Modifications to COBRA-TF to model dispersed flow film boiling with two flow, four field Eulerian–Eulerian approach – Part 2

Ergün, Şule; Hochreiter, L. E.; Mahaffy, J.H.

doi:10.1016/j.anucene.2008.02.014

Cited by 8 publications

(4 citation statements)

References 3 publications

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“…The underpredicted cladding and vapor temperatures are consistent with a recent assessment work on a modification of the COBRA-TF code by Ergun and coworkers [9][10][11]. To improve the dispersed flow film boiling model in the code, they introduced a new small droplet field with modifying other three fields (vapor, liquid, and large droplet) [9,10].…”

Section: Comparison Results For the Lower Flooding Ratesupporting

confidence: 80%

“…Since the three-field model deals with a separate droplet field with gas and continuous liquid fields, it has a substantial advantage when a large amount of droplets works as the dominant heat transfer medium. During the blowdown and reflood phases, many droplets are expected to appear in the region of dispersed flow film boiling (DFFB), which occurs at the high local void fraction greater than 80% and a rod wall temperature above minimum film boiling temperature [3,[8][9][10][11]. In this flow regime, poor heat transfer leads to the PCT.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the DFFB model in the COBRA-TF code has been improved using the RBHT experimental data. Ergun et al introduced a new small droplet field, modifying the other three fields (vapor, liquid, and large droplet) in their recent assessment work on a modification of COBRA-TF [9][10][11]. Adding the small droplet field led to improved predictions of the quenching time and droplet entrainment at the quench front.…”

Section: Introductionmentioning

confidence: 99%

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Numerical analysis of RBHT reflood experiments using MARS 1D and 3D modules

Seo

Son

Kim

2014

Journal of Nuclear Science and Technology

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The Rod Bundle Heat Transfer (RBHT) program was performed experimentally to analyze the reflood heat transfer phenomena under the conditions of reflood phase following a hypothesized loss of coolant accident (LOCA) by the team of Penn State University. In order to verify the experimental data using a numerical analysis, the Multi-dimensional Analysis of Reactor Safety (MARS) assessment of the RBHT experimental data was carried out for the flooding rates of 0.0254 and 0.1524 m/sec with the upper plenum pressure of 276 kPa. The RBHT experimental data of Tests 1285 and 1383 were compared with the calculation results of the MARS 1D and 3D modules. The MARS code shows a good agreement in the general trend of the peak cladding temperatures although there are limitations in predicting accurate quenching time for both modules. However, in comparison to the MARS 1D module simulation, the MARS 3D module shows the improved calculation capability in that the code can capture local enhanced heat transfer with implication of spacer grids. Moreover, the temperature profiles simulated by the 3D module show the accurate prediction at which the local peak temperatures occur. For more enhanced simulations, local flow parameters such as cross flow and vortex flow need to be analyzed for a more accurate prediction of quenching behavior.

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Section: Comparison Results For the Lower Flooding Ratesupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Numerical analysis of RBHT reflood experiments using MARS 1D and 3D modules

Seo

Son

Kim

2014

Journal of Nuclear Science and Technology

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“…Spacer grids have a significant influence on the thermal-hydraulic performance of fuel assemblies under both normal and abnormal conditions, as highlighted in references (Cho et al, 2007;Ergun et al, 2008;Koszela, 1998;Miller, 2012). During the reflood phase, the DFFB regime occurs, and heat transfer occurs through various mechanisms, including convection between the heating surface and the vapor phase, interfacial convection between vapor and liquid droplets, radiation heat exchange between the heating surface and the vapor/droplets, as well as direct heat transfer between the heating surface and liquid droplets.…”

Section: Spacer Grid Droplet Breakup Modelmentioning

confidence: 99%