scholarly journals A DNBR Analysis to Patterns of Subchannel Control Volume

2019 ◽  
Author(s):  
Byeung-Seok Kim ◽  
Kang-Hoon Moon ◽  
Kang-Hoon Kim ◽  
Jong-Seon Lim
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Mass Velocity ◽  
Control Volume ◽  
High Quality ◽  
Rod Bundle ◽  
Subchannel Analysis

The sensitivity of DNBR values to approaches of subchannel control volume selection has been investigated for the TS01 and TS03 out of HIPER17 CHF tests. In rod bundle analysis, most of the subchannel analyses used the coolant-centered subchannel nodal layout. But, it has been known that the rod-centered subchannel analysis showed good results for high quality critical heat flux. In this study, it was demonstrated that the rod-centered subchannel analysis showed more effective and conservative results than the coolant-centered subchannel analysis with the DNBR value, the quality, and the mass velocity. Also, it was verified that when the both results yielded from each subchannel analysis were compared, the subchannel locations at which DNBR occurred were similar.

Experimental Investigation of Critical Heat Flux in Microchannels for Flow-Field Probes

2009 ◽  
Author(s):  
Ali Kos¸ar ◽  
Yoav Peles ◽  
Arthur E. Bergles ◽  
Gregory S. Cole
Keyword(s):  
Heat Flux ◽  
Experimental Investigation ◽  
Critical Heat Flux ◽  
Mass Velocity ◽  
Thermal Condition ◽  
Average Error ◽  
New Correlation ◽  
Hydraulic Conditions ◽  
Data Points ◽  
Heated Length

Critical heat flux (CHF) of water in circular stainless steel microchannels with inner diameters ranging from ∼127μm to ∼254 μm was investigated. Forty-five CHF data points were acquired over mass velocities ranging from 1,200 kg/m2s to 53,000 kg/m2s, heated lengths from 2 cm to 8 cm, and exit qualities from −0.2 to 0.15. Most of the exit qualities fell below 0.1. It was found that CHF conditions were more dependent on mass velocity and heated length than on exit thermal condition. The results were also compared to six CHF correlations, with a mean average error ranging from 22% to 261.8%. A new correlation was proposed to better predict the critical heat flux data under the thermal-hydraulic conditions studied in this investigation. In developing the correlation, 319 data points were added from two previous studies.

Critical Heat Flux and Onset of Nucleate Boiling Tests in a Finned Rod Bundle

2004 ◽  
Vol 148 (3) ◽  
pp. 287-293
Author(s):  
Hee Taek Chae ◽  
Jong Hark Park ◽  
Heonil Kim ◽  
Soon Heung Chang
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Nucleate Boiling ◽  
Rod Bundle

scholarly journals Numerical investigation of the Critical Heat Flux in a 5 × 5 Rod Bundle with Multi-grid

2021 ◽  
Author(s):  
Wei Liu ◽  
Zemin Shang ◽  
Shihao Yang ◽  
Lixin Yang ◽  
Zihao Tian ◽  
...  
Keyword(s):  
Heat Flux ◽  
Numerical Investigation ◽  
Critical Heat Flux ◽  
Rod Bundle

Critical Heat Flux in a Heater Rod Bundle Cooled by R-134a Fluid near the Critical Pressure

2007 ◽  
Vol 44 (9) ◽  
pp. 1189-1198 ◽  
Author(s):  
Se-Young CHUN ◽  
Sung-Deok HONG ◽  
Hiroshige KIKURA ◽  
Masanori ARITOMI
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Critical Pressure ◽  
Rod Bundle ◽  
R 134A

The Applicability of NFI-1 DNB Correlation and Fluid-to-Fluid Similarities to Freon DNB Test

2008 ◽  
Author(s):  
Shumpei Kakinoki ◽  
Keizo Matsuura ◽  
Kenichi Kitagawa ◽  
Isao Kataoka
Keyword(s):  
Heat Flux ◽  
Equivalent Condition ◽  
High Heat Flux ◽  
Diffusivity Coefficient ◽  
Test Results ◽  
Hydraulic Test ◽  
Rod Bundle ◽  
Test Loop ◽  
R 134A ◽  
Subchannel Analysis

Freon thermal hydraulic test is expected to be one of the workable methods to develop high thermal hydraulic performance PWR fuel. That is, high pressure water and high heat flux condition in PWR core can be substituted with lower pressure Freon and lower heat flux by applying appropriate fluid-to-fluid similarity and modeling parameters. Freon DNB tests and mixing tests were carried out against a 4×4 rod bundle configuration where R-134A flowed vertically upwardly. The tests were carried out at Freon thermal hydraulic test loop in Korea Atomic Energy Research Institute (KAERI). The spacer grid used in these tests was modeled on that of conventional PWR fuel, that is, square lattice grid with split type mixing vanes. Diameter of heater rod simulating PWR fuel rod is about 10.7mm and heating length is about 2000 mm. Freon mixing tests were carried out to estimate Turbulence Diffusivity Coefficient (TDC), which was normally used in conventional thermal hydraulic design of nuclear reactor. Freon CHF test results showed that parametric trends agreed with those of existing CHF data. To predict CHF of 4×4 rod bundle, subchannel analysis code Modified COBRA-3C and NFI-1 DNB correlation were applied. TDC value used in subchannel analysis was determined by fitting Freon mixing test data. NFI-1 DNB correlation was developed for predicting DNB heat flux in rod bundle configuration by using water CHF test results at HTRF test loop at Columbia University. The design of spacer grids used in KAERI Freon DNB test was similar to that used in water CHF test at HTRF. Water equivalent flow condition of this R-134A test was estimated using fluid-to-fluid similarities. NFI-1 DNB correlation was applied to this water equivalent condition to estimate water equivalent DNB heat flux. Then R-134A equivalent DNB heat flux was estimated reversely, and compared to Freon DNB test result. The test results were predicted well and applicability of NFI-1 DNB correlation and fluid-to-fluid similarities in 4×4 rod bundle is discussed.

Critical Heat Flux of R-123 in Silicon-Based Microchannels

2006 ◽  
Vol 129 (7) ◽  
pp. 844-851 ◽  
Author(s):  
Ali Koşar ◽  
Yoav Peles
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Heat Sink ◽  
Mass Velocity ◽  
Heat Fluxes ◽  
Microchannel Heat Sink ◽  
New Correlation ◽  
Mass Fluxes ◽  
System Pressure ◽  
Silicon Based

Critical heat flux (CHF) of R-123 in a silicon-based microchannel heat sink was investigated at exit pressures ranging from 227kPato520kPa. Critical heat flux data were obtained over effective heat fluxes ranging from 53W∕cm2to196W∕cm2 and mass fluxes from 291kg∕m2sto1118kg∕m2s. Flow images and high exit qualities suggest that dryout is the leading CHF mechanism. The effect of mass velocity, exit quality, and system pressure were also examined, and a new correlation is presented to represent the effect of these parameters.

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