Aspects of Laminar and Turbulent Burning Velocity Relevant to SI Engines

Laminar and turbulent burning velocity are important parameters of a combustible mixture. Each is used in mathematical models of spark ignition engine combustion. However, reported data are inconsistent and sparse at elevated pressure and temperature.

The present paper presents precise definitions and results of fundamental experiments at Leeds on both laminar and turbulent burning velocities. Reasons for the considerable differences in reported values are put forward and the often neglected effects of flame stretch rate and instabilities on burning velocities are discussed. Relevance is discussed in relation to observations of turbulent flame propagation in a research engine.