Analysis and modeling of nucleate boiling in highly-wetting liquids

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5554376

Tong, W

In recent years, the incessant drive towards higher heat flux and power density in nearly all categories of electronic equipment has turned attention to the use of dielectric liquids, such as the Fluoro-Fluorocarbons (Fluorinerts) and the Chloro-Fluorocarbons (Freons) for the thermal control of electronic components. Since these liquids, referred to as highly-wetting liquids, possess some unusual characteristic properties as compared with conventional liquids, it is expected that the boiling process and dominant heat transfer mechanisms of highly-wetting liquids may be different from those of conventional liquids. Nucleate boiling incipience is one of the most important parameters in boiling heat transfer. In the present study, the effect of contact angle and contact angle hysteresis on boiling incipience is investigated; a set of models for predicting the critical bubble radius and the incipience superheat, as well as the superheat excursion, are presented. Analyses of air/gas trapping in microcavities and of the bubble growth process have been used to relate boiling incipience superheat to the maximum value of the inverse bubble radius. Since both Fluorinerts and Freons possess unusually high gas solubility, the effect of dissolved gas on boiling incipience has been investigated. A theoretical analysis and photographic study of bubble flow regimes in nucleate boiling were performed. The results suggest that thermal transport models such as Rohesnow's, based on isolated bubble behavior, may be applicable to nearly the entire range of nucleate boiling of electronic cooling fluids.

• Research Organization: Minnesota Univ., Duluth, MN (United States)
• OSTI ID: 5554376
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
BOILING
BUBBLES
CONTROL
COOLANTS
COOLING SYSTEMS
DIELECTRIC MATERIALS
ELECTRONIC EQUIPMENT
ENERGY SYSTEMS
ENERGY TRANSFER
EQUIPMENT
FLUIDS
FREONS
HALOGENATED ALIPHATIC HYDROCARBONS
HEAT FLUX
HEAT TRANSFER
HEATING
HYSTERESIS
LIQUIDS
MATERIALS
MATHEMATICAL MODELS
NUCLEATE BOILING
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHOTOGRAPHY
SATURATION
SOLUBILITY
SUPERHEATING
TEMPERATURE CONTROL