Research On The Shell Side Flow Field And Performance For The Shell And Tube Heat Exchanger

With the deepening development of economy and the strategy of sustainable development, energy conservation and emission reduction are the issues everyone must face that caused by harsh climate and environment, unrestrained exploitation of resourcesSo when we do the research of heat exchanger performance on shell and tube heat exchangers, we must first consider its comprehensive in thermal efficiency, especially the flow state and distribution characteristics of shell fluid, a deep understanding of the flow field change on improving the structure design of heat exchanger,optimization heat exchanger equipment performance and energy utilization rate has important significance.In this paper,shell side flow field were simulated under the three dimensional numerical simulation by CFD software FLUENT which be based on the model of single shell pass and double tube passes for tube heat exchanger and the method to improve the accuracy of numerical simulation be also analyed.Shell and tube heat exchanger shell diameter is350mm, the heat transfer tubes specifications is φ25x2.5, the length of heat exchanger tube is1500mm, the number of heat transfer tube is76, heat transfer tube using equilateral triangle arrangement. Single segmental baffle heat exchanger were simulated five different baffle spacing and four different baffle plate gap height. The simulation results show that:when the baffle spacing is smaller, the heat transfer performance is better, the baffle plate gap is larger, retention area of fluid produced in the baffle the windward and leeward is larger, pressure drop of heat exchanger shell is smaller.For double segmental baffle heat exchanger, this paper adopts a baffle plate gap, four different inlet velocity of shell-side, simulate the flow field change under the same baffle spacing, when A board, B board as the first baffle plate, the effects of different shell-side inlet velocity on the distribution of flow field.Through the comparative analysis of the flow field of the shell in the shape of the two baffles, while the decrease of double arched baffle plate heat exchanger to reduce the total pressure drop in the shell plays a positive role, but the surface heat transfer coefficient is far less than the single segmental baffle heat exchanger.Standard k-ε turbulence model,the pressure velocity coupling SIMPLE algorithm are used in the simulation process of shell and tube heat exchanger, Standard format is used in the pressure equation discretized equations. Through numerical simulation, we not only have a deep understanding with the changes of the shell on the results of shell and tube heat exchanger performance, also can determine the optimum heat exchanger baffle plate spacing and baffle gap height combinations optimization, provide a theoretical reference for optimization design and R&D the heat exchanger shell type.