An Experimental Study of Structure and Reaction Rate in Turbulent Premixed Flames

Abstract

To close the turbulent combustion equations, the time mean chemical source terms must be estimated. This paper reports the measurements of saturation ion current in the turbulent premixed flame to obtain the mean turbulent reaction rate. Detailed measurements were carried out of mean, rms and probability density functions of saturation ion current using a water-cooled electrostatic probe. For the wrinkled laminar flame model, the saturation ion current is shown to be proportional to the mean turbulent reaction rate. Roughly linear relationship is found between the mean saturation ion current and mean temperature, which results in an important fact that mean turbulent reaction rate is proportional to mean temperature. This Fact supports the Eddy-Break-Up model 3-peak PDF of saturation ion current is observed on the burnt side of the turbulent flame zone, each peak corresponding to unburnt gas, burnt gas and laminar flame zone, and confirms that the present turbulent premixed flame zone is composed of the wrinkled laminar flame.