Weak Extinction Limits of Turbulent Flowing Mixtures

An equation has been derived for predicting the weak extinction limits of stabilized flames supplied with turbulent, flowing mixtures of uniform composition. Experiments have been conducted to investigate the influence on weak extinction limits of wide variations in inlet air pressure, temperature, velocity, and turbulence level. The apparatus comprised a flameholder, in the form of a hollow cone, which was mounted at the center of a circular pipe with its apex pointing upstream. Fourteen, geometrically similar, conical baffles were manufactured to various sizes and used in conjunction with three different pipe diameters in order to allow the effects of baffle size and blockage ratio to be studied independently over a fairly wide range. The fuel employed was gaseous propane. The experimental results obtained on weak extinction limits were found to be in close agreement with the corresponding predicted values.