ID 265

Dynamics of a vertical liquid sheet originating from a slotted cone-disc deflector

 

Abstract:

The dynamical behaviour of a radially expanding vertical liquid sheet is examined experimentally in the present work. When a cylindrical liquid jet impinges orthogonally on a single slotted cone-disc deflector, two liquid sheets form at a time– a radial liquid sheet issues at the solid part of a deflector and a vertical sheet forms from the slot of a deflector. Since the radially expanding sheet is studied extensively, the present work is restricted to the radially expanding vertical sheet. The goal is to correlate the breakup events at leading and lower edges of a vertical sheet to the dimensions of ligaments and droplets that are formed. High-speed shadowgraphy at 5.4 kHz framing rates is carried out simultaneously on the front, side, and top views of the vertical liquid sheet at different jet Weber numbers over the range 523<We_jet<3786. It is found that the breakup distance of the leading edge increases with the We_jet. The breakup frequency of the vertical sheet is higher as compared to the radial sheet because of faster streamwise velocity. Further, in the vertical sheet, the surface tension force is high at the lower edge, which causes ligaments larger in size as compared to those produced from the leading edge. The Sauter mean diameter (SMD) of the droplet from the leading and lower edges is measured and found to follow the We_jet^(-1/3) law. Correlations are obtained between the SMD at the leading and lower edges with We_jet, sheet thickness, and breakup distance and frequencies.