Condensation Heat-Transfer Measurements of Refrigerants on Externally Enhanced Tubes.
Abstract
An apparatus was designed and fabricated for testing of a horizontal bundle of five tubes in a vertical row with R-114 as the working fluid. Twenty-four tubes with rectangular-section fins ansd a smooth tube were tested in a single-tube apparatus using R-113 as the working fluid. An enhancement ratio (based on constant vapor-side temperature drop) of about 7.0 was obtained for the best-performing tube. Among the tubes tested, the optimum fin spacing was found to be between 0.25 mm to 0.5 mm. The optimum fin thickness for tubes with a 1.0 mm fin height was found to be 0.5 mm. The vapor-side enhancement ratio increased with increasing fin height. However, the rate of increase in the vapor-side enhancement was found to be smaller with increasing fin height compared to the rate of area increase. The indirect measurement of the local condensing heat-transfer coefficient around a finned tube showed a local value at the top of each of the two tubes tested that is approximately twice the average value for the entire tube.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1987
- Accession Number
- ADA185383
Entities
People
- David S. Zebrowski
Organizations
- Naval Postgraduate School