Insertion of twisted tapes in smooth channels is one of the passive methods used for enhancing heat transfer. Flow and associated heat transfer characteristics of these channels are very complex. Understanding this complex flow is helpful while designing new passive methods. Numerical methods like computational fluid dynamics (CFD) are gaining much popularity for analyzing and designing these heat transfer enhancement techniques. This paper focuses on such a numerical study. The preliminary study is focused on development of numerical methodology through validation. Successive studies are aimed at development of an innovative design for twisted tape. Twisted tapes with taper angle (tapered twisted tapes, i.e., tape width decreases along the flow direction) are developed and evaluated on the basis of the performance of these tapes with those of conventional tapes. A circular tube with tapered twisted tape with a twist ratio of 3 and taper angles of 0.3, 0.4, 0.5, 0.6, and 0.7 is considered for this study along with a plain tube. Three Reynolds numbers (Re) of 8545, 11393, and 13333 are considered to examine the sensitivity of the performance. Simulations are performed with a commercially available CFD tool, ansys fluent (v14.0). Heat transfer and pressure drop results are presented in the form of Nusselt number (Nu), friction factor (f), and overall enhancement ratio (η). An increase of 17% in overall enhancement is predicted with taper angle of 0.5.

References

References
1.
Naphon
,
P.
,
2006
, “
Heat Transfer and Pressure Drop in the Horizontal Double Pipes With and Without Twisted Tape Insert
,”
Int. Commun. Heat Mass Transfer
,
33
(
2
), pp.
166
175
.
2.
Bas
,
H.
, and
Ozceyhan
,
V.
,
2012
, “
Heat Transfer Enhancement in a Tube With Twisted Tape Inserts Placed Separately From the Tube Wall
,”
Exp. Therm. Fluid Sci.
,
41
, pp.
51
58
.
3.
Bharadwaj
,
P.
,
Khondge
,
A. D.
, and
Date
,
A. W.
,
2009
, “
Heat Transfer and Pressure Drop in a Spirally Grooved Tube With Twisted Tape Insert
,”
Int. J. Heat Mass Transfer
,
52
(
7–8
), pp.
1938
1944
.
4.
Eiamsa-ard
,
S.
, and
Promvonge
,
P.
,
2010
, “
Thermal Characteristics in Round Tube Fitted With Serrated Twisted Tape
,”
Appl. Therm. Eng.
,
30
(
13
), pp.
1673
1682
.
5.
Thianpong
,
C.
,
Eiamsa-ard
,
P.
,
Promvonge
,
P.
, and
Eiamsa-ard
,
S.
,
2011
, “
Effect of Perforated Twisted-Tapes With Parallel Wings on Heat Transfer Enhancement in a Heat Exchanger Tube
,”
Energy Procedia
,
14
, pp.
1117
1123
.
6.
Eiamsa-ard
,
S.
,
Wongcharee
,
K.
,
Eiamsa-ard
,
P.
, and
Thianpong
,
C.
,
2010
, “
Heat Transfer Enhancement in a Tube Using Delta-Winglet Twisted Tape Inserts
,”
Appl. Therm. Eng.
,
30
(
4
), pp.
310
318
.
7.
Woei Chang
,
S.
,
Jena Jan
,
Y.
, and
Shuen Liou
,
J.
,
2007
, “
Turbulent Heat Transfer and Pressure Drop in Tube Fitted With Serrated Twisted Tape
,”
Int. J. Therm. Sci.
,
46
(
5
), pp.
506
518
.
8.
Eiamsa-ard
,
S.
, and
Promvonge
,
P.
,
2010
, “
Performance Assessment in a Heat Exchanger Tube With Alternate Clockwise and Counter-Clockwise Twisted-Tape Inserts
,”
Int. J. Heat Mass Transfer
,
53
(
7–8
), pp.
1364
1372
.
9.
Wongcharee
,
K.
, and
Eiamsa-ard
,
S.
,
2011
, “
Heat Transfer Enhancement by Twisted Tapes With Alternate-Axes and Triangular, Rectangular and Trapezoidal Wings
,”
Chem. Eng. Process.
,
50
(
2
), pp.
211
219
.
10.
Eiamsa-ard
,
S.
,
Thianpong
,
C.
, and
Promvonge
,
P.
,
2006
, “
Experimental Investigation of Heat Transfer and Flow Friction in a Circular Tube Fitted With Regularly Spaced Twisted Tape Elements
,”
Int. Commun. Heat Mass Transfer
,
33
(
10
), pp.
1225
1233
.
11.
Eiamsa-ard
,
S.
,
Thianpong
,
C.
,
Eiamsa-ard
,
P.
, and
Promvonge
,
P.
,
2010
, “
Thermal Characteristics in a Heat Exchanger Tube Fitted With Dual Twisted Tape Elements in Tandem
,”
Int. Commun. Heat Mass Transfer
,
37
(
1
), pp.
39
46
.
12.
Wongcharee
,
K.
, and
Eiamsa-ard
,
S.
,
2011
, “
Friction and Heat Transfer Characteristics of Laminar Swirl Flow Through the Round Tubes Inserted With Alternate Clockwise and Counter-Clockwise Twisted-Tapes
,”
Int. Commun. Heat Mass Transfer
,
38
(
3
), pp.
348
352
.
13.
Woei Chang
,
S.
,
Lirng Yang
,
T.
, and
Shuen Liou
,
J.
,
2007
, “
Heat Transfer and Pressure Drop in Tube With Broken Twisted Tape Insert
,”
Exp. Therm. Fluid Sci.
,
32
(
2
), pp.
489
501
.
14.
Eiamsa-ard
,
S.
,
Thianpong
,
C.
, and
Eiamsa-ard
,
P.
,
2010
, “
Turbulent Heat Transfer Enhancement by Counter/Co-Swirling Flow in a Tube Fitted With Twin Twisted Tapes
,”
Exp. Therm. Fluid Sci.
,
34
(
1
), pp.
53
62
.
15.
Murugesan
,
P.
,
Mayilsamy
,
K.
,
Suresh
,
S.
, and
Srinivasan
,
P. S. S.
,
2011
, “
Heat Transfer and Pressure Drop Characteristics in a Circular Tube Fitted With and Without V-Cut Twisted Tape Insert
,”
Int. Commun. Heat Mass Transfer
,
38
(
3
), pp.
329
334
.
16.
Eiamsa-ard
,
S.
,
Yongsirib
,
K.
,
Nanan
,
K.
, and
Thianpong
,
C.
,
2012
, “
Heat Transfer Augmentation by Helically Twisted Tapes as Swirl and Turbulence Promoters
,”
Chem. Eng. Process.
,
60
, pp.
42
48
.
17.
Naga Sarada
,
S.
,
Sita Rama Raju
,
A. V.
,
Kalyani Radha
,
K.
, and
Shyam Sunder
,
L.
,
2010
, “
Enhancement of Heat Transfer Using Varying Width Twisted Tape Inserts
,”
Int. J. Eng. Sci. Technol.
,
2
(
6
), pp.
107
118
.
18.
Gunes
,
S.
,
Erdemir
,
D.
,
Ozceyhan
,
V.
, and
Altuntop
,
N.
,
2012
, “
Numerical Investigation of Thermal Performance of a Tube Fitted With Regularly Spaced Twisted Tape Elements
,”
ASME
Paper No. HT2012-58078.
19.
Mwesigye
,
A.
,
Bello-Ochende
,
T.
, and
Meyer
,
P.
,
2013
, “
Heat Transfer Enhancement in a Parabolic Trough Receiver Using Wall Detached Twisted Tape Inserts
,”
ASME
Paper No. IMECE2013-62745.
20.
Kumar Saha
,
S.
,
Kumar Barman
,
B.
, and
Banerjee
,
S.
,
2012
, “
Heat Transfer Enhancement of Laminar Flow Through a Circular Tube Having Wire Coil Inserts and Fitted With Center-Cleared Twisted Tape
,”
ASME J. Therm. Sci. Eng. Appl.
,
4
(
3
), p.
031003
.
21.
Giniyatullin
,
A.
, and
Tarasevich
,
S.
,
2013
, “
CFD Modelling of Subcooled Boiling in Tubes With Twisted Tape Insert
,”
ASME
Paper No. FEDSM2013-16298.
22.
Lin
,
Z.-M.
, and
Wang
,
L.-B.
,
2009
, “
Convective Heat Transfer Enhancement in a Circular Tube Using Twisted Tape
,”
ASME J. Heat Transfer
,
131
(
8
), p.
081901
.
23.
Kumar Saha
,
S.
, and
Kumar Pai
,
P.
,
2014
, “
Experimental Investigation of Laminar Flow of Viscous Oil Through a Circular Tube Having Integral Spiral Corrugation Roughness and Fitted With Twisted Tapes With Oblique Teeth
,”
Exp. Therm. Fluid Sci.
,
57
, pp.
301
309
.
24.
Patil
,
A. G.
,
2000
, “
Laminar Flow Heat Transfer and Pressure Drop Characteristics of Power-Law Fluids Inside Tubes With Varying Width Twisted Tape Inserts
,”
ASME J. Heat Transfer
,
122
(
1
), pp.
143
149
.
25.
ANSYS
,
2011
,
ICEMCFD User Manual
,
ANSYS, Inc.
,
Canonsburg, PA
.
26.
ANSYS
,
2011
,
FLUENT User Manual
,
ANSYS, Inc.
,
Canonsburg, PA
.
27.
Groves
,
C. E.
,
Ilie
,
M.
, and
Schallhorn
,
P. A.
,
2012
, “
Comprehensive Approach to Verification and Validation of CFD Simulations Applied to Backward Facing Step-Application of CFD Uncertainty Analysis
,” NASA, Washington, DC, Technical Report No. 20120013081.
28.
Celik
,
I. B.
,
2008
, “
Procedure for Estimation and Reporting of Uncertainty Due to Discretization in CFD Applications
,”
ASME J. Fluids Eng.
,
130
(
7
), p.
078001
.
You do not currently have access to this content.