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Detailed information on the selected research project
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| Title |
Development of a Numerical Simulation Model for Thermo-Fluid Analysis and Design Optimization of Cryogenic Storage Systems with Zero Boiloff |
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Subjects
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Compression & Liquefaction, Liquid, University Graduate Programs, University Undergraduate Programs
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Investigator/
Organization
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Rahman , M; University of South Florida/Clean Energy Research Center
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Funding
Source(s) |
Florida Solar Energy Center; under contract with:NASA
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| Dates |
Project start date:01-Jan-2002, Project end date:31-Dec-2005 |
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Abstract
The development of a finite-element numerical simulation model for the analyses of fluid flow and heat transfer in zero boil-off (ZBO) cryogenic storage systems is the objective. The model is being used to explore the effects of each design parameter. A numerical simulation was carried out by solving equations for the conservation of mass, momentum, and energy. The physical model equations were discretized using finite-elements and incorporated in the solver of the commercial code FIDAP. |
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Work Significance
Liquid storage of hydrogen has very significant advantage over gaseous or chemical storage because of much lower storage volume and ease of regeneration of the fuel with its demand. Traditional cryogenic storage tanks suffer loss of hydrogen due to boil-off of the cryogen induced by heat leak to the tank from the surrounding environment. In order to control the tank pressure within its structural limits, the stored fluid needs to be bled off periodically. The Zero Boil Off (ZBO) concept has evolved as an innovative means of storage tank pressure control by a synergistic application of passive insulation, active heat removal, and forced mixing within the tank. A cryocooler (with a power supply, radiator, and controls) is integrated into a traditional cryogenic storage subsystem to reject the storage system heat leak. Therefore, the fuel can be stored for a very long time without any loss.
In recent years, a number of efforts have been done toward the guidelines of building cryogenic storage systems, especially with the ZBO concept. Hasting et al. introduced an overview of the efforts in the development of the ZBO storage systems at NASA, showing that the ZBO system has mass advantage over passive storage. Kittel suggested an alternative approach for the long term storage of cryogenic propellants using a re-liquefier, which uses the propellant vapor as the working fluid. Salerno et al. presented a proposed Mars reference mission and the concomitant cryogenic fluid management technology with a combination of both active and passive technologies to satisfy a wide range of requirements. Hofmann presented a theory to boil-off gas-cooled shields for cryogenic storage vessels using analytical method to determine the effectiveness of intermediate refrigeration. Haberbusch et al. developed a design tool for thermally zero boil-off densified cryogen storage system model for space. The model predicts that a ZBO densified liquid hydrogen storage system minimizes the overall storage system mass and volume for nearly the same input power for cooling. Kamiya et al. consecutively presented the development of a large experimental apparatus to measure the thermal conductance of various insulations and used that for the testing of insulation structures. The apparatus could test specimens with dimensions up to 1.2 m diameter and 0.3 m thickness. Different insulation structures, a vacuum multilayer insulation with glass fiber reinforced plastic (GFRP) and a vacuum solid insulation, were tested.Most of the efforts have been done by using analytical approach or simplified calculations, which can be limited to simple geometric design. Numerical simulation using computational fluid dynamics (CFD) has the advantage of modeling complex geometry and loading situations. This report presents a detailed analysis and numerical simulation using finite element method for fluid flow and conjugate heat transfer in a ZBO cryogenic storage system. |
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Supporting Documents
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Document Description
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Project Website
http://cerc.eng.usf.edu/
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