Paper Info
Title
Heat Transfer Enhancement in a Novel Annular Tube with Outer Straight and Inner Twisted Oval Tubes.
Abstract
The thermal-hydraulic performance in a novel annular tube formed by outer straight and inner twisted oval tubes is numerically investigated. An annular tube formed by two straight oval tubes is also studied for comparison. Inner twisted oval tubes with different aspect ratios and twist ratios are studied. The heat transfer is well improved by the symmetrical secondary flow in the annulus. The Nusselt number generally increases when the inner oval tube becomes flatter and the twists stronger in the studied range of geometrical parameters. The largest Nusselt numberNuof the inner twisted tube increases by 116% while the friction factorfincreases by only 46% compared with that of the inner straight tube, and the largest value of the thermal performance factor (JF) can be up to 1.9. Correlations of the Nusselt number and friction factor are proposed for laminar and turbulent flows, and the deviations of the correlations are within +/- 5% and +/- 4% forNuandf, respectively.
Year
DOI
Venue
2020
10.3390/sym12081213
SYMMETRY-BASEL
Keywords
DocType
Volume
twisted oval tube,annular tube,double-pipe heat exchanger,thermal performance
Journal
12
Issue
Citations 
PageRank 
8
0
0.34
References 
Authors
0
4
Name
Order
Citations
PageRank
Chao Luo15817.22
KeWei Song200.68
T. Tagawa311.34
Tengfei Liu448834.13