离心泵内示踪粒子运动的离散相模型模拟  

Simulation of Tracer Particles Movement by Discrete Phase Model in the Centrifugal Pump

作　　者：李亚林[1] 袁寿其[1] 汤跃[1] 黄萍[1] 李晓俊[1] 

机构地区：[1]江苏大学流体机械工程技术研究中心,镇江212013

出　　处：《农业机械学报》2012年第11期113-118,64,共7页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家杰出青年基金资助项目(50825902);江苏省自然科学基金攀登项目(BK2009006);江苏省研究生创新计划资助项目(CXLX12_0641)

摘　　要：采用离散颗粒模型(DPM)对离心泵内示踪粒子运动进行了数值计算。在该模型中,采用经典的RNG k-ε模型来求解离心泵内的清水流场,并与试验对比验证模拟计算的可靠性,然后在清水流场基础上对离散示踪粒子采用Lagrange方法模拟,求解不同性质的粒子运动方程。通过粒子运动轨迹线与恒定或准恒定流线的对比,以及粒子相对速度随流场空间尺度的变化关系分析了粒子的跟随特性。数值模拟结果表明:当粒子直径大于50μm,不同密度的粒子在泵内跟随性差别很大,而直径在20μm以下,粒子跟随性对密度的敏感度降低;粒子密度与流体密度相等是一个重要的界点;对于流道内存在漩涡等不稳定流的追踪,只有无量纲密度比ε接近1,且直径足够小的粒子其轨迹线才与流体的流线接近;直径在20μm以下的粒子相对速度大小与流体接近,跟随精度较高;考虑到粒子的散射特性,建议本泵选用直径在20μm左右的聚苯乙烯粒子作为示踪粒子。Motion of tracer particles in the centrifugal pump was calculated by discrete phase model. In this model, the fluid field of the centrifugal pump was solved by the two-equation RNG k - 6 turbulence model. The pump performance curves were simulated to check the calculation accuracy by comparing with the experimental performance curves. Based on the result of the flow field, the tracks of tracer particles with different densities and diameters in various conditions were achieved by using Lagrange method. Through 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. Numerical simulation results showed that tracking characteristics of different densities, particles were significantly different when their diameters were greater than 50 μm. While diameters were less than 20 μm, densities were very low impact on the following performance. It was very important when the particle density was equal to the density of fluid. In the channel with unstable flow such as the vortex flow, the particle trajectory line was closed to the fluid flow line when the tracer particle with smaller diameters and the density was the same with the fluid density. Changing with spatial scale, the particle＇s speed was closed to the fluid velocity when the particle＇ s diameter was under 20 μm. Finally, taking the particle scattering characteristics into account, it was recommended that 20 μm polystyrene should be chosen as tracer particles for this centrifugal pump.

关 键 词：离心泵 示踪粒子 离散相模型 跟随性 数值模拟 

分 类 号：TH311[机械工程—机械制造及自动化]