HEAT-TRANSFER IN A ROTATING CAVITY WITH A PERIPHERAL INFLOW AND OUTFLOW OF COOLING AIR

This paper describes a combined computational and experimental study o f the heat transfer in a rotating cavity with a peripheral inflow and outflow of cooling air for a range of rotational speeds and flow rates . Measurements are made in a purpose-built rig, with one of the two ro tating discs heated, and computations are conducted using an axisymmet ric elliptic solver incorporating the Launder-Sharma low-Reynolds-numb er k-epsilon turbulence model. Measured values of the tangential compo nent of velocity, V-phi, exhibit Rankine-vortex behaviour which is not accurately modelled by the computations. Both computed and measured v alues of the radial component of velocity, V-r, confirm the recirculat ing nature of the flow. In the outflow region, agreement between compu ted and measured values of V-r is mainly good, but in the inflow regio n the computations exhibit a ''peaky'' distribution which is not shown by the measurements. The measured and computed Nusselt numbers show t hat Nu increases as the magnitudes of the flow rate and the rotational speed increase. The computed Nusselt numbers (allowing for the effect s of conduction through and radiation to the unheated disk) reproduce the measured trends but tend to underestimate the experimental values at the larger radii.