Effects of local flow on the heat transfer characteristics of a cowled, finned system

Abstract: Experimental studies of the local flow and heat transfer characteristics within the finned region of a cowled, annularly finned cylinder are presented. The temperature and local heat fluxes across fin surfaces were measured using thermocouples and Micro-foil ™ heat flux sensors. Areas of maximum heat transfer coefficients greater than 60 W/m2 K were observed in the forward fin tip and base regions. A local minimum of 12 W/m2 K was found in the mid-fin regions behind the finned cylinder. The local flow characteristics within the finned region were measured using laser Doppler anemometry at an inlet Reynolds number of 4×105. Areas of high turbulence intensity and shifting high-velocity zones were found. Correlation between the heat transfer and flow characteristics confirm the existence of boundary layer development, forward edge separation, and root and tip vortices. The application of the cowl system on a finned cylinder leads to a heat transfer enhancement of greater than 29 per cent. Localized fluctuations of the heat flux on the fin surface are also discussed