A moving piston boundary condition including gap flow in OpenFOAM
Sprache des Vortragstitels:
Englisch
Original Tagungtitel:
13th International Conference on Fluid Mechanics & Aerodynamics
Sprache des Tagungstitel:
Englisch
Original Kurzfassung:
Fuel injection as well as digital switching strategies in fluid power applications are not only famous
representatives of a large field of technology but also a main reason for the increasing interest in wave propagation
effects in research. While there is a huge number of works dealing with the pressure drop of different hydraulic
components in the steady state, many issues still remain unresolved in the transient regime, even in the case of
laminar fluid flow. A better understanding of these processes would be a great benefit as it would lead to a higher
accuracy of predicted system responses. In order to reach a higher degree of precision, the highly sophisticated
computational fluid dynamics (CFD) codes are a wide-spread tool. These codes solve the famous Navier-Stokes
equations in all three dimensions of space and therefore result in the full resolution of the pressure field as well as of
the velocity field. A very awkward topic of performing a CFD simulation is the choice of the boundary condition,
which should correspond to a physical one. At the latest when measurements for validation are carried out, the
boundary condition of the experimental setup should match the one used in the simulation. Especially the use of
a volumetric flow rate boundary condition is fraught with problems. Using a moving piston, a definite volumetric
flow rate could be forced on a boundary. In an experimental setup only the measurement of the position of the piston
would be necessary to use it in the simulation. This measurement has no backlash on the system, which is therefore
well separated. In this work a moving piston boundary condition including gap flow is implemented and used in
OpenFOAM. For this reason moving walls have to be used and the mesh has to change during the simulation.
Results of simulations done with this moving piston boundary condition are compared with simulations done with
an ordinary volumetric boundary condition.
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