Most operating nuclear reactors use water to both cool the reactor and transfer the heat from the nuclear fuel to use in electricity generation. Understanding the details of bubbly turbulent flow within a nuclear reactor core is important for design of safe and efficient reactors; however the geometry, high pressure/temperature conditions and boiling nature of the flow in the nuclear reactor core make the analysis of this complex phenomenon a challenge.

This project supports simulations of turbulent multiphase flows important for nuclear reactor analysis. Direct numerical simulation (DNS) of turbulent bubbly two‐phase flows at a leadership computing facility will enable modeling at an unprecedented level of detail and can answer fundamental questions about the interaction between the bubbles and the liquid turbulence. Detailed simulation will enable collecting and obtaining statistical information about the turbulence parameters, such as turbulent kinetic energy and turbulent viscosity. The outcome of this project will be to improve the multiphase computational fluid dynamics (CMFD) closure models in applications to nuclear reactor thermal‐hydraulics modeling. This will allow for better safety margin predictions for existing light water reactors and facilitate the development of next generation energy systems.