Numerical Simulation And Structure Optimization Of Transition Section From Non-pressure Flow To Pressure Flow In Water Project

When the water state changes from non-pressure to pressure, the structure design and the size design of the transition section between the two is related to the amount and investment of the whole project. The water state of the transition section has direct effects to operational safety and stability of pressure flow section. Therefore, it is of great significance to research the water state of the transition section for selecting a reasonable type and size for it.Present research on transition section from non-pressure flow to pressure flow focuses on the water of Pumping Station forebay. Research methods mainly include theoretical analysis, physical modeling experiments and computer simulation. Each research method has made many useful results. With the progress of numerical solution techniques of fluid dynamics and computer technology, using computer to simulate the water state will be one of the important directions in the future research of fluid engineering.This paper simulates the water of the transition section from non-pressure flow to pressure flow connecting a rectangular open channel and a pressure pipe in a water project by using the standard k ?εtwo-equation turbulence model of the software Fluent 6.2.16. The water state of the transition section is studied and analyzed by the way of velocity vector and velocity contour. By comparative analysis to the results of simulation and experiments, the turbulence model is tested and scientific validated. The research reflects that the results between simulation and experiments are consistent. When the width of the transition section is small, the velocity distribution along the width is more uniform. The main water flow along the water depth focuses on above the bottom of non-pressure flow and near the outlet of the transition section. There is a whirlpool or dead zone below the main water flow zone when the flow changes and the size of which is related to flow but its location basically unchanged. According to the reasons above and to reduce the amount and investment of the whole project, this paper proposes that a reasonable structure type of a transition section is a transition section that bottom tilted when connecting a rectangular open channel and a pressure pipe in a water project. The problems of free surface and bubble simulation of the transition section should be studied.