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提出用围带或凸肩接触面上的法向作用力来表征叶片相邻围带或凸肩的接触关系,并通过迭代计算接触法向力从0转变为正的临界转速值(即接触转速).迭代计算中,接触面上的法向作用力由三维接触有限元分析获得,并取上一次有限元分析结果作为本次有限元分析的初始值来提高收敛速度.应用该方法对工作转速为3 000r/min的某200MW汽轮机组末级叶片相邻围带、凸肩的接触转速进行了计算.结果表明:迭代7次后接触转速的计算误差小于11.7r/min;该叶片围带、凸肩接触法向力随转速的加快而增大,且在工作转速下达到最大值.
It is proposed to use the normal force on the contact surface of the shroud or shoulder to characterize the contact relationship between the adjacent shrouds and shoulders of the blade and to calculate the critical rotation speed (ie the contact speed ) In the iterative calculation, the normal force on the contact surface is obtained from the three-dimensional contact finite element analysis, and the last finite element analysis result is used as the initial value of the finite element analysis to improve the convergence speed.This method is applied to the working speed The contact speeds of the adjacent shrouds and shoulders at the last blade of a 200 MW steam turbine unit at 3 000 r / min were calculated. The results show that the calculation error of contact speed after 7 iterations is less than 11.7 r / min. The contact force of shoulder contact increases with the increase of rotational speed, and reaches the maximum at the working speed.