PENGARUH TWIST RATIO TERHADAP KARAKTERISTIK PERPINDAHAN PANAS DAN FAKTOR GESEKAN PADA PENUKAR KALOR PIPA KONSENTRIK SALURAN ANNULAR DENGAN TWISTED TAPE INSERT

FATCHURAHMAN, SEPTIAN (2011) PENGARUH TWIST RATIO TERHADAP KARAKTERISTIK PERPINDAHAN PANAS DAN FAKTOR GESEKAN PADA PENUKAR KALOR PIPA KONSENTRIK SALURAN ANNULAR DENGAN TWISTED TAPE INSERT. Other thesis, Universitas Sebelas Maret.

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    Abstract

    This research was conducted to examine the effect of twist ratio on characteristics of heat transfer and the friction factor in the annular channel concentric tube heat exchanger with twisted tape insert. 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 difference measurement in the inner tube was 2,010 mm. Flows in the inner tube and in annulus were in opposite directions. 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 ± 27oC. The twisted tape inserts were made from aluminum strips with thickness of 0.76 mm, and the width of 12.61 mm. The twisted tape inserts were varied with twist ratio of 4, 6, and 8, which its pitch length were 50.35 mm, 80.025 mm, and 100.7 mm, respectively. Twisted tape insert installed in the inner tube of the concentric tube heat exchanger The research result showed that at the same Reynolds number, the heat transfer rate in the inner tube with the addition of twisted tape inserts with twist ratio 4, 6, and 8 was higher than plain tube. The smaller the twist ratio of the twisted tape insert, the greater the heat transfer rate in inner tube. At the same Reynolds number, the enhancement of the average Nusselt number in inner tube with the addition of twisted tape inserts with twist ratio of 4, 6, and 8 were 56.6%, 33.49%, and 19.54% than the plain tube, respectively. At the same pumping power, the addition of twisted tape inserts with a twist ratio of 4, 6, and 8, the average Nusselt number decreased 1.62%, 13.58% and 18.60% compared with plain tube, respectively. At the same Reynolds number, the average friction factor in inner tube with the addition of the twisted tape inserts with twist ratio of 4, 6, and 8 were 3.7, 3.37, and 2.98 times compared with the plain tube, respectively. At the same pumping power, the average friction factor in inner tube with the addition of the twisted tape inserts with twist ratio of 4, 6, and 8 were 4.63, 4.08, and 3.42 times compared with plain tubes, respectively. Keywords : Reynolds number, Nusselt number, friction factor, twisted tape insert, twist ratio

    Item Type: Thesis (Other)
    Subjects: T Technology > TJ Mechanical engineering and machinery
    Divisions: Fakultas Teknik
    Fakultas Teknik > Teknik Mesin
    Depositing User: AB Kusuma
    Date Deposited: 16 Jul 2013 07:58
    Last Modified: 16 Jul 2013 07:58
    URI: https://eprints.uns.ac.id/id/eprint/4915

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