Condensation of Refrigerant-11 on the outside of vertical enhanced tubes

Technical Report · Sat Aug 01 04:00:00 EDT 1981

DOI:https://doi.org/10.2172/6167136· OSTI ID:6167136

Domingo, N

Experiments were conducted to determine heat transfer performance of single vertical tubes with Refrigerant-11 condensing on its outside surface. Twelve enhanced (fluted, spiraled, roped, and corrugated) tubes of 2.54-cm (1-in.) nominal outside diameter and 1.2-m (4-ft) length were tested. Several of the tested tubes featured internal enhanced geometries. A previously tested smooth tube served as the basis for comparison. Composite heat transfer coefficients (coefficients that include the resistances of both the condensing film and the tube wall), based on the total tube outside surface area, ranged from 850 to 6530 W/m/sup 2/ . K (150 to 1150 Btu/h . ft/sup 2/ . /sup 0/F) over the heat flux range of 5675 to 31,375 W/m/sup 2/ (1800 to 9950 Btu/h . ft/sup 2/). The primary conclusions from this study are: (1) for a given heat flux, an external fluted tube can increase composite condensing heat transfer coefficients by up to 5.5 times the smooth tube values, giving better condensing performance than any of the other geometries tested; (2) further increase in composite condensing coefficients can be achieved by using skirts to divide the fluted tube into equal condensing lengths; and (3) for a given overall temperature difference and water flow rate, internal flutes can increase the overall performance by up to 17% over that for a tube with identical outside flutes and a smooth inside surface.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6167136
• Report Number(s): ORNL/TM-7797; ON: DE81026085
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150802* -- Geothermal Power Plants-- Power Plant Systems & Components
BINARY-FLUID SYSTEMS
CONDENSERS
ENERGY SYSTEMS
ENERGY TRANSFER
FLUIDS
Geothermal Legacy
HEAT TRANSFER
PERFORMANCE TESTING
PHYSICAL PROPERTIES
REFRIGERANTS
TEST FACILITIES
TESTING
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
TUBES
VAPOR CONDENSATION
VAPOR CONDENSERS
WORKING FLUIDS