An Evaluation of Jet Impingement Heat Transfer Correlations for Piccolo Tube Application

Greek Letters Impinging jets have been used for a wide variety of applications where high rates of heat transfer are desired. This report will present a review of heat transfer correlations that have been published. The correlations were then added to the LEWICE software to evaluate the applicability of these correlations to a piccolo tube anti-icing system. The results of this analysis were then compared quantitatively to test results on a representative piccolo tube system. NOMENCLATURE A Area ratio (dimensionless) c chord (m) c n spanwise distance between holes (m) c x chordwise distance between holes (m) C p heat capacity (kJ/kgK) d jet hole diameter (m) D diameter of semi-cylinder (m) G mass flux (kg/m 2 s) h Heat transfer coefficient (kW/m 2 K) k Thermal conductivity (kW/mK) m  Mass flow rate per unit span (kg/ms) N r Number of jet rows Nu Nusselt number = hdk a Nu average Nusselt number q" Heat flux (kW/m 2 ) Pr Prandtl number = C p µ a k a leading edge through small holes drilled in a pipe. Ice r radial distance from hole (m) Re Reynolds number