基于V3V的泵站进水池内附底涡动力特性研究

Investigation on Dynamic Characteristics of Floor-attached Vortex in Pump Sump by V3V

采用体三维速度场测试系统V3V测量漩涡工况下立式轴流泵喇叭管下方的流场,分析了附底涡演变过程中漩涡区速度梯度分布、漩涡强度及漩涡涡动能的变化。结果表明:附底涡的发生过程是一个伴随着附底涡区速度梯度、漩涡强度及漩涡涡动能不断变化的过程。随着时间的推移,附底涡区速度梯度、漩涡强度及漩涡涡动能先增大,达到最大后保持0.4 s,然后迅速减小,附底涡形成发展的时间大于漩涡溃退消失的时间。在漩涡发展初期,随着距离进水池底部高度的增大,漩涡强度逐渐减小;在漩涡进入保持阶段后,附底涡满足漩涡强度守恒定理;受喇叭管内复杂环境的影响,附底涡强度从喇叭管内最先溃退消失,从上向下逐渐减小。本研究可为进水池优化设计提供理论指导。

The three-dimensional velocity field measurement system V3V was used to measure the flow field under the bell mouth of vertical axial-flow pump.The velocity gradient,vortex intensity and vortex kinetic energy in the vortex region during the evolution of floor-attached vortex were analyzed.The experimental results showed that the formation process of the floor-attached vortex was accompanied by the constant changes of velocity gradient,vortex intensity and vortex kinetic energy.The velocity gradient,vortex strength and kinetic energy of vortex in the vortex region was firstly increased with time and reached the maximum,and then maintained for 0.4 s,and then decreased rapidly.The duration of the formation and development of the floor-attached vortex was longer than that of the collapse and disappearance of the vortex.The vortex intensity was changed in different stages and positions reflected the characteristics of vortices in the evolution of vortices.The intensity of the floor-attached vortex was firstly increased with time,then maintained for a period of time,and then decreased rapidly.In the initial stage of vortex development,the vortex intensity was gradually decreased with the increase of the height from the bottom of the pump sump,after the floor-attached vortex entered the maintenance stage,the floor-attached vortex satisfied the vortex intensity conservation law;affected by the complex environment in the bell,the vortex was firstly collapsed and disappeared from the impeller inlet,and the floor-attached vortex intensity was gradually decreased from up to down.The research provided theoretical guidance for the optimal design of the pump sump.