An Unstructured Parallel Solver for Engine Intake and Combustion Stroke Simulation 2002-01-1120
KIFP, an hexahedral unstructured version of KIVA-MB (KMB), the current CFD code for engines at IFP, has been developed. Based on KIVA algorithms (finite volume on staggered grids, time-splitting, SIMPLE loop, sub-cycled advection…), the new solver has been built step by step with a strong control on the numerical results.
This paper shows the different phases of this work. The numerical approaches and developments are discussed. Several moving grids algorithms have been tested without the flow and results are presented. The flow with its physical properties has been implemented step by step. Some academic examples are shown and compared with KMB or analytical results, like scalar advection or multi-species diffusion. Better precision and convergence in the physical fields are observed. Iterative loops and advective sub-cycles are also reduced thanks to the unstructured formalism.
Super-scalar machines being widely used and developed, KIFP is dedicated for them. Because of its low cost of implementation, the OPEN-MP paradigm is used to parallelize the code. The paper gives results on performance and speed-up (more than 3 for 4 processors in the best case).
A helical port on a steady state bench has been computed and compared with KMB and measurements. A part of an intake stroke is also shown for a pent roof engine. Temporal interpolation is successfully used for moving the grid. At last, combustion is computed for the same engine with the extended coherent flame model (ECFM) implemented in the new solver. Pressure curves are compared with experiments.