Characteristic Model of Combined Governing Valve and Governing Stage and Optimization of Steam Distribution of Steam Turbine

For the nozzle steam turbine, the combined flow characteristics calculation model of governing valve and governing stage is established by calculation, and tested with open literature experimental data. The accurate flow of the governing valve can be calculated with the model by using the combination pressure ratio and the valve opening, which is convenient for engineering application. Method a calculation model for the off-design performance of a 300 MW steam turbine unit based on the combined valve model, and the valve distribution function is optimized, and the flow character of the sequential valve is obtained. Then the steam distribution optimization is analyzed by using the load and valve position. Analysis shows that the combined flow characteristics calculation model of governing valve and governing stage can reflect the characteristics of the valve accurately. According to the model, the flow characteristic is optimized, the reasonable overlap degree is obtained. The optimal slip pressure curve of the unit is obtained, which reduce the heat consumption during low-load operation of the unit and improves the flexibility and peak-regulating capacity of the unit and provides the theoretical basis for optimization test.