Date of Award

2007

Degree Type

Thesis

Department

Mechanical Engineering

First Advisor

Sawicki, Jerzy

Subject Headings

Refrigeration and refrigerating machinery, Low temperature engineering, Cryogenic, Refrigeration, Joule-Thomson, Spacecraft, Fluid management

Abstract

Cryogenic fluid systems are fundamental to space flight architecture. Due to the unique properties of cryogenic fluids and the environments in which they operate for space flight, cryogenic fluid management systems must be developed to maintain these fluids at conditions in which they can be utilized. Liquid oxygen boils at 90 K, and liquid hydrogen boils at 20 K. Significant care must be taken to provide a thermal management system that prevents heat entering these fluids with consequential adverse effects on the performance of the cryogenic fluid systems. One critical component of a cryogenic thermal management system is a Joule-Thomson device. This one small component provides the driving force not only for the production of cryogenic fluids, but for the effective management of thermal loads in many cryogenic fluid systems including those used in space flight architectures. As a fundamental understanding of the Joule-Thomson effect and J-T devices is critical to the effective design of cryogenic fluid management systems, the intent of this work is to examine J-T devices as they relate to space flight systems. This work will examine where these devices are used in space based cryogenic fluid management systems. It will consider research conducted to date that examines both the fundamental fluid physics behind how these devices operate and their application in real systems. Finally, it will report on the potential impact that fluid metastability has as it relates to J-T devices for certain cryogenic fluids. An analytical assessment is made of the stability limits of single phase cryogenic fluids as a J-T device operates on them. This is compared to experimental results for tests conducted in liquid oxygen, and liquid methane. Results show that several factors influence the performance of J-T devices, and that the metastability of single phase cryogenic fluids below the saturation line must be considered in the design of cryogenic fluid management systems

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