Numerical Study On Heat Transfer Characteristics Of Indirect Air-Cooled Condenser Finned Tubes

With the development of modern industry and population growth, the phenomenon of the energy shortage is becoming more and more serious, especially reflected on the water resources. As a major water user, the thermal power generation enterprises take unavoidable responsibility for water-saving. Air-cooled radiators is the basic radiating element of indirect air-cooled system in thermal plant, and it is of great importance to study the structure feature and the flow and heat transfer property in order to optimize the whole air-cooled system.By using FLUENT software, this thesis makes numerical simulation of heat transfer and flow characteristics of rectangular finned round tube air side in indirect air-cooled condenser. By analyzing the diameter of base pipe and temperature distribution on the fin surface and velocity distribution between the fin, the variation of cooling air flow resistance and convective heat transfer coefficient with the average face velocity of air-cooled heat sink were obtained, the correlating equations of the friction factor versus Reynolds number, and the Nusselt number versus Reynolds number were fitted. By using comprehensive performance assessment criteria of convective heat transfer, finned tubes for the flow and heat transfer performance were compared. The results show that with the increase of the diameter of the base pipe, pressure drop and flow convection heat transfer coefficient of the finned tube increase at the same time. With a diameter of 25mm for base pipe gets the maximum comprehensive evaluation index PEC under different frontal velocity; when wind speed is small, there is no big difference between a diameter of 20mm、25mm、30mm and 35mm for base pipe, but they are significantly higher than the PEC when the diameter is 40mm. Overall, a diameter of 25mm exhibits better performance.Based on the corrugated circular base fin tube bundles, impact of changes of fin surface structure on the flow and heat transfer was studied. The results show that for corrugated fins, surface wave fin tube bundles not only reduces the flow pressure drop, but also improve convective heat transfer coefficient at the same time compared to a flat waveform fin tube bundles. When the Reynolds number is less than 700, there is no difference between A type of flat waveform and B type of surface waveform fin tube bundles; When the Reynolds number is more than 700, the overall performance of B3 type is better than the other finned tube tubes, it can provide reference for relevant research and engineering applications.