22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-5.5.3

HEAT TRANSFER IN A 180 DEG TURN RIBBED SQUARE CHANNEL

G. Cardone , T. Astarita, G. M. Carlomagno
DETEC - University of Naples, Italy

Keywords: rib, 180 deg turn, heat transfer, infrared thermography

Local measurements of the heat transfer distribution nearby a 180deg sharp turn in a square channel with rib turbulators are carried out by means of infrared (IR) thermography associated to the heated-thin-foil technique. Ribs are mounted on two opposite walls and are placed at 30° with respect to the channel axis. Two rib pitches are used during the tests. The convective heat transfer coefficient is evaluated from the measured temperature maps and the local bulk temperature of the flow which is obtained by making a one-dimensional energy balance along the channel. Results are presented in terms of local Nusselt number which is normalised with the classical Dittus and Boelter correlation. The fluid used during the test is air and the Reynolds number, based on the flow average velocity and channel hydraulic diameter, is 30,000.

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