| As a major equipment for national development,the advanced nature of industrial steam turbine manufacturing is an important manifestation of our country’s comprehensive strength.As a driving equipment,Industrial steam turbines have been widely used in chemical industry,power generation,nuclear power,etc.With the development of the national economy and modern industry,traditional steam turbine technology has also developed rapidly in our country,generally towards higher power density and higher steam inlet parameters.While industrial steam turbines are widely used,in order to ensure the safe and reliable operation of steam turbine units in harsh environments,it is necessary to carry out strength calculation and reliability analysis of rotor and stator assembly under operating conditions.This paper takes a certain type of high-pressure industrial steam turbine as the research object.The general finite element analysis software ANSYS/Workbench is used as the platform to carry out the thermo-solid coupling analysis of the whole casing and complete the strength check under initial steady-state operation.The off-design conditions are calculated for each stage of the steam turbine,and the influence of parameter fluctuations on the constant power operation of the steam turbine is analyzed.Check the dynamic and static strength of the eighth stage steam turbine blisk.It provides a reference for safety inspection during service and the formation of a complete reliability analysis specification for steam turbine components.Taking the industrial steam turbine casing and its components as the research object,the temperature field,stress field and steam tightness of its hydraulic test conditions,initial steady-state operation,and 100,000-hour operation conditions are calculated.By introducing Norton-Bailey creep constitutive equation and Cocks-Ashby multi-axis toughness coefficient,carry out the casing creep strength check with multi-axis effect.The research results show that the structural strength and steam tightness of the casing under the hydraulic test conditions,initial steady-state and long-term operation meet the requirements of normal operation,and the high temperature creep causes the original stress field of the casing to relax significantly.There is a large accumulation of creep at the cylider steam chamber pipe port,in the nozzle and around the high temperature bolt hole.The manufacturer should pay attention to it during the safety inspection during the service period.After the main steam temperature and pressure parameters of the steam turbine fluctuate,the off-design conditions of the steam turbine at constant power are calculated to determine the steam temperature and pressure changes in each stage.The calculation platform for the convection heat transfer coefficient of the steam turbine is compiled,and the off-design condition reanalysis of the steam turbine is realized by Matlab drive,and the influence of the fluctuation of the inlet steam parameter on the temperature field,stress field and creep behavior in each stage of the steam turbine is analyzed.The analysis results show that the change of inlet steam parameters has different influence rules and degrees on the temperature field,stress field and strain field in each stage,but it will not cause position redistribution.It will have a greater impact on the temperature field in each stage and the creep in the high temperature area,and will have a greater impact on the stress fields of the first three stage and the end two stage.Finally,taking the blisk s composed of the eighth stage moving blades of the steam turbine as the research object,the cyclic symmetry method is used to study the dynamic and static characteristics of the blade and blisk under different constraints,and the static strength of the blisk is checked.Use campbell diagram and interferogram to analyze the vibration safety of the blisk.The results show that the dynamic and static strength of the blisk meets the design requirements. |
