获取固定管板换热器管板一次弯曲应力的一种方法及其应用

A METHOD TO OBTAIN TUBESHEET PRIMARY BENFDING STRESS OF FIXED TUBESHEET HEAT EXCHANGER AND ITS APPLICATION

利用载荷分解施加,提出一种构建固定管板换热器管板一次结构、获取一次弯曲应力的方法,一次结构中可保留筒体对管板转动的有利多余约束。以一台甲醇合成塔为例,结合非一次结构法设计存在的问题,利用所提出的方法进行了有限元设计计算。计算表明,该方法给出的许用载荷与极限载荷分析法给出的许用载荷相当,方法可行。值得注意的是,如果应力评定线位于管板的换热管管孔,应充分考虑换热管与管板孔共节点简化对计算结果的影响,一般可乘以一个合适的应力强度增大系数。

With the aid of applying decomposed loads,a method is suggested to construct primary structure and obtain the primary bending stress for the tubesheet of fixed tubesheet heat exchanger. The favorable redundant rotation constraint of the cylinder to the tubesheet can be remained in the primary structure. Taking a methyl alcohol synthetic reactor as example,the mentioned method is used in the FEA to solve the problem without primary structure analysis. It is founded that the allowable load yielded by the mentioned method is comparative to that by direct limit load analysis,which indicates the feasibility of the mentioned method. It should be noted that the conode simplication of the tube and the tube hole are generally non-conservative. If the stress intensity evaluation line is located on the tube hole,a suitable stress intensity enlargement factor should be employed.