developments and applications of SGEmac make use of the AVBP LES code
co-developed and co-owned by IFP and CERFACS. AVBP solves the unsteady,
compressible, reactive, multi-species Navier-Stokes equations on unstructured
moving meshes. Time advancement is explicit, and convective schemes are
centered second order FV and third order FE schemes.
demonstrated its unique linear efficiency on all parallel computers on the
market and for up to 8000 processors.
Moving meshes are handled via a Conditional Temporal Interpolated (CTI)
combined with an ALE method.
Available LES models include turbulence models (constant coefficient and
dynamic Smagorinsky, WALE, filtered structure function, subgrid kinetic
energy), combustion models (TF-LES, ECFM-LES, PCM-FPI) and liquid injection
models (Eumlerian and Lagrangian).
Boundary conditions are handled via the NSCBC approach particularly suited for
accurate treatment of acoustics.
Project work is structured
based on 5 Tasks:
- Task 1 is the starting point and concerns
the acquisition, based on advanced optical diagnostics, of an experimental
database on a single cylinder, PFI and DI spark ignition engine,
comprising stable and unstable operating points;
- Task 2 aims at developing complementary
LES methods allowing to simulate the behaviour of the combustion chamber,
but also of the whole intake and exhaust system, as they may be of
importance in the appearance of cyclic variabilities. These developments
will be validated on stable operating points acquired in Task 1;
- Task 3 consists of having the industrial
partners use the methods from Task 2 to define methodologies for the
prediction of cyclic variabilities in the case of a PFI SI engine, which
will be validated using unstable operating points from Task 1;
- Task 4 is dedicated to exploring the
possibility of extending the PFI LES methodologies to predicting cyclic
variability in DI engines;
- Finally Task 5 aims at synthesizing all
the realised work, by comparing the obtained predictions in order to
identify their respective strong and weak points, as well as by
identifying elements that will have to be addressed in future
research and in particular for DI studies.