工业锅炉鳍片管温差应力计算及结构设计

A New Method and Formula for Structure Design and Calculation of Thermal Stress of Finned Tube Used in Industial Boiler

工业锅炉采用鳍片管时,《蒸汽锅炉安全技术监察规程》以及各种设计计算资料,都只要求校核各部位温度不超过所用材料的许用温度即可,并不考虑温差应力造成的强度失效和低周疲劳破坏。文章通过建立鳍片管温差应力计算数学模型,提出一种工业锅炉鳍片管温差应力和低周疲劳强度校核计算方法和结构尺寸设计公式,此前未见报道。通过计算分析,得出了只要鳍片高度大于厚度,鳍片管的最高温度只在鳍端发生;温差应力满足强度要求时,不会发生低周疲劳破坏。

According to《The Rules of the safety supervisory technique for steam boiler》and the regulations for design calculation of boiler, only restricted condition have to be checked and satisfied that the temperature of every part is lower than the critical temperature of material permitted to use when the finned tube was used in industrial boiler, and the strength failure and low cycle fatigue damage caused by thermal stress have not taken account of in the calculation. In the paper a kind of new calibrated method and formula for structure design and calculation of thermal stress and low cycle fatigue strength of finned tube was proposed. By ar,alyzing the calculating results, we concluded that so long as the rib height is larger than its thickness, the maximum temperature will only occurred at the tip of rib, and when the thermal stress satisfied the requirement of strength the low cycle fatigue damage will not occurred.