Date of Award

2015

Document Type

Thesis

First Advisor

Dr. John P. Kizito

Abstract

The current study investigates the dynamics of a two phase flow in a circular cylinder under zero gravity conditions. Zero gravity fluid mechanics is applicable in both spaceflight and terrestrial applications. Plug formation obstruct lung passages and is the cause of asthma and pulmonary disease .In spaceflight applications, the helium bubbles occlude fuel lines of hydrazine arc-jet thrusters on satellites which cause operational problems. The process of plug formation is not fully understood. Previous studies have been limited to static solutions in cylinders. The goal of the current study is to investigate the dynamics of two phase flow under zero gravity conditions and low bond numbers. The specific objectives of this study are to model a two-phase flow into a circular cylinder via a side tube in zero gravity and confirm the existence of droplet, annulus, and plug topologies through experiment and simulation. Interim stages between topologies and steps of transition are analyzed in terms of flow quantities such as flow rate and kinetic energy. The effect of varying inlet pressure on topology formation is also determined and investigated. An experiment was conducted to determine the dynamics of silicone oil-air interface in a cylinder under low bond number conditions using a high speed camera to capture the fluid. Numerical simulations were carried out for both static and dynamic conditions. Results confirmed the existence of droplet, annulus and plug for the dynamic system. A characteristic time where plug is formed is identified and has a value of approximately 13. An instability regime between the annulus and plug was identified which gets narrower for higher pressure differences. Stable plug solutions are delayed for lower pressure differences. Stable plug solutions in dynamic systems were found to be higher than those in static systems under the same conditions.

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