The effect of the spiral angle on the heat transfer performance in micro-fin tube condensers has not yet been clearly established because other geometric parameters affecting the heat transfer performance were simultaneously varied in previous studies. This paper reports on the influence of the spiral angle on the heat transfer during condensation inside spiralled micro-fin tubes having all other geometric parameters constant. Tests were conducted for condensation of R-22, R-134a, and R-407C inside a smooth (9.52 mm outer diameter) and three micro-fin tubes with approximately the same diameter, having spiral angles of 10 deg, 18 deg, and 37 deg, respectively. Experimental results indicated a heat transfer augmentation with spiral angle increase. A new semi-empirical predictive correlation was developed for practical design of spiralled micro-fin tubes. The proposed new correlation predicted the majority of experimental results of the present study within a deviation zone of ±20%.

Issue Section:
Evaporative Boiling and Condensation
Keywords:
heat exchangers, refrigerants, cooling, condensation, pipe flow, two-phase flow, Condensation, Enhancement, Finned Surfaces, Heat Transfer
Topics:
Condensation, Heat transfer, Heat transfer coefficients, Refrigerants, Vapors, Flow (Dynamics)
1.
Schlager
,
L. M.
,
Pate
,
M. B.
, and
Bergles
,
A. E.
,
1990
, “
Evaporation and Condensation Heat Transfer and Pressure Drop in Horizontal 12.7 mm Microfin Tubes With Refrigerant 22
,”
ASME J. Heat Transfer
,
112
, pp.
1041
–
1047
.
2.
Yasuda
,
K.
,
Ohizumi
,
K.
,
Hori
,
M.
, and
Kawamata
,
O.
,
1990
, “
Development of Condensing Thermofin-HEX-C Tube
,”
Hitachi Cable Rev.
,
9
, pp.
27
–
30
.
3.
Chiang
,
R.
,
1993
, “
Heat Transfer and Pressure Drop During Evaporation and Condensation of Refrigerant R-22 in 7.5 mm Diameter Axial and Helical Grooved Tubes
,”
AIChE Symp. Ser.
,
295
(
89
), pp.
205
–
210
.
4.
Tatsumi
,
A. K.
,
Oizumi
,
K.
,
Hayachi
,
M.
, and
Itoh
,
M.
,
1982
, “
Application of Inner Grooves Tubes to Air Conditioners
,”
Hitachi Rev.
,
32
(
1
), pp.
55
–
60
.
5.
Cavallini
,
A.
,
Del Col
,
D.
,
Doretti
,
L.
,
Longo
,
G. A.
, and
Rossetto
,
L.
,
2000
, “
Heat Transfer and Pressure Drop During Condensation of Refrigerants Inside Horizontal Enhanced Tubes
,”
Int. J. Refrig.
,
23
, pp.
4
–
25
.
6.
NIST, 1998, NIST Thermodynamic and Transport Properties of Refrigerants and Refrigerant Mixtures Database (REFPROP Ver. 6.01), National Instruments of Standards and Technology, Gaithersburg, MD.
7.
Kline
,
S. J.
, and
McClintock
,
F. A.
,
1953
, “
Describing Uncertainties in Single Sample Experiments
,”
Am. Soc. Mech. Eng.
,
75
, pp.
3
–
8
.
8.
Briggs
,
D. E.
, and
Young
,
E. H.
,
1969
, “
Modified Wilson Plot Techniques for obtaining Heat Transfer Correlations for Shell and Tube Heat Exchangers
,”
Chemical Engineering Progress Symposium
,
92
(
65
), pp.
35
–
45
.
9.
Coetzee, S., 2000, “The Development of an Experimental Set-Up to Investigate Heat Transfer Enhancement in Tube-in-Tube Heat Exchangers,” MEng thesis, Department of Mechanical Engineering, Rand Afrikaans University, Johannesburg, South Africa.
10.
Eckels
,
S. J.
, and
Tesene
,
B. A.
,
1999
, “
A Comparison of R-22, R-134a, R-410A and R-407C Condensation Performance in Smooth and Enhanced Tubes: Part 1, Heat Transfer
,”
ASHRAE Trans.
,
105
, pp.
428
–
441
.
11.
Muzzio
,
A.
,
Niro
,
A.
, and
Arosio
,
S.
,
1998
, “
Heat Transfer and Pressure Drop During Evaporation and Condensation of HCFC-22 Inside 9.52-mm O.D. Microfin Tubes at Different Geometries
,”
J. Enhanced Heat Transfer
,
5
, pp.
39
–
52
.
12.
Eckels
,
S. J.
, and
Unruh
,
B. J.
,
1999
, “
Local Heat Transfer Coefficients During Condensation of HCFC-22 and R-32/R-125 Mixtures
,”
HVAC&R Res.
,
5
(
1
), pp.
59
–
76
.
13.
Smit
,
F. J.
,
Thome
,
J. R.
, and
Meyer
,
J. P.
,
2002
, “
Heat Transfer Coefficients During Condensation of the Zeotropic Refrigerant Mixture HCFC-22/HCFC-142b
,”
ASME J. Heat Transfer
,
124
(
6
), pp.
1137
–
1146
.
14.
Smit
,
F. J.
, and
Meyer
,
J. P.
,
2002
, “
R-22 and Zeotropic R-22/R-142b Mixture Condensation in Microfin, High-Fin, and Twisted Tape Insert Tubes
,”
ASME J. Heat Transfer
,
124
(
5
), pp.
912
–
921
.
15.
Bukasa, J. P. M., 2002, “Heat Transfer Performance During Condensation Inside Spiralled Microfin Tubes,” Ph.D. thesis, Department of Mechanical Engineering, Rand Afrikaans University, Johannesburg, South Africa.
16.
Liebenberg, L., 2002, “A Unified Prediction Method for Smooth and Micro-Fin Tube Condensation Performance,” Ph.D. thesis, Rand Afrikaans University, Johannesburg, South Africa.
17.
Akers
,
W. W.
,
Deans
,
H. A.
, and
Crosser
,
O. K.
,
1959
, “
Condensing Heat Transfer Within Horizontal Tubes
,”
Chemical Engineering Progress Symposium Series
,
55
(
29
), pp.
171
–
176
.
18.
Yu, J., and Koyama, S., 1998, “Condensation Heat Transfer of Pure Refrigerants in Microfin Tubes,” Proceedings International Refrigeration Conference, Purdue, pp. 325–330.
19.
Kedzierski, M. A., and Goncalves, J. M., 1997, “Horizontal Convective Condensation of Alternative Refrigerants Within a Micro-Fin Tube,” NISTIR 6095, U.S. Dept. Commerce, Washington, D.C., p. 74.
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