High Fidelity Simulation of Atomization in Diesel Engine Sprays

Report No. ARL-RP-0555
Authors: L Bravo; CB Ivey; D Kim; ST Bose
Date/Pages: September 2015; 16 pages
Abstract: A high fidelity numerical simulation of jet breakup and spray formation from a complex diesel fuel injector has been performed. A full understanding of the primary atomization process of diesel fuel injection has not been achieved for several reasons, including the difficulties in accessing the optically dense region. Due to recent advances in numerical methods and computing resources, high fidelity simulations of realistic atomizing flows are currently feasible, providing a new mechanism to study the jet breakdown process. In the present study, a novel volume-of-fluid (VOF) method coupled to a stochastic Lagrangian spray (LSP) model is employed to simulate the atomization process. A common rail fuel injector is modeled by a nozzle geometry provided by the engine combustion network (ECN). The working conditions correspond to a single 90 µm orifice JP-8 fueled injector operating at 90 bar and 373 K and releasing into a 100% nitrogen, 29 bar, 300 K ambient with a Rel = 16, 071 and Wel = 75, 334, putting the spray in the full atomization mode. The experimental dataset from Army Research Lab (ARL) is used for validation and the Kelvin-Helmholtz/Rayleigh-Taylor (KH-RT) breakup model (Reitz & Bracco 1979) is used for verification, both in terms of spray angle. Droplet distributions of the simulated spray are provided for future experimental comparisons and secondary atomization simulations using LSP modeling.
Distribution: Approved for public release
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Last Update / Reviewed: September 1, 2015