| China is rich in hydropower resources, leading the world with680million kilowatts hydropower reserves. And hydroelectric power plays an important part in the country's national economic development. However, what with one thing and another there are many heavy slit laden rivers in China, and serious silt erosions have been occurring on hydraulic machinery operating in those rivers. The runner is the core components of hydro-turbine during the process of energy transformation, so for the runner of Francis turbine, the hydraulic design has a pivotal role in hydrodynamic performance. In addition, the ablation degree of discharge apparatus caused by sand is closely allied to the flow condition. Therefore, it is so necessary to grasp the flow mechanism and the law of motion in hydro-turbine which running under the heavy slit laden rivers to predict and reduce, even resolve the abrasion and cavitation problem of Francis turbine's runner.In recent years, with the fast development of computer technology and computational fluid dynamics, numerical simulation has gradually taken the place of physical experiments because of its advantages like low cost and short experimental period. Currently the numerical simulation methods which are implemented on the computer provide overall process in simulating the model of the Francis turbine as well as the prototype so as to provide accurate results for the numerical analysis and model the situation of the flow field in3dimensions. In this paper, numerical simulation of three-dimensional turbulent flow for the inner flow of solid-water two-phase flow in the flow passage of Francis turbine's runner with long and short blades and long blades. And the prototype of calculation is HLA351-LJ-170. Some conclusions are drawn, they could be used in the optimize design of hydraulic turbine. The main achievements of this paper are listed as follow:Firstly, according to practical parameters of the Francis turbine HLA351-LJ-170, establish the3D geometric model of long and short blades runner and long blades runner using software Pro/ENGINEER.Secondly, lead the hydraulic turbine models into the software GAMBIT, according to the characteristics of the runner, unstructured tetrahedral grid was used successfully so that mesh of the runner was high-quality. And the work of setting up boundary types and regionality types were done.Thirdly, using solid-liquid flow theory and Eulerian model of FLUENT, carry out the3-D numerical simulation for the inner flow of solid-water two-phase flow in the flow passage of runner, and gained the velocity and pressure intensity distribution in the flow channel. What's more, the volume fraction of solid was also gained. While the runner of Francis turbine HLA351is the prototype. From the analysis of the two-phase flow in the runner and the forecast of the wearing of the runner, the results as follows were elicited:under the same condition, compared to the long blade runner, the velocity and pressure distribution of the long and short blade runner was more reasonable, the wearing area was smaller on the same position, and the performance was more excellent. In addition, this conclusion offers references to the design and optimal structure for hydraulic machinery.Finally, through using and analyzing the software FLUENT, the shortcomings of numerical simulation are found out, and some development prospects are drawn. |
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