Global Response of Spray Flames due to Oscillatory Spray Dynamics*

A significant literature exists for the modeling of the response of premixed and non-premixed gaseous diffusion flames to various source fluctuations. These source fluctuations can stem from: (1) velocity fluctuations, (2) equivalence ratio/mixture fraction fluctuations, or (3) pressure fluctuations. Recently, the author has presented a reduced order modeling framework for the response of spray flames to velocity disturbances. In that study, the effect of acoustic and vortical component velocity fluctuations on the spray flame response for various spray parameters was explored, showing the sensitivity of the global response to droplet loading and vaporization. However, that model did not consider the effect of the oscillatory combustor environment on the sprays themselves. In the fluctuating environment where the fuel is injected, there exists fluctuations in the spray atomization, droplet loading and oscillatory evaporation. These spray fluctuations, collectively, can cause significant influences on the global flame response which has been explored in this study. The governing equations are reformulated to consider fluctuations in the spray properties and new parameters associated with these fluctuations are used to understand their effect on the global flame response.