Browse Publications Technical Papers 2008-01-2410

Modification of a Diesel Oil Surrogate Model for 3D CFD Simulation of Conventional and HCCI Combustion 2008-01-2410

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:
  1. 1
    3C14H28 + O2 => 4C7H16 + 2C7H8 +2H2O
  2. 2
    2C14H28 => 3C7H16 + C7H8
  3. 3
    3C14H28 + 3.5O2 => 5C7H16 + 0.5C7H8 + 3.5CO2
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.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 17% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

A Four-Stroke Homogeneous Charge Compression Ignition Engine Simulation for Combustion and Performance Studies


View Details


Comparing Large Eddy Simulation of a Reacting Fuel Spray with Measured Quantitative Flame Parameters


View Details


Model Calibration for Spray Penetration and Mixture Formation in a High Pressure Fuel Spray Using a Micro-Genetic Algorithm and Optical Data


View Details