University of Technology-Iraq
Engineering and Technology Journal
1681-6900
29
4
2011
03
01
Experimental Study of the Effect Geometrical Shape and Vertical Vibrations on Forced Convection Heat Transfer Coefficient from Circumferentially Triangle-Cross Section Finned Cylinder
153
174
28063
10.30684/ etj.29.4.16
EN
Journal Article
2011
03
01
The aim of this work is to perform an experimental study for the effect of forced<br /> vertical vibrations on forced convection heat transfer coefficient, by the use of a<br /> circumferential finned cylinder made of Aluminum. The cylinder was heated under the<br /> condition of a constant heat flux which is generated by applying an alternating voltage<br /> on a fixed resistor mounted inside the interior space of the cylinder which was located<br /> horizontally or inclined in multiple angles of (0°, 30°, 45°). In this experimental study,<br /> the circumferential finned cylinder prototype of inner diameter (16 mm), and outer<br /> diameter including the fin of (48 mm)was used, and the effect of the frequency at a<br /> range of (2-16 Hz) and the vibration amplitude range of (0 - 2.2mm) have been studied<br /> with heat flux rates (500,1000,1500 W/m2) on heat transfer coefficient. From the results<br /> of this study, it was found that the relation between the heat transfer coefficient and<br /> amplitude of vibration is incrementally for angles (0°, 30°, 45°). And reaches a<br /> maximum ratio of (12.85%) with respect to the frequency equals zero. The increment of inclination angle reduces the values of forced convection heat transfer coefficient,<br /> because the fins work as path lines that help to increase the movement of convection<br /> currents in the case of horizontal prototype, but in case of inclined cylinder, the fins<br /> work as obstructions for the convection currents, thus reducing the ranges of forced<br /> convection vibrational heat transfer coefficient. Generally, the heat transfer coefficient<br /> increases as Reynolds number increases. The experimental results were compared with<br /> results of reference [9] and found that the effect of Geometrical shape on heat transfer<br /> coefficient of the cylinder used in this research less than that for reference [9] because<br /> the total surface area for the sample used in reference[9] was larger than that for the<br /> sample used in the current study .
https://etj.uotechnology.edu.iq/article_28063_97864856795a45d84583c66e07845a7c.pdf