This paper presents a fundamental study of two-phase combustion using a quasi mono-sized droplet aerosol configuration generated with the Wilson cloud chamber principle. Experiments were conducted under microgravity conditions to prevent droplet settling, using a dual chamber apparatus that ensures safe operation in these conditions. Two relevant parameters, the Sauter Mean Diameter and the number of droplets, were considered to describe the aerosols. In order to properly highlight the aerosol impact, the initial conditions were selected so as to avoid gaseous instabilities. It was found that the presence of an aerosol triggers cellular instabilities whereas the equivalent gaseous flame is totally stable. The cellularity of laminar flames increased both with the Sauter Mean Diameter and the number of droplets but differed in terms of cell size and flame shape. It was demonstrated that the aerosol flame speed can greatly exceed the gaseous flame speed. Conversely, the results also show that droplet evaporation during flame propagation can act as a thermal sink on the flame, and may thus reduce the flame speed.

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