Burning velocity measurement

Article By:

Agosta, Vito Polytechnic Institute of Brooklyn, Brooklyn, New York.

Last reviewed:January 2020

DOI:https://doi.org/10.1036/1097-8542.100000

The velocity at which the combustible gases move through a flame in the direction perpendicular to the flame surface defines the burning velocity. The term flame as used here refers to the burning of combustible gases. The process of combustion, or burning, is described as a chemical reaction of two or more substances in which a large quantity of heat is evolved. This heat is self-absorbed and goes into heating the products of combustion. Part of the light that is emitted is due to the heat of the flame, and part is due to the chemical reaction within the flame zones or thickness. It is the combustion of gases that forms the basis of a flame; and the zone in which chemical reactions occur, together with the concomitant temperature gradient, determines the location of the flame. An expression of the laminar flame speed for premixed homogeneous combustible gases has been obtained analytically, and indicates that the flame speed is proportional to the square root of the diffusivity and the reaction rate. The diffusion of heat and mass cause the flame to propagate. The reaction rate determines the temperature gradient by its effect on the thickness of the reaction zone: the slower the reaction, the thicker the zone.

The content above is only an excerpt.