Study On Thermal Stress And Vibration Related Problems Of Steam Turbine Rotor In Combined Cycle Start Process

With the growth of China’s economic level,the electricity consumption structure has also undergone great changes.The peak-to-valley difference of electricity consumption has also gradually increased.At the same time,due to the poor economic performance of thermal power units at low load,it is impossible to participate in the peak regulation of the power grid in time.Due to the formation of the competitive bidding pattern,the gas-steam combined cycle was studied to analyze the thermal stress of the rotor during operation and the life calculation,as well as the vibration-related problems encountered during the start-up process of the gas-steam combined cycle unit.It is of great practical significance to improve the safety and economy of the unit.During the frequent start-stop process of the unit,the turbine rotor is subjected to a large amount of alternating stress,especially in the part where the thermal stress is concentrated,such as the temperature of the metal in the regulating stage,which will change drastically,resulting in a large thermal stress and safety to the unit.Both the life of the rotor and the life of the rotor pose a serious threat.At the same time,it also limits the target of fast start and stop,and reduces the ability of the unit to peak the peak.Taking a gas-steam combined cycle power plant of Huaneng Suzhou as the actual engineering background,firstly,the rotor thermal stress of the steam turbine startup process of the power plant was analyzed,and the ANSYS Workbench was used as a tool to simplify the two-dimensional simplification of the gas turbine rotor of the gas power plant.The rotor model selects the appropriate meshing and locally encrypts the stress concentration parts,then performs thermal-structural coupling on the turbine rotor to obtain the thermal stress of the turbine rotor and calculates the life loss of the primary start,and then uses the turbine rotor.Based on the thermal stress,and then by changing the different temperature rise rate,find the appropriate temperature rise rate without exceeding the thermal stress limit of the rotor,aiming to increase the start-up rate as much as possible,reduce the start-up time,increase the peak-shaving ability and economy.Sex.Secondly,the Hertz model of rotor rubbing is proposed and the main factors affecting the rubbing are analyzed based on Workbench,including the friction coefficient,dynamic and static gap and the speed of the rotor.The third part is analyzed.The vibration problem,the detailed problem description and analysis of the vibration problems during the start-up process,such as dynamic and static rubbing,elevation adjustment,bracket resonance and differential expansion,have important guiding significance for the analysis of similar engineering problems.