Heat transfer and pressure drop in a rectangular channel with diamond-shaped elements

Heat transfer and pressure drop experiments were performed for a rectangula r channel equipped with arrays of diamond-shaped elements. Both in-line and staggered fin arrays were considered, for Values of the longitudinal and t ransverse spacings, relative to the diamond side, from 4 to 8 and from 4 to 8.5, respectively. The height-to-side ratio of the diamonds was 4.0. Liqui d crystal thermography was used to determine the heat transfer coefficients on the surface of the channel (endwall) on which the fins were mounted. Lo cal variations in heat transfer coefficients induced by the arrangements of the diamond-shaped elements were measured and discussed. Correlations givi ng the average Nusselt number for each fin configuration as a function of t he Reynolds number were developed. Thermal performance comparisons with dat a for a rectangular channel without fins showed that the presence of the di amond-shaped elements enhanced heat transfer by a factor of up to 4.4 for e qual mass flow rate and by a factor of up to 1.65 for equal pumping power. (C) 2001 Elsevier Science Ltd. All rights reserved.