Thermo-mechanical Analysis of Gas Turbine Casing to Enhance Fatigue Life

Abstract

The vulnerability of gas turbine casings is the area which are found to be the geometries featuring sudden or abrupt changes, such as holes and cross sections. Thermal and mechanical fatigue, which is being exerted on the casing by virtue of factors such as mechanical vibration, thermal cyclic loads and mechanical loads, the fatigue life cycle of the casing is on stake. At the same time, fatigue life of casing is also influenced by the tension exerted by the bolt during assembly called "bolt pre-tension". This work is aimed to address the effect of bolt pre-tension on fatigue life of gas turbine casing taking accountability of its impact. The existing casing is analysed for impact of parameters such as pressure, bolt pre-tension and deformation and is being coupled with thermal boundary conditions and the model is analysed in ANSYS workbench. Based on the results of existing design, casing had to be modified geometrically so that its fatigue life is enhanced. From the analysis, it was found that the fatigue life of modified casing was 16533 cycles more than the fatigue life of existing casing for the same boundary conditions of bolt pre-tension of 1000 N and pressure of 3 MPa.

Análisis térmico numérico de la carcasa de la turbina de un turbocompresor

“…En la turbina es donde se realiza la expansión de los gases que provienen de los cilindros del motor. La entrada de estos gases se realiza por un orificio cuya disposición optimiza la incidencia del flujo sobre los álabes, con esto y la ayuda de la carcasa en forma de caracol los gases se distribuyen a lo largo de la turbina perdiendo presión para poder hacer girar al eje [1], [3].…”