A new experimental technique for the simultaneous determination of single droplets size, velocity and optical properties inside an evaporating hydrocarbons spray

A new experimental technique for the determination of the size, velocity and/or the optical propertiesof single droplets is proposed. It is based on the different behaviour of scattering cross sections uponthe size for vertically and horizontally polarized incident light, as it is predicted by the Lorenz-Mietheory. Measurements of the scattering polarization ratio y = CHH/CVV in the side scattering regioncan be employed for sizing transparent droplets while the optical depth kD can be obtained in theforward region for absorbing droplets.An interpherometric apparatus has been realized for the simultaneous determination of thepolarization ratio and velocity of individual droplets. Experimental results obtained on arrays ofmonodisperse and bidisperse droplets with different refractive index illustrate the potentiality of themethod.