I. Gokalp et al., VAPORIZATION OF MISCIBLE BINARY FUEL DROPLETS UNDER LAMINAR AND TURBULENT CONVECTIVE CONDITIONS, Atomization and sprays, 4(6), 1994, pp. 661-676
Convective vaporization of single bicomponent droplets under different
flow conditions is investigated. Pure and mixture droplets of n-hepta
ne and n-decane are suddenly exposed to cold or heated laminar or turb
ulent flows generated by a controlled flow system. A real-time image a
nalysis procedure has been developed to determine the instantaneous va
porization rates. Distillation-type vaporization is observed for all t
he mixtures investigated under stagnant or cold flow conditions. It is
shown that the first vaporization sequence is intrinsically nonstatio
nary and that the quasi-steady vaporization rate of the second sequenc
e is equal to that of pure n-decane under the same conditions. The pre
ferential vaporization process disappears when the flow is moderately
heated. However, another nonstationary process, corresponding to the h
eatup of the droplet, appears. In heated convective conditions, a cons
tant vaporization rate equal to that of the less volatile component ch
aracterizes the post-preheating period. These experimental results are
discussed by using a formalism based on the comparison between the dr
oplet vaporization rate and the liquid-phase mass diffusion rate. Prel
iminary experimental results are also reported on bicomponent droplet
vaporization in a turbulent flow, in the distillation-type vaporizatio
n regime.