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

Experimental studies of the local how and heat transfer characteristics wit hin the finned region of a cowled, annularly finned cylinder are presented. The temperature and local heat fluxes across fin surfaces were measured us ing thermocouples and Micro-foil(TM) heat flux sensors. Areas of maximum he at transfer coefficients greater than 60 W/m(2) K were observed in the forw ard fin tip and base regions. a local minimum of 12 W/m(2) K was found in t he mid-fin regions behind the finned cylinder. The local flow characteristi cs within the finned region were measured using laser Doppler anemometry at an inlet Reynolds number of 4 x 10(5). Areas of high turbulence intensity and shifting high-velocity zones were found. Correlation between the heat t ransfer and flow characteristics confirm the existence of boundary layer de velopment, forward edge separation, and root and tip vortices. The applicat ion of the cowl system on a finned cylinder leads to a heat transfer enhanc ement of greater than 29 per cent. Localized fluctuations of the heat flux on the fin surface are also discussed.