Abstract of INFRARED HEAT MEASUREMENTS ON A ROTATING DISK,
G. Cardone, T. Astarita and G. M. Carlomagno,
University of Naples, DETEC, P.le Tecchio 80, 80125 Naples, Italy.

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Heat transfer to a rotating disk is measured for a wide range of rotational Reynolds number values in the laminar, transitional and turbulent flow regimes. Measurements are performed by making use of the heated-thin-foil technique and by gauging temperature maps with an infrared scanning radiometer. The use of the IR radiometer is advantageous on account of its relatively good spatial resolution and thermal sensitivity and because it allows one to perform measurements down to very low local rotational Reynolds numbers. Data is obtained on two disks, having an external diameter of 300mm and 450 mm. Heat transfer results, presented in terms of Nusselt and Reynolds numbers based on the local radius, show a substantial agreement with previous experimental and theoretical analyses. Transition to turbulent flow is found at about Re =2500000. A discussion about the role played by the adiabatic wall temperature is also included.

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