HEAT TRANSFER TO BOILING LIQUIDS UNDER CONDITIONS OF HIGH TEMPERATURE DIFFERENCE AND FORCED CONVECTION. Final Technical Report
Heat transfer coefficients have been determined for forced convection film boiling under conditions of high temperature difference. The results should be of value in design of cooling systems where large and variable heat fluxes are encountered. The studies were made with two different liquids. Freon-113 and methanol. Data were obtained at entering liquid velocities of from 1.0 to 8.5 ft/ sec, and with wall-to-fluid temperature differences which ranged from a maximum of 320 deg F down to values around 80 deg F where nucleate boiling was encountered. Peak heat flux data and pressure drop data were also obtained in most cases. The heat transfer coefficients varied from around 58 Btu/(hr)(deg. F.)(sq.ft.) at the lowest temperature differences to around 44 Btu/(hr) (deg. F.) (sq.ft.) at the highest temperature dlfferences. The effect of entering liquid velocity was quite small. An equation has been derived for prediction of the coefficients of heat transfer for this case. The experimental results yield heat transfer coefficients which are about twice as large as those predicted by the derived equation. This seemns to indicate that the flow of vapor in the vapor film was turbulent. The degree of stability of the vapor film was examined. A mathematical derivation is presented to show that vapor repulsion forces are sufficient to provide for a stable interface under any velocity condition. (auth)
- Research Organization:
- Delaware. Univ., Newark
- NSA Number:
- NSA-12-006580
- OSTI ID:
- 4306517
- Report Number(s):
- UD-FB-13
- Country of Publication:
- United States
- Language:
- English
Similar Records
An experimental investigation of the individual boiling and condensing heat-transfer coefficients for hydrogen
CRITICAL HEAT FLUX OF SOME POLYPHENYL COOLANTS