IMPINGEMENT HEAT-TRANSFER AT A CIRCULAR-CYLINDER DUE TO A SUBMERGED SLOT JET OF WATER

An experimental investigation was carried out on the heat transfer due to a submerged slot jet of water impinging on a circular cylinder in crossflow. The cylinder diameter and the slot width are of the same order of magnitude, specifically D-s = 2.0 and 3.0 mm and D-c = 2.5 and 3.0 mm. The experimental apparatus allowed variation of the slot width, the cylinder diameter, and the distance from nozzle exit to heater. Conditions of impingement from the bottom (ascending flow) were taken into consideration as well as impingement from above (descending flow). The Nusselt number was determined as a function of Reynolds and Prandtl numbers in the range 1.5 x 10(3) < Re < 2.0 x 10(4), 2.7 < Pr < 7.0, and 1.5 less than or equal to z/D-s less than or equal to 10. The experimental data were correlated with a simple equation that fits 90% of the data with a precision of 20%.