Internal heat transfer experiments in a simulated OTEC evaporator tube
Internal heat transfer tests have been conducted for ammonia in two-phase flow inside a nearly horizontal 3-in.-diameter, 20-ft-long aluminum tube. This tube simulates one pass of a multipass evaporator tube for use in a low-cost ocean thermal energy conversion (OTEC) plant-ship concept. The 29 tests covered mass flows of 1.0 to 2.8 lbm/sec, heat fluxes of 1100 to 2300 Btu/hr-ft/sup 2/, qualities up to 20 percent vapor by mass, and tube angles varying from a 0.26/sup 0/ downward tilt to a 2.0/sup 0/ upward tilt in the flow direction. Results from the 16 tests in the final run at 2.0/sup 0/ upward tilt, for which accuracy is best because of added instrumentation, are in agreement with the Chaddock--Brunemann correlation for two-phase-flow heat transfer. Stratified wavy or intermittent flow occurred to some degree in all tests, and it is clear that a downward tilt, which could trap vapor bubbles, should be avoided. The results as a whole are judged to indicate that overall internal heat transfer coefficients essentially equivalent to the prior predictions for this heat exchanger concept will be obtained in evaporators using horizontal tubes.
- Research Organization:
- Johns Hopkins Univ., Laurel, MD (USA). Applied Physics Lab.
- OSTI ID:
- 7228249
- Report Number(s):
- APL/JHU/AEO-76-066
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
140800* -- Solar Energy-- Ocean Energy Systems
AMMONIA
ENERGY TRANSFER
EVAPORATORS
FLUID FLOW
FLUIDS
HEAT EXCHANGERS
HEAT TRANSFER
HYDRIDES
HYDROGEN COMPOUNDS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OCEAN THERMAL POWER PLANTS
ORIENTATION
POWER PLANTS
SOLAR POWER PLANTS
TWO-PHASE FLOW
WORKING FLUIDS