Numerical Study Of Air Side Heat Transfer And Fluid Flow Characteristics For Wavy Fin-and-tube Heat Exchanger

In recent years, energy and environmental issues increase, protecting the environment and reducing energy consumption are the themes of the present world. Scholars in various industries have to shoulder the heavy task of reducing energy consumption. Fin-and-tube heat exchanger is widely used in refrigeration, air conditioning and other fields. It is the important part of the air conditioner, the research of fin-and-tube heat exchanger helps to improve the efficiency of heat transfer and enhance heat transfer. Because inner flow field of wavy fin-and-tube heat exchanger is complicated, experimental results are restricted to the analysis of the overall heat transfer characteristics, and the analysis of inner flow field is limited. Using the Computational Fluid Dynamics (CFD) method to simulate the temperature field, velocity field, pressure field of a wavy fin-and-tube heat exchanger, the internal morphology of the flow field can be acquired intuitively. At the same time, the experimental expenditure can be reduced, and the study time can be shortened.In this paper, FLUENT is used to simulate the coupled heat transfer processes of convection and conduction on the air side of a wavy fin-and-tube heat exchanger, and the results are compared with the experiment data. Based on these results, the effects of Reynolds number, tube row number, tube diameter and other parameters on air side heat transfer and flow characteristics are studied. The results show that both heat transfer coefficient and pressure drop significantly increase with the increase of Reynolds number when the tube row number is constant. Heat transfer coefficient of the air side reduces along with the increase of tube row number when Reynolds number is low. Heat transfer coefficient of multi-tube rows is larger than that of single tube row when Reynolds number is high. In this paper, temperature field, flow field, local resistance and local heat flux distribution of the air side are also analyzed.In addition, taking into account the disadvantage of wavy fin-and-tube heat exchanger that the heat transfer effect of the backward of the finned tube is poor, the fins are slotted in proper place and equipped with rectangular wings. The numerical results are analyzed by field synergy principle. The average intersection angles of wavy fin-and-tube heat exchanger with rectangular-wing vortex generators are compared with that without rectangular-wing, examining the convective heat transfer mechanism from the interactive viewpoint of the velocity field and temperature field.