Temperature Fleld Analysis For The Low Pressure Casing Of Steam Turbine

Modern turbines are developing in the direction of high parameters and flexible operation.This poses challenges to structural design,clearance assessment,and lifetime prediction.To calculate the thermal stress,thermal expansion,lifetime,and creep of the cylinder in steady state or transient conditions,accurate temperature field results are criticalTraditional temperature analysis method only for the casing has natural defects that cannot be calculated by using real boundary conditions(temperature field and heat transfer coefficient).This method uses a one-dimensional thermal calculation or fluid simulation to find the average temperature of the wall,and uses the empirical formula to calculate the convection heat transfer coefficient.This will inevitably result in limited accuracy of the solution.In this paper,based on the conjugate heat transfer principle of fluid-solid coupling analysis method,the whole machine simulation of a certain type of ultra-supercritical steam turbine low pressure cylinder(without shaft)is considered,and the importance of blade flow path,extraction steam structure,wet steam,etc.is considered.Characteristics,the internal flow of the low pressure steam turbine and the temperature field distribution of the cylinder are given.One-dimensional thermal calculation data was used to verify the correctness of the CFD flow simulation results.The relationship between the distribution of temperature field and heat transfer coefficient in the solid domain such as the cylinder and the blade carrier and the steam parameters is analyzed.The results of this study show that the results of detailed flow field and solid temperature field can be obtained by conjugate heat transfer analysis,which can provide comparison and verification for the engineering method of cylinder temperature field analysis.The research method used in this paper can also be used for temperature field analysis of high pressure steam turbine and intermediate pressure steam turbine.