LAUSR

Abstract Nowadays, the leading driver for the development of internal combustion engines is the search for increased fuel efficiency and reduced emissions. To develop and optimize new combustion systems, a high degree of accuracy is needed in 3D-CFD simulations. In particular, detailed chemical kinetics models and fuel surrogates able to represent the main physical and chemical properties of the real commercial fuels are needed. A series of fuel surrogate formulation methodologies were presented in the recent past with the aim of matching fuel properties and combustion-related characteristics using a set of well-known compounds. While most of the gasoline-targeted available studies mainly focused on the possibility to simultaneously match the gross fuel properties, the evaporating characteristics and the auto-ignition behaviour of the fuel, none of them explicitly targeted the flame propagation characteristics. In this work, a novel methodology is introduced to formulate gasoline fuel surrogates able to match the main chemical and physical properties, the auto-ignition and the flame propagation characteristics of a commercial gasoline. Due to the increasing presence of oxygenated fuels in the market share, an average gasoline fuel named ULG95, representative of a European oxygenated gasoline with Research Octane Number RON = 95, is targeted to validate the presented methodology. Three fuel surrogates of increasing complexity are formulated and validated against laminar flame speed, shock-tube and rapid compression machine experiments available in literature for oxygenated gasolines. The results suggest that a unique gasoline fuel surrogate can be used, together with validated chemical kinetics mechanisms, to model auto-ignition and flame propagation characteristics.