Objectif
Objectives
The combustion process and spray formation inside internal combustion engines (IC engines) are greatly influenced by the characteristics of the aerodynamic turbulent field. The objective of this project is to investigate the influence of compression on a turbulent field with or without rotation or shear effect as is encountered in IC engines with special emphasis on the near-wall properties of the flow. The long-term goal is to develop reliable models for computational codes in particular those used by IC engines manufacturers in order to optimize the flow with regards to emissions and fuel consumption.
Technical Approach
The proposal contains theoretical, numerical and experimental investigation of wall-bounded turbulence submitted to the isolated or combined effects of compression, rotation and shear. Two experimental studies on idealized systems will be developed. The first one is related to the generation of a swirl inside a rotating cylinder and its interaction with a one-dimensional compression. In the second one, the effect of a cyclic compression with a flat or a bowl-in piston is studied more specifically. Large-Eddy simulation will be obtained in the case of a turbulent flow compressed by two infinite parallel walls moving one to the other. A solid-body rotation and a pressure gradient parallel to the wall will be superimposed to the flow in order to mimic the squish and swirl effects as observed in the case of bowl-in piston. The effects of compression, rotation and swirl on confined turbulence will be studied in the framework of second-moment closure models. The experimental and numerical data basis will be used to test existing models and to suggest improvements that will be evaluated in numerical codes used by the partners.
Expected Achievements and Exploitation
At the end of project, a better understanding of the turbulence inside internal combustion engine will be achieved, and thus more reliable turbulence models will be proposed for the computational codes used by the car industry. By improving the predictability of the numerical codes used for the designn of IC engines, clean and more efficient engines could then be designed.
Champ scientifique
Thème(s)
Appel à propositions
Data not availableRégime de financement
CSC - Cost-sharing contractsCoordinateur
69131 Ecully
France