An open-source density-based solver for two-phase CO2 compressible flows: Verification and validation

A density-based solver based on the OpenFoam library coupled with a tabulated equation of state is developed. The Navier-Stokes characteristic boundary condition is considered to guarantee the accuracy and stability of the simulation. Firstly, two validation test cases are considered to illustrate the solver capability. Then, the flows in two converging-diverging nozzles are simulated under supercritical and subcritical conditions. A good agreement in terms of pressure distribution is obtained for all nozzles. The bulk viscosity and turbulence effects are then carefully assessed. The bulk viscosity does not affect significantly the predictions of the new solver, whereas it is of prime importance to well model the thermal and flow fields up to the wall. Finally, it is recommended to use an unsteady density-based solver for CO2 flows in converging-diverging nozzles associated with a Homogeneous Equilibrium Model and the k-omega SST closure to get the best overall predictions. (C) 2019 Elsevier Ltd and IIR. All rights reserved.