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Design and Bolt Optimization of Steam Turbine Casing using FEM Analysis


Prathap S , Department of Mechanical Engineering, VVCE, Mysuru ; Prathap S, Department of Mechanical Engineering, VVCE, Mysuru ; Dr. L J Sudev, Department of Mechanical Engineering, VVCE, Mysuru


Casing, FEM, Bolt Pretension, Pressure, Optimization


Steam turbines are the device used to convert thermal energy of steam into mechanical energy to produce electrical energy. Its components are made up of alloy steels operated at high temperature and high pressures. Steam turbine casings are the massive cast structure where high temperature and high pressure steam from boiler passes through nozzles. Casing withstands steam pressure & support internal components. Material used for casing is chromium steels. Bolts and diameter of bolt holes play a vital role between casings failure of which is harmful to external environment. High pressure steam causes stresses on casing wall which is responsible for cracking & casing distortion (deformation) if it crosses yield stress. Holes & notches are the critical area for crack growth as it is highly stress concentrated area. If it is reduced the stresses can be reduced greatly and also material can be saved considerably. In the present study, design of casings is done using UG software. Linear static analysis and bolt optimization is carried out with FEM Analysis using ANSYS WORKBENCH 14.5. Linear static analysis is carried out to check the structural performance of the casing under static load condition of pressure. The bolt diameters are varied and the resulting stresses are compared for optimization. However, the results show the design is safe since stresses caused by pressure is below yield stress of 535 MPa, deformation is under limiting value of 1. Stress concentration area is reduced with the bolt optimization. Since casing with 26mm bolt diameter produces least stress it is recommended.

Other Details

Paper ID: IJSRDV4I70292
Published in: Volume : 4, Issue : 7
Publication Date: 01/10/2016
Page(s): 1084-1088

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