Condensation heat transfer and pressure drop of R-134a saturated vapour inside a brazed compact plate fin heat exchanger with serrated fin

• Published in: Heat and mass transfer 2017, Vol.53 (1), p.331-341
• Main Authors: Ramana Murthy, K. V., Ranganayakulu, C., Ashok Babu, T. P.
• Format: Article
• Language: English
• Subjects: Coefficient of friction; Condensation; Correlation analysis; Dependence; Engineering; Engineering Thermodynamics; Forced convection; Heat and Mass Transfer; Heat exchangers; Heat flux; Heat transfer; Heat transfer coefficients; Industrial Chemistry/Chemical Engineering; Kinetic energy; Original; Plate-fin heat exchangers; Pressure drop; Pressure effects; Product testing; Refrigerants; Saturation; Sensitivity; Simulation; Surface properties; Thermodynamics
• ISSN: 0947-7411; 1432-1181
• DOI: 10.1007/s00231-016-1827-0

This paper presents the experimental heat transfer coefficient and pressure drop measured during R-134a saturated vapour condensation inside a small brazed compact plate fin heat exchanger with serrated fin surface. The effects of saturation temperature (pressure), refrigerant mass flux, refrigerant heat flux, effect of fin surface characteristics and fluid properties are investigated. The average condensation heat transfer coefficients and frictional pressure drops were determined experimentally for refrigerant R-134a at five different saturated temperatures (34, 38, 40, 42 and 44 °C). A transition point between gravity controlled and forced convection condensation has been found for a refrigerant mass flux around 22 kg/m 2 s. In the forced convection condensation region, the heat transfer coefficients show a three times increase and 1.5 times increase in frictional pressure drop for a doubling of the refrigerant mass flux. The heat transfer coefficients show weak sensitivity to saturation temperature (Pressure) and great sensitivity to refrigerant mass flux and fluid properties. The frictional pressure drop shows a linear dependence on the kinetic energy per unit volume of the refrigerant flow. Correlations are provided for the measured heat transfer coefficients and frictional pressure drops.