Vaporization and Combustion of Single Liquid Fuel Droplets in a Turbulent Environment

Abstract

Vaporization and combustion processes of liquid fuel droplets in a fluctuating turbulent gas environment without any time-mean flow velocity are investigated. Such environment simulates adequately the flow field where average flow velocity is nearly equal to the droplet particle velocity. This paper also deals with the methods and instruments used in measuring turbulence quantities such as intensity and scale in this turbulent environment. Steady state empirical equations of heat and mass transfer for liquid sphere are applicable accurately to the evaporation of droplets under the condition of quasi-steady state in this turbulent environment. On the other hand, combustion in the turbulent environment is not like that under the forced convection and the flame shape is not tailed but almost spherico-symmetrical with wrinkled edges. The burning rate increases proportionately with eddy diffusivity and the ratio of this value to that in a stagnant atmosphere is represented by the ratio of eddy diffusivity to thermal diffusivity.