Using a Cross -grooved Inner Surface for Enhancement of Heat Transfer Characteristics Inside Horizontal Tubes for Zeotropic Refrigerant
Abstract
The condensation characteristics of zeotropic refrigerant(R407C) inside horizontal tubes has been investigated experimentally using two types of new cross -grooved tube which are formed by varying the helix angle of second set of grooves at the same fin height. The performance of the two types of cross-grooved surface are compared to that of single -grooved surface. The improved cross-grooved tube(second helix angle β2=0°) has provided with higher condensation heat transfer coefficients than the single grooved tube at a low mass flow velocity. However, at a high mass flow velocity, the difference between condensation heat transfer coefficients for single and cross -grooved tube is not evident. The pressure drop of improved cross-grooved tube is slightly higher than that of the single grooved tube.
- Publication:
-
Transactions of the Japan Society of Refrigerating and Air Conditioning Engineers
- Pub Date:
- 2011
- Bibcode:
- 2011TRACE..16..189U
- Keywords:
-
- Heat Transfer;
- Condensation;
- Refrigerant Mixture;
- Pressure Drops;
- Horizontal Tube;
- Experiment;
- Cross-grooved tube