Progress Toward Simulating Departure from Nucleate Boiling at High-Pressure Applications with Selected Wall Boiling Closures

Journal Article · Mon May 04 00:00:00 EDT 2020 · Nuclear Science and Engineering

DOI:https://doi.org/10.1080/00295639.2020.1743579· OSTI ID:1726184

Kim, Seung Jun ^[1]; Johns, Russell C. ^[1]; Yoo, Junsoo ^[2]; Baglietto, Emilio ^[3]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Idaho National Lab. (INL), Idaho Falls, ID (United States)
3. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

Recently, a Eulerian-based two-fluid computational fluid dynamics (CFD) framework with a wall heat flux partitioning approach has been intensively investigated for departure from nucleate boiling (DNB) simulation under the U.S. Department of Energy–funded Consortium for Advanced Simulation of Light Water Reactors (CASL) program. Understanding of the DNB characteristics over a range of pressurized water reactor–like operating conditions and accurate prediction of boiling crisis in the nuclear power system have been grand challenges because of the large impact of DNB on reactor safety and operational economics. The ultimate goal of this task in the CASL program is to introduce a robust multiphase CFD–based DNB modeling framework that is capable of characterizing an entire boiling history in which the wall boiling mode experiences the following through multiple stages of heat transfer mode: (1) single-phase convective heat transfer, (2) nucleate boiling heat transfer, and (3) identification of the departure of nucleate boiling. To validate the CASL boiling model, we have benchmarked simulated DNB over three different flow channel configurations (pipe flow, 5 × 5 fuel bundle with mixing vane tests, and 5 × 5 fuel bundle without mixing vane tests) against experimental measurements, and the validation result with open literature is reported. The DNB detection criteria in the simulation are checked by monitoring the peak wall temperature, wall dryout factor, and net energy balance. In addition to the DNB performance test, some preliminary sensitivity results on closure model selection are reported to address the prediction capability of local void profile against measurements. The boiling simulation tested in this study exhibits a maximum deviation of 24% from the measured DNB value in a high-pressure (i.e., 138 bars) subcooled pipe flow test. The ranges of operating conditions are as follows: 1650 to 2650 kg/m²·s for mass flux and 8.5 to 96 K for subcooled inlet temperature. The deviation is even reduced to 7% when the subcooled temperature is less than 40 K. Besides accuracy, base practice guidelines for DNB detection criteria are tested by monitoring three simulation variables: (1) maximum wall temperature, (2) wall dryout factor (i.e., K-value), and (3) energy balance. Numerical robustness of DNB simulation is largely achieved in most of the validation test except for a few high subcooled test cases.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE). Nuclear Reactor Technologies
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1726184
• Report Number(s): LA-UR--19-32679
• Journal Information: Nuclear Science and Engineering, Journal Name: Nuclear Science and Engineering Journal Issue: 8-9 Vol. 194; ISSN 0029-5639
• Publisher: American Nuclear Society - Taylor & Francis
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
DNB simulation
Departure from nucleate boiling simulation
M-CFD
Wall boiling closures
multiphase CFD