Stress Analysis And Life Assessment Of Thermal Power Plant Main Steam Pipe

In the boiler of thermal power plant and main steam pipe work in high temperature and cyclic loading conditions for long time. Their typical failure forms mainly are fatigue, creep and fatigue creep interaction caused by material damage. General, the design life of power plant high temperature metal parts of boiler is 30 years or 200000 hours. Unit 2 of Baogang power plant has cumulative operated more than 200000 hours. This paper takes baogang power plant main steam pipe as the research object, Processing the stress analysis and life evaluation, which have important reference value for the safe operation of power plant.This article build main steam pipe model and analyze stress based on CAES ARⅡ.Giving the detailed description of how to build the model and the problem when building the model. Find out the position of the maximum three-dimensional stress through the checking of the first stress and secondary stress for pipeline.This article takes the position of three-dimensional stress of baogang power plant main steam pipe as the research object, established the mathematical and the finite element model of the transient temperature field, stress field. Determine the boundary conditions, constraint conditions and initial conditions when the power unit starts of the main steam pipe elbow and simulate the transient temperature field and stress field of the elbow. Got the change law of temperature and temperature gradient and found the positiontion of the maximum thermal stress and change rule; Analyzes the distribution of mechanical stress, and got the regular between mechanical stress and the steam pressure. Analyzed the total press under the temperature load combined with pressure load for main steam pipe bend. Get the total stress distribution and the change law.Provided the reference basis of the life assessment of main steam pipe.This paper introduces three main failure mode of the main steam pipe, namely fatigue failure, the creep and the failure caused by fatigue creep interaction and introduces the life evaluation method under the three failure modes; Consider the main steam pipe failure is mainly caused by high temperature creep when the the power plant running smoothly, use high temperature creep life evaluation method to calculate the pipeline material life.