Abstract
Recently, Eulerian based two-fluid approach with empirical wall-boiling closure model has been intensively investigated for Departure from Nucleate Boiling (DNB) simulation under the DOE-funded Consortium of Advanced Simulation for LWR (CASL) program. Over years of model validation tests, a baseline DNB model has presented with an under-predictive behavior at the high pressure of interest for PWR application. All validation tests as well as relevant sensitivity studies are compared with an existing DNB dataset at the following operating conditions (System pressure: 138 bar, Mass flux: 1650 ~ 2650 kg/m2-s, Sub-cooled inlet temperature: 8.5 ~ 96K). DNB detection criteria are demonstrated by the following three monitoring variables: 1) max wall temperature, 2) wall dry-out factor (i.e. K-value) and 3) energy balance. Interfacial momentum transfer closures govern the bubble distribution, especially in the lateral direction, as well as bubble mean diameter. A clear correlation between interfacial momentum closure and DNB performance is not observed in the current tests. However, it was found that void distributions are changed with different interfacial momentum closures which should be a critical link to the DNB detection criterion. A preliminary sensitivity study of wall boiling closure on DNB performance is reported and some practical suggestions for improved DNB models are also reported.
Original language | English |
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Pages | 3649-3662 |
Number of pages | 14 |
State | Published - 2019 |
Externally published | Yes |
Event | 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019 - Portland, United States Duration: Aug 18 2019 → Aug 23 2019 |
Conference
Conference | 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019 |
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Country/Territory | United States |
City | Portland |
Period | 08/18/19 → 08/23/19 |
Keywords
- Departure from nucleate boiling
- M-CFD
- Wall boiling closures