FLAME STABILIZATION AND BLOWOFF OVER A SINGLE DROPLET

Abstract

The burning behavior of a liquid fuel droplet under forced convection has been investigated numerically. The normalized governing system makes up the complete Navier-Stokes momentum, energy, species, and continuity equations in r-z coordinates with a one-step overall chemical reaction and finite-rate global kinetics. The evaporation process obeys the Clausius-Clapeyron law. The effects of incoming velocity (ū_∞) and droplet diameter (d¯) are investigated separately. The envelope flame exists when free stream velocity is low. When ū_∞ increases gradually, a critical velocity can be reached, at which the flame suddenly converts into a wake flame. No side flame is found. The envelope flames are retained throughout the decrement of the droplet diameter under the low-speed flow regime. The d² law is found to still hold in such an environment.