Estimation of the Characteristic Time Scale of a Laminar Flame by Particle Image Velocimetry

Abstract

This paper first presents particle image velocimetry measurements of the chemical time scales versus equivalence ratio and the concentration of the inhibitor trimethyl phosphate for premixed methane–air and dimethyl ether–air flames at atmospheric pressure. Comparison of the experimental results with theoretical estimates based on the Zel’dovich–Barenblatt hypothesis shows their qualitative agreement. Within the accuracy of the experiment, the chemical time scale depends only on the burning rate, rapidly decreasing as it increases. At fuel–air flame speeds close to and above 0.6 m/s, the results of the experiments show the high accuracy of theoretical estimates based on the Zel’dovich–Barenblatt hypothesis.