Strength Analysis And Steam Tightness Study On Industrial Steam Turbine Cylinder With Variable Parameter

With the development of modern industry,the traditional steam turbine technology hasbeen rapidly developed in recent years,which has directed to the larger capacity,higher parameter and power.Under the the background of the uncertainty of energy supply and lack of alternative and sustainable energy resources,how to improve energy efficiency is becoming more and more attractive to the people.In order to make full use of existing resources,a multi-stage back-pressure turbine was on modification with the minimum cost.The original turbine cylinder and base were utilized by changing the rotor to adapt to new conditions where there was heavier steam flow capacity,higher steam pressure and temperature.However,the improvement of steam parameter is bound to cause the increase of deformation and stress of the cylinder.Thus whether the original cylinder can run stably and reliably under new conditions has been one of the key factors of turbine transformation.With the rapid development of computer simulation technology and the finite element theory,some finite element numerical methods have been widely applied in the design and manufacture of steam turbine,which made the design cycle shorter and the design cost lower.The constantly improved simulation accuracy has been mainly applied to the fields including product development,the evaluation of life and so on,which also provided technical support for expansion of this study.This study took a multistage back pressure steam turbine cylinder as the research object,adopted the finite element technology as the main research methods,and chose the modeling software,Solid Works,and finite element analysis platform,ANSYS Workbench as the main research tools.Through the establishment of the steam turbine cylinder geometry model and the finite element model,multiple physical fields’ thermosetting coupling method has been used to simulate the temperature field,stress field and displacement field of cylinder under the new working condition and the water-pressure test condition.Focused research on the strength of the cylinder and the contact pressure of the mid-split bolted flanges has been conducted to gain accurate distribution of the stress and the mid-split surface pressure,as well as the cylinder displacement in directions.The steam tightness performance of the original cylinder under the new condition has been judged to provide for its modification with theoretical basis.Steam tightness test on thecylinder has been taken in this study,considering not only the actual circumstances of the bolt pretension of the turbine mid-split flange,but also the cylinder intensity and mid-split surface pressure.The displacement of each chamber of the cylinder has been considered as the early data for axial dynamic and static clearance.A relatively comprehensive assessment of the steam tightness performance of the original cylinder has been conducted,which has certain reference value.