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Title: NUCLEATE-BOILING STUDIES WITH AQUEOUS ThO$sub 2$ SLURRIES

Abstract

Nucleate-boiling heat-transfer measurements were made with aqueous thorium oxide slurries containing up to about 1000 g of Th per kg of H/sub 2/O (0.105 volume fraction of solids, 1- to 3- mu average diameter). Boiling took place from the surface of 1/16- and 1/8-in.-diam. platinum tubes submerged in slurry. The results may be represented in terms of the equation q/A = K( DELTA T)n, where q/A = heat flux, Btu/(hr) (ft/sup 2/) K = dimensional constant, DELTA T = temperature difference between heated tube wall and bulk slurry temperature, deg F. For the slurries studied, the heat flux at a 4T of 10 deg F was about 10/ sup 4/ ever, the value of the exponent, n, decreased as the volume fraction of solids was increased. The value of n was 3.3 with no thorium oxide present and approached unity at a voiume fraction of solids of 0.10. The maximum heat fiux attainable under nucleate-boiling conditions (often called the critical heat flux or burnout heat flux) at slurry concentrations of 200 g of Th per kg of H/sub 2/O was about the same as for water. However, at a concentration of 1000 g of Th per kg of H/sub 2/O,more » the burnout heat flux was 210,000 Btu/(hr)(ft/sub 2/), compared with a value of 490,000 Btu/(hr)(ft/sub 2/) for water under corresponding conditions. At constant heat flux, the temperature difference between the heated tube surface and the fluid saturation temperature increased 5 to 6 deg F per hour. This result might be explained by a ''soft'' film that surrounded the heated metal surface. This film was apparently less than 1/32 in. thick and was never distinguishable as an adhering film after the tube was removed from the slurry system. No hard cakes were observed on the surface from which boiling took place during any of the tests. The nucleate-boiling tests were made with aqueous thorium oxide slurries which had non-Newtonian laminar flow characteristics and which were almost Newtonian under turbulent flow conditions. No phenomena were observed which could be attributed to the effect of the solid particles on the gross physical properties of the slurry; for example, the nonNewtonian laminar flow characteristics of the slurry had no discernible effect on the nucleate- boiling heat transfer. (auth)« less

Authors:
; ;
Publication Date:
Research Org.:
Oak Ridge National Lab., Tenn.
OSTI Identifier:
4237204
Report Number(s):
ORNL-2722
NSA Number:
NSA-13-015712
DOE Contract Number:  
W-7405-ENG-26
Resource Type:
Technical Report
Resource Relation:
Other Information: Orig. Receipt Date: 31-DEC-59
Country of Publication:
United States
Language:
English
Subject:
REACTORS; BOILING; BURNOUT; ENRICHMENT; EQUATIONS; FILMS; FLUID FLOW; FLUIDS; HEAT TRANSFER; MEASURED VALUES; NUCLEAR REACTIONS; PLATINUM; POWER; SLURRIES; SOLIDS; SURFACES; TABLES; TEMPERATURE; TESTING; THICKNESS; THORIUM OXIDES; TUBES; TURBULENCE; VARIATIONS; VOLUME; WATER

Citation Formats

Thomas, D. G., Felten, L. D., and Summers, R. M. NUCLEATE-BOILING STUDIES WITH AQUEOUS ThO$sub 2$ SLURRIES. United States: N. p., 1959. Web. doi:10.2172/4237204.
Thomas, D. G., Felten, L. D., & Summers, R. M. NUCLEATE-BOILING STUDIES WITH AQUEOUS ThO$sub 2$ SLURRIES. United States. https://doi.org/10.2172/4237204
Thomas, D. G., Felten, L. D., and Summers, R. M. 1959. "NUCLEATE-BOILING STUDIES WITH AQUEOUS ThO$sub 2$ SLURRIES". United States. https://doi.org/10.2172/4237204. https://www.osti.gov/servlets/purl/4237204.
@article{osti_4237204,
title = {NUCLEATE-BOILING STUDIES WITH AQUEOUS ThO$sub 2$ SLURRIES},
author = {Thomas, D. G. and Felten, L. D. and Summers, R. M.},
abstractNote = {Nucleate-boiling heat-transfer measurements were made with aqueous thorium oxide slurries containing up to about 1000 g of Th per kg of H/sub 2/O (0.105 volume fraction of solids, 1- to 3- mu average diameter). Boiling took place from the surface of 1/16- and 1/8-in.-diam. platinum tubes submerged in slurry. The results may be represented in terms of the equation q/A = K( DELTA T)n, where q/A = heat flux, Btu/(hr) (ft/sup 2/) K = dimensional constant, DELTA T = temperature difference between heated tube wall and bulk slurry temperature, deg F. For the slurries studied, the heat flux at a 4T of 10 deg F was about 10/ sup 4/ ever, the value of the exponent, n, decreased as the volume fraction of solids was increased. The value of n was 3.3 with no thorium oxide present and approached unity at a voiume fraction of solids of 0.10. The maximum heat fiux attainable under nucleate-boiling conditions (often called the critical heat flux or burnout heat flux) at slurry concentrations of 200 g of Th per kg of H/sub 2/O was about the same as for water. However, at a concentration of 1000 g of Th per kg of H/sub 2/O, the burnout heat flux was 210,000 Btu/(hr)(ft/sub 2/), compared with a value of 490,000 Btu/(hr)(ft/sub 2/) for water under corresponding conditions. At constant heat flux, the temperature difference between the heated tube surface and the fluid saturation temperature increased 5 to 6 deg F per hour. This result might be explained by a ''soft'' film that surrounded the heated metal surface. This film was apparently less than 1/32 in. thick and was never distinguishable as an adhering film after the tube was removed from the slurry system. No hard cakes were observed on the surface from which boiling took place during any of the tests. The nucleate-boiling tests were made with aqueous thorium oxide slurries which had non-Newtonian laminar flow characteristics and which were almost Newtonian under turbulent flow conditions. No phenomena were observed which could be attributed to the effect of the solid particles on the gross physical properties of the slurry; for example, the nonNewtonian laminar flow characteristics of the slurry had no discernible effect on the nucleate- boiling heat transfer. (auth)},
doi = {10.2172/4237204},
url = {https://www.osti.gov/biblio/4237204}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1959},
month = {6}
}