Advanced Computational Thermal Studies & Their Assessment for Supercritical-Pressure Reactors (SCRS)

by D. M. McEligot1, J. Y. Yoo2, J. S. Lee2, E. Laurien3, S. O. Park4, R. H. Pletcher5, B. L. Smith6, P. Vukoslavcevic7, J. M. Wallace8
1Idaho National Laboratory
2Seoul National University
3University of Stuttgart
4Korea Advanced Institute of Science and Technology
5Iowa State University
6Utah State University
7University of Montenegro
8University of Maryland

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The goal of this laboratory / university collaboration of coupled computational and experimental studies is the improvement of predictive methods for supercritical-pressure reactors. Its general objective is to develop supporting knowledge needed of advanced computational techniques for the technology development of the various concepts and their safety systems.

This basic thermal fluids research applied first principles approaches (Direct Numerical Simulation - DNS and Large Eddy Simulation - LES) coupled with experimentation (heat transfer and fluid mechanics measurements). Turbulence is one of the most important unresolved problems in engineering and science, particularly for the complex geometries and fluid property variations occurring in these advanced reactor systems and their safety systems. DNS, LES and differential second moment closures (DSM or Reynolds-stress models) are advanced computational concepts in turbulence "modeling" whose development is being extended to treat complex geometries and severe property variation for designs and safety analyses of SCRs.

Prof. Pletcher extended LES to generic idealizations of such geometries with property variation; Prof. Yoo supported these studies with DNS. Prof. Park developed DSM models and evaluated the suitability of other proposed RANS (Reynolds-averaged Navier-Stokes) models by application of the DNS, LES and experimental results. Prof. Laurien examined the difficulties of modeling the large fluctuations of fluid properties in the pseudocritical region for commercial RANS codes. INL obtained fundamental turbulence and velocity data for generic idealizations of the complex geometries of these advanced reactor systems. Profs. Wallace and Vukoslavcevic developed miniaturized multi-sensor probes to measure turbulence components in heated supercritical flows in the experiments of Profs. Lee and Yoo. Accomplishments of this partnership are reviewed.