D0 CC Cryostat Test Cooldown - Cooldown Time [electronic resource].
- Washington, D.C. : United States. Dept. of Energy. Office of Science, 1987.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 10 pages : digital, PDF file
- Additional Creators:
- Fermi National Accelerator Laboratory, United States. Department of Energy. Office of Science, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- The D0 CC Cryostat is to be cold tested with LN₂. Calculations show that the time required for the 12.5 ton stainless steel inner vessel to reach equilibrium is around 5 hours if the vessel is cooled by introducing liquid into a nozzle at the bottom. The heat transfer calculations contain many assumptions. As a result, the vessel will be cooled by spraying LN₂ through a nozzle at the vessel top, providing as fast a cooldown as desired. Although calculations of the bottom-fill cooldown method indicate a reasonable cooldown time, the assumption of uniform gas temperature (absence of stratification) is vital to the analysis and in fast may not be valid. Initially, as liquid is introduced into the bottom of the vessel, it will boil rapidly creating large amounts of cold gas which then cool the walls above. As the vessel bottom cools and LN₂ begins to pool, however, the boiloff rate could decrease significantly. Thus the cold gas assumed in the free convection calculations is not generated. For this reason and in the interest of