Parametric Study And Software Design Of Fined-Tube Heat Exchanger

As a thermal system equipment in the refrigeration and air-conditioning,finned tube heat exchanger is an important component.It has many advantages, such as compact structure manufacture simple, a wide range of options.Fined tube heat exchanger occupies a very large proportion in the energy.chemical and other industries. Researchers have been on the focus of heat transfer performance of air side, the velocity profile and temperature profile. In this work, the type design program of fin and tube heat exchanger has been developed by VB software. Numerical simulation and experimental study on the air-side heat transfer behavior and resistance characteristics provide the basis for reinforcement design of fin and tube heat exchanger, and provide a reference for future design and project selection.The main research content as follow:(1) This program used a steady-state lumped parameter model, using the techniques of modular development to improve the computational efficiency and accuracy, to avoid errors caused by repeated application of the formula and tedious iterative calculation. The core part of the program use dichotomy, combined with the the specific design example to verify the reliability of the compiler software.The output of the program including the basic parameters of the heat flux, heat transfer coefficient, pressure drop and the size of the evaporator and evaporator supplies.The program choose a variety of fin forms and types of refrigerant.and the accuracy can meet the engineering design requirements of the air-cooled evaporator.(2) Simulation and analysis on the air-side heat transfer of fin and tube heat exchanger was studied. The enhanced performance of parameters, such as Reynolds number, fin spacing, fin thickness, tube diameter on the heat transfer and resistance characteristics was investigated, with different structural parameters of the velocity field, temperature field distribution on heat transfer.The results show that, the enhanced performance of fin spacing and piping diameter on air-side heat exchanger has significantly improved. Nusselt number and heat transfer coefficient increased by a big margin, but the fan energy consumption increased along with the increase of corresponding pressure drop. The effect of heat transfer and pressure drop didn’t change dramatically with change of the fin spacing. As copper was used as the fin material, the fin efficiency and the Nusselt number are better than aluminum, but there is no significant difference between the two in terms of heat transfer rate.(3) The study found that, for the straight fin and tube heat exchanger, the performance of heat transfer had a close relationship with the frontal velocity. The increase of wind speed would help enhance the performance of heat transfer, with a lower temperature of evaporator outlet. The physical heat transfer coefficient and Nusselt number were calculated by compile software, degree of agreement with the experimental data measured, the accuracy is about15%.(4) Parameters on the finned tube heat exchanger of field synergy effects can be described. Through the rows of finned tube heat transfer enhancement or deterioration of the velocity gradient and the temperature gradient between the synergy angle change are intrinsically linked. Field synergy principle results show that the finned tube air inlet side of the field synergy angle is small, speed and temperature gradient between the synergy effect, while the leeward side of the pipeline area field synergy angle, a synergistic effect is poor.