Performance Research And Optimization Design On Louvered Fins For Subcompact Radiator

Fin is an important part of the radiator, which constitutes the second heat transfer of the radiator. The performance of fin has a direct bearing on heat dispersion and resistance of radiator. Louver fin is widely used by radiator designers of subcompact industry because of its highly efficient heat transferring surface. Foreign researches on the performance of louver fin started earlier, the early time mainly on mechanism of flow, and then on performance. On the contrary, there are few similar researches in our country, especially on subcompact radiator fins, leading to lack of adequate data support for the selection of subcompact radiator. Therefore, this paper mainly researches on the radiator fins of a subcompact by the combination of experiment and simulation. The performance and structure of fin was optimized through studying relations between its resistance performance, heat dispersion and the service condition respectively, relations between two performances respectively with essential sizes, as well as the optimization design of the essential sizes. The content and the result of the research had the practical value to the louver design of the automobile, and was significant to the performance enhancement of automobile radiator in theoryThe main work of this paper are as follows:(1) An air duct experiment of a subcompact radiator was carried out to obtain the relationship between the performance of fin and working conditions, specifically the relational expression between the pressure difference and air velocity, the curves between heat dissipation and air velocity. Then they were nondimensionalized to obtain the relational expressions between of friction factor and Reynolds number, between heat factor and Reynolds number, respectively.(2) Based on the fluid analysis software Fluent, the numerical analysis on the fin, was carried out to simulate the work status of fin in air duct experiments. The air-pressure field, velocity field and temperature field distribution of fin in every experimental condition were obtained. Compared with the experimental results, the error of the performance of resistance by model was less than 13%, and the error of the forecast of thermal performance was less than 17%. (3) The size of fin height and fin spacing of the series of subcompact radiator fins were optimized. In the range of use, each five dimensions of fin height and fin pitch were chose, respectively, to model and numerical analysis. The relational expression between friction factors and the fin pitch, and the relational expression between friction factors and fin height were obtained. The performance of fin comprehensively by using dimensionless factor j/f1/3 was evaluated and optimized respectively. Results showed that the overall performance is best when fin spacing is 2.52mm, fin height is 8.5mm.