离心泵内大颗粒下运动特性数值模拟与磨损分析

Numerical simulation of erosion and particle motion trajectory in centrifugal pump with major diameter particles

针对离心泵内固液两相流动问题,采用离散模型(DPM),考虑液相与固体颗粒之间相互作用,对离心泵内固液流场中大直径颗粒的粒子运动进行了数值模拟。并对颗粒的运动轨迹、固液两相流磨损进行了进一步的分析。使用UDF文件对颗粒加入Basset力,通过粒子运动轨迹线与恒定非恒定流线的对比,得出了粒子随直径变化对离心泵内流动情况的影响,并在此基础上进行了内部流动对性能的影响以及磨损规律分析。研究结果表明,当粒子直径大于1 mm时,通过使用DPM模型能更准确地获得粒子在泵内的运动情况,颗粒的运动轨迹向叶片工作面偏转较大并且存在多次撞击过程对叶片的磨损程度大,小颗粒易与叶片工作面后端发生撞击,且速度较低,对叶片的冲蚀磨损相对弱些。

Aiming at the Solid-liquid two phase flow problems,considering the turbulence coupling of the liquid phase and the interaction between solid particles,motion of tracer particles in the centrifugal pump was simulated. Solid-liquid two phase flow wear was calculated by discrete phase model. UDF about Basset force was used in the simulation. Comparing particle trajectory with fluid streamline and analyzing the particle speed changed in the relationship with the spatial scale,the particles tracking characteristics were studied. Based on the analysis,Inner flow characteristics of centrifugal pump and wear rules were carried out. The results indicate that when the particle diameter is greater than 1 mm DPM model can carry out the movement of the particles much better. By contraries,little particle is liable to impact the rear-end surface of impeller near to the outlet side. The major solid particle could repeatedly impact machine surface easier than the little particle.