Fundamental Investigation of Fuel Spray Atomization

  Primary breakup WSA Microscopic images of the primary breakup of a full-cone Diesel spray on various scales: the intact liquid jet of the spray surrounded by ligaments, films/bags and droplets, as well as droplet interaction and secondary breakup

Combustion efficiency and hence performance of internal combustion engines are directly influenced by the mixture formation process inside the cylinder. The initial conditions of this process are controlled by primary breakup of the liquid jet, which exits the injector nozzle and disintegrates into ligaments and primary droplets.

Therefore, this project aims for an in-depth phenomenological understanding of primary breakup with focus on fuel-specific characteristics. Complementary experimental techniques, optimized for measurements in the dense spray region close to the orifice, will provide comprehensive insight into the primary breakup process with high spatial and high temporal resolution. Thus, unique experimental data will be available for improved modeling of primary breakup and new correlations will be derived for fundamental fuel spray properties such as near-nozzle spray cone angle, liquid spray core length, mean ligament size or the nozzle outlet velocity field. These findings will be based on the wide range of fuels provided by the Cluster of Excellence.

The experiments will be carried out with a typical Diesel injector as well as with an outwardly opening nozzle as employed in present DISI- engines. To gain a broad understanding of primary breakup the results will be compared to experiments with various generic nozzles that provide the opportunity to study the influence of fuel-specific nozzle flow.