Suscripción a Biblioteca: Guest

ISSN Online: 2377-424X

ISBN Print: 0-89116-909-1

International Heat Transfer Conference 9
August, 19-24, 1990 , Jerusalem, Israel

ON THE INFLUENCE OF VIBRATION ON FREE CONVECTION HEAT TRANSFER AND FLUID FLOW AROUND THE HEATED CYLINDER

Get access (open in a dialog) DOI: 10.1615/IHTC9.3330
pages 573-577

Sinopsis

The report considers the results of the experimental heat transfer examination from a vibrating horizontal cylinder (d=39.18 mm) to air. The vibrations are harmonically and gravitationally directed. The parameters examined are: frequency (0≤f≤400 Hz), amplitude (0≤a≤9 mm) and wall temperature (20≤TCw≤200°C). The analysis of obtained results shows that the vibration velocity is the heat transfer parameter. This fact enables determining of the vibrational Reynolds number Rev=vmax·d/ν using the vibrational velocity amplitude vmax=2πa·f. The results show that the average heat exchange intensity is considerably increased (up to 250%) by vibrations. The applied method of measuring local heat fluxes made possible to derive conclusions on the changes of the fluid flow pattern, called thermovibrational flow, which is established at 0.1<a·f<0.15 m/s. It is analogous to the thermoacoustical streaming in sound fields at sound pressure level SPL≥140 dB (corresponding to a·f≥0.113 m/s). Obviously, the mechanical method, applied in the present work, yields nearly identical effects as the acoustical method, when the fluid flow is considered. The lower limit of the described flow pattern changes is found to be Revcrit = 2000.