摘要

A novel method of preparation of uniform droplets using a direct-mode jet pulse spray system has been developed. By means of the periodical switch-on between a membrane-like rotating distribution exit and a micronozzle, a fluid stream was stimulated to be disintegrated into monodisperse droplets. The effects of the rotational speed (n) and thickness (H) of the distribution exit and flow rate of the dispersed phase (Q) on droplet characteristics were investigated. It was found that the uniformity of droplets would be enhanced with increased rotational speed and decreased thickness of the distribution exit, even for a relatively high flow rate of the dispersed phase. A relatively steady value of the coefficient of variation in size less than 10% could be obtained under the conditions of n = 350 rpm and H = 3 mm at Q = 7.5-8.7 mL/min. The influence of vortices was characterized by the Taylor number and parameter K, showing that the parameter K is capable of more precisely predicting the turbulence transition. Therefore, the system has effectively attained an improvement not only in uniformity but also in productivity of droplets generation.

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