Heat transfer during reflux condensation of R134a inside a micro-fin tube with different tube inclinations


YILDIZ S. , Duymaz G., Ziegler F., Auracher H.

INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID, cilt.74, ss.425-434, 2017 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 74
  • Basım Tarihi: 2017
  • Doi Numarası: 10.1016/j.ijrefrig.2016.11.004
  • Dergi Adı: INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID
  • Sayfa Sayıları: ss.425-434

Özet

This study presents an experimental investigation of the heat transfer occurring during reflux condensation of refrigerant R134a in an inclined micro-fin tube (0.008 m OD, 0.5 m length). The experiments were carried out at a system pressure of 0.74 MPa and at inclination angles of 30, 38, 45, 60 and 90 from the horizontal. The experiments indicated that the inclination angle has a significant effect on heat transfer during reflux condensation. The maximum reflux heat transfer coefficient was found at 30 inclination angle. At this arrangement, the heat transfer increased by a factor of 2.45 compared to the vertical case. A comparison with previous studies suggests that the heat transfer in a micro-fin tube is 2.2 times better than that in a plain tube, and 1.34 times better than that in a plain rectangular channel both at 30 inclination. (C) 2016 Elsevier Ltd and IIR. All rights reserved.