New Applicable Correlations to Predict Pressure Drop of R134a for the Flattened Tubes

Main Article Content

Ronee Bilmud
Amawasee Rukruang
Somchai Wongwises
Jatuporn Kaew-On

Abstract

The objective of this study that proposed new correlations to predict pressure drop during condensation
of R134a for the flattened tubes. The flattened tubes are made from 3.55 mm inner diameter of round tubes. The tested tube configurations are as follows: circular tube with 3.55 mm inner diameter; flattened tube with aspect 0.72 (FT1); 3.49 (FT2); and 7.06 (FT3) aspect ratio respectively. The experimental range covers mass flux of 200-800 kg/m2s, heat flux 10 - 40 kW/m2, saturation pressure 8, 10 and 12 bar, and vapor quality 0.1 - 0.8. The results showed that condensation pressure drop increased with the increase of mass flux, heat flux and vapor quality in the other hand; pressure drop decreased that have significantly affected by saturation pressure 8, 10, and 12 respectively. The existing correlations are not successful for the prediction condensation pressure drop of flattened tubes. A proposed correlation can be used to predict pressure drop as 80 % of the experimental data within ± 30 %.

Article Details

Section
Research Articles

References

[1] Kwang-II, C., Pamitrana. A.S., Ohb, J.T. and Saitoc, K. (2009).”Pressure Drop and Heat Transfer during
Two-phase Flow Vaporization of Propane in Horizontal Smooth Mini Channels”, International
Journal of Refrigeration. 32, 837–845.
[2] Kim, N.H., Lee, E.J. and Byun, H.W. (2013). “Condensation Heat Transfer and Pressure Drop in Flattened
Smooth Tube Shaving Different Aspect Ratios”, International Journal of Experimental Thermal
and Fluid Science. 46, 245–253.
[3] Chisholm, D. (1973). “Pressure Gradients Due to Friction during the Flow of Evaporating Two-phase Mixtures
in Smooth Tubes and Channels”, International Journal of Heat and Mass Transfer. 16, 347–358.
[4] Friedel, L. (1979). “Improved Frictional Pressure Drop Correlation for Horizontal and Vertical Two-phase
Flow”, Proceedings European Two Phase Flow Group Meeting. 18(7), 485–491.
[5] Lockhart, R.W. and Martinelli, R.C. (1949). “Proposed Correlation of Data for Isothermal Two-phase,
Two-Component Flow in Pipes”, Chemical Engineering Progress. 45, 39–48.
[6] Mishima, K. and Hibiki, T. (1996). “Some Characteristics of Air–water Two-phase Flow in Small Diameter
Tube”, International Journal of Multiphase Flow. 22, 703–712.
[7] Zhang, M. and Webb, R.L. (2001). “Correlation of Two-phase Friction for Refrigerants in Small Diameter
Tubes”, Experimental Thermal and Fluid Science. 25, 131–139.
[8] Müller-Steinhagen, H. and Heck, K. (1986). “A Simple Friction Pressure Drop Correlation for Two-phase
Flow in Pipes”, Chemical Engineering and Processing. 20, 297–308.
[9] Wang, W.W., Radcliff, T.D. and Christensen, R.N. (2002). “A Condensation Heat Transfer Correlation
forMillimetre-scale Tubing with Flow Regime Transition”, Experimental Thermal and Fluid
Science. 26, 473–485.
[10] Tran, T.N., Wambsganss, M.W. and France D.M. (1996). “Small Circular and Rectangular Channel
Boiling with Two Refrigerants”, International Journal of Multiphase Flow. 22, 485–498.
[11] Wilson, M.J., Newell, T.A., Chato, J.C., Infante, C.A. and Ferreira, A. (2003). “Refrigerant Charge Pressure
Drop and Condensation Heat Transfer in Flattened Tubes”, International Journal of Refrigeration.
26, 442–451.