Effect Of Baffle On Vibration-Enhanced Heat Transfer Characteristics Of Elastic Tube Bundle By Fluid-Induced

Based on the theory of vibration enhanced heat transfer,the elastic bundle heat exchanger can realize enhanced heat transfer while using the vibration of the bundle,and ensure the service life.However,this kind of heat exchanger has the disadvantages of poor vibration enhancement heat transfer effect and low comprehensive heat transfer performance.To solve the above problems,combined with the analysis of the research status of elastic tube bundle and baffle heat exchanger,the method of adding baffle inside the heat exchanger while improving the structure of tube bundle or an important scheme to improve the comprehensive heat transfer performance of heat exchanger.Therefore,this paper studies the influence of baffle on the heat transfer enhancement characteristics of elastic tube induced by beam vibration,in order to obtain the optimal heat transfer structure scheme.The main research contents and conclusions of this paper are summarized as follows:1)The overall heat transfer performance of the improved heat exchanger has been significantly improved by improving tube bundle structure and by installing folded plates inside the heat exchanger to enhance the vibration characteristics of the tube bundle itself while changing the flow characteristics of the internal flow field.2)The fluid-solid-thermal coupling model of the improved heat exchanger with multiple sets of baffle and tube bundles was established.The effects of baffle on the vibration response and heat transfer characteristics of the traditional/improved elastic tube bundle at different inlet flow rates were systematically studied.At the same time,the comprehensive heat transfer performance of four kinds of heat exchangers was compared.The results show that:(1)As the inlet velocity increases,the vibration amplitude at the monitoring points of the conventional elastic tube bundle increases by a maximum of42.97% with the installation of the baffle,and the vibration-enhanced heat transfer performance of the heat exchanger increases by 1.18%,0.93%,0.73% and 0.63%respectively.This means that the installation of the baffle promotes the vibrationenhanced heat transfer performance of conventional elastic tube bundle.(2)At different inlet velocities,for the improved elastic tube bundle,the installation of the baffle resulted in a maximum reduction of 4.06% in the average amplitude of the bundle monitoring points,a maximum increase of 23.24% in the average heat transfer coefficient and a maximum increase of 2.06% in the vibration-enhanced heat transfer performance of the heat exchanger.This indicates that the installation of baffle inside the improved elastic tube bundle heat exchanger results in a reduction in the vibration intensity of the tube bundle but an enhancement in the heat transfer performance.So,the baffle can improve the enhanced heat transfer performance while suppressing the vibration of the improved elastic tube bundle.(3)At different inlet velocities,the heat transfer capacity of the improved elastic tube bundle is increased by a maximum of 8.44% compared to the conventional elastic tube bundle,while the heat transfer capacity is increased by a maximum of 5.14%.The improved elastic tube bundle heat exchanger with baffle had the best overall heat transfer performance.3)Based on the improved elastic tube bundle heat exchanger,further improvement of the baffle structure is proposed and the effect of different baffle structures(height and arcs)on the overall heat transfer performance of the heat exchanger at different inlet velocities is investigated.The results show that:(1)Increasing the inlet velocities significantly improves the vibration strength of the improved elastic tube bundle,but increasing the height of the baffle reduces the vibration lift strength.As the height of the baffle increases,the amplitude of the improved elastic tube bundle decreases by a maximum of 10.05%,but the overall heat transfer performance of the heat exchanger becomes stronger.In other words,increasing the height of the baffle can improve the overall heat transfer performance of the heat exchanger while suppressing the vibration of the improved elastic tube bundle.(2)At different inlet velocities,the vibration of the improved elastic tube bundle is strongest at baffle arcs of 10°,with a maximum increase in amplitude of 10.79% compared to other arcs,and the improved elastic tube bundle vibration-enhanced heat transfer performance increases with increasing arcs.Considering the heat transfer and pressure drop of the integrated heat exchanger,the integrated heat transfer performance of the heat exchanger at an arc of 10° is optimal.The conclusions presented in this paper on the effect of baffle on the flow-vibration enhanced heat transfer characteristics of elastic tube bundles can provide guidance for practical applications.When designing and optimising an elastic tube bundle heat exchanger,the installation of baffle can be considered in order to enhance the heat transfer performance by promoting the vibration of the tube bundle or to improve the heat transfer performance while suppressing the vibration of the tube bundle.At the same time,according to the results of this paper,the inlet velocity,height and curvature of the baffle should be taken into account when designing the baffle in order to obtain the optimum overall heat transfer performance.The conclusion can provide theoretical basis and guidance for the design and optimisation of flexible tube bundle heat exchangers.Figure [62] Table [13] Reference [100]...