Numerical Analysis Of The Heat-Flow Coupling For Rotor Of Supercritical Steam Turbine

With the continuous improvement of thermal power units'parameters, the security issues of steam turbine have become increasingly prominent, and a variety of means must be used to ensure the safe operation of generating units. Therefore, accurately service life prediction and reasonable life management of steam turbine equipment are of great significance to extend life span and ensure safe and reliable operation of the unit. Using the developed CFD technology to research the aerodynamic performance in the steam turbine can get the detailed parameters when the turbine starts and shuts down and other conditions,which is of practical significance to the life assessment of steam turbine. This paper studies the numerical method of heat and flow coupling and analyzes the impact of numerical grid, especially the boundary layer grid on the results, so the number of computational grid must be coordinated with the computing time and computer capacity. In addition, through the numerical analysis of two classic problems of coupling of heat transfer and flow, and combing the flow and heat transfer characters of supercritical steam, the general numerical method of using the FLUENT software to solve the coupling problem under supercritical pressure was obtained.On the basis of the above, the paper take the numerical and theoretical methods to calculate the seal leakage and the flow characteristics of the high-pressure cylinder, and combined with variable conditions thermal calculation, pressure and temperature in different conditions of the high-pressure cylinder are got as the boundary conditions of the calculation of turbine. And then, a 600MW supercritical steam turbine was taken as the research object. The geometric modeling was created through the reasonable simplification of the internal structure of high-pressure cylinder, especially for the simplification of the pressure-level blade. Finally the flow and heat transfer in the high pressure cylinder was calculated with the FLUENT software and the temperature of rotor surface and the heat exchange between high pressure steam and the cylinder were obtained, which provide the temperature boundary conditions to thermal stress analysis using the finite element method. Based on the research of numerical method of coupling calculation of flow and heat transfer, a general method to calculate and analyze the problem of flow and heat transfer coupling was obtained by using the CFD software, and then the high pressure cylinder of a 600MW steam turbine was calculated in variable conditions and the flow and heat transfer conditions were showed clearly, especially the rotor surface temperature distribution which is the basis for evaluation of the rotor life.