深度调峰下锅炉高温再热器进口集箱应力分析OA

In order to reveal the influence of deep peak shaving on the thermal mechanical response of the inlet header of high temperature reheater of ultra supercritical boiler,SA-335 P91 steel header of a 1 000 MW unit is taken as the research object,based on the actual peak shaving operation data,a refined numerical model is established by using the finite element method,and the temperature field,mechanical stress and thermal mechanical coupling total stress are systematically analyzed under the design steady state and deep peak shaving transient conditions.The results show that:under the design condition,the temperature distribution of the header is uniform,and the total stress after the coupling of mechanical stress and thermal stress is concentrated at the root of the connection between the nozzle and the cylinder,which is in an elastic and safe state as a whole.During deep peak shaving,the steam temperature and pressure fluctuate frequently and sharply,the inner and outer walls of the header form a significant radial temperature gradient,the heat concentration at the connection between the nozzle and the cylinder is serious,and the thermal stress superposition significantly increases the total stress,and the peak value is 1.2～1.3 times of the mechanical stress.The nozzle root is a permanent high stress danger zone,and the alternating load is easy to induce creep fatigue damage.The research results can provide theoretical support for the optimization of header structure,safe operation and life management of similar units.