关于固定管板热交换器壳程圆筒轴向应力的讨论

ON AXIAL STRESS IN SHELL SIDE CYLINDER OF FIXED TUBE SHEET HEAT EXCHANGERS

我国管板计算标准GB/T 151和JB 4732中给出了固定管板式热交换器壳程圆筒轴向薄膜应力σc的计算公式及其校核条件。该条件对σc取绝对值按材料许用应力进行校核,不区分拉伸应力和压缩应力。JB 4732标准中虽然根据变形协调方程求解得到了与管板连接的壳程圆筒端部的作用内力素V s、M s,但是并没有要求进一步计算壳程圆筒端部的局部应力。文章针对我国标准对于壳程圆筒轴向应力计算和校核条件的简化处理,通过工程实例和有限元分析,对其可行性和合理性进行了验证。

The calculation formula and checking conditions of the axial membrane stressσc in the shell side cylinder of fixed tubesheet heat exchangers are given in our country's standards GB/T 151 and JB 4732 for tube sheet calculation.The absolute value of the stress is checked according to allowable stress of the material without distinguishing whether it is tensile stress or compressive stress.Although the components of resultant force and moment V s and M s at the end of the shell connected with the tubesheet are obtained by solving the equations of deformation compatibility in JB 4732,the local bending stress at the end of the shell is not required to be further calculated.Aiming at the simplification of shell axial stress checking conditions in our national standards,this paper verifies the feasibility and rationality ofthe simplification through engineering examples and finite element analysis.