Numerical model for 3-D thermal elastic contact analysis and its application in steamtight analysis of high pressure casing of turbine

The high temperature and large pressure of inlet steam lead to large thermal stress and large thermal deformation in high pressure casing of turbine, it may lead to steamtight problem of the casing. Based on the temperature filed analysis and elastic contact theory, a three dimensional finite element model to analyze the deformation and stress of casing has been developed, some new methods to solve the elastic contact problem of the casing were also introduced. Then the high pressure casing of a 100 MW steam turbine is analyzed, some numerical results such as temperature distribution, stress and deformation are obtained. The analysis results is applied in a redesigned high pressure casing, the operation experience of the casing shows the numerical analysis can provide usable data for casing design and improve its reliability.