Finite Element Analysis And Optimization Of Low-Pressure Rotor Of Steam Turbine In Nuclear Power Plant

Steam turbine generating sets are widely used in power generation enterprises and belong to the power source equipment of the entire power system.The safe operation of steam turbine generating sets is directly related to the electricity safety of the entire national economy.It is very necessary to study the dynamic characteristics of the steam turbine generating set.This paper within the nuclear power plant steam turbine generator set of low pressure rotor dynamic characteristics analysis and research of low-pressure rotor modal,critical speed,rotor of the steady state and transient vibration displacement,the analysis of the effect of low pressure rotor critical speed factors,find out the key elements affecting critical speed,optimization of rotor bearing stiffness to ensure the safe operation of the low pressure rotor in the process of running..Based on an electric power station group in the production of low pressure steam turbine rotor as an example,the low pressure rotor of equivalent simplification,and modeling.Focusing on low pressure rotor coupling state after the red set of deviation model,analyzes the influential elements of the rotor critical speed,compared to two kinds of cases of low-pressure rotor modal shapes,analysis the difference of both modal,judge coupling red set of deviation change characteristics of low pressure rotor.For coupling the red set of deviation of the low pressure rotor steady-state analysis,calculate the rotor under steady state operating conditions,the low pressure rotor bearing position of maximum displacement,the steady state characteristic analysis of low pressure rotor.Next,the low pressure rotor transient response analysis,analysis of the rotor when starting,acceleration,smooth running,low pressure rotor vibration situation,judge the running state of the low pressure rotor.Combination of low pressure rotor equivalent simplification and analysis,find out the influence of low pressure rotor critical speed of the two main factors: low pressure rotor structure and low pressure rotor bearing stiffness.Through the optimization of low-pressure rotor bearing stiffness,achieve the goal of the rotor to avoid critical rotational speed.Make full use of the experimental means to analyze the low-pressure rotor.Determine the difference between the modal value of the low-pressure rotor with the coupling deviation and the theoretical calculation value through the air hammer striking experiment,and verify the accuracy of rotor modeling.At the same time,the reasonability of the theoretical calculation is verified by connecting the external equipment to the low-pressure rotor support and collecting the vibration value of the low-pressure rotor under various rotating speeds.Through the DCS distributed monitoring system,the running state of the low-pressure rotor was detected,and the vibration state of the low-pressure rotor was obtained.Finally,the low-pressure rotor is verified to be safe to operate.A method for the analysis of this type of problem can be established by analyzing the unbalance of the rotor's mode,steady state and transient state.When the unevenness of turbine blade and impeller is measured in different degrees,this method can be used to analyze and judge the unevenness of turbine blade and impeller,providing a more reasonable calculation scheme for the treatment of subsequent field problems.