The information below was gathered from the 2018 Simcenter Conference - Americas that took place October 15-17 in Detroit, Michigan.
Author: Stephen Gent, Associate Professor, Mechanical Engineering Department
Natural convection-driven flows are present in many engineering applications such as HVAC, electronics cooling, and cryogenic systems. Predicting the flow behavior of such systems requires experimentation or numerical simulation through Computational Fluid Dynamics due to the complex interactions of natural convection. Recent advances in computing resources have made CFD increasingly popular for engineering analysis of fluid dynamics and heat transfer.
The goal of this study was to create a modeling framework for simulating natural convection using CFD that maximizes computational efficiency without sacrificing the quality of the solution. This framework includes the selection of buoyancy models, turbulence models, mesh type, and level of mesh refinement using Simcenter Star-CCM+. These methods are applied to a case study of natural convection in a large neutrino detector filled with liquid argon (LAr), which will be used for the Deep Underground Neutrino Experiment (DUNE).
DUNE is an international particle physics experiment with the goal of studying neutrinos as they travel long distances. Research scientists hope this will lead to a better understanding of the nature of neutrinos and the beginnings of the universe, as well as enable the detection of cosmic events such as supernova core-collapse.
This study specifically employs CFD to predict the flow mechanics, thermal profiles, and impurity levels of liquid argon within a large neutrino detector that is influenced greatly by natural convection. A uniform distribution of impurities is desired to ensure accurate electron lifetime readings throughout the cryostat. The analysis investigated the optimum location of filtration inlets and outlets and simulated various operating conditions the detector will experience. This study was done in collaboration with Fermilab and the Deep Underground Neutrino Experiment. Results were compared with available experimental data of a prototype neutrino detector.