VELOCITY, INTERFACE COMPLEXITY AND DROPLETS PRODUCTION IN THE NEAR NOZZLE REGION OF A DIESEL SPRAY: COMPARISON BETWEEN EXPERIMENTAL ANALYSIS AND DIRECT NUMERICAL SIMULATION

A transillumination imaging arrangement using a double-pulsed femtosecond laser system coupled to a double frame camera was used to record high-resolution time-correlated image-pairs in the near-nozzle region of a high pressure Diesel jet. On the other hand, direct numerical simulations (DNS) using coupled volume of fluid/level set (VOF/LS) method for interface tracking have been carried out for this kind of injection. For the sake of precision of these numerical simulations, the flow inside the injector was also computed by using a commercial CFD code (Fluent 6.3). A quantitative comparison between numerical simulations and experimental images has been performed by applying the same tools. From the numerical point of view, some jet characteristics are well reproduced and this study allowed detecting the features that need improvement.