ABSTRACT
This paper presents an experimental study of the heat transfer and flow friction for turbulent flows of air over a heated flat plate mounted downstream of a fence. A rectangular brass plate is attached to a heating unit and fixed inside the test section of a subsonic wind tunnel. A number of fences with different heights are used separately to promote turbulence over the plate. A series of experiments are conducted to examine the following parameters: fence height to plate length ratio (H/L),the distance between the fence and plate relative to plate length (S/L) and the Reynolds number, which is calculated based on the stream wise length of the plate (1.5×105≤ ReL≤ 4.5×105). The first set of the results, which is obtained for the case of the plate without a fence, shows very good agreement with other published results. The results in the cases of the plate behind a fence reveal that the Nusselt number and friction factor are critically dependent on the fence height and the distance between the fence and the plate. A maximum Nusselt number enhancement ratio of 1.7 is achieved corresponding to a friction factor ratio of 2.5. New correlation is obtained for the thermal efficiency (η) based on the Nusselt number enhancement ratio and friction factor ratio at different arrangements of the considered parameters.
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