A Model of Turbulent Burning Velocity Taking the Preferential Diffusion Effect into Consideration.

Abstract

In our previous work, we found that the preferential diffusion in a turbulent flame played an important role in its turbulent combustion characteristics, and estimated the local burning velocity in premixed turbulent combustion experimentally, taking account of the preferential diffusion effect. In this study, a model, which takes the preferential diffusion effect into consideration, is proposed to predict the premixed turbulent burning velocity, using the local burning velocity as a reference instead of the original laminar burning velocity. The model can be explained as follows. The turbulence affects the turbulent burning velocity by increasing the flame surface area and stretching the flame. Consequently, the turbulent burning velocity and quenching limit are determined by the balance of both effects. The predicted velocities are compared with the measured turbulent burning velocities where the fuel, equivalence ratio and the laminar burning velocity were varied extensively. As a result, quantitative accuracy of this simple model is confirmed.