The objective of this study is to investigate the effect of coiling on the flow characteristics of R-407C in an adiabatic spiral capillary tube. The characteristic coiling parameter for a spiral capillary tube is the coil pitch; hence, the effect of the coil pitch on the mass flow rate of R-407C was studied on several capillary tube test sections. It was observed that the coiling of the capillary tube significantly reduced the mass flow rate of R-407C in the adiabatic spiral capillary tube. In order to quantify the effect of coiling, the experiments were also conducted for straight a capillary tube, and it was observed that the coiling of the capillary tube reduced the mass flow rate in the spiral tube in the range of 9–18% as compared with that in the straight capillary tube. A generalized nondimensional correlation for the prediction of the mass flow rates of various refrigerants was developed for the straight capillary tube on the basis of the experimental data of R-407C of the present study, and the data of R-134a, R-22, and R-410A measured by other researchers. Additionally, a refrigerant-specific correlation for the spiral capillary was also proposed on the basis of the experimental data of R-407C of the present study.

1.
Ito
,
H.
, 1959, “
Friction Factors for Turbulent Flow in Curved Pipes
,”
ASME J. Basic Eng.
0021-9223,
D81
, pp.
123
134
.
2.
Kuehl
,
S. J.
, and
Goldschmidt
,
V. W.
, 1990, “
Steady Flows of R-22 Through Capillary Tubes: Test Data
,”
ASHRAE Trans.
0001-2505,
96
(
1
), pp.
719
728
.
3.
Wei
,
C. Z.
,
Lin
,
Y. T.
,
Wang
,
C. C.
, and
Leu
,
J. S.
, 1999, “
An Experimental Study of the Performance of Capillary Tubes for R-407C Refrigerant
,”
ASHRAE Trans.
0001-2505,
105
(
2
), pp.
634
638
.
4.
Kim
,
S. G.
,
Ro
,
S. T.
, and
Kim
,
M. S.
, 2002, “
Experimental Investigation of the Performance of R22, R407C and R410A in Several Capillary Tubes for Air-Conditioners
,”
Int. J. Refrig.
0140-7007,
25
, pp.
521
531
.
5.
Zhou
,
G.
, and
Zhang
,
Y.
, 2006, “
Numerical and Experimental Investigations on the Performance of Coiled Adiabatic Capillary Tube
,”
Appl. Therm. Eng.
1359-4311,
26
, pp.
1106
1114
.
6.
Park
,
C.
,
Lee
,
S.
,
Kang
,
H.
, and
Kim
,
Y.
, 2007, “
Experimentation and Modeling of Refrigerant Flow Through Coiled Capillary Tube
,”
Int. J. Refrig.
0140-7007,
30
(
7
), pp.
1168
1175
.
7.
Khan
,
M. K.
,
Kumar
,
R.
, and
Sahoo
,
P. K.
, 2008, “
Experimental Study of the Flow of R-134a Through an Adiabatic Helically Coiled Capillary Tube
,”
HVAC&R Res.
,
14
(
5
), pp.
749
762
.
8.
Khan
,
M. K.
,
Kumar
,
R.
, and
Sahoo
,
P. K.
, 2008, “
An Experimental Study of the Flow of R-134a Inside an Adiabatic Spirally Coiled Capillary Tube
,”
Int. J. Refrig.
0140-7007,
31
(
6
), pp.
970
978
.
9.
Bansal
,
P. K.
, and
Rupasinghe
,
A. S.
, 1996, “
An Empirical Model for Sizing Capillary Tubes
,”
Int. J. Refrig.
0140-7007,
19
(
8
), pp.
497
505
.
10.
Choi
,
J. M.
, and
Kim
,
Y. C.
, 2002, “
The Effects of Improper Refrigerant Charge on the Performance of Heat Pump With an Electronic Expansion Valve and Capillary Tube
,”
Energy
0360-5442,
27
(
4
), pp.
391
404
.
11.
Jabaraj
,
D. B.
,
Kathirvel
,
A. V.
, and
Lal
,
D. M.
, 2006, “
Flow Characteristics of HFC407C/HFC600a/HC290 Refrigerant Mixture in Adiabatic Capillary Tubes
,”
Appl. Therm. Eng.
1359-4311,
26
, pp.
1621
1628
.
12.
Fiorelli
,
F. A. S.
,
Huerta
,
A. A. S.
, and
Silvares
,
O. M.
, 2002, “
Experimental Analysis of Refrigerant Mixtures Flow Through Adiabatic Capillary Tubes
,”
Exp. Therm. Fluid Sci.
0894-1777,
26
, pp.
499
512
.
13.
Melo
,
C.
,
Ferreira
,
R. T. S.
,
Neto
,
C. B.
,
Goncalves
,
J. M.
, and
Mezavila
,
M. M.
, 1999, “
An Experimental Analysis of Adiabatic Capillary Tubes
,”
Appl. Therm. Eng.
1359-4311,
19
(
6
), pp.
669
684
.
14.
Wijaya
,
H.
, 1992, “
Adiabatic Capillary Tube Test Data for HFC-134a
,”
Proceedings of the IIR-Purdue Refrigeration Conference
, West Lafayette, IN, Vol.
1
, pp.
63
71
.
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