S.A. Sherif – WHEC2022 – 23rd World Hydrogen Energy Conference
Name Prof. S.A. Sherif
Affiliation University of Florida
Department of Mechanical and Aerospace Engineering
Gainesville, Florida, USA
Presentation Title Liquid Hydrogen Storage in Microgravity
Abstract Cryogens such as liquid hydrogen are frequently stored over long periods of time particularly in space applications. The operating conditions of cryogenic storage systems are strongly influenced by several factors including heat leak. Cryogens are stored at temperatures close to their respective boiling points. As a result, any addition of energy could lead to the vaporization of a portion of the liquid cryogen. In the absence of gravity, gaseous cryogens could form a vapor bubble, the shape and location of which are not known a priori. The boil-off losses associated with the storage, handling, and transportation of cryogens can result in severe losses. Heat leak causes an increase in the internal pressure of the dewar. Several mechanisms influence the size and position of the vapor bubble in the dewar. Understanding these mechanisms is important to designing storage vessels under optimum conditions and also to the development of cryogenic transfer systems. The work upon which this presentation partially reports aimed at investigating some of the fluid physics observed in a cryogenic dewar under microgravity. The objective is to quantify changes in the storage pressure and temperature and the amount of boil-off observed in a typical dewar under microgravity conditions.
Biographical
Sketch
Dr. S.A. Sherif is a tenured Professor of Mechanical and Aerospace Engineering and is the Founding Director of the Wayne K. and Lyla L. Masur HVAC Laboratory, the Director of the Industrial Assessment Center and the Director of the Mobile Energy Laboratory at the University of Florida. He served as Co-Director of the Southeastern Center for Industrial Energy Intensity Reduction at the University of Florida (2009-2013). He also served on the faculties of the University of Florida (1991-present), University of Miami (1987-1991), and Northern Illinois University (1984-1987). He is a Life Fellow of ASME, a Life Fellow of ASHRAE, a Fellow of the Royal Aeronautical Society, and an Associate Fellow of AIAA. He served as Technical Editor of the ASME Journal of Thermal Science and Engineering Applications (2014-2019), Technical Editor of the ASME Journal of Solar Energy Engineering (2020-2025), and as Subject Editor of the International Journal of Hydrogen Energy (2005-2011). He has also served as Subject Editor, Associate Editor, or Editorial Board Member of 30 other journals. He has one book, more than 400 publications, and two US patents.

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