Study drop pressure R-407C

8/10/2019 Study drop pressure R-407C

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CORRELATIONS OF TWO-PHASE

PRESSURE DROP FOR THE MIXTURE

R-407C IN A SMOOTH HORIZONTAL

TUBE

Juan Jose Garcia Pabon

Matheus Porto

Luiz Machado

Ricardo Koury


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INTRODUCTION

Juan Garcia, Matheus Porto, Luiz Machado and Ricardo Koury

The ozone depletion phenomenon haveraised in the 1970s a discussion on the

environmental impacts and short term

solutions, regarding caused by CFCs

refrigerant fluids


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INTRODUCTION


The R-407C is a ternary blend of HFCs

comprising 23% of R32 , 25% of R125 and 52% ofR134a, in weight. Due to this fact R-407C has

ODP = 0 (Ozone Depletion Potential), and has a

low GWP (Global Warming Potential), also is not

flammable or toxic.

Because the R-407C is a zeotropic mixture, it is

expected a temperature glide during the phasechange, which is approximately 6C


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TWO-PHASE FLOW PRESSURE DROPCORRELATIONS


Homogeneous model

Homogeneous models consider an average of liquid and vapor properties

McAdams et al. (1942)


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Separated flow approach

This model considers the two-phases as two different flows, each one flowing through itsown tube


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Separated flow approach

Correlation Parameter Correlation Parameter

Chisholm (1967) 2 Mishima and Hibiki

(1996)

2

Chisholm (1973) 2 Wang et al. (1997)

2

Friedel (1979) 2 Tran et al. (2000)

2

Gronnerud (1979) 2 Sun and Mishima

(2009)

2

Mller-Steinhagen

and Heck (1986)

2


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Phenomenological approach

Quibn and Thome (2007) developed a

method to calculate pressure drop

separately for each type of flow pattern,

based on the flow pattern maps

proposed by Wojtan et al. (2005).


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RESULTS AND DISCUSSION


The experimental data presented in this section was obtained from

during convective boiling were obtained for horizontal smooth tube with an inner

diameter of 6 mm


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CONCLUSION


The correlations of Mller-Steinhagen and Heck (1986) and Sun

and Mishima (2009) predict the experimental data under

intermittent and annular flow patterns and are recommended

for use in two-phase pipe flow with R-407C.


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ACKNOWLEDGMENTS


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Study drop pressure R-407C