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Title: Measurement of Key Pool BOiling Parameters in nanofluids for Nuclerar Applications

Abstract

Nanofluids, colloidal dispersions of nanoparticles in a base fluid such as water, can afford very significant Critical Heat Flux (CHF) enhancement. Such engineered fluids potentially could be employed in reactors as advanced coolants in safety systems with significant safety and economic advantages. However, a satisfactory explanation of the CHF enhancement mechanism in nanofluids is lacking. To close this gap, we have identified the important boiling parameters to be measured. These are the properties (e.g., density, viscosity, thermal conductivity, specific heat, vaporization enthalpy, surface tension), hydrodynamic parameters (i.e., bubble size, bubble velocity, departure frequency, hot/dry spot dynamics) and surface conditions (i.e., contact angle, nucleation site density). We have also deployed a pool boiling facility in which many such parameters can be measured. The facility is equipped with a thin indium-tin-oxide heater deposited over a sapphire substrate. An infra-red high-speed camera and an optical probe are used to measure the temperature distribution on the heater and the hydrodynamics above the heater, respectively. The first data generated with this facility already provide some clue on the CHF enhancement mechanism in nanofluids. Specifically, the progression to burnout in a pure fluid (ethanol in this case) is characterized by a smoothly-shaped and steadily-expanding hot spot.more » By contrast, in the ethanol-based nanofluid the hot spot pulsates and the progression to burnout lasts longer, although the nanofluid CHF is higher than the pure fluid CHF. The presence of a nanoparticle deposition layer on the heater surface seems to enhance wettability and aid hot spot dissipation, thus delaying burnout.« less

Authors:
 [1];  [2];  [2];  [1]
  1. ORNL
  2. Massachusetts Institute of Technology (MIT)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); High Temperature Materials Laboratory
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1026703
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: 15th In'll Conf on Nuclear Engineering, Nagoya, Japan, 20070422, 20070426
Country of Publication:
United States
Language:
English
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; BOILING; BUBBLES; BURNOUT; COOLANTS; CRITICAL HEAT FLUX; DEPOSITION; ECONOMICS; ENTHALPY; ETHANOL; EVAPORATION; HEATERS; HOT SPOTS; HYDRODYNAMICS; NUCLEAR ENGINEERING; NUCLEATION; POOL BOILING; PROBES; SAFETY; SPECIFIC HEAT; TEMPERATURE DISTRIBUTION; THERMAL CONDUCTIVITY

Citation Formats

Bang, In C, Buongiorno, Jdacopo, Hu, Lin-wen, and Wang, Hsin. Measurement of Key Pool BOiling Parameters in nanofluids for Nuclerar Applications. United States: N. p., 2007. Web.
Bang, In C, Buongiorno, Jdacopo, Hu, Lin-wen, & Wang, Hsin. Measurement of Key Pool BOiling Parameters in nanofluids for Nuclerar Applications. United States.
Bang, In C, Buongiorno, Jdacopo, Hu, Lin-wen, and Wang, Hsin. Mon . "Measurement of Key Pool BOiling Parameters in nanofluids for Nuclerar Applications". United States. doi:.
@article{osti_1026703,
title = {Measurement of Key Pool BOiling Parameters in nanofluids for Nuclerar Applications},
author = {Bang, In C and Buongiorno, Jdacopo and Hu, Lin-wen and Wang, Hsin},
abstractNote = {Nanofluids, colloidal dispersions of nanoparticles in a base fluid such as water, can afford very significant Critical Heat Flux (CHF) enhancement. Such engineered fluids potentially could be employed in reactors as advanced coolants in safety systems with significant safety and economic advantages. However, a satisfactory explanation of the CHF enhancement mechanism in nanofluids is lacking. To close this gap, we have identified the important boiling parameters to be measured. These are the properties (e.g., density, viscosity, thermal conductivity, specific heat, vaporization enthalpy, surface tension), hydrodynamic parameters (i.e., bubble size, bubble velocity, departure frequency, hot/dry spot dynamics) and surface conditions (i.e., contact angle, nucleation site density). We have also deployed a pool boiling facility in which many such parameters can be measured. The facility is equipped with a thin indium-tin-oxide heater deposited over a sapphire substrate. An infra-red high-speed camera and an optical probe are used to measure the temperature distribution on the heater and the hydrodynamics above the heater, respectively. The first data generated with this facility already provide some clue on the CHF enhancement mechanism in nanofluids. Specifically, the progression to burnout in a pure fluid (ethanol in this case) is characterized by a smoothly-shaped and steadily-expanding hot spot. By contrast, in the ethanol-based nanofluid the hot spot pulsates and the progression to burnout lasts longer, although the nanofluid CHF is higher than the pure fluid CHF. The presence of a nanoparticle deposition layer on the heater surface seems to enhance wettability and aid hot spot dissipation, thus delaying burnout.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

Conference:
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