CFD Method and Simulations on a Section of a Detailed Multi-Louvered Fin Where the Incoming Air is Directed at 90° and 30° Relative to the Compact Heat-Exchanger

摘要

This paper presents results and a Computational Fluid Dynamics (CFD) method for simulation of a detailed louvered fin for a multi-louvered compact heat-exchanger. The airflow was angled at 90°, +30° and ?30° relative to the heat-exchanger to evaluate changes in static pressure drop and airflow characteristics. The investigation was based on three heat-exchangers with thicknesses of 52mm and two of 19mm. One period of a detailed louvered fin was simulated for two airflows for each heat-exchanger. The pressure drop data was thereafter compared to experimental data from a full-size heat-exchanger. From the pressure drop and the airflow characteristic results recommendations were made that those kinds of simulations could be defined as steady state, and with the kω-SST turbulence model. For the same heat-exchanger angle the airflow within the core was similar, with a turbulent characteristic behind it. The static pressure drop was reduced significantly for the ±30° cases compared to the 90° angled heat-exchanger to approximately one third, when comparing for the same mass airflow rates. Since the test section area was defined as constant the velocity through the heat-exchanger core varied for the 90° and the 30° cases. When comparing the core velocity it was observed that there were minor losses due to the redirection of the airflow for the 30° angle compared to the 90° case. The results showed that the 30° case, where the inlet airflow was parallel to the louvers, had a higher pressure drop than the other 30° case. It was also observed that even when the inlet airflow angle varied, the outlet airflow angle from the heat-exchanger only varied 4.3-6.4°.