Investigation was executed to predict the heat transfer and friction factor in circular tube fitted with different shape of spiral insert under different values of heat flux and flow rates. Experimental test platform includes a horizontal circular copper tube with other accessories used to investigate the heat transfer enhancement. The lengths, inner and outer diameter of tube are 100cm, 2.2cm and 2.4 cm, respectively. Different shapes of spiral insert are made from copper tube, and then it is inserted in the test section tube. The lengths of spiral insert and pitch distance between the coils were 18 cm and 2 cm respectively. Four parts of spiral were inserted inside the test tube. The spiral shapes include Cylindrical Spiral (CS), Barrel Compression Spiral (BCS), Hourglass Compression Spiral (HCS), and Conical Compression Spiral (CCS) configurations. The aim of present experiments was to determine the best insert type to enhance heat transfer with minimum pressure loss. All experimental tests were conducted under a fully developed turbulent flow with a range of Reynolds number (3500-7500) and constant heat flux range were (4500-10500 W/m^2). In general, the use of spiral insert increases the heat transfer from the wall tube to the working fluid (water). Results show that the Nusselt number increases as the Reynolds number increases as well for all ranges of heat flux. Results show that CS insert gives the best thermo-hydraulic characteristics. The results show that the Nusselt number increased by 40% when using CS insert type compared to a plain tube at Re=7500 and heat flux equal 10500. While, the pressure drop with CS insert was lower than (HCS, BCS, and CCS) inserts. Results show that the friction factor with CS insert was higher by (61%) than the plain tube, followed by the ratio of (69 %), (73 %) and (76 %) when using (HCS), (BCS) and (CCS) insert respectively. Therefore, it was concluded that the CS insert was the best type to enhance the heat transfer with low increment in pressure loss.

1.
A.
Kumar
,
B. N.
Prasad
,
Investigation of twisted tape inserted solar water heaters-heat transfer, friction factor and thermal performance results
,
Renew. Energy
19
(
3
) (
2000
), pp.
379
398
.
2.
Qasim S.
Mahdi
and
Noor A. M.
Mohammed
,
2016
,
Heat Transfer Augmentation of Laminar Nanofluid Flow in Horizontal Tube Inserted with Twisted Tapes
,
International Research Journal of Engineering and Technology (IRJET)
Volume:
03
Issue:
06
I June.
3.
S. W.
Chang
,
K.
Yu
,
M. H.
Lu
,
Heat transfers in tubes fitted with single, twin, and triple twisted tapes
,
Exp. Heat Transfer
18
(
2005
), pp
279
294
.
4.
S. K.
Saha
,
A.
Dutta
,
S. K.
Dhal
,
Friction and heat transfer characteristics of laminar swirl flow through a circular tube fitted with regularly spaced twisted tape elements
,
Int. J. Heat Mass Transfer
44
(
2001
), pp
4211
4223
.
5.
S.
Jaisankar
,
T. K.
Radhakrishnan
,
K. N.
Sheeba
,
Experimental studies on heat transfer and friction factor characteristics of forced circulation solar water heater system fitted with helical twisted tapes
,
Sol. Energy
83
(
2009
)
1943
1952
.
6.
Kumar V.
Sudheer
CFD Analysis on Heat Transfer Enhancement in Horizontal Tube by Forced Convection with Inserts
",
International Journal & Magazine of Engineering, Technology, Management and Research
Volume
3
, issue no.
2
, Feb
2016
.
7.
R. L.
Webb
,
Principles of Enhanced Heat Transfer
, second ed.,
Wiley Inter science
,
New York
, (
1994
).
8.
Dong H.
Lee
,
Jin M.
Jung
,
Jong H.
Ha
,
Young I.
Cho
, “
Improvement of Heat Transfer with Perforated Circular Holes in Finned Tubes of Air-Cooled Heat Exchanger
",
International Communications in Heat and Mass Transfer
, Vol.
39
, (
2012
), pp.
161
166
.
9.
