Numerical Simulation Of Compact Heat Exchanger Heat Transfer And Flow Characteristics

The research and development of high-performance heat exchanger, which is applicable to different working conditions, has become the main trends in technological development of the heat exchanger. Compact heat exchangers due to its advantages of high efficiency and energy saving have been widely used, and research of different fins which are the basic components of compact heat exchanger was focused on enhancing the system performance, improving the design of fins, and directing the design of the compact heat exchangers with less energy consumption.In this paper, the heat transfer and fluid flow characteristic of the compact heat exchangers are numerically investigated. Simulations are performed for louvered fin, serrated fin and corrugated fin, which are common in compact heat exchangers. According to the calculation and analysis of the models with variable geometries, the results are present as following:(1) For the louvered fins, it is resulted that the heat transfer performance is the best for the louver angle at 26°～28°, with the lager pressure drop. The overall performance of fins can be improved with increase of louvered fin height, and the optimized ratio of fin pitch to louver pitch ranges from 1.25 to 1.55.(2) For the serrated fins, the overall performance of fins is favorable when the offset strip fin pitch is 0.5 times to the fin pitch. The heat transfer performance of fins could be improved by decreasing the fin pitch and the fin length, but the overall performance is affected by the different fin height.(3) For the corrugated fins, decreasing fin pitch results in better heat transfer performance and decreasing pressure drop. The heat transfer performance could be improved by increasing fin height, decreasing fin length and increasing the ratio of fin pitch to fin height, but result in pressure drop increase. The overall performance is the best when the ratio of 2 times amplitude to wavelength ranges from 0.15 to 0.3.(4) Two plate-fin heat exchangers are numerically studied, and obtains the total heat transfer coefficient and pressure drop value, and then compare the numerical results with the thermodynamic calculation.The calculation results provide a reference for the optimization of finned heat exchanger.