深海采矿两级离心泵固液两相流数值模拟研究

Numerical Simulation of Solid-liquid Two-phase Flow of Two-stage Slurry Pump for Deep-sea Mining

针对陆地用离心泵不能满足1 000 m深海矿浆提升要求,设计了一种高性能新型两级矿浆泵。选取叶轮和空间导叶为研究对象,采用三维雷诺时均N-S方程和修正的RNGκ-ε湍流模型,采取压力-速度隐式修正SIMPLEC算法,对两级矿浆泵内部湍流进行数值模拟,分析固液流场的分布规律,预测工作性能。结果表明:不同流量工况下,同一圆柱半径上,叶轮叶片压力面上的压力大于吸力面上的压力。流量越大,叶轮流道入口处速度越小,叶轮对固液流体的加速作用越弱,叶轮流道出口处的速度也越小。流量越大,空间导叶出口和入口处固液流体的速度差越小,空间导叶的转能效果越差,导致后流道出口处的压力越低,扬程越小,设备性能下降。但矿浆泵的效率随着流量的增加迅速增大,1 000 m矿浆泵的最佳流量工作范围为500 m3/h^600 m3/h。

In view of the fact that a centrifugal pump for land use can not meet the requirements of 1 000 m deep-sea mining,a high-performance two-stage type slurry pump was designed. The impeller and the space guidance vane were selected. The inner turbulent flow of the two-stage pump was simulated with the three-dimensional Reynolds-average N-S equations and the RNG κ-ε turbulence model. The distribution law of solid-liquid two-phase flow was analyzed and the performance of the slurry pump was predicted with the SIMPLEC algorithm. The simulation results show that under different flow conditions,the pressure on the pressure surface of the impeller blade on the same cylinder radius is greater than that on the suction surface. When the flow is greater,the impeller entrance velocity is smaller,and the influence of the impeller on solid and fluid acceleration is weaker; the outlet velocity in the impeller is small. Then the outlet and inlet fluid velocity differences are smaller in the space guidance vane,producing a worse rotational effect and a smaller head,and the performance of the equipment is reduced. Efficiency increases with the increase of flow rate,so the work flow should be selected 500 m^3/h ~600 m^3/h.