ISSN Online: 2377-424X
ISBN Print: 978-1-56700-421-2
International Heat Transfer Conference 15
Study on Free Convection Heat Transfer in Finned Tube Array
Abstrakt
We have been developing a free convection air cooled heat exchanger without power supply to improve economical efficiency and mechanical reliability. However, it has the problem that installation area becomes large comparing forced draft type air cooled heat exchanger since large heating surface is needed due to small natural convection heat transfer. Then, we have been investigating heat exchanger consists of finned tube banks and chimney to increase heat transfer coefficient. However, heat transfer characteristics of finned tube banks have not been clarified. Then, we carried out experiment with finned tube array to obtain the relation between finned tubes configuration and heat transfer coefficient in tube array. The experiment results show that average heat transfer coefficient increased with vertical direction pitch, and it became constant when the pitch was over 5 times of the fin diameter. The average heat transfer coefficient became increased by about 1.4 times compared with single finned tube in free space. The multiplication factor of average heat transfer coefficient of finned tube array with chimney to single finned tube was founded to be with temperature difference between tube surface and air.
SCHLÜSSELWÖRTER:
Convection, Heat exchanger, finned tube bank, heat transfer, pressure drop, tube arrantement