Research On The Feature Of High-intermediate Pressure Seal In600MW Grade Steam Turbine

In a600MW grade steam turbine, the pressure difference, geometry and flowfield complexity, mass flow rate and temperature are all much higher in thehigh-intermediate pressure seal than in others. Bending also often occurs in themiddle of high-intermediate pressure rotors, so the research and optimization ofhigh-intermediate pressure seals is important to increase the efficiency, diagnosis andprotection of rotor bending.Based on theoretical, experimental and numerical research findings, a set ofnumerical research methods for analyzing high-intermediate pressure seals is putforward. This method is backed by experimental data. Using this method, the featuresof a high-intermediate pressure seal in both subcritical and supercritical steamturbines are analyzed.The mass flow rate and temperature in different clearance conditions areanalyzed, and the calculated numerical data is checked by experimental results. Thetemperature distribution is obtained which can be used as a boundary condition in thestress analysis of the rotor. Based on the analysis of mass flow rate and temperaturedistribution, the clearance of both subcritical and supercritical seals can be optimizedfor cooling the blade root in the first stage of intermediate pressure cylinder with theleakage flow to protect the rotor from creepage.The influence of different rotation rates and axial movement of the rotor andstator are also analyzed. The influence of heat transfer on the stator surface isanalyzed as well.