Use of Derivations of Thermal Ignition Theory to Determine the General Flame Stabilization Condition with a Bluff Body PDF Download

Author: V. A. Mironenko
Publisher:
ISBN:
Category :
Languages : en
Pages : 13

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Book Description
In solving the problem of flame stabilization, it is necessary to consider equally both the flow structure behind the bluff bodies and the kinetics of the chemical reaction. The article demonstrates, however, that, with certain assumptions and simplifications, the blow-out characteristics of a flame holder in the form of a bluff body can be satisfactorily explained and calculated, by using the thermal theory of ignition and the theory of turbulent flow. In deriving quantitative correlations, the following assumptions were made: (1) Up to the ignition point, the velocity, temperature, and concentration distributions of the turbulent boundary layer behind the holder are in accordance with the theory of turbulent flows for nonisothermal counter flows; they are not changed by the heat release resulting from the chemical reaction, for, according to the thermal theory of ignition, during the period of ignition delay, the heat release and temperature rise are insignificant. (2) The static pressure in the boundary layer behind the holder is equal to the free-stream static pressure. An expression was derived to determine the effect on the blow-out characteristics of the combustion chamber of the physical flow parameters (pressure, flow velocity, temperature) and type of fuel. If the dependence of the length of the reverse-flow zone on the dimension and shape of flame holder are known, the effect of its geometric parameters may also be determined. (Author).