基于CFD-DEM耦合算法的开式设计旋流泵磨损研究

Wear Analysis of Open-design Vortex Pump Based on CFD-DEM Coupling

摘要:

为了探究开式设计旋流泵的磨损规律, 基于 CFD-DEM (Computational fluid dynamics-discrete element method)耦合方法,并结合 Archard 磨损模型,在 1% 、3% 、5% 共 3 种不同体积分数下,开展数值模拟与实验研究。 重点分析旋流泵内部流动规律、颗粒分布特征以及关键部件(叶轮、蜗壳及进口内壁)的磨损规律。 研究结果表明, 随着颗粒浓度的增加,旋流泵的扬程和效率均出现下降趋势,当颗粒体积分数从 1% 提升到 3% 时,其下降幅度大于体积分数从 3% 增至 5% 的情况。 旋流泵关键部件的磨损程度随颗粒浓度的增加而加剧。 颗粒对叶片的切向累计剪切强度显著高于法向累计冲击强度,这说明叶片的磨损主要是由摩擦作用引起的。 进一步分析发现,压力面的磨损程度明显高于吸力面,尤其是压力面的进口边受切向摩擦与法向冲击作用相对其他区域均较高,所以其磨损最为严重。 此外,叶片的整体磨损主要集中于靠近后盖板的区域,并且从压力面到吸力面,后盖板的磨损程度逐渐减轻。 蜗壳的磨损程度次于叶轮,其中隔舌处由于过流面积较小,导致颗粒流速加快,撞击频率增高,成为蜗壳中磨损最为严重的部位。 具体来看,从第Ⅰ到第Ⅴ断面,蜗壳壁面的磨损主要集中在后侧,且磨损较为严重;而在第Ⅴ到第Ⅹ断面,由于受到无叶腔内循环流的影响,磨损逐渐向前侧扩展,因颗粒分布变得更加扩散,磨损程度相对较轻。 有一股螺旋流从无叶腔沿着进口内壁逆向流动,颗粒浓度越大,螺旋回流长度越短,且进口管壁面的磨损呈现螺旋状特征,距无叶腔越远,磨损程度越轻。

Abstract:

In order to investigate the wear patterns of the open-design vortex pump, it was based on the computational fluid dynamics-discrete element method (CFD-DEM)coupling method and combined with the Archard wear model to conduct numerical simulations and experimental research, considering three different volume fractions: 1% , 3% , and 5% . Focusing on analyzing the internal flow pattern of the vortex pump, the particle distribution characteristics, and the wear patterns of key components, including the impeller, volute casing, and inlet wall, the results showed that as particle concentration was increased, the head and efficiency of the vortex pump exhibited a decreasing trend, with a more pronounced decline when the concentration was increased from 1% to 3% compared with the increase from 3% to 5% . The wear of key components was increased with the increase of particle concentration. The cumulative tangential shear force exerted by the particles on the vanes was significantly higher than the normal cumulative impact force, indicating that vane wear was primarily attributed to friction. Further analysis revealed that the wear on the pressure side was significantly more severe than on the suction side. Especially at the leading edge of the pressure side, both tangential friction and normal impact were relatively more intense than in other regions, resulting in the most severe wear. In addition, overall blade wear was primarily concentrated near the rear cover plate, with the wear on the rear cover plate gradually decreasing from the pressure surface to the suction surface. The wear on the volute casing was the second only to that on the impeller, with the tongue of the volute casing experiencing the most severe wear due to the reduced flow area, which accelerated particle velocity and increased impact frequency. Specifically, from section I to section V, wear on the volute casing wall was primarily concentrated on the back side, where it was more severe; while from section V to section X, due to the influence of circulating flow in the bladeless cavity, wear gradually expanded to the front side, although the degree of abrasion was relatively light as the particle distribution became more diffuse. Additionally, a spiral flow was observed as moving in the reverse direction from the bladeless cavity along the inlet wall. As particle concentration was increased, the spiral reflux length was decreased, and the inlet pipe wall exhibited a spiral wear pattern, with wear intensity diminishing as the distance from the bladeless cavity increased. The results can provide a theoretical reference for the optimization and structural improvement of the vortex pump.