1997 Volume 23 Issue 5 Pages 679-686
An experimental investigation of heat transfer and fluid flow on a heated rotating disc in a stagnation flow has been carried out. From the measured results of heat transfer coefficients, the conditions of transition from the region in which the stagnation flow is dominant to the region in which the forced convection by the disc rotation is dominant, and the transition from the forced convection dominant to the natural convection dominant region are determined. Empirical equations of Nusselt numbers for the three regions are also given. Flow visualizations by shadowgraphy and laser induced fluorescence techniques show that circumferential vortices due to buoyancy force appear on a rotating disc in the natural convection dominant region. The circumferential vortices are generated in the central region of the disc and move outwards in a radial direction. The radial velocity of the circumferential vortices is calculated from the time correlation of the temperature fluctuation. The calculated results indicate that the circumferential vortices have constant velocity at the outer region of the disc.
