Thermal growth prediction on 4 MW steam turbine casing using finite element method

Adjustment of shaft alignment in steam turbine installations is an important procedure in carrying out preventive maintenance. The shaft alignment specification consists of a coupling target and the thermal growth which depends on the operating temperature and the material used. In the new steam turbine, the value of thermal growth can be calculated theoretically, but in fact, experience has proven that this method has missed a lot, whereas when using the experimental method (hot & cold alignment), the costs are quite large. To solve this problem, predicting the value of thermal growth can be done by simulating thermal expansion using the finite element method. In this study, the lower casing steam turbine simulates its thermal expansion according to its operating temperature so that the value and direction of deformation due to thermal expansion are known. The simulation results of this prediction give the thermal growth value on 4 MW backpressure steam turbine foots 0.021 mm (foot 1) and -0.055 mm (foot 2).