3D-PIV Measurement And Numerical Simulation Of Flow Field In The Forebay Of A Pumping Station

Pumping station project has provided an important guarantee for the sustainable development of national economy. Moreover, because of its great energy consuming, improving the operating efficiency of pumping station has the important practical significance. Forebay is an important intake structure of pumping station, and its flow pattern can affect the pump performance greatly.With the rapid development of computer technology, based on the the theory of CFD, the numerical simulation by using computer has become one of the important directions to do research on the flow pattern of forebay. The disadvantage is that it is only the numerical solution on a finite number of discrete points, and it exists some errors. In normal case, we need to use the model test to verify the numerical simulation which will cost plenty of time and funds.This paper takes an example of a pumping station forebay. By using FLUENT software, based on the standardκ-εand RNGκ-εturbulence model respectively, the three-dimensional numerical simulation of forebay is obtained. Furthermore, two kinds of operating conditions are added, including a large discharge and a design discharge. and the flow field of the surface layer, middle layer, bottom layer is compared preliminarily. The results of numerical simulation show that flow separation phenomenon occurs in the forebay. Because of the enough length of forebay, in general, the flow in the forebay is smooth.PIV(Particle Image Velocimetry) is to use particle tracking to measure flow speed and other motion parameters. The PIV technique starts relatively late in our country, what's more, using PIV to measure the flow pattern of intake structure of pumping station is few. With the technique of the 3D-PIV, flow field in the part of the space of forebay is measured accurately and the reliable measurement data is acquired. In the process of measurement, three-dimensional calibration for the measuring section is needed. some relevant softwares are needed for data processing, afterwards, the three-dimensional flow field is obtained.Based on the comparatively accurate test data,the numerical simulation results and experimental results are quantitatively compared to verify and validate reliability and practicability of the selecting turbulence model. a number of measuring sections are selected to compare the flow pattern and velocity.Through the above work, this paper can conclude as follows, under a large discharge, RNGκ-εturbulence model is closer to the test results, and under a small discharge, standardκ-εturbulence model is closer to the test results, which verifies that with the correct settings in the boundary conditions, numerical simulation can also be a reliable method to study on the forebay of pumping station.