Dynamics and Structure of Weakly-Strained Flames at Normal and Microgravity

Strained laminar flames have been the subject of extensive studies the last thirty years or so, typically in opposed-jet, stagnation-flow configurations. The motivation behind such extensive efforts emerges from the relevance of such flames to a number of combustion phenomena and issues. First, it is believed that such flames are of relevance to turbulent combustion, given that under certain conditions, turbulent flames can be viewed as an assembly of strained laminar flamelets. Second, the opposed-jet, stagnation-flow configuration is a particularly meritorious configuration, in which the details of the physico-chemical processes can be probed and understood. More specifically, the stagnation-flow configuration allows for the accurate determination of fundamental flame properties and can be modeled conveniently with the use of detailed description of chemical kinetics and molecular transport. Thus, on one hand the interaction between fluid mechanics and chemical kinetics can be investigated from first principles and on the other, existing kinetic and/or transport models can be (partially) validated with confidence. The response and phenomena of interest of laminar flames are quite different, depending on whether the strain rate is low or high.