Direct Numerical Simulation of Single- and Two-Phase Flows for Nuclear Engineering Geometries

The significant progress in the last decade of high-resolution single- and two-phase flow simulations of reactor-relevant flows is summarized in this review paper. The rapid development of high-performance computing capabilities creates exciting opportunities to study complex reactor thermal-hydraulic phenomena. Today’s advances in thermal-hydraulic analysis, interface capturing simulations, and advanced data processing and analysis approaches will help pave the way to the next level of understanding of two-phase flow behavior in nuclear reactors.

This paper discusses two major topics: (1) a brief review of interface-capturing simulations in recent years and (2) several opportunities to advance these numerical research tools in the future. The first part discusses typical computational methods used for these simulations and provides some examples of past work, as well as computational cost estimates and affordability of such simulations for research and industrial applications. In the second part, some specific examples are discussed that could be analyzed using exascale supercomputers being designed and projected to be online in the next several years. New-generation methodologies are required to take full advantage of these capabilities to greatly enhance the scientific understanding of complex two-phase flow phenomena in various conditions relevant to industrial applications.