RT Journal Article ID 4016108768ec24e5 A1 Akbari, M. Mustafa A1 Murata, Akira A1 Mochizuki, Sadanari A1 Iwamoto, Kaoru A1 Saito, Hiroshi T1 FLOW VISUALIZATION USING HYDROGEN BUBBLE TECHNIQUE OF A FIN-AND-TUBE TYPE HEAT EXCHANGER WITH PUNCHED-OUT VORTEX GENERATORS JF Journal of Flow Visualization and Image Processing JO JFV YR 2010 FD 2011-01-08 VO 17 IS 4 SP 309 OP 320 K1 hydrogen bubble K1 vortex generators K1 secondary flow K1 heat exchanger K1 friction factor AB A study of the flow structure inside a fin-and-tube heat exchanger was performed by using hydrogen bubble visualization technique to examine the effects of different vortex generator geometries on the flow field, understand the formation of vortices and identify the punched-out hole effect on the flow behavior. Flow visualization results clarified flow structures and the effect of the punched holes for the studied vortex generator configurations. It is found that the vortices are created in the installed or punched forms. The strength of the vortices of installed vortex generators is more prominent compared to that of the punched vortex generators but the punched vortex generators showed smaller friction factors compared to the installed vortex generators. PB Begell House LK https://www.dl.begellhouse.com/journals/52b74bd3689ab10b,0b54a88d4ac558ac,4016108768ec24e5.html