TY - JOUR
T1 - Validation and Uncertainty Quantification for Two-Phase Natural Circulation Flows Using TRACE Code
AU - Borowiec, Katarzyna
AU - Kozlowski, Tomasz
AU - Brooks, Caleb S.
N1 - Funding Information:
This material is based upon work supported by the U.S. Department of Energy under award number DE-NE0008573.
Publisher Copyright:
© 2020 American Nuclear Society.
PY - 2020
Y1 - 2020
N2 - The work presents validation of the TRAC/RELAP Advanced Computational Engine (TRACE) code for natural circulation two-phase flow in a vertical annulus. Natural circulation experiments were recently conducted for a vertical internally heated annulus at the Multiphase Thermo-Fluid Dynamics Laboratory at the University of Illinois. The experimental matrix consists of 107 experiments with system pressure in the range of 145 to 950 kPa and heat flux up to 275 kW/m2. Void fraction, gas velocity, and interfacial area concentration were measured in five axial locations along the test section with six measurements of bulk liquid temperature and pressure. To validate the capability of the TRACE code under natural circulation flow conditions, a complete model of the experimental facility was created and validated using forced convection and single-phase natural circulation data. Sensitivity and uncertainty quantification were performed. The sensitivity to important simulation parameters was studied using Sobol’s variance decomposition and the Morris screening method. The sensitivity of boundary conditions on void fraction measurement was investigated. The sensitivity study has shown significant differences in model sensitivity between different experimental conditions. With heat flux being the most influential parameter for high-pressure cases without flashing and pressure, temperature and heat flux have a combined strong effect in the case of low-pressure experiments when flashing occurs. Additionally, higher uncertainty in void fraction prediction was observed for experimental conditions at low pressure with flashing.
AB - The work presents validation of the TRAC/RELAP Advanced Computational Engine (TRACE) code for natural circulation two-phase flow in a vertical annulus. Natural circulation experiments were recently conducted for a vertical internally heated annulus at the Multiphase Thermo-Fluid Dynamics Laboratory at the University of Illinois. The experimental matrix consists of 107 experiments with system pressure in the range of 145 to 950 kPa and heat flux up to 275 kW/m2. Void fraction, gas velocity, and interfacial area concentration were measured in five axial locations along the test section with six measurements of bulk liquid temperature and pressure. To validate the capability of the TRACE code under natural circulation flow conditions, a complete model of the experimental facility was created and validated using forced convection and single-phase natural circulation data. Sensitivity and uncertainty quantification were performed. The sensitivity to important simulation parameters was studied using Sobol’s variance decomposition and the Morris screening method. The sensitivity of boundary conditions on void fraction measurement was investigated. The sensitivity study has shown significant differences in model sensitivity between different experimental conditions. With heat flux being the most influential parameter for high-pressure cases without flashing and pressure, temperature and heat flux have a combined strong effect in the case of low-pressure experiments when flashing occurs. Additionally, higher uncertainty in void fraction prediction was observed for experimental conditions at low pressure with flashing.
KW - natural circulation sensitivity study
KW - TRACE
KW - two-phase flow
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U2 - 10.1080/00295639.2020.1713671
DO - 10.1080/00295639.2020.1713671
M3 - Article
AN - SCOPUS:85079734130
VL - 194
SP - 737
EP - 747
JO - Nuclear Science and Engineering
JF - Nuclear Science and Engineering
SN - 0029-5639
IS - 8-9
T2 - 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019
Y2 - 18 August 2019 through 23 August 2019
ER -