Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.
Annular radiators can be used for heavy-duty vehicle engine cooling systems, domestic air conditioning, and electronic devices cooling system. A test apparatus was set up to investigate the flow and heat transfer characteristics in annular radiators. An infrared camera was used to measure the temperature distribution. The experimental results show that the temperature is not uniform along the radiator height because of the air flow non-uniformity. The internal flow field was numerically investigated and a variable fin pitch optimization method was presented to reduce the flow non-uniformity. The porous medium model was used to predict the radiator pressure drop. The simulation accuracy was verified by the experimental data. The numerical results show that the flow non-uniformity is greatly influenced by the fan diameter and height ratio and can be reduced by the variable fin pitch method.