scholarly journals Direct measurement of advective heat flux from several Yellowstone hot springs, Wyoming, USA

Geosphere ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 1860-1874 ◽  
Author(s):  
Nicholas McMillan ◽  
Peter Larson ◽  
Jerry Fairley ◽  
Joseph Mulvaney-Norris ◽  
Cary Lindsey
Keyword(s):  
Heat Flux ◽  
Direct Measurement ◽  
Hot Springs

Direct measurement of local heat flux during flow boiling in a minichannel

2020 ◽  
Vol 2020 (0) ◽  
pp. 0187
Author(s):  
Masanori Morisaki ◽  
Shota Minami ◽  
Koji Miyazaki ◽  
Tomohide Yabuki
Keyword(s):  
Heat Flux ◽  
Direct Measurement ◽  
Flow Boiling ◽  
Local Heat ◽  
Local Heat Flux

scholarly journals Problems of irradiance characteristics measurement of solar simulators for ground spacecraft tests

2020 ◽  
Vol 4 (3) ◽  
pp. 129-140
Author(s):  
A. A. Shevchuk ◽  
O. V. Pastushenko ◽  
V. V. Dvirniy ◽  
G. V. Dvirniy ◽  
A. A. Filatov
Keyword(s):  
Heat Flux ◽  
Direct Measurement ◽  
Thermal State ◽  
Solar Spectrum ◽  
Experimental Tests ◽  
Thermal Vacuum ◽  
Solar Simulator ◽  
Vacuum Chambers ◽  
Mismatch Correction ◽  
Photoelectric Converters

The reliability of both spacecraft as a whole and of their systems is confirmed at the stage of complex ground-based experimental tests, including complex thermal vacuum tests. The thermal state of the test object in thermal vacuum chambers is obtaining, in particular, using a solar simulator. Radiometers based on silicon photoelectric converters are most often used to control the irradiance of a solar simulator under conditions of thermal vacuum tests. At the same time, an analysis of the features of silicon photoelectric converters shows that their direct measurement with the accuracy required for ground-based tests of spacecraft is impossible; their output is nonlinear, depends on the received spectrum, their own temperature and has long-term instability. The achieved measurement accuracy directly depends on the number and accuracy of the tools used and the methods of the necessary correction, of which the mismatch correction between the solar simulator spectrum and the solar spectrum is the most difficult and laborious. At the same time, spectrally nonselective heat flux radiometers are free from the above disadvantages. In the course of the experiment we carried out, the significant dependence of the accuracy of measuring the irradiance with radiometers based on silicon photoelectric converters on the received spectrum was confirmed. The conclusion is made that direct measurement by heat flux radiometers of the irradiance of the solar simulator is most justified under the conditions of thermal vacuum tests.

Direct Measurement of Heat Flux Partitioning in Boiling Heat Transfer

2017 ◽  
Author(s):  
A. Richenderfer ◽  
A. Kossolapov ◽  
J. H. Seong ◽  
G. Saccone ◽  
M. Bucci ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Direct Measurement ◽  
Boiling Heat Transfer ◽  
Nuclear Reactors ◽  
Flow Boiling ◽  
Ir Camera ◽  
Flux Partitioning ◽  
Development And Validation ◽  
Transfer Models

The development and validation of mechanistic boiling heat transfer models has been a focal point in the efforts to improve the efficiency and profitability of power generation systems, e.g. nuclear reactors. The primary goal of these models is improving the accuracy of boiling heat transfer simulations and reducing the uncertainty margins that affect both the design and the safety of a system. However, the emergence of these models has also stimulated the need for high-fidelity experiments and experimental data for validation and verification. In this work we present first-of-a-kind data of heat flux partitioning in boiling heat transfer, obtained using cutting-edge diagnostics and post-processing techniques. A HSV camera was used to visualize the boiling surface at 10,000 frames per second with simultaneous front and side views of the two-phase flow. A high-speed IR camera was used to capture the 2-D radiative signal from the boiling surface to visualize bubble nucleation, growth and detachment at a 115 μm/pixel resolution at 2,500 frames per second. A coupled radiation-conduction calibration model was used to calibrate the IR data and extract the full local temperature and heat flux distributions on the boiling surface, which enable a direct measurement of the partitioned heat fluxes. Here we report the results of investigations performed in flow boiling conditions with a mass flux of 500 kg/m2/s, at atmospheric pressure and 10 K of subcooling. These data will be leveraged to inform the development and validation of the next generation of mechanistic boiling heat transfer models, to be used in Computational Fluid Dynamics (CFD) codes for the design and the safety analysis of nuclear reactors.

Direct Measurement of Hot-Wall Heat Flux

2012 ◽  
Vol 26 (3) ◽  
pp. 430-438 ◽  
Author(s):  
Clayton A. Pullins ◽  
Tom E. Diller
Keyword(s):  
Heat Flux ◽  
Direct Measurement ◽  
Wall Heat Flux

scholarly journals Direct measurement of heat flux from cooling lake thermal imagery

2008 ◽  
Author(s):  
Alfred J. Garrett ◽  
Eliel Villa-Aleman ◽  
Robert J. Kurzeja ◽  
Malcolm M. Pendergast
Keyword(s):  
Heat Flux ◽  
Direct Measurement ◽  
Thermal Imagery
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