The effect of an external excitation on a heat transfer in an impinging jet

Abstract

Paper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.Heat transfer in a submerged round water jet impinging on a flat heated plate and the effect of external flow excitation on heat transfer have been experimentally studied using Infrared Thermography. Convective heat transfer in the stagnation point area can be influenced (enhanced or suppressed) by periodic pulsations of flow velocity. In the tested range of flow parameters excitation of the flow at dimensionless frequency Sh={J.S leads to maximum heat transfer reduction. Heat transfer is affected significantly at low nozzle-to-plate spacing. Increased excitation amplitude results in further decrease of heat transfer for Sh=0.5.