VAPORIZATION OF BINARY FUEL MIXTURE DROPLETS IN A THERMAL WIND-TUNNEL

The authors present the study of vaporization, in forced convection, o f two or three binary fuel mixture droplets. The droplets are situated one behind the other and are evaporated by forced convection in a the rmal wind tunnel equipped with a video recording system. The image pro cessing provides the radius regression of the droplets in accordance w ith the elapsed time, which is compared with results from a calculated model based on the concept of the gaseous film surrounding the drople ts and the source of heat and mass transfer. During the period of susp ension of the droplets, their vaporization begins in natural convectio n. From the opening of the obturator that allows the arrival of hot ai rflow, the forced convection sequence begins, as does the interaction between droplets. Average Nusselt and Sherwood numbers used for the ca lculation of gaseous film thicknesses surrounding droplets come from e stablished correlations in natural and forced convection. In the case of interaction, these Nusselt and Sherwood numbers are corrected. The experiments and calculations that are undertaken for several mixtures of heptane and decane, and for several distances between the droplets, are in good agreement. Numerical results of the validated model are a nalyzed using a systematic parametric study.