Selected characteristics of spray jets and flames with different inlet conditions

This paper presents an experimental study of turbulent spray jets and flames of acetone where the atomization condition at the jet exit plane can be varied by maintaining a constant mass loading, such that the spray ranges from dilute to moderately dense. The flow configuration is a hybrid of designs by Meares and Masri [1] and Gounder et al. [2] in that a piloted spray jet is generated using a needle that may be translated within a surrounding stream of co-flowing air. The burner geometry allows for a versatile control of the spray inlet conditions without changing the global Weber number or bulk jet Reynolds number, offering isolated control of key variables leading to spray flame stabilization. Time averaged photographs along with microscopy and laser/phase Doppler anemometry of the spray have revealed some initial characteristics of the burner, showing the evolution of droplet velocity fields and droplet sizes as a function of recession distance for both non- reacting and reacting conditions. Similar to Meares and Masri [1] the global blow-off limit reduces as the fuel injecting needle is brought closer to the burner exit plane. However, this is not only due to the lack of premixing and increased inhomogeneity, but also due to the lack of atomization and evaporation. This burner, in conjunction with recently published work from the same group [3] will form part of an extensive database for the understanding of the effects of atomization, evaporation, inhomogeneity and turbulent mixing on the stabilization of spray flames.