Abstract:

In order to improve the pump wear performance and optimize pump design, the flow fields under some work conditions were calculated by solving the N-S equation group with RNG κ-ε model. The algorithm of SIMPLEC was used to correct the compression. Computing about four work conditions of slurry pump, the relative velocity was obtained, and the reflex and peripheral phenomenon were also analyzed; based on the results of flow fields, particle tracks in varied conditions were achieved by using Lagrange method, and the results were visualized. Some particle motion patterns were given involving the effects of particle diameters and work conditions. The results show that the reflex appears in the blade inlet of pressure sides in high flow conditions, but appears in the blade inlet of suction sides in low flow conditions, which possibly induce the cavitation erosion. In low flow conditions, reflex and eddies appear in the blade outlet of both the pressure sides and the suction sides, and the reflex areas even extend to the middle of blades. Particles and heads of blades impact more possibly in low work conditions. With the particle diameter increasing, particles collide with pressure sides more possibly. From the analysis results, this impeller is not suitable for particles whose diameters are more than 1mm and particles of 0.5~1mm are appropriate in the design condition.

Key words: slurry pump, impeller, work condition, flow field calculation, particle track

摘要：

为提高渣浆泵的抗磨性能并优化泵的设计，采用RNG κ-ε湍流模型和SIMPLEC算法对多工况下渣浆泵叶轮内部清水流场进行了数值计算，得到叶片表面相对速度矢量分布，分析了叶片表面回流、旋涡现象;基于单颗粒动力学模型，采用拉格朗日法计算了多工况下固相颗粒的运动轨迹,分析不同粒径颗粒对叶片表面磨损的影响。结果表明：叶片压力面进口在大流量工况下开始出现回流，而叶片吸力面进口则在小流量工况下回流、旋涡严重，叶片进口的回流、旋涡不仅容易引起NPSHr增高，诱发空化现象，还会导致颗粒聚集、反复冲击该区域;在小流量工况下，叶片压力面出口和吸力面出口均出现大区域的回流，甚至延伸至叶片中段，随着流量增大，回流和旋涡区域逐渐缩小，由此可见叶片出口在小流量工况下的磨损比较严重;其他因素一定时，固液混合物的流量越小，颗粒在进入叶片流道前停留的时间越长，导致颗粒与叶片头部的碰撞概率增大;随着颗粒直径增大，颗粒向叶片压力面靠近的趋势越明显，与压力面的碰撞机会也增多，从模拟结果可以看到，该叶轮对1mm以上的大颗粒适应性不好，在设计流量工况下，0.5~1mm粒径范围内颗粒适应性最好。

关键词: 渣浆泵, 叶轮, 工况, 清水流场计算, 颗粒轨迹