Spray evaporation heat transfer performance in R-123 in tube bundles

Book · Tue Dec 31 04:00:00 EST 1996

OSTI ID:433729

Moeykens, S ^[1]; Kelly, J E ^[2]; Pate, M B ^[3]

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1. Trane Co., LaCrosse, WI (United States)
2. Kansas State Univ., Manhattan, KS (United States). Dept. of Mechanical Engineering
3. Iowa State Univ., Ames, IA (United States). Mechanical Engineering Dept.

This study focuses on evaluating the heat transfer performance of refrigerant R-123 in the spray evaporation environment for pure refrigerant and for the case of lubricant addition. Tests were conducted with triangular-pitch tube bundles made from enhanced boiling tubes, enhanced condensation tubes, and plain-surface tubes. A second enhanced boiling surface tube bundle, made with a square-pitch tube alignment, was also tested so a comparison could be made between the square- and triangular-pitch geometries. In addition to pure refrigerant work, experiments were performed with small concentrations of a 305 SUS naphthenic mineral oil to evaluate its effect on falling-film heat transfer performance. Two different refrigerant supply rates were used in this work so the effects of film-feed supply rate could be interpreted from the data. Refrigerant was introduced to the test section via low-pressure-drop, wide-angle nozzles located directly over the tube bundle. Data were taken over a heat flux range of 40 kW/m{sup 2} (12,688 Btu/[h{center_dot}ft{sup 2}]) to 19 kW/m{sup 2} (6,027 Btu/[h{center_dot}ft{sup 2}]), while the refrigerant supply rate remained fixed. Collector tests were performed in parallel with the heat transfer experiments so the amount of refrigerant bypassing the tube bundle could be determined. It was found that the heat transfer coefficients were dependent upon film-feed supply rate, oil concentration, and heat flux. The enhanced boiling surface yielded higher heat transfer coefficients than either the enhanced condensation surface or the plain surface.

• OSTI ID: 433729
• Report Number(s): CONF-960606--
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
DIAGRAMS
EVAPORATION
EXPERIMENTAL DATA
HEAT EXCHANGERS
REFRIGERANTS
SPRAY COOLING