Progress toward simulating departure from nucleate boiling (DNB) at high pressure applications with selected wall boiling closures

Seung Jun Kim, Mario R. Naranjo, Russell C. Johns, Emilio Baglietto

Research output: Contribution to conferencePaperpeer-review

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 languageEnglish
Pages3649-3662
Number of pages14
StatePublished - 2019
Externally publishedYes
Event18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019 - Portland, United States
Duration: Aug 18 2019Aug 23 2019

Conference

Conference18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019
Country/TerritoryUnited States
CityPortland
Period08/18/1908/23/19

Keywords

  • Departure from nucleate boiling
  • M-CFD
  • Wall boiling closures

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