考虑制造影响的凝汽器壳体外压稳定性分析

Stability Analysis for Shell of Condenser Subjected to External Pressure and with Fabrication Defects

正常工况下,凝汽器壳程在真空下操作,属于外压工况。为研究外载荷作用下凝汽器外壳的稳定性,建立了凝汽器外壳非线性屈曲分析方法,分析了结构对屈曲载荷的影响,并选择制造引起的壳体不圆度为预加缺陷,通过比较屈曲载荷等参数的变化规律,考察制造因素对外压稳定性的影响。结果表明,凝汽器外壳属于极值屈曲;进汽口结构对屈曲载荷的影响最为显著;热井结构能够在一定程度上平衡壳体两侧缺陷,弱化进汽口带来的影响,小幅提高外压稳定性;外壳的外压稳定性对不圆度的敏感性较低。

In normal working condition,the shell side in condensers is subjected to vacuum.In order to study the stability of the shell of condenser under external pressure,nonlinear buckling analysis method was used so as to analyze the effect of structural imperfections to buckling load beating capacity.Ovality of shell was selected as pre-existed imperfection produced in fabrication,by comparing the changes in values of buckling load,the effects of fabrication to shell stability under external pressure were studied.It was shown as follows:the failure of the shell is limit load buckling;the steam inlet structure has the most prominent effect to buckling load bearing capacity;hot-well structure can be used to balance the imperfections at two sides of the shell and reduce the effect induced from the inlet,then enhance the stability under external pressure a little;finally the stability under external pressure is insensible to ovality.