Coupling Vaporization Model With the Eulerian-Lagrangian Spray Atomization (ELSA) Model in Diesel Engine Conditions

In this study, a 3D model for atomization based on an Eulerian single-phase approach has been implemented in a professional CFD code for simulations in engines: AVL Fire 8.3. The method improves the description of the primary break-up by representing the strong interactions between the liquid and the gas phase that take place in the atomization process. In the region where the spray is considered to be diluted enough, the classical representation of the spray by the way of a set of stochastic particles representing the droplets with a Lagrangian approach (DDM Method, see [1]) is then initiated to precisely describe the dispersed spray finally formed. Coming back to this standard approach also permits to benefit of an important background, in particular concerning vaporization models and eventually combustion models. Up to now, the model permits to simulate continuously the spray from inside the injector to the completely vaporized spray. Results concerning penetrations of liquid and vapour will be presented by comparisons with experimental results and the behaviour of the dense spray region will be studied. The experimental conditions incorporate the change of: back-pressures, fuel volatilities, injection pressures and ambient temperatures. This Eulerian single-phase approach needs only two modeling constants and a global agreement is found for the whole set of conditions without changing the constants values. These results demonstrate the ability of this Eulerian single-phase approach to simulate all sorts of sprays in injection conditions without needing to adjust any parameter, thanks to an improved representation of the primary break-up.