Abstract
This study aims to perform an experimental study of heat transfer by forced convection for three cylinders (with 12 triangular, rectangular shape fins and without fins) made of aluminum. The inner and outer diameters of these cylinders considered in this study ware (16 mm) and (48 mm) respectively .The study has been performed for different,geometry, slope angles (0°-45°) and range of air velocities (0.5-4m/s). The three cylinders ware heated by a constant heat flux generated by passing an alternative current (AC) through a resistance placed inside the internal space for each cylinder . The effects of air velocity , inclined angle and geometry of fins have been studied in this study for a range of heat fluxs (13-247) W. The results show that the rate of heat transfer increases as the air velocity increases but it decreases with increasing inclined angle. The heat transfer coefficient increases generally with increasing Reynolds number (Re) and the heat transferred from triangular test sample (12) fins is greater than that from rectangular test sample and without fin type. An empirical relationships between Reynolds number (Re) and Nusselt number (Nu) is concluded:
Test sample (12) fins with triangular section : Nu=0.02474 Re^0.939
Test sample (12) fins with rectangular section: Nu=0.047 Re^0.8353
Test sample without fins Nu=0.06 Re^0.71
