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ISSN Online: 2377-424X

International Heat Transfer Conference 3
August, 7-12, 1966, Chicago, USA

INVESTIGATION OF FORCED CONVECTION HEAT TRANSFER TO SUPERCRITICAL PRESSURE CARBON DIOXIDE

Get access (open in a dialog) DOI: 10.1615/IHTC3.1680
pages 257-266

Abstract

Heat transfer through a turbulent flow of carbon dioxide confined between planes has been measured at slightly supercritical pressures. One of the surfaces was maintained at subcritical temperatures, the other being held at temperatures from below to slightly above critical. The design of the apparatus was such that fully developed temperature and velocity distributions across the flow could be established, and the effect of severe transverse physical property variations could be studied in the absence of longitudinal effects.

The results indicate a sharp increase in the heat flux as the hotter wall reaches the critical temperature, this increase being more marked when the cooler wall is closer to the critical temperature. Attempts to explain the results in terms of a peak in the thermal conductivity of carbon dioxide near the critical point, or in terms of a level of turbulent diffusion in the so-called "laminar sub-layer" that is higher than is normally found, have proved unsuccessful. A tentative model in which it is assumed that turbulent diffusion is amplified in proportion to the local coefficient of thermal expansion of the fluid, gives better agreement with experiment.