Liquid and Vapor Fuel Distributions from an Air-Assist Injector - An Experimental and Computational Study 920422
Air-assist fuel sprays have been investigated experimentally with exciplex laser-induced fluorescence visualization and computationally with the KIVA-3 code. The exciplex-fluorescence technique provided simultaneous but distinct cross-sectional images of the liquid and vapor fuel distributions under simulated light-load conditions in both an atmospheric-pressure test rig and in a motored two-stroke engine. The computations resolved the flow through the injector passages upstream of and around the poppet, and included the effects of aerodynamic drop breakup, drop collisions and vaporization. Both the measurements and the calculations show that the fuel initially emerges from the injector as a hollow-cone jet. This two-phase jet collapses downstream as entrainment of air produces a low-pressure region beneath the poppet. Highly stratified fuel-air distributions with steep vapor-concentration gradients are found for injection and ignition timings typical of light-load operation of a direct-injection two-stroke-cycle engine.
Citation: Diwakar, R., Fansler, T., French, D., Ghandhi, J. et al., "Liquid and Vapor Fuel Distributions from an Air-Assist Injector - An Experimental and Computational Study," SAE Technical Paper 920422, 1992, https://doi.org/10.4271/920422. Download Citation
R. Diwakar, Todd D. Fansler, Donald T. French, Jaal B. Ghandhi, Cameron J. Dasch, David M. Heffelfinger
General Motors Research Labs.
International Congress & Exposition
Two-Stroke Engine Diagnostics and Design-SP-0901, Two-Stroke Engines-PT-69, SAE 1992 Transactions: Journal of Engines-V101-3