T. S.
Ravigururajan
,
A. E.
Bergles
,
Development and verification of general correlations for pressure drop and heat transfer in single-phase turbulent flow in enhanced tubes
,
Exp. Therm. Fluid Sci.
13
(
1996
), pp.
55
70
.
10.
Shuai
Shi
,
Chang-qi
Yan
, “
Numerical Study of Heat Transfer and Pressure Drop of Integral Pin-Fin Tubes
", Vol.
978-1
(
2011
), pp.
4244-6255-1
/
11
,.
11.
M. A.
Akhavan-Behabadi
,
R.
Kumar
,
M. R.
Salimpour
,
R.
Azimi
,
Pressure drop and heat transfer augmentation due to coiled wire inserts during laminar flow of oil inside a horizontal tube
,
Int. J. Therm. Sci.
49
(
2010
), pp.
373
379
.
12.
Kapatkar
A. V. N.
,
B. Dr. A. S.
Padalkar
and
C. Sanjay
Kasbe
,
2011
, “
Experimental Investigation on Heat Transfer Enhancement in Laminar Flow in Circular Tube Equipped with Different Inserts
",
AMAE Int. J. on Manufacturing and Material Science
, Vol.
01
(
1
).
13.
R. H.
Martin
,
A.
Garcia
,
J. P.
Garcia
,
Experimental heat transfer research in enhanced flat-plate solar collectors
, in:
Solar Thermal Applications. World Renewable Energy Congress
,
Sweden
, (
8-13 May
2011
).
14.
Naga S.
Sarada
,
A. V. Sita Rama
Raju
,
K. Kalyani
Radha
and
L. Shyam
Sunder
,
Enhancement of heat transfer using varying width twisted tape inserts
,
International Journal of Engineering, Science and Technology
, Vol.
2
, No.
6
(
2010
), pp.
107
118
.
15.
Sahiti
N.
,
Durst
F.
,
Dewan
A.
, “
Heat Transfer Enhancement by Pin Elements
",
International Journal of Heat and Mass Transfer
Vol.
48 (2005
), pp.
4738
4747
.
16.
P.
Promvonge
,
Thermal augmentation in circular tube with twisted tape and wire coil turbulators
,
Energy Convers. Manage.
49
(
11
) (
2008
), pp.
2949
2955
.
17.
N. S.
Sarada
,
K. K.
Radha
,
A. V. S.
Raju
,
Experimental investigations in a circular tube to enhance turbulent heat transfer using mesh inserts
,
ARPN J. Eng. Appl. Sci.
4
(
5
) (
2009
), pp.
53
60
.
18.
Yadav
A. S.
,
Effect of Half Length Twisted-Tape Turbulators on Heat Transfer and Pressure Drop Characteristics inside a Double Pipe U Bend Heat Exchanger
,
Jordan Journal of Mechanical and Industrial Engineering
, Vol.
3
, No.
1
(
2009
), pp.
17
22
.
19.
K. E.
Amori
and
R. K.
Insayif
, “
Investigation of Twisted Tape Turbulator for Fire Tube Boiler
", Part I. Heat Transfer"
Journal of Engineering / Iraqi Academic Scientific Journals
, Vol.
17
, No.
4
, (Iraq,
2011
).
20.
A. A.
Hussein
, “
Heat Transfer Enhancement in Tube using Modified Twisted Tape Inserts
",
Research Journal of Applied Sciences, Engineering and Technology
, Vol.
13
, No.
8
(Iraq,
2016
), pp.
617
625
.
21.
Luay B.
Hamad
, “
Parametric Study of Heat Transfer and Pressure Drop Characteristics in A Tube Using Different Types of Inserts
" Thesis in
institute of science and technology mechanical and aeronautical engineering department
, (
2017
).
22.
Rouse
H.
Elementary Mechanics of Fluids
.
John Wiley & Sons
(
1946
).
23.
Holman
J. P.
"Experimental Methods for Engineers"
McGraw-Hill
, 8th Edition, (
2012
).
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