First Advisor

Mark Weislogel

Term of Graduation

Spring 2020

Date of Publication

7-14-2020

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Mechanical Engineering

Department

Mechanical and Materials Engineering

Language

English

Subjects

Fluid mechanics -- Research, Reduced gravity environments, Pipettes

DOI

10.15760/etd.7423

Physical Description

1 online resource (xv, 67 pages)

Abstract

The breakup and rupture of liquid bridges, thin films, bubbles, droplets, rivulets, and jets can produce satellite droplets that are subsequently ejected into their surrounding environment. For example, when any solid object is withdrawn from a liquid bath, the formation of an ever-thinning columnar liquid bridge eventually ruptures along the axis of the bridge. When rupture occurs under typical pipetting conditions the dynamics governing the rupture almost always produce at a minimum a satellite droplet. When these droplets occur they are often too small and too fast to be observed by the human eye. In a terrestrial environment they are of little concern due to the gravitational force imperceptibly returning these droplets back to the bulk fluid. This is not the case for low-g environments where activities such as pipetting creates satellite droplets that are ejected far away from the source fluid creating a risk of contamination within the surrounding working environments. In this work we demonstrate a variety of droplet ejections for the application of pipetting in space and highlight how in a low-g environment such dynamics depend on system geometries, fluid properties, wettability, and withdrawal rate. A drop tower data set is collected in support of a regime map organized by withdrawal Weber and Capillary numbers that highlight when different fluid ejection types are to be expected. Mitigation techniques are presented as a design guide for further applications aboard spacecraft.

Rights

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Comments

This work was supported by NASA Cooperative Agreements 80NSSC18K0436 and 80NSSC18K0161.

Persistent Identifier

https://archives.pdx.edu/ds/psu/33658

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