EVALUATION OF A NEW GENERATOR OF SINGLY D ISPERSED DROPLETS

A new droplet generator was designed to benefit from the aerodynamic e ffects and the kinematic of a liquid jet emitted from an orifice mount ed on the wall of a rotating cylinder. Such an approach should permit to reduce the minimum diameter of droplets generated from a fixed diam eter orifice while maintaining a homogeneous distribution. The new dro plet generator is described and the results of measures taken at vario us flow rates and various liquid jet excitation frequencies for a give n orifice diameter show that work objectives were reached. It was demo nstrated that: the instability of a liquid jet emitted from an orifice mounted at the periphery of a rotating cylinder can be excited and co ntrolled with a piezoelectric crystal; the rotational motion gives dro plets whose diameter is only 1.26 times the orifice diameter compared to 1.89 for a stationary jet; the increase of the ratio of the cylinde r peripheral speed to the liquid radial speed up to a value of 1.7 giv es a decrease in the droplet size; the presence of satellites cannot b e avoided but their proportion can be maintained under 3% of the spray ed volume.