Dynamics of Drop Release from the Edge of a Spinning Disc

Sahoo, K and Kumar, S (2021) Dynamics of Drop Release from the Edge of a Spinning Disc. In: Industrial and Engineering Chemistry Research .

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Abstract

The direct formation of drops at the edge of a spinning disc is of fundamental interest. We use high-speed imaging to report here on the process of release of drops from a perfectly wetted disc at low inflow rates. A drop-detachment event begins by forming an incipient bulge on the disc edge, which grows into a series of shapes-triangle, inverted U, pear, and finally a nearly spherical bulge connected to the disc with an elongated neck. Neck pinching at the base of the bulge releases a primary drop followed by several secondary drops. The drop shape versus time plots show high variability under fixed conditions, which disappears on a single curve for time scaled with individual drop cycle time. The measurements at a different disc speed show the same scaled time evolution, pointing to a universal drop release process. The rapid stretching of the liquid thread as the bulge moves away before pinch-off follows a parabolic relationship with time but with only half the relative acceleration of a free object released from the disc edge. The mean values of cycle time and necking time follow a power-law decrease with disc speed. All of the drops generated in a single event move with the speed of the disc. There is no slip, which is not the case with the ligament mode of breakup. The intervals of quiescence between the successive release of drops from the entire disc follow the Poisson process. ©

Item Type:	Journal Article
Publication:	Industrial and Engineering Chemistry Research
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society
Keywords:	Condition; Cycle time; Disc speed; Drop detachment; Drop shape; High speed imaging; Inflow rate; Single curves; Spherical bulge; Spinning disks, Drops
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	13 Dec 2021 11:35
Last Modified:	13 Dec 2021 11:35
URI:	http://eprints.iisc.ac.in/id/eprint/70754

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