Simulation and Measurement of Transient Fluid Phenomena within Diesel Injection

Martin Gold, Richard Pearson, Jack Turner, Dan Sykes, Viacheslav Stetsyuk, Guillaume de Sercey, Cyril Crua, Pheovos Koukouvinis, Manolis Gavaises

Research output: Chapter in Book/Conference proceeding with ISSN or ISBNConference contribution with ISSN or ISBN

Abstract

Rail pressures of modern diesel fuel injection systems have increased significantly over recent years, greatly improving atomisation of the main fuel injection event and air utilisation of the combustion process. Continued improvement in controlling the process of introducing fuel into the cylinder has led to focussing on fluid phenomena related to transient response. High-speed microscopy has been employed to visualise the detailed fluid dynamics around the near nozzle region of an automotive diesel fuel injector, during the opening, closing and post injection events. Complementary computational fluid dynamic (CFD) simulations have been undertaken to elucidate the interaction of the liquid and gas phases during these highly transient events, including an assessment of close-coupled injections.
Microscopic imaging shows the development of a plug flow in the initial stages of injection, with rapid transition into a primary breakup regime, transitioning to a finely atomised spray and subsequent vaporisation of the fuel. During closuring of the injector the spray collapses, with evidence of swirling breakup structures together with unstable ligaments of fuel breaking into large slow-moving droplets. This leads to sub-optimal combustion in the developing flame fronts established by the earlier, more fully-developed spray. The simulation results predict these observed phenomena, including injector surface wetting as a result of large slow-moving droplets and post-injection discharge of liquid fuel. This work suggests that post-injection discharges of fuel play a part in the mechanism of the initial formation, and subsequent accumulation of deposits on the exterior surface of the injector. For multiple injections, opening events are influenced by the dynamics of the previous injection closure; these phenomena have been investigated within the simulations.
Original languageEnglish
Title of host publicationInternational Powertrains, Fuels & Lubricants Meeting
PublisherSAE International
Volume2019-January
EditionJanuary
DOIs
Publication statusPublished - 15 Jan 2019
EventSAE International Powertrains, Fuels and Lubricants Meeting - Rio de Janeiro, Brazil
Duration: 5 May 2010 → …

Publication series

NameSAE Technical Papers

Conference

ConferenceSAE International Powertrains, Fuels and Lubricants Meeting
Period5/05/10 → …

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    Gold, M., Pearson, R., Turner, J., Sykes, D., Stetsyuk, V., de Sercey, G., Crua, C., Koukouvinis, P., & Gavaises, M. (2019). Simulation and Measurement of Transient Fluid Phenomena within Diesel Injection. In International Powertrains, Fuels & Lubricants Meeting (January ed., Vol. 2019-January). [2019-01-0066] (SAE Technical Papers). SAE International. https://doi.org/10.4271/2019-01-0066