Research On Modeling Of Flows In Inflow And Outflow Conduits Based On Fluent Software

With the rapid progress in the national economy and the continuous advance in science and technology, more and more large scale pumping stations have been built, which play a very important role in every aspect of the national economical construction and the people's life in our country. In order to promote the level in the construction and the management of pumping stations, the modeling of flows in hydraulic machinery and it's installation by the use of the computer is very important for the supply of better flow patterns to the pumps, and for the reduction of the hydraulic losses in the flowing processes, so as to increase the installation efficiency of the pumping station, and to reduce it's energy consumption. At the same time, it will also greatly decrease the cost of model experiment of pumping stations, and supply technical bases for the optimum design and the economical operation of them, which has important theoretical meanings and application values.The major contents of the thesis include:(1) It briefly introduces the current state and the development of the pumping stations in China. Based on analysis of the current state of the flow pattern modeling abroad and at home, explains the meaning of the mathematical simulation of the flows in the inflow and outflow conduits of pumping stations.(2) It sets up the control equation sets for the flow modeling in the conduits with the Reynolds-averaging equation as the principal by adopting Navier-Stokes fundamental equations, and at the same time, derives the differential equations and the corresponding discrete equations, as well as the computational models through the use of the k-ε turbulence model and the solid-wall-surface functional method.(3) After checked by a classical 3-D flow problem, the FLUENT software are used as a calculating platform to compute numerically the flow patterns in the conduits of the large scale pumping stations, which broadens the application scope of the numerical experiment in the fluid engineering.(4) By the use of real projects as the objective, the 3-D flows in the conduits are computed, and through the analysis of the results, suggestions beneficial for the project design and the operational management are obtained.The innovations in the thesis include:(1) It has a deep analysis for the control equations and the turbulence models, andderives a common differential equation, which lays a foundation for the second development of the software of the fluid modeling procedure.(2) It derives a discrete type of the common differential equations by the use of the finite volume method, and the formulas for the calculation of the coefficients. Based on the comparison and the analysis of the difference schemes, the availability ranges are given, and the forged diffusion in the discretion processes are analyzed.(3) In light of the difficulty in the solution of the flow field, the alternate grid suitable for the flow computation is put forward, and the application of the software of FLUENT in the flow modeling is of the pumping stations are probed, a computational platform are set up, which of importance for the application of a commercial software in the fluid engineering.(4) It applies GAMBIT of the FLUENT software to form the grids, and substitutes the cuboid for the commonly used hexahedron grids, which will raise the precision of the mathematical simulation effectively.