Design by Finite Element Analysis on Tubesheet of Heat Exchanger With a Central Hole Available to Purchase

As one of major components of heat exchanger, tubesheet is of paramount importance to enhance the safety of heat exchanger whether its design is reasonable. As the diversity of the heat exchangers’ operating condition, structures of tubesheets also become very special. A fixed tubesheet heat exchanger with a central pipe whose diameter is greater than other heat exchanger tubes is presented in this paper. A central hole in tubesheet will weaken the stiffness and intensity of the tubesheet and cause local stress concentration along the central hole’s edge. However, there is no design method for this kind of tubesheet with a central hole and it is unable to be calculated using various international standards available. In this paper, finite element analysis code ANSYS is used to simulate the real complex structure, real loads and boundary conditions of the tubesheet so that the design problem can be visualized. The three-dimensional finite element model of the tubesheet is built considering the influence of tube channel, partial shell and heat transfer tube bundle. The different pressure in shell-side and tube-side will cause the mechanical stress. The temperature gradient exists widely and the tubesheet, shell as well as heat transfer tubes can’t transform freely. Therefore, there may exists high thermal stress due to the high temperature difference in shell-side and tube-side. The thermal stress has great impact on the total stress distribution. So the simulation of the temperature field is very important. By means of thermal analysis coupling with structure analysis, the distribution of temperature, stress and deformation is obtained. Through evaluating the stress intensity of the tubesheet, it is found that the dangerous region is located at the edge of the tube distribution region and local stress concentration along the edge of the central hole is not obvious. The result shows that the tubesheet is appropriately designed and the design by finite element analysis method is feasible. This paper provides a solution for this kind of structure’s analysis design in engineering application.