The Welded Residual Stress Analysis About Runner Of Large Hydraulic Turbine Taking Account Of Phase Change

In recent year, China has exploited water resources energetically. And China has applied large turbines to construct great hydraulic generating sets. Through investigating and analysing the working runner, one of the main causes which affects the working life-span of runners is arisesing a lot of fatigue flaws in the runners. With the working time increasing, the flaws begin to extend. In the end, the runners should destroy. Due to most of the laminas of runners is welded with the crowns and bands, the welding lines are usually the main areas of arisesing fatigue flaws. To investigate the destruct causes of the working runners, we must analyse the stress in the welding lines, and find out the causes of arisesing fatigue flaws. The paper calculates the welded residual stress of large runner with three-dimension thermal elastic plastic finite element theory, and takes account of phase change in the progress of thermal analysis. It applies the great finite software, Ansys, to analyse the welded residual stress in the welding lines and distributing rule. To improve precision of the results, the paper adopts mid-node hexahedron element to mesh the runner. The welding lines areas are meshed six welding lines, which is consistent with the known fact. The paper choices seemlier constitution relation to simulate mechanics attribute of specifically material in differ temperature. After gaining the results, the paper makes it to compare with the results that are not considering the phase change. It can analyse effect of phase change theory in welded process. In addition, the result of before and after anneal should be compared with test results and another paper results in the same time. It can estimate the facticity of the paper results. I hope that the results of the paper can help to analyse the fatigue flaws arisesing in the runners. In the near future, the issue of runners fatigue work should be solved.