This study investigated the production characteristics of large soybean oil droplets dispersed in an aqueous solution containing an emulsifier using newly designed microchannel (MC) emulsification chips. The silicon MC emulsification chips consisted of numerous asymmetric through holes with a characteristic cross-sectional size of 20μm to 50μm, each consisting of a microslot and a circular MC. MC emulsification using such chips enabled the stable production of uniform large droplets with average diameters of 75μm and 179μm and a coefficient of variation below 2%. The detachment behavior of the large droplets generated from the asymmetric through holes was analyzed and discussed based on results obtained by real-time optical microscopy. The size of droplets smaller than 100μm was independent of the flow rate of the cross-flowing continuous phase (
Qc) applied in this study. In contrast, the size of droplets larger than 100μm became sensitive to
Qc in its range over a critical value. The results for the effect of
Qc is discussed by analyzing the force balance acting on a dispersed-phase droplet that expands over the microslot. Large droplets with a very narrow size distribution were obtained at dispersed-phase fluxes (
Jd) of 50 L m
-2 h
-1 or less, whereas their average diameter was somewhat dependent on
Jd.
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