Large Eddy Simulation of sCO2 flow with a discontinuous Galerkin method
We present large eddy simulations (LES) of heat transfer in sCO2 at 8 MPa in a plane channel geometry with various temperature ranges. This presents a numerical challenge, as the density can vary by more than a factor 2. We use a pressure-based solver with a high-order discontinuous Galerkin discretization. The large eddy simulation is based on the Wall-averaged Local Eddy viscosity (WALE) model and a constant turbulent Prandtl number. We resolve the flow near the wall. Though our geometry allows for a structured grid, our numerical scheme is highly flexible with respect to unstructured meshes. We validate our LES with an isothermal flow, and with a simulation in a temperature range that is far from the pseudocritical line. The results for non-isothermal flow show that the LES can accurately predict the average velocity and temperature profiles, despite reducing the number of degrees of freedom by several orders of magnitude compared to the reference direct numerical simulation. This paper is a precursor to future work, in which we will present more extensive validation of the non-isothermal test case. Our results are a first step toward using a pressure-based discontinuous Galerkin solver for sCO2 flows.
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