Couple-field Analysis And Structural Optimization Of The Fixed Tube-sheet Heat Exchanger

Heat exchangers are equipments used for the operation of heat exchanging. In this paper, the development and investigation were carried on in detail, and the current method of intensity calculation was also included. The way of FEM and analytical design was adopted for the intensity calculation and verification without the limitations of traditional methods. The fixed tube-sheet heat exchangers are structural complex and partly discontinuous.This paper took a fixed tube-sheet heat exchanger in the sulfurate plant of some petrifaction as research object for the failure reasons. Because of the loadings of pressure and heat, it was very important to carry on the couple-field analysis which was similar to research other exchangers.The three-dimensional model of the exchanger was set up by APDL language based on ANSYS. The operational statuses were classified by the loadings and degree of danger in order to analyze the exchanger in turn. The maximum dangerous stress and results of intensity verification of every operational status were got. With the analysis of prescriptive paths, the pressed models of exchanger and regulations of all kinds of stresses were found under the loading of pressure, heat and couple-field, also the maximum pipe pulling forces.According to the results of intensity verification, we found that there were undoubtedly failures happened of the exchanger in actual operations. In this paper two effective ways were advanced to overcome those failures. One was increasing the contour radius of the fillet connecting the tubesheet and the shell, the tube shell. It was obtained that increasing the radius could significantly decrease the membrane force and peak force and improve the stress distribution; the other was reducing the thickness of the tubesheet which effectively weakened the heat stress in the condition that the temperature was the mainly manipulative loading. At the last, the appropriate radius and thickness were obtained after the satisfactory intensity verification.