Off-Design Performance Analysis of a 7 MW Class Steam Turbine by Meanline Analysis

Steam turbines have been used for various applications. The published data for the performance analysis of steam turbine are very limited due to the exclusive policy between leading manufactures even though it has been used since the nineteenth century. Therefore, a study was conducted to predict the performance of steam turbine at off-design points. A meanline analysis method was developed, which was validated on a used steam turbine. The compared results showed that they were quite well agreed. In addition, it was applied to a designed 7 MW class steam turbine of ten stages for obtaining the performance at off-design points. The comparable result at design point was well agreed, and the performance at off-design points showed that the output power of the turbine was quite sensitive for the varied mass flow rate and temperature at turbine inlet. The output power was decreased by 12.7% for a 10% decrease of mass flow rate, and it was also decreased by 8% for a 10% decrease of temperature at inlet.