Investigation of the penetration, the spreading, and the atomization of a Diesel injection jet using high speed cinematography

The knowledge of the penetration, the spreading, and the atomization of a Diesel injection jet is important to improve the combustion in a Diesel combustion chamber. There are some results from investigations of the mechanism of the breakup of stationary fluid jets. But the question is, whether those results are valid for instationary jets i.e. Diesel injection jets. For this reason many tests on injection jets are carried out in order to improve the knowledge of the Diesel injection. For these studies a rotating mirror camera with frequencies up to 1.000.000 f/s. and an exposure time of 15 ns was utilized. To investigate a single injection an electronic test control was used. With this arrangement it is possible to investigate this event from the start up to the end. The optical system was optimized. The jet was injected in a test chamber. In those studies the penetration velocity, the velocity and the path of single droplets, the spreading and the atomization of a Diesel injection jet were investigated. Besides the structure of the jet as function of time was interesting. The interpretation of the frames was performed by a digital image analysis system. These investigations give new insights in the Diesel injection jet.