Analysis of the freeze/thaw characteristics of external artery heat pipes /
Monogroove heat pipes are one of the high performance heat
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1997.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=736824361&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Monogroove heat pipes are one of the high performance heat pipe configurations planned for use on the space station to reject the waste heat generated inside the habitation modules. These devices work well under normal operating conditions, however, the working fluid inside the heat pipes may be in a solid state initially, due to the extreme cold conditions encountered during build up. Thus, how the heat pipes behave during the initial startup from a frozen state will determine if the heat pipes will work properly or fail completely. Following is an analysis of the freeze/thaw characteristics of the monogroove heat pipes during the startup from a frozen state in reduced and one-g environments. The startup of monogroove heat pipes from the frozen state at the very early stages is essentially a transient heat conduction problem with phase transformation of the working fluid from a frozen state to a liquid state. Although the heat conduction mechanism is well understood, the addition of a phase transformation introduces a latent heat term and a moving interface between the two phases, making it a highly non-linear problem, which is difficult to solve in a multi-dimensional domain. In this study, a computer model has been developed to solve the frozen startup of monogroove heat pipes. The numerical computation scheme utilizes the fixed grid finite element method with implicit time step procedures. A special technique, referred to as the budget node method is used in the numerical algorithm to accommodate the latent heat and moving boundary problem. Although the computer model is very sensitive to the time step, convergent results can be obtained by appropriate selection of the time step size. To check the validity of the computer model, a simple experimental setup was designed and an experimental work was conducted to compare the experimental data with the results from the numerical model. In general, a good agreement between the numeral and experimental data was obtained. |
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| Item Description: | Vita. "Major Subject: Mechanical Engineering". |
| Physical Description: | xvi, 208 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 134-138. |