旋流泵内颗粒分布及对盐析特性的影响

PARTICLE CONCENTRATION DISTRIBUTION AND ITS EFFECT ON SALT-OUT FEATURES IN A VORTEX PUMP

对旋流式模型泵内部两相流场进行了非定常计算,获得了盐析晶体颗粒在泵内的体积浓度分布结果,并对颗粒迁移规律进行了分析。旋流泵内晶体颗粒浓度分布较稳定。在叶轮内,颗粒集中于叶片工作面附近;无叶腔中,颗粒更易向蜗壳壁面迁移。无叶腔内的浓度远大于叶轮内,且呈良好的轴对称分布。颗粒存在提供了二次成核与非均相成核的机会,加速了盐析进程。泵内盐析层最初在蜗壳内壁及叶片工作面形成并不断增厚,最终堵塞流道。

Unsteady calculation of liquid-solid two-phase flow field is carried out in a vortex pump. The salt-out crystal particle concentration distribution （PCD） in the pump is obtained, and used to analyze the law of particle motion. The PCD is stable in the pump. In the pump impeller, particles are accumulated near the pressure side of blades. But they easily move to the wall of the pump casing in the volute. The particle concentration is much higher in the volute than that in the impeller. It presents a good axial symmetrical distribution. Secondary nucleation and heterogeneous nucleation take place in the pump because of the particles, which also accelerate the salt-out process. In the pump, the salt-out layer is formed on the casing wall and pressure side of blades at first, and thickening increasingly, and finally blocking the flow channel.