Experimental investigation of the onset of nucleate boiling in ammonia flowing inside a large-diameter smooth aluminum tube
A series of experiments has been completed which investigates the occurrence of the Onset of Nucleate Boiling (ONB) in ammonia flowing inside a large-diameter aluminum tube. The tube simulates one pass of a multipass evaporator which is proposed by APL for use in a low-cost Ocean Thermal Energy Conversion (OTEC) plant-ship heat exchanger. The 25 tests covered mass flows of 0.7 to 1.5 1bm/sec, heat fluxes of 1100 to 3600 Btu/hr-ft/sup 2/ and levels of subcooling of the ammonia of 4 to 20/sup 0/F. Observations of the onset of nucleate boiling (ONB) were judged to occur at several flow conditions where the local heat transfer coefficients were measured to be much higher than the all-liquid flow coefficient; in some cases, the presence of vapor dryout at the upstream part of the tube also indicated ONB. The observations were compared with predictions made by the correlation method of Bergles and Rohsenow (as modified by Frost and Dzakowic) and indications are that this correlation predicts the occurrence of ONB very well. The conclusion that this prediction method be used in design work with smooth tubes is made in addition to the recommendation that similar ONB tests be performed with an enhanced surface.
- Research Organization:
- Johns Hopkins Univ., Laurel, MD (USA). Applied Physics Lab.
- DOE Contract Number:
- AB01-76ET20330
- OSTI ID:
- 5229044
- Report Number(s):
- DOE/ET/20330-T1; ON: DE84006677
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
140800* -- Solar Energy-- Ocean Energy Systems
AMMONIA
BOILING
CONVERSION
ENERGY CONVERSION
ENERGY TRANSFER
EVAPORATORS
HEAT EXCHANGERS
HEAT TRANSFER
HYDRIDES
HYDROGEN COMPOUNDS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NUCLEATE BOILING
OCEAN THERMAL ENERGY CONVERSION
OCEAN THERMAL POWER PLANTS
PHASE TRANSFORMATIONS
POWER PLANTS
SIMULATION
SOLAR ENERGY CONVERSION
SOLAR POWER PLANTS
THERMAL POWER PLANTS
TUBES