Analysis Of Stress And Calculation Of Fatigue Life In The Procedure Of Starting Up For 300MW Bioler Drum

Recent years, along with the growth of national economy, the peak-valley difference of electrical network increases day by day, a lot of thermoelectricity generator units with high running parameters and large capacity have to take part in changing the loads and even to startup-halt for adjusting the peak output. The diameter and wall thickness of the boiler drum is relative big. During the process of starting or stopping and altering loads, the pressure rising or dropping and temperature varying will make mechanical and thermal stress of the drum greatly change. The varying of the stress will result in fatigue damage to drum material and shorten the service life of the drum.For this reason, people had paid great attention to this and a lot of research work about drum was carried out. Among these work, the distribution of transient temperature field and stress field, the calculation of low-cycle fatigue life are significant to ensure boiler in good condition and safety running.The thesis takes 300MW sub-critical natural circulation boiler HG1025/ 18.2/540/540-PM2 drum of a Power Plant as object. Based on test data, the multi-disciplinary research across transient temperature field, transient stress field, Low-cycle fatigue life etc was carried out. The thesis mainly carried on the discussion in the followed respects.Firstly, author built a calculating model of the discontinuous area.Then utilized the test data as border condition of the model. The three-dimensional finite element unit was adopted; ANSYS software were used and the transient temperature field, thermal stress, mechanical stress, total stress of the drum were calculated to the model.Secondly, the position of maximum stress of the drum was found out through the analysis of calculating result, some proportionate regulation between mechanical stresses or total stresses and steam pressure also found out. Then used the optimum function of ANSYS applied to the optimization design of part structure. Finally, processed calculation of the Low-cycle fatigue life.