Study of natural convection heat transfer in a finned horizontal fluid layer

Numerical experiments have been carried out to investigate natural convection heat transfer and fluid flow characteristics from a horizontal fluid layer with finned bottom surface. The effects of fin height and fin spacing have been investigated for a sufficiently wide range of Rayleigh number. Quantitative comparisons of heat transfer rates and finned surface effectiveness have been reported. The insertion of heat conducting fins has been found to induce an upward fluid motion along the fin walls. For a given value of fin spacing, the number of convection cells between two adjacent fins is function of the values of fin height and Rayleigh number. In comparison with a bare plate, the heat transfer rates for low values of fin height may be decreased by the insertion of fins. For high values of fin height, the finned surface effectiveness is greater than one for a wide range of fin spacing. For low values of Rayleigh number and high values of fin height, the finned surface effectiveness increases linearly with the decrease of fin spacing. Useful guidelines have been suggested to enhance the heat transfer rates from the finned surface.