Research On Mechanical Behavior Of Self-Tight Seal Tubesheet For U-Tube Heat Exchanger

Shell and tube heat exchangers are typical process equipments in petrochemical industries, and tubesheet is the most important and complicated part of shell and tube heat exchangers. Analyzing stress correctly performs an important role in assuring the economy of heat exchanger and saving the material while keeping sufficient strength of the tubesheet.It is difficult to find out an engineering example that plain cushion self-tight seal applied to tubesheet seal in domestic and overseas references. At the same time, there is nobody to do the finite element analysis of self-tight seal tubesheet of U-tube heat exchanger. Basing on the opportunity, this paper researches self-tight seal tubesheet of U-tube heat exchanger.The paper introduces several common structure types of shell and tube heat exchanger, and briefly describes seal types of tubesheet for U-tube heat exchanger. It can't adopt traditional method to design and calculate self-tight seal tubesheet of U-tube heat exchanger. So this paper uses finite element numerical analysis method to research temperature field and stress field of tubesheet.There's no calculation method about plain cushion self-tight seal among the common seal structures'. Therefore, the article does the related theoretical calculation of plain cushion self-tight seal.In the part of tubesheet temperature field analysis, it introduces the production of thermal stress and analysis method of temperature field. First do these correctly: model building, mesh generation and loading of the temperature field. Then get the solution to temperature field. Finally, analyzing path results and summing up rules.The paper also researches the stress distribution condition. Tubesheet stresses of seven operation cases are analyzed and evaluated. The stress intensity of tubesheet is eligible. At the same time it researches total stresses and membrane stresses of seven paths in tubesheet. Through stress analysis of tubesheet, we can find out the most dangerous operating case and position, and then it can provide reference for tubesheet design.Furthermore, the paper still studies the self-tight seal tubesheet of U-tube heat exchanger deeply. For the first time it studies stress changes of tubesheet which radius is diminished, the stress changes of inner and outer wall of heat exchanger tube and axial stress changers of which.In the process of study, it finds that radial stress formulas of U-tube heat exchanger's tubesheet in national standard 151-1999 whose prescriptive scope of uses does not include self-tight seal tubesheet. If self-tight seal tubesheet of U-tube heat exchanger is still designed by this method, it'll produce large error. So, this paper also applies finite element numerical analysis to study radial stress of self-tight seal tubesheet of U-tube heat exchanger.The paper studies self-tight seal tubesheet of U-tube heat exchanger from many aspects and angles, analyzes and sums up mechanics characteristic of this tubesheet. And it also provides a mass of analysis results which has certain value for this kind of tubesheet.