火电机组脱硫泵的设计及其磨损

Design and abrasion of desulphurization pump for thermal power unit

根据两相流的理论设计方法对火电机组所用脱硫泵的叶轮直径、叶轮出口宽度、叶片进出口安放角和压水室等几何参数进行优化设计,适当增大叶片出口宽度和涡室排出口直径、并减小叶片出口安放角以减小磨损,提高泵的效率和水力性能.基于Pro/E软件建立泵的三维全流场模型,结合计算流体动力学软件Fluent 6.3,采用欧拉多相流模型对泵内两相流场进行了数值模拟.对两相流场的磨损机理进行了阐述,根据泵的设计工况对流道内固相体积分数分布进行数值计算及分析,同时对过流部件的基本磨损情况和主要磨损部位进行了预测.结果表明:叶轮的主要磨损部位在叶轮进出口处、叶片工作面、叶片前流线和前盖板处;设计的压水室耐磨衬板间隙自动补偿装置的可更换的结构形式能够保证泵的高效运行并延长泵的使用寿命;泵的性能试验结果表明该泵设计合理,额定点效率提高了3.8%.

Geometric parameters of a desulphurization pump for thermal power plant such as impeller diameter,impeller outlet width,blade stagger angles,and pumping chamber were optimal designed based on the design method of two-phase flow theory.The hydraulic performance and efficiency of the desulphurization pump had been improved by increasing the blade outlet width and chamber discharging diameter properly,and abrasion of the pump was reduced by decreasing the blade outlet angle.The three-dimensional full flow field model was built based on Pro/E software,and the solid-liquid two-phase flow field of the desulphurization pump was calculated through CFD software Fluent 6.3 with Eulerian multiphase flow model.Abrasion mechanism of the two-phase flow field was indicated.Wear of the flow passage components and the main wear parts were predicted according to numerical calculation and analysis of the solid volume concentration distribution in the desulphurization pump passage at design point.It can be concluded that main wear parts of the impeller are impeller inlet and outlet,pressure surface,front lines,and front shroud.A replaceable structure form of wear-resisting lining board clearance self-compensation device in pumping chamber is designed,which ensures the pump to have higher efficiency and longer service life.Test of the pump performance show that the pump had reasonable structure,and the pump efficiency at design point is improved by 3.8%.