PENGUJIAN KARAKTERISTIK PERPINDAHAN PANAS DAN FAKTOR GESEKAN PADA PENUKAR KALOR PIPA KONSENTRIK SALURAN ANNULAR DENGAN TWISTED TAPE INSERT WITH OBLIQUE TEETH
Abstract: This research was conducted to examine the characteristics of heat
transferand friction factor in the
annular channel concentric
tube heat exchangerwith the addition of twisted tape
insert with oblique teeth. Test section was the single pass
concentric tube heat
exchanger with inner
tube and outer
tube made of aluminum.
The length of
heat exchanger was 2,110
mm and the length of pressure drop measurement in the inner
tube was 2,240 mm. Flows in the inner tube and in annulus were counter
flow. Working fluid in the inner tube
was hot water
which its inlet
temperature was maintained
at 60°C, whereas the
working fluid in the annulus
was cold water
with its inlet temperature of ± 28oC. For
comparison, inner tube tested without twisted tape insert (plain tube) and with
the addition of twisted tape insert without oblique teeth (classic twisted tape
insert). Classic twisted tape insert and twisted tape insert with oblique
teeth made of aluminum strip with a thickness of 0.7 mm, width 12.6 mm, which had a twist
ratio of 4.0 and the pitch length of 50.3 mm. While the twisted
tape inserts with
oblique teeth varied
with tooth angle
of 15°, 30° and
45°. Classic twisted
tape insert and
twisted tape inserts
with oblique teeth installed in the inner tube of the concentric tube
heat exchanger. The research result has showed that the inner tube with the
addition of twisted tape insert with
oblique teeth produce
Nusselt number, friction
factor and thermal performance
that was greater than the addition of classic twisted tape insert and
plain tube. Values
of Nusselt number,
friction factor and
thermal performance increase with the increase in tooth angle of twisted tape inserts with the
oblique teeth. At the same Reynolds number, the
addition of twisted tape insert
with oblique teeth with a tooth angle 15°, 30°, and 45° resulting in an
increased average Nusselt number in the inner tube, of 61.8%, 75.3% and 89.2% when
compared to the
plain tube, respectively.
Compared to classic twisted tape
inserts, inner tube
with twisted tape
inserts with oblique
teeth with a tooth
angle 15°, 30°,
and 45° experienced
increase Nusselt numbers, an
average of 10.2%,
19.4% and 28.9%,
respectively. At the
same Reynolds number, the
addition of classic twisted tape insert and twisted tape insert with oblique teeth
with a tooth
angle 15°, 30°,
and 45° in the
inner tube has produced
an average friction
factor of 2.4;
2.9; 3.4; and
3.9 times than
the friction factor of
plain tube, respectively.
The average thermal
performance with the addition
of classic twisted
tape inserts, twisted
tape inserts with oblique teeth with a tooth angle 15°,
30°, and 45° in the inner tube of 1.003; 1.060; 1.106; and 1.151 respectively.
Penulis: Mirando Eka Wicaksono,
Tri Istanto, Wibawa Endra Juwana
Kode Jurnal: jptmesindd120012
