Monte-Carlo based laminar flame speed correlation for gasoline

Abstract

Laminar flame speed and autoignition properties of gasoline play key role in the overall performance of spark-ignition and modern engines. Since gasoline is a complex fuel containing hundreds of species, it is not feasible to model all components present in gasoline. Researchers tend to employ surrogates, comprising of few components, that mimic targeted physical and chemical properties of gasoline. Detailed kinetic models of the surrogates can still be prohibitively large for CFD simulations and/or fuel-screening studies. For fuel-engine optimization efforts, it is highly desirable to have simple methods which can be used to accurately predict autoignition and laminar flame speed of real fuels. In this work, a laminar flame speed correlation is proposed for typical gasolines. This correlation is based on Monte-Carlo simulations of randomly generated mixtures comprising of 21 gasoline-relevant molecules. Laminar flame speed of each molecule is numerically computed over a wide range of thermodynamic conditions using detailed chemical kinetic models, and flame speed of each mixture is estimated with a suitable mixing rule. The proposed correlation is validated against experimentally-measured laminar flame speeds of various gasoline fuels.