of impeller ring structure. When the fluid flows through the cavity between two rings, volume expansion and energy dissipation violently can prevent fluid restore its pressure, maximum dispersion the kinetic energy of high-speed injection fluid sealing from sealed gear. The internal fluid velocity gradient and pressure gradient are enlarged, and turbulent kinetic energy increases, and so the leakage is reduced.