Numerical Simulation Of Shell-and-Tube Heat Exchanger And Research On Fin Heat Transfer Enhancement

Energy conservation and emission reduction has become an important direction of development for energy equipment. Heat transfer enhancement and energy efficiency promotion of the heat exchanger has always been the goal of the relevant industry and academia.This paper aims to use CFD methods to simulate the flow and heat transfer performance within the heat exchanger.Firstly introduces the basic classification of heat exchanger and the shell and tube heat exchanger characteristics and its basic advantages, then under the guidance of computational fluid dynamics theory and convection heat transfer optimization theory-"the field synergy principle", get the numerical simulation of common fluid flow and conjugate heat transfer performance in the heat exchanger. Through 3d engineering design software Pro/Engineer establish a whole assembly model of the oil cooler including the fluid of both shell side and tube side. Generate finite element mesh in ANSYS Workbench simulation platform, loading the relevant boundary conditions (temperature, pressure, etc.), Using Fluent software to solve, Obtain the pressure field, velocity field, temperature distribution and other details in both shell side and tube side under operating conditions. In view of the significant impact of the baffles on the shell side fluid flow and heat transfer performance, Compare different forms of heat exchange, including single segmental baffle enhanced, double segmental baffle, triple segmental baffle, spiral baffle,Disk-and-doughnut baffle, etc. Their varying type of fluid flow state, convection heat transfer performance and pressure drop. Among them, add another baffle between single segmental baffle, heat transfer performance improved and the flow pressure drop increases; Spiral baffle improve flow uniformity, reduce flow dead zone, the pressure drop and resistance decrease to a lower level, but the baffle inlet and outlet flow resistance is large and should be improved; the double segmental baffle and triple segmental baffle fluid flow show a up-and-down within the multi-stream flow form, heat transfer performance is worse than single segmental baffle, but the pressure drop and resistance also decreased; Disk-and-doughnut baffle presents axial symmetry of flow, flow dead zone increased, although the flow resistance is lower, but the total heat transfer performance is poor.Fin is the major heat transfer component of air coolers, is the typical application of the extended surface heat transfer enhancement method in the heat exchanger. In view of finned air cooler heat transfer model analysis; the results show that slotted fin heat may enhance heat transfer; along the direction of gas flow, the upstream region around finned tubes represent a better heat transfer performance corresponding to the exuberant flow, the downstream region around finned tubes show a low velocity trailing vortex region, flow and heat transfer performance are very poor; Heat transfer performance and pressure drop have a tendency to increase when gas flow velocity increases, the pressure drop growth rate increasing but on the contrary heat transfer is gradually increasing flat; Using a larger thermal conductivity of fin material can enhance heat transfer; Also compared 15 different forms of slotted fin and the corresponding effect of heat transfer performance, summed up the high heat transfer performance of finned layout principles, such as under the same conditions, Rectangular slit-type fin has a better heat transfer performance than fan ring-type, rectangular and trapezoidal slit behavior better than curved slit, fin slit layout is not the more complex arrangement the better, the higher slit density is not possible, should be in conjunction with overall consideration of the rational distribution; Slit layout should have a sparse in-front and a dense behind, double-sided layout if possible, you can obtain a better heat transfer performance. Simulation provides a reference for the optimization of fin structures, represents the value of numerical simulation in engineering applications.