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采用有限元软件MSC/NASTRAN计算分析了汽轮机汽缸结构上下缸接触状态的应力分布和变形.分析了汽缸在温度场作用下以及温度场同内压联合作用下的应力分布情况,重点分析上下半缸的螺栓连接面——中分面上的应力和变形情况.建立了气缸三维实体有限元分析模型,并对每根连接螺栓均建立了模拟模型.分析结果表明,同内压引起的应力相比,热应力是缸体中应力的主要成分.当内外壁温差达到100℃时,缸体中最大应力为1230 MPa,出现在约束处应力集中部位,缸体绝大部分应力水平在600-700 MPa;汽缸外壁温度为25℃时,缸体中最大应力为1080MPa,缸体绝大部分应力水平在100MPa,得出减小汽缸内外壁的温差能有效减小缸体中应力的结论.分析表明,缸体轴向最大伸长量为2.55 mm,横向最大变形为2.02 mm.z向最大位移为1.24 mm.中分面有分离,但分离程度较小,分离值均在10-3mm量级上.
The finite element software MSC / NASTRAN is used to calculate and analyze the stress distribution and deformation of the upper and lower cylinder of the turbine cylinder structure under the action of temperature field and the combination of temperature field and internal pressure. The analysis of upper and lower half cylinder Of the bolt connection surface - the middle of the surface of the stress and deformation of the cylinder established three-dimensional solid finite element analysis model and the establishment of a simulation model for each bolt has been analyzed.The results show that compared with the stress caused by internal pressure , The thermal stress is the main component of the stress in the cylinder.When the temperature difference between the inner and outer wall reaches 100 ℃, the maximum stress in the cylinder is 1230 MPa, appearing in the stress concentration part of the constraint, most of the stress level of the cylinder is between 600-700 MPa ; When the outer wall temperature of the cylinder is 25 ℃, the maximum stress in the cylinder is 1080MPa, most of the stress level in the cylinder is 100MPa, and the conclusion is drawn that reducing the temperature difference between the cylinder wall and the outer wall can effectively reduce the stress in the cylinder body. The maximum axial elongation of the cylinder is 2.55 mm, the maximum horizontal deformation is 2.02 mm, the maximum displacement is 1.24 mm, the middle surface is separated, but the separation is small, and the separation values are on the order of 10-3 mm.