Experimental determination of circular fin effectiveness

Abstract

The flow and heat transfer at the surface of a single circular fin and a finned cylinder were investigated comprehensively. The technique was carried out by combining PIV (Particle Image Velocimetry), gradient heat flux measurement and thermometry. The experiments were performed for a hollow (isothermal) fin and a fin made of titanium alloy VT22. The fins with a height of 20 and 60 mm were alternately mounted on a hollow cylinder. The cylinder was heated by saturated water vapor at atmospheric pressure. The angling device allowed us to investigate both the cross and non-cross flows around the model. The yaw angle β was 5, 10 and 15°. Visualization of the flow and measurement of the heat flux per unit area was carried out separately and independently in the same experiment. The PIV results revealed the influence of the yaw angle and intercostal space on the flow between the fins. Gradient heat flux sensors made it possible to obtain a distribution of the heat flux per unit area. Then the local heat transfer coefficients were calculated using thermometry data. It was possible to determine experimentally the effectiveness of the circular fins. This approach opens up new opportunities for study of convective heat transfer at surfaces of various shapes and purposes.