Developing Adiabatic Two-Phase Flow

In order to understand the characteristics of the adiabatic development of two-phase flow this study was performed using H2FC-CF 3 - 1,1,1,2-Tetrafluoroethane (R134A) as a working fluid in three different transparent tubes. The flow was visualized using a high speed camera. To better (faster and more objectively) analyze the flow, a technique was developed to determine the separation distance using a statistical method known as Change Point Analysis. The distance at which the phases become separated can be an important parameter in design of inlet tubes to evaporators. A method for determining the void fraction from the visualization results was developed and presented. This method allows for a local, instantaneous or time averaged, void fraction determination in Stratified, Intermittent, and Annular flows and could conceivably be implemented into an online void fraction determination. Qualitative examination of these images allowed for the determination of the distinct regions of flow development: Well-Mixed, Separating, Separated but Developing, and Developed regions. Dynamic examples of transitions between flow regimes in the process of flow development were also presented; specifically, transitions from Stratified to Intermittent flow.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Bowers, Chad D.

Contributors dc:contributor

• Predrag Hrnjak

• Engineering, Mechanical

Language dc:language

eng

Identifier

(MiAaPQ)AAI3362735

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/83925