Experimental Research On Flow In The Closed Pump Sump With PIV

Pump sump is the connection between the flange of the inlet of the pump and the inlet of the impeller. With the rapidly increasing awareness of pump efficiency, more and more attention has been paid to the appropriate design of pump sump. A critical developing trend of pump sump is to develop new type pump sump based on the rule of inner flow field.In present thesis, PIV technology has been researched first. By the research on the application range and the theory of PIV technology, it was demonstrated that PIV technology can be used to research the flow field of pump sump. And the process of measurement was made. The means to get three dimensional velocity, which was gotten from two two-dimensional flow fields, was brought forward. These were the basis of researching the inner flow field of the pump sump where PIV technology was used.The other work was the research of closed pump sump. Based on the former design of pump sump, some parts were modified for the facility of making and measurement. With PIV technology, the flow field was measured to judge the performance of pump sump. By analyzing the pictures of velocity, streamline, turbulent kinetic energy and vorticity, we found that the turbulence was bigger while the ratio of the runoff increased. And the vortices always appeared in the field where the runoff was small. This phenomenon could be explained by the theory. Three dimensional velocity and turbulent kinetic energy were gotten. These results showed that the vortices always appeared near the center of the inlet and the vertical velocity was much bigger than the horizontal ones. By measuring the size of air core and the probability of its appearance, we found that the probability of middle-size air core is the biggest while the ratio of runoff is big. And the probability of small-size air core is the biggest while the ratio of runoff is small.