Study On The Characteristics Of Steam Turbine Unit Under Peak Depth Regulation In Thermal Power Plant

Along with the growing with intermittent features,instability of renewable energy sources such as wind power and solar energy power grid,and power users demand changing,leading to power grid peak valley load difference increasing,network has become more and more urgent to the requirement of thermal power unit load,but also brings a series of economic and security problems,the ability to adapt to the steam turbine unit peak put forward higher requirements.In this paper,a 600 MW supercritical steam turbine set in China is selected as the research target,and its performance under deep peak regulation is studied and analyzed successively.First,under the depth of peak shaving,the turbine engines running state is more complex,in order to grasp the thermal economic performance of steam turbine unit,calculation and analysis on the load of steam turbine unit energy consumption characteristic,varying load peakload energy consumption calculation model is established,and then to the unit under different load conditions of the test data are collected,after finishing a simple calculation and analysis,determine the steam turbine unit energy consumption indexes under different load load condition,the load rate and the steam turbine unit under different conditions of various economic indicators,the relation between the brief analysis of its economy.Secondly,on the basis of the research on steam turbine unit efficiency,in order to better understand the depth of peak shaving of low pressure cylinder at the end of the level of the influence of the aerodynamic performance,in a 600 MW steam turbine as the main research object,based on the provided commercial computational fluid software Ansys CFX 16.1,by changing the way the export back pressure of steam turbine unit level at the end of the flow characteristics are numerically simulated,analyzed its the last stage blade in design conditions and the flow characteristics of high back pressure condition,the results show that with the increase of level at the end of the back pressure,at the end of the steam turbine unit slopes flow state should be,great changes have taken place within the main show is the import negative Angle of attack and the effect of adverse pressure gradient,Flow separation occurs at the trailing edge of the blade,and a reflux vortex is gradually formed.The loss in the stage increases and may lead to blade blast,flutter and water erosion.Finally,from the perspective of the safety of the crew,in order to ensure that the last stage blade in the working condition of high back pressure is small volume flow downstream field of the safe and reliable work,adopt the method of fluid-structure coupled heat,on different conditions of back pressure level at the end of the moving vane strength for security check,the result shows that under the condition of different back pressure and equivalent stress level at the end of the moving blade slightly lower,with back pressure from the simulation results,this paper studies the last stage blade strength in line with the allowable stress conditions,in the operation process of peaking,the last stage blade itself strength to meet the requirements of the depth of peak shaving.The simulation results have a certain reference value for the design and modification of turbine end-stage blades and are of great significance for improving the safety of thermal power plants in the actual peak regulation process.