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Journal of Enhanced Heat Transfer

Theory and Application in High Performance Heat and Mass Transfer

ISSN for PRINT: 1065-5131

Institutional price:	$577.00
Issues per year:	4

Best Paper Award Selection - Editorial Board Site

2004, Volume11

94 pages

DOI: 10.1615/JEnhHeatTransf.v11.i1

Issue price - $138.00

Heat Transfer and Fluid Flow in Rectangular Fin and Elliptic Tube Heat Exchangers under Dry and Dehumidifying Conditions

Shin-Li Chen
Department of Mechanical Engineering, National Cheng-Kung University, Tainan, Taiwan 70101

Jiin-Yuh Jang
Department of Mechanical Engineering, National Cheng-Kung University, Tainan, Taiwan 701

ABSTRACT

Experimental and numerical analyses were carried out to study the thermal-hydraulic and mass transfer characteristics of four-row rectangular fin and elliptic tube heat exchangers having a major/minor axis ratio of 2.83. Four types of rectangular finned configurations have been investigated for various inlet frontal velocities ranging from 1 to 6 m/s under dry and dehumidifying conditions: two staggered tube arrangements with fin heights of 7 mm and 10 mm, respectively; and two in-lined tube arrangements with fin heights of 7 mm and 10 mm, respectively. The results indicated that the sensible Colburn factor j_s and the friction factor f for the wet coils are, respectively, 56-71% and 2-16% higher than those for dry coils. In addition, a two-dimensional fin efficiency analysis for rectangular fins with elliptic tubes was presented for a wide range of air relative humidities and Biot numbers. It is shown that the fully wet fin effciency is lower than that of the dry fin by 20% and 31% with respect to fin heights of 7 and 10 mm.