PENGUJIAN KARAKTERISTIK PERPINDAHAN PANAS DAN FAKTOR GESEKAN PADA PENUKAR KALOR PIPA KONSENTRIK DENGAN SISIPAN PITA TERPILIN BERLUBANG
Abstract: This research was
conducted to examine the characteristics of heat transfer and friction
factor in the
annular channel concentric
tube heat exchanger with a
classic twisted tape insert and
perforated twisted tape
inserts. Test section was
the single pass concentric tube heat
exchanger with inner tube and outer tube made of aluminum. Dimensions of outer
tube; outer diameter of 21.87 mm and inner diameter of 20.67 mm, and dimensions
of inner tube, outer diameter of 15.84 mm and inner diameter of 14.34 mm. The
length of heat exchanger was 2,000 mm and the length of pressure drop
measurement in the inner tube was 2,010 mm. Flows in the inner tube and in annulus was counter flow. Working fluid in the inner tube was hot
water which its inlet temperature was maintained at 60°C, whereas in
the annulus was cold water at 28oC.
Both of classic twisted tape insert and perforated twisted tape insert with a
twist ratio of 4.0
were made of
aluminum strips with a
thickness of 0.76 mm and width of 12.61
mm which it was twisted so forming twist
with the length of pitch was 50.35 mm. Perforated twisted tape inserts were
varied with holes diameter
of 4 mm and
6.5 mm,
respectively, where the
distance between the center holes of 4 cm. Twisted tape insert
installed in the inner tube of the
concentric tube heat
exchanger. The results
showed that at the
same Reynolds number,
the addition of
classic twisted tape
insert and perforated twisted
tape insert with holes diameter of 4 mm and 6,5 mm in the inner tube increasing
the average Nusselt numbers w ere 79,20%, 68,7%, and 57,8% than
the inner tube
without a twisted
tape insert (plain
tube), respectively. At the same pumping power, the average Nusselt
number in the inner tube with
the addition of
perforated twisted tape
inserts with holes diameter of 6.5 decreased 1.62%,
whereas the addition of perforated twisted tape
inserts with holes
diameter of 4
mm classic tw isted
tape inserts increased the
average Nusselt number were 3.2% and
5,84% compared with plain tube, respectively. At the same Reynolds
number, the addition of classic twisted tape inserts and perforated twisted
tape insert with holes diameter of 4
mm and 6,5
mm in the
inner tube increased
the average friction
factor 339.25%, 298.49% and
269.6% than plain
tube, respectively. At
the same pumping power,
the addition of
classic twisted tape inserts
and perforated twisted tape
insert with holes
diameter of 4
mm and 6.5 mm in
inner tube increased the average
friction factor 485.39%, 416.48 % and 362.72% than plain tube, respectively.
Penulis: Tri Istanto, Wibawa
Endra Juwana
Kode Jurnal: jptmesindd110019
