Life Loss Of Heavy Gas Turbine Rotor During The Process Of Peak-load Adjustment

.According to the statistics of the generation capacity in these years, thermal power is still the most mainly form of electricity generation. Gas turbines are more and more used in field of electricity generation among the thermal power plants. They not only pollute less, but also have an excellent capacity in peak load. Due to the characteristics of rapid peak load and some fault occurring on the machine side or the grid side in daily operation, the actual operation life of gas turbine will be lower than its design life.This paper take the GE 9FA gas turbine rotor as the research objects and carry out a series of researches, such as building the rotor model, response analysis and life loss. In this paper, we will discuss the distribution characteristics of the dangerous cross section of the gas turbine rotor torsional viberation frequency and stress.Calculating the toeque response of the dangerous section of the rotor by transfer matrix and numerical analysis. The main conclusions are as follows:(1) Study and summarize the domestic and foreign typical gas turbine rotor structure and arrangement overall, inducting the principle of gas turbine process of peak and analysing and its influencing factors.(2) Calculating the natural mode of torsional vibration of the rotor shaft system by the transfer matrix method. The first order torsional vibration frequency is lower than the power frequency.(3) Calculating the torsional vibration response of shaft system by using the method of combining the transfer matrix and numerical integration. Combined gas turbine peaking and the starting process for calculating the torsional vibration response. The torque oscillogram shows that first natural frequency about the response of torsional vibration occuring in the process of peak and starting without power frequency. However, the torsional vibration response will contain the power frequency when the grid is connected with it in mistake.(4) Analysing the advantages and disadvantages of common fatigue life loss calculating methods. Make a combination between rain flow counting method and fatigue calculation theory concluded by the local stress for calculating the life loss caused by gas turbine rotor torsional vibration during the process of peak. The calculating results shows that the life loss caused by gas turbine torsional vibration during the process of peak or starting is higher than that during the normal operation.