Influence of gravity on pool boiling on a flat plate: Results of parabolic flights and ground experiments

Experimental data obtained at both earth-normal and elevated gravity, in a variety of organic liquids and water, are used to verify the hydrodynamic theory for the peak pool boiling heat flux on flat plates. A modification of Zuber’s formula, which gives a 14 percent higher peak heat flux, is verified as long as the flat plate is more than three Taylor wavelengths across. For smaller heaters, the hydrodynamic theory requires a wide variation in heat flux owing to discontinuities in the number of escaping jets. Data for smaller plates bear out this predicted variation with heat fluxes that range between 40 percent and 235 percent of Zuber’s predicted value. Finally, a method is suggested for augmenting the peak heat flux on large heaters, and shown experimentally to be viable.

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Pool boiling characteristics of multiwalled carbon nanotube (CNT) based nanofluids over a flat plate heater

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2010.10.002 ◽

2011 ◽

Vol 54 (5-6) ◽

pp. 1289-1296 ◽

Cited By ~ 41

Author(s):

R. Kathiravan ◽

Ravi Kumar ◽

Akhilesh Gupta ◽

Ramesh Chandra ◽

P.K. Jain

Keyword(s):

Carbon Nanotube ◽

Flat Plate ◽

Pool Boiling ◽

Multiwalled Carbon Nanotube ◽

Multiwalled Carbon ◽

Plate Heater

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Hydrodynamic Prediction of Peak Pool-boiling Heat Fluxes from Finite Bodies

Journal of Heat Transfer ◽

10.1115/1.3450013 ◽

1973 ◽

Vol 95 (2) ◽

pp. 152-158 ◽

Cited By ~ 183

Author(s):

J. H. Lienhard ◽

V. K. Dhir

Keyword(s):

Heat Flux ◽

Flat Plate ◽

Pool Boiling ◽

General Concept ◽

Heat Fluxes ◽

The Body ◽

Cross Sectional ◽

Vapor Velocity ◽

General Ground ◽

Peak Heat Flux

Since Zuber made a hydrodynamic prediction of the peak pool-boiling heat flux on an infinite flat plate, his general concept has been used to predict the peak heat flux in two finite heater configurations. These latter predictions have differed from Zuber’s in the introduction of a largely empirical variable—the thickness of the vapor escape path around the body. The present study shows how measurements of this thickness can be combined with the hypothesis that the vapor velocity within the vapor blanket must match the vapor velocity in the escaping jet above the heater. The result is a more exact description of the hydrodynamics of vapor removal. This idea is used to suggest the possibility of a universal value for the ratio of the cross-sectional area of escaping jets to the heater area for large finite heaters and for long slender heaters. A set of general ground rules is developed for predicting the peak heat fluxes on both large and small heaters. These rules are used in turn to predict the peak heat flux from horizontal ribbons. They are also used to correct the traditional prediction for infinite-flat-plate heaters. The predictions are supported with new data.

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