The simulation of the primary liquid atomization in industrial geometries of atomizers for Gasoline Direct Injection (GDI) requires to accurately resolve the gas/liquid interface and time-resolved turbulence modeling. A dynamic multiphase volume-of-fluid (VOF) dynamic solver has been implemented in the OpenFOAM ® technology to simulate flow cavitation during needle opening and closure events. The solver is based on the extension of an already existing multiphase two-fluid model; it makes use of ad-hoc implemented cavitation sub-models and, with respect to the solver available in the official distribution of OpenFOAM, it includes some novel features: it is coupled to an advanced fully-automatic parallel mesh motion solver supporting topological changes of the mesh, where dynamic addition and removal of cell layers is performed to simulate the prescribed motion of the injector needle; also, needle opening and closure events are simulated by performing dynamic detach/attach of one mesh region into multiple regions. In the fluid-dynamic solver, a pressure-correction equation to enforce continuity after topological changes in the pressure-velocity coupling algorithm of the segregated solver and to to favor the solver convergence without compromising the accuracy of the solution. The resulting solver supports cavitation sub-models as well as LES and hybrid RANS/LES models for turbulence. Code validation is performed against standard test cases available from the litterature and against experiments.

Development of a VOF Dynamic Solver in OpenFOAM: an Application to the Simulation of the Opening and Closure Events in High Pressure GDI Injectors

PISCAGLIA, FEDERICO;MONTORFANO, ANDREA;
2016

Abstract

The simulation of the primary liquid atomization in industrial geometries of atomizers for Gasoline Direct Injection (GDI) requires to accurately resolve the gas/liquid interface and time-resolved turbulence modeling. A dynamic multiphase volume-of-fluid (VOF) dynamic solver has been implemented in the OpenFOAM ® technology to simulate flow cavitation during needle opening and closure events. The solver is based on the extension of an already existing multiphase two-fluid model; it makes use of ad-hoc implemented cavitation sub-models and, with respect to the solver available in the official distribution of OpenFOAM, it includes some novel features: it is coupled to an advanced fully-automatic parallel mesh motion solver supporting topological changes of the mesh, where dynamic addition and removal of cell layers is performed to simulate the prescribed motion of the injector needle; also, needle opening and closure events are simulated by performing dynamic detach/attach of one mesh region into multiple regions. In the fluid-dynamic solver, a pressure-correction equation to enforce continuity after topological changes in the pressure-velocity coupling algorithm of the segregated solver and to to favor the solver convergence without compromising the accuracy of the solution. The resulting solver supports cavitation sub-models as well as LES and hybrid RANS/LES models for turbulence. Code validation is performed against standard test cases available from the litterature and against experiments.
ICMF-2016 – 9th International Conference on Multiphase Flow
openFOAM
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/1010578
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