| As a common heat exchanger,finned tube heat exchanger is widely used in chemical industry,refrigeration and air conditioning,aerospace ship and other fields.As a key component in the air conditioning system,the heat exchange performance directly affects the operating efficiency of the air conditioning system.It is of great practical significance to study the high performance finned tube heat exchanger.In this paper,the aluminum finned tube heat exchanger is taken as the research object,and the influence of the change of base tube material and the installation of eddy current generator on the finned tube heat exchange performance,resistance characteristics and comprehensive performance is explored from the perspective of manufacturing materials and structure optimization by numerical simulation.The main research contents are as follows:(1)By comparing the numerical simulation results with the experimental results in literature,it is found that the errors of Nusselt number Nu and friction factor f are both less than10%,which meets the error requirements of engineering calculation,thus verifying the rationality of the mathematical model and the reliability of the simulation method.(2)The influence of different base tube materials on the heat transfer performance of finned tube heat exchangers was studied by taking aluminum fin of copper tube and aluminum fin of aluminum tube as the research object.The results show that for two finned tube heat exchangers with different base tube materials,the heat transfer and heat transfer coefficient increase with the increase of inlet wind speed,and the fin efficiency decreases with the increase of inlet wind speed.When the head-on wind speed is 1-5m/s,the heat exchange of the same structure aluminum tube aluminum fin tube heat exchanger is 4%-12% lower than that of the copper tube aluminum fin tube,and the heat exchange coefficient is reduced by 7%-9%.The cost of aluminum tube aluminum fin tube is only 8% of the copper tube aluminum fin tube,which can save the cost.(3)In the aspect of fin structure,the influence of eddy current generator installed on the fin surface on the comprehensive performance of aluminum finned tube heat exchanger is studied.The results show that the heat transfer capacity of aluminum finned tube heat exchanger can be improved by installing eddy current generator on the finned tube surface,and the pressure loss is less.The Nussel number of aluminum finned tube heat exchanger equipped with eddy current generator is 9%-20% higher than that of straight finned tube,the heat transfer coefficient is 6%-12% higher,and the friction factor is 7%-16% higher.(4)The influence of vortex generator structure and installation mode on the performance of aluminum finned tube heat exchanger was studied.The results show that: When the headwind speed is 1-5m/s,the heat transfer coefficient of the curved rectangular small fin tube is 4%-7% higher than that of the flat rectangular small fin tube,the friction factor is 6%-11%lower,and the PEC factor is 6%-9% higher.The curved rectangular aluminum fin tube heat exchanger has better comprehensive performance.From the perspective of field synergy,compared with the flat rectangular small fin tube,The field synergy Angle of curved rectangular tube with small wing fin is smaller,which reflects its better heat transfer performance.Compared with the way of perforating and installing winglets,the aluminum finned tube heat exchanger with winglets directly installed on the surface of the fin has better thermal performance,the friction factor is reduced by 11.5%-13.8%,and the comprehensive performance is improved by 12.9%-18.7%.From the perspective of field synergy,the field synergy Angle of the finned tube heat exchanger with directly installed winglets is smaller,and it has better heat transfer characteristics.In conclusion,the performance of aluminum finned tube heat exchangers can be improved significantly by directly installing curved rectangular fins on the fin surface. |
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