Numerical Simulation Of The Heat Transfer Performance In Heat Exchanger Of Internally Finned Tube

With the development of modern industry and the continuous improvement of living standards, human energy demand is also growing, energy saving more and more people's attention. Heat exchanger in the refrigeration, petroleum, chemical industry account for a large proportion, while the technique of enhancing heat transfer has been developed greatly.The heat exchanger of internally finned tube has a high energy saving rate, small size and low cost advantages.In this paper, the theoretical analysis was discussed and the mathematic and theoretical models of convection process in internaly finned tube with four different number of waves and smooth tube are built in different condition of the velocity of flow. By applying FLUENT software, this paper studied convection process of heat exchanger in which the medium is air by three-dimension numerical simulation. According the special characteristics of the research object,the laminar flow model,the standard k ?εmodel and and the realizable k-εmodel are used to predict the heat transfer and flow behavior.The distribution of temperature, velocity and pressure in internaly finned tube with four different number of waves were simulated by adopting laminar flow model and turbulent flow model in view of different velocity of flow, the enhancing heat transfer mechanism has been obtained. The relationships between velocity and the temperature distribution, the resistance coefficient of internaly finned tube with different number of waves were summarized. The feature of heat transfer enhancement is described compared with the smooth tube. As the Reynolds number increases, the curves of the outlet average temperature, the wall heat transfer exchange, the wall Nusselt number, the pressure difference between the inlet and the outlet and the resistance coefficient were obtained, which proved that the heat transfer characteristics of a internaly finned tube tube is higher.Using the Webb heat performance guide line, the results of the comparisons between the internally finned tubes and the smooth tube were: On the supposition that the pump power and the heat transfer area were the same,under the numerical simulation scope of theReynolds number, the heat transfer exchange of the numberⅠ~Ⅳinternally finned tubes respectively reach 1.55~3.57,2.78~4.43,3.23~5.25 and 3.51~5.68 times as that of the smooth tube. the effect of heat transfer enhancement in internally finned tubes decline as the increase of Reynolds number.The results of numerical simulation of numberⅣinternaly finned tube and experimental results were proved to be inosculated and compared to validate reliability of numerical simulation. Therefore, the technique of numerical simulation is a perfect and effective means to research the heat transfer study.