Modification of a Diesel Oil Surrogate Model for 3D CFD Simulation of Conventional and HCCI Combustion Chalmers University of Technology

Format:

Conference/Event

Author/Creator:

Bergman, Miriam, author.

Conference Name:

Powertrains, Fuels and Lubricants Meeting (2008-10-06 : Chicago, Illinois, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2008

Summary:

This paper describes an analysis of the Diesel Oil Surrogate (DOS) model used at Chalmers University (Sweden), including 70 species participating in 310 reactions, and subsequent improvements prompted by the model's systematic tendency to under-predict the combustion intensity in simulations of kinetically-driven combustion modes, e.g. Homogeneous Charged Compression Ignition (HCCI).Key bases of the model are the properties of a model Diesel fuel with the molecular formula C14H28. In the vapor phase, a global reaction decomposes the starting fuel, C14H28, into its constituent components; n-heptane (C7H16) and toluene (C7H8). This global reaction was modified to yield a higher n-heptane:toluene ratio, due to the importance of preserving an n-heptane-like cetane number. Three different (composite) versions of this global decomposition reaction were investigated separately and compared:Reaction 1 is the original formulation and reactions 2 and 3 are novel alternatives. The effects of modifying the activation energies (E), collision frequency factors (A) and oxygen concentration exponents (AEO) of these reactions was examined when integrated into the 3D KIVA-3V CFD code, while leaving the elementary reactions unchanged. The results were compared with data obtained from measurements of a High Speed Direct Injected (HSDI) engine, operating in both conventional and HCCI combustion modes. Finally, the global reaction version and the rate constants giving the best agreement for the examined regimes were identified

Notes:

Vendor supplied data

Publisher Number:

2008-01-2410

Access Restriction:

Restricted for use by site license