Experimental Investigation of Heat Transfer Characteristics from Arrays of Free Impinging Circular Jets and Hole Channels [Elektronische Ressource] / vorgelegt von Mohamed Attia Mahmoud Attalla

Experimental Investigation of Heat Transfer Characteristics from Arrays of Free Impinging Circular Jets and Hole Channels Dissertation zur Erlangung des akademischen Grades Doktoringenieur (Dr. –Ing.) vorgelegt von M. Sc. Eng. Mohamed Attia Mahmoud Attalla geb. am 28.12.1968 in Kena, Ägypten genehmigt durch die Fakultät für Verfahrens- und Systemtechnik der Otto-von-Guericke-Universität Magdeburg, Deutschland Gutachter Prof. Dr.-Ing. Eckehard Specht Prof. Dr.-Ing. Ibrahim M. M. El-Moghazy Promotionskolloquium am 21.12.2005 DEDICATION This work is dedicated to my father, my mother and my wife, my children, who supported me with their love, care and prayers M. Attalla Abstract An experimental investigation of the convective heat transfer on a flat surface in a multiple-jet system and hole channel is described. The system consists of free jets with an undisturbed flow of the air. Principle arrays were considered as in-line as well as staggered with different spacing distance in X- and Y-directions. For measuring the heat transfer, a metal sheet made of nickel alloy of size 200 mm × 170 mm was heated electrically with direct current supply up to 400 A and 7 V. The top side was cooled with air from the nozzle array. The temperature distribution on the black coated bottom side was recorded with an infrared thermo camera.