Calculation Method And Application For Differential Expansion Of Steam Turbine Based On Reciprocal Theorem Of Works

Steam turbine differential expansion is one of the most important factors which effect the start-up time and generator unit security. The reciprocal theorem of works is first applied on the online monitoring of steam turbine differential expansion. A new method for calculating axial displacement of steam turbine rotor and cylinder is put forward and the varieties of differential expansion with respect to time are given. A new shape function calculating transient temperature field is formed and the variable step difference formula is also proposed considering the character of practical transient temperature field, which can improve the efficiency and precision of the result. Based on the data of starting from cold state in 300MW unit, the axial displacements of HP rotor and cylinder with respect to time are obtained which directly reflect the variety of real space of rotor/stator. The method in this paper is accurate, efficient and robust, which has great significance of realizing the online monitoring of differential expansion.