1D/3D Coupling Calculation Research On Removing-humidity Stage Of Nuclear Steam Turbine

As key equipment in conventional island of nuclear power plant (NPP), nuclear steam turbine plays a very important role in the safety and efficiency of NPP. It is of great importance to analyze the internal flow characteristics of key components during transient change process in the researches of steam turbine. It will expend a large amount of computing resource by 3-dimensional calculation for entire steam turbine. However, it lacks precise boundary conditions during transient flow process if 3-dimentional calculation only aims to the key components, and it can not analyze the internal flow characteristics of key components if 1-dimensional calculation is applied to entire steam turbine. Thus, it is necessary to adopt the coupling simulation of 3-dimensional calculation for key components and 1-dimensional systematic model which can further obtain transient characteristics of key components.This research takes steam turbine with 16 stages as its research subject, and takes the 12th stage as removing-humidity stage. By using discrete particle model, the 3-dimensional flow of removing-humidity stage is calculated. According to different situations of the capture of removing-humidity groove to different diameter droplets, the place of moisture-removal groove is determined, and 3-dimensional coupling simulation is processed finally.When 3-dimensional calculation model has been established, 1D/3D coupling calculation programs are developed by C# programming language. This simulation program functions include automatic operation of Flowmaster and CFX as well as controlling the transfer of boundary data of 1-dimensional systematic model and 3-dimensional components model. By using developed coupling calculation platform, full power steady calculation is completed smoothly. Compare the calculation results with design values to testify the validity of the coupling calculation programs.To improve the stability and efficiency in steady coupling calculation process, four potential factors are researched, which namely are the initial boundary conditions, the iteration times of the 3-dimensional CFD model, relaxation factor and data mapping mode of the coupling calculation. In this paper, the author respectively discusses the above four factors and then explores several ways to coupling calculation, which will lay a solid foundation for further study on complex coupling calculation.To get the basic characteristics of removing-humidity stage, the steady coupling calculation for 3-dimensional CFD model of removing-humidity stage is done smoothly. On the basis of the steady coupling calculation, transient calculation of main steam vale shutdown for the steam turbine is completed smoothly. Analyze the flow distribution and parameter variation of key positions in removing-humidity stage. As a result, provide a new thought to discover 3-dimensional flow distribution of steam turbine which can benefit engineering practice with a reference value.