Study On The Hydraulic Optimization And The Parametric Software Programming Of The Bell Inlet Conduit

The inlet conduit which connects the fore-bay and the pump is an important part of a pump system. The main function of the inlet conduit is to adjust the flow patterns and to satisfy the requirements of hydraulic design conditions of the impeller. The ideal flow pattern is a necessary condition to ensure the pump system to work in the best condition and get the best energy performance and cavitation performance for a pump. Bad flow patterns in the inlet conduit may lead to the decrease of the efficiency, even threat the safe operation of the pumping station. So study on the hydraulic performance of the inlet conduit has theoretical and practical value.It takes you plenty of time to draw the line diagram in a program design. If we can design an interface, in which users only need to input the basic parameters of the inlet conduit, and the system will map automatically, users can save a lot of time and improve work efficiency greatly. Therefore, to design a parametric two-dimensional graphics software has some practical value.Elbow, bell, dustpan, oblique and culvert shaped inlet conduit are main kinds of conduit to match the low lift vertical pump. This paper focus on the bell shaped inlet conduit, and the research content is divided into two parts. The first part is to study the hydraulic optimization design of the inlet conduit, and the second part is to design a parametric two-dimensional graphics software.Based on a numerical simulation adopting Navier-Stokes equations and the standard k-ε turbulence model, the hydraulic optimization design of the bell shaped inlet conduit was studied, by investigating the influence of geometric parameters of the bell conduit on hydraulic performance, including the impeller center height, the inlet conduit length, the imported width of the inlet conduit, the horn tube height and the bottom line angle. The results show that among all these parameters, the impeller center height has the maximum influence on the properties of hydraulic. The imported width of the inlet conduit has some effects on the performance of hydraulic. The length of the bell inlet conduit has little influence on the hydraulic performance, which mainly depends on the structure of the upper part of the pump room. With constant impeller center height, the horn tube height has some effects on the hydraulic performance. When the horn tube height equals to 0.6D0, the hydraulic performance achieves the best efficiency. The larger the bottom line angle is, the worse the inlet conduit performs, but the less the construction costs. Therefore, we should consider the balance between two aspects during design.On the basis of previous optimized results and the parameters of an elbow inlet conduit of a pumping station, a bell inlet conduit was designed. The comparison between the original inlet conduit and the new designed inlet conduit shows that the bell inlet conduit has better hydraulic performance and costs less in construction.According to the design method of the flow line of bell inlet conduit, a parametric two-dimensional graphics software was designed by programming for the horn tube, water guide cone, volute suction chamber and imported linear segment of the bell shaped inlet conduit. In the graphics software, the process of drawing cross sectional view, vertical view and sectional view of the bell shaped inlet conduit was programmed by using AutoCAD drawing software and Visual Basic language as the drawing platform and its interface. Hence, two-dimensional graphics of the bell inlet conduit can be easily drawn in the software.