End Gas Inhomogeneity, Autoignition and Knock

An advanced gas dynamic/chemistry interaction code, SPRINT2D, has been developed to simulate end gas autoignition and knock. This confirms that an earlier hypothesis of three distinct modes of autoignition was not an artefact of the previous numerical code. A comprehensive chemical kinetic scheme has predicted autoignition onset and demonstrated a mechanism for creating the end gas temperature gradients assumed in, as well as generated heat release rates for use in, SPRINT2D.

Using the combined modelling techniques, good matches between theoretical and experimental autoignition centre growth (at up to 750,000 frames/second), particle tracking and pressure development sequence at multiple transducer sites have been obtained for “thermal explosion” and “developing detonation” autoignition events.