Results of an experimental study are reported for combustion of unsupported n-heptane droplets emulsified with water burning while levitated in microgravity where the effects of external convection are negligible. The results are compared to a pure heptane droplet and a mixture of two miscible liquids (methanol/dodecanol) burning under similar low convection conditions. The effect of water concentration on flame luminosity and sooting tendency, preferential vaporization of the emulsion components, and the role of the emulsifying agent in promoting disruptive burning were examined. The photographs showed less sooting for the emulsions relative to pure heptane, and a preferential vaporization process was revealed from the image analysis by an abrupt change in the vaporization rate. A period exists near the end of burning during which the droplet diameter is nearly constant, followed by a disruptive burning event.-A quasi-steady complex chemistry analysis with variable properties shows that a frozen evaporation mode occurs after an initial delay period during which heptane is evaporating from the droplet. Predicted and measured burning rates are in good agreement during this later period.