Dynamic analysis of the reheat-stop-valve mechanism with revolute clearance joint in consideration of thermal effect

The dynamic analysis of the reheat-stop-valve mechanism with revolute clearance joint is presented in this work. The effect of joint clearance variation induced by the manufacturing tolerance of components is analyzed combined with the thermal influence of the high temperature steam in working condition. It is shown that by increasing the combined clearance of the revolute joint, a favorable reduction of the friction torque between the bush and the valve shaft can be obtained for normal operation conditions of the reheat-stop-valve mechanism. However, if the temperature of steam reaches to 650 °C, the friction torque between the bush and the valve shaft becomes larger and the sticking phenomena exists. Based on the numerical results, several design recommendations to the partitioning engineer are advanced at the end of the paper.