Measuring the Burning Rate of Premixed Turbulent Flames in Stagnation Flows

Abstract

Abstract A method is proposed to measure the burning rate of planar premixed turbulent flames in stagnation flows. The method is based on the balance of conditional mass fluxes in a control volume that extends from pure reactants to the stagnation plane. The principle is that the difference between the mass of reactants flowing into and out of the control volume is the mass that has reacted within the control volume. Similarly, if only reactants flow into the control volume then the mass flow rate of products out of the control volume constitutes the burning rate in that region of the flame. The measurement techniques necessary to use this approach are all available. Experimental measurements were conducted on the stagnation plate geometry. The burning rate characterized by a leading edge velocity overestimated the value determined from the conditioned mass fluxes by 41% The extension of this approach to other burner geometries and more general flame shapes is discussed and suggestions for its use in rod stabilized flames are made. In this case the shape and orientation of the control volume are set by the maximum gradient in space of the progress variable. For curved flame zones and more general flows the choice of control volume remains ambiguous.