Projects / Programmes
Development of methods and models for simulation of thermal-hydraulic phenomena in innovative nuclear reactors
| Code |
Science |
Field |
Subfield |
| 2.13.01 |
Engineering sciences and technologies |
Process engineering |
Multi-phase systems |
| Code |
Science |
Field |
| T160 |
Technological sciences |
Nuclear engineering and technology |
| Code |
Science |
Field |
| 2.11 |
Engineering and Technology |
Other engineering and technologies |
nuclear thermahydraulics, nuclear reactors of generation IV
Researchers (19)
Organisations (2)
Abstract
Project proposal is splitted into two rather independent parts, which both fall into the field of nuclear thermal hydraulics. First part of the proposal is dealing with thermal hydraulics of liquid metal cooled reactors and second part thermal hydraulics of water cooled reactors.
Analyses of liquid metal cooled breeder reactors requires simulations of turbulent flows at low Prandtl numbers. In the current project, more detailed direct numerical simulations of channel flows will be provided at higher Reynolds numbers including conjugate heat transfer using various low Prandtl numbers, various thermal activity ratios, and various wall thicknesses. These results will give accurate Nusselt numbers, mean temperature profiles, profiles of thermal fluctuations in the liquid and in the wall, and near-wall profiles of turbulent Prandtl numbers. All these quantities are more or less affected by the presence of the hot wall. DNS results will be obtained with a pseudo-spectral channel-flow code. Produced databases will be used suitable for development and verification of turbulent heat transfer models, required in computational fluid dynamics (CFD) computer codes.
Reactors that might be cooled with supercritical water in the future, will require simulations of transients between the fluid in various states: supercritical in one part of the system and subcritical in the other part. An important part of supercritical water simulations are steam tables in the supercritical area. The main goal within this task is careful pre-tabulation of the fluid properties and development of special interpolation algorithms for these steam tables. Such tables will be needed to ensure acceptable behavior of the main thermodynamic variables: smooth density or specific internal energy as functions of pressure and temperature, "reasonable" behavior of derivatives of these functions: specific heat capacity, isothermal compressibility, coefficient of thermal expansion, sonic velocity. New models and steam tables will be implemented in the in-house computer code WAHA and applied for several transients, where temperature and pressure varies in the supercritical area and also with transients where fluid at supercritical pressure and temperature is exposed to a sudden pressure drop to subcritical values (Loss of Coolant Accident for supercritical water cooled reactors).
Significance for science
Liquid metal turbulence: - New knowledge and new detailed data on turbulent heat transfer at low Prandtl numbers have been generated. Databases of DNS simulations with detailed turbulent statistics, which are suitable for verification or development of new CFD turbulent models are in open-access domain. - Database with detailed description of the interaction between the temperature fluctuations in the liquid and inside the wall are available. These data are applicable for verification of the models that are being used to study thermal fatigue problems. Supercritical water: - Equation-of-State for water in the supercritical range has been approximated with various methods that are applicable for implementation in the multi-phase CFD models. Advantages and drawbacks of the tested approximations were analysed. - Two-phase critical flow models were tested with simulations of two experimental devices. "Standard" critical flow model used in a new geometry and with new boundary conditions of the German experimental device have shown rather large discrepancies between the measurements and simulations.
Significance for the country
Proposed fundamental research enabled active participation of Slovenia in the international research community that works in the field of new generation reactors development. That collaboration could present an entry point for other research groups and Slovenian companies. Research project represented also a part of our contribution to the four year project of the 7th Framework Program of EU THINS, which started in 2010 and successfully ended in 2015 with a launch of a new similar project SESAME within the Horizon2020 programme. Both projects connects JSI with approximately 20 cooperating European institutions. Slovenia is the only new member state in THINS project. Both EU projects are enhancing exchange and cooperation between the research groups, and are improving the quality of the nuclear engineering education in Slovenia. Two PhD students participated in the research project.
Most important scientific results
Annual report
2011,
2012,
2013,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2011,
2012,
2013,
final report,
complete report on dLib.si
