Numerical Simulation Of Flow And Heat Transfer For Flow Across Tube Banks

There are many kinds of heat exchangers,tubular heat exchanger is a traditional type and is widely used in industrial production processes.Changing the arrangement of the tube banks is the main means of enhancing the heat transfer capacity of the heat exchanger in industry.In this article,the flow and heat transfer process of the fluid in the heat exchange tubes was numerically simulated,and the effect of different arrangement of the tube banks on the heat transfer efficiency was also investigated.The heat transfer mechanism of the tube banks was quantitatively analyzed.Based on this,the tube banks were further analyzed by fluid-structure-interaction.It can be found that average Nusselt number of the tube in the tube banks is increased by 37%compared with the single tube,and the heat transfer enhancement is obvious.The effect of longitudinal and transverse tube pitch ratio of in-line tube banks on the transfer characteristics have been investigated.And comprehensive heat transfer effect has been evaluated.The results showed both increasing the longitudinal and transverse tube pitch ratio can increase Nu,but at the same time the resistance coefficient also increased.And the intensification of heat transfer is more sensitive to the variation of the transverse tube pitch ratio.The tube banks with arrangements as SL/D=2.7,ST/D=2.5 show the strongest overall heat transfer capability.In addition,the effect of the Re on the vortex shedding of the in-line tube banks was investigated,and the relation between St and Re is obtained by linear fitting.it has been found that the structure of tube banks can reduce the frequency of vortex shedding and inhibit the vibration from the vortex shedding.The flow and heat transfer process of the fluid in staggered tube banks were numerically simulated under the same conditions.The distribution of the flow field and Nu between in line tube banks and staggered tube banks were compared.It was found that the staggered tube banks show a better heat transfer enhancement ability.The field synergy principle was used to analyze the mechanism of the structure of tube banks on the heat transfer enhancement.It was found that in staggered tube banks,the synergy between the velocity field and temperature field is better,and heat transfer was enhanced greatly.The numerical investigation of the one way fluid-structure-interaction of tube banks was performed.The stress and total deformation distribution rules under different Reynolds number,SL/D and arrangement of tube banks were analyzed.The results showed that Reynolds number has little effect on the stress and total deformation distribution of the in-line tube banks.When increasing SL/D,the maximum Equivalent Stress increases first and then decreases.Compared with in-line tube banks,the stress and total deformation in staggered tube banks was larger.