离心式纸浆泵内部流动的数值模拟

Numerical Simulation of Internal Flow in Centrifugal Pulp Pump

为研究小流量工况下离心式纸浆泵内部流动特性,采用Mixture多相流模型对某一离心式纸浆泵内部流动进行三维不可压两相湍流流动计算,并与清水工况的计算结果进行了比较。对比分析了不同流量工况及介质对泵内流体速度、压力和体积浓度分布的影响,并预测了水力性能。结果显示:纸浆泵叶轮流道内速度变化不均,存在大面积回流;相同介质时,流量越小叶轮流道内部流动越不稳定;相同工况下,清水介质下的流动较两相流时更为稳定;两相流时泵的扬程及效率整体都低于清水介质;纸浆分布局部不均,叶片表面进口处叶根和叶顶部位浓度较大,易造成局部磨损,降低叶轮寿命。

To study the internal flow features of centrifugal pulp pump under small flow working condition, this paper conducts three-dimensional incompressible two-phase turbulence flow computing for internal flow in a centrifugal pulp pump with Mixture multiphase flow and compares with the calculation result under fresh water working conditiom conducts contrastive analysis on the influence of different flow working conditions and mediums on fluid velocity in the pump, pressure and volume concentration distri=bution and predicts the hydraulic performance; finds that the velocity change in impeller passage of pulp pump is nonuniform and there is a large area of backflow;with the same medium, the smaller the flow, the more unstable the internal flow in impeller passage; under the same working condition, the flow with fresh water medium is more stable than two-phase flow; the lift and efficiency of pump under two-phase flow are lower than that under fresh water medium; pulp distribution is nonuniform locally and its concentration in the root and on the top at the entrance on the blade surface, which is easy to cause local abrasion and reduce the life of impeller.