Fuel Surrogate Physical Property Effects on Direct Injection Spray and Ignition Behavior
MICHIGAN UNIV ANN ARBOR DEPT OF MECHANICAL ENGINEERING
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Typical hydrocarbon fuels used in internal combustion engines, such as gasoline, diesel, or jet fuel, are composed of hundreds to thousands of hydrocarbon HC species. Such a large number of species in high fidelity Computational Fluid Dynamics CFD with detailed chemistry is beyond our current computational capability. Therefore, surrogate fuels and their associated chemical mechanisms have been developed and utilized to represent the combustion behavior of typical HC fuels within CFD simulations. The most common surrogate formulation approach seeks to match the combustion related properties of the target fuel. This approach requires reliable models of the HC mixture properties for mathematical optimization, which determines the surrogate composition that minimizes the deviation from the target properties. For modern diesel engines, which employ direct fuel injection, the physical properties of liquid fuel influence the spray, mixture development and ultimately the ignition and combustion process. To more accurately predict the diesel combustion process, it is very important to understand which fuel properties have a major impact on the combustion physics . To date, most studies into the importance of liquid fuel physical properties to combustion behavior have been experimental. While these experiments provided valuable insights, it is difficult to isolate the effect of each property by simply comparing results from different fuels. Computational studies offer a more effective approach to isolate physical fuel property effects from the complex processes occurring during spray combustion. The focus of the current work is on the effect of temperature-dependent physical properties of the liquid fuel such as density and viscosity on spray penetration, the evolution of the local thermodynamic states within the jet, and the ignition delay period of compression ignited combustion.
- Physical Chemistry
- Combustion and Ignition