The Research Of Tube And Tubesheet Hydraulic Expanded In Heat Exchanger

Hydraulic expanded of tube and tubesheet in the heat exchange used more and more widely because of its good performance. Although hydraulic expanded research has become more mature, but there is still no corresponding standards to guide enterprise selecting a suitable expansion joint parameters because the whole process of hydraulic expanded is very complex. At the same time, the residual contact stress, the important characterization of joint performance parameters, is not easy to measure in experimental way, and the method of the finite element analysis can effectively solve the problem.In this paper, according to the existing research results, based on given general material stress strain curve of ASME standard, double linear curve model of material is fitted. The differences of this simplified model calculation results and the actual results are very small, and it can be used in engineering. On this basis, through reasonably simplifying calculation model and using the material elastic-plastic theory, the theoretical calculation formula of residual contact stress is deduced under certain expansion pressure in this paper. The comparision of calculation results and simulation results verify the accuracy of the formula. Besides, the different initial clearance of calculation model is established and solved, the results show that residual contact stress gradually reduce with the increase of the gap. Meanwhile, two special cases that the tube is not in tubesheet center and thick tubesheet is expanded partially are researched. And rational suggestions are put forward according to the existing problems.The theoretical calculation formula of residual contact stress is deduced through reasonably simplifying calculation model and material model in this article. And based on this, a series of optimization and research of hydraulic expansion joint are conducted, it has important theoretical research and engineering application value.