Physical model setup and tests on cooling circulation water pumping intake system

Abstract

Abstract The thermal power plant built by the Taiwan power company intends to use multiple cooling circulation water intake systems to introduce seawater from adjacent sea areas. The water in the front pool of the water inlet is introduced into the pump chamber through the large pump in the circulating water pump sump. The primary function of the pump chamber is to provide a stable and uniform flow condition before the large pump sucks in the seawater. When the hydro-dynamic conditions outside the pumping station are not ideal, and the inflow is relatively unstable, the pumping chamber can provide a buffer space for rectification. In addition, when the flow field near the suction intake of a large pump can maintain a certain degree of stability in space and time, it can reduce the frequency and intensity of the vortex or other harmful factors caused by the flow field. Moreover, a pump sump flow field can also maintain the pump's working efficiency, reducing vibration and maintenance costs. Although the relevant design standards such as the Hydraulic Institute (H.I.) standard in the United States or the British Hydromechanics Research Association (B.H.R.A.) standard in the United Kingdom can be consulted for different types of pumping room geometric layout planning and design recommendations. However, most design references are obtained from the boundary conditions of general cases. Therefore, these design criteria indicate that when the pump room geometry and flow conditions have special considerations or detail design, physical model tests should be conducted to verify it or correct the layout according to the model test results. Because the fluid mechanisms involved in the relevant research are complex, the current theoretical or numerical models are not enough to fully simulate flow fields. Therefore, it is necessary to conduct a physical model test based on the feasibility model scale. Based on the similarity theory to scale down prototype structures, the flow mechanism of preliminary design is reproduced, and the revised plan is also verified in the physical model to satisfy the project objectives. The qualitative flow field visualization method was used to observe the free surface vortex, subsurface vortices, and the swirl angle in the suction pipe under different layout schemes at each physical test case. The tested results show that the flow pattern and vortex strength are both acceptable with designed anti-vortex devices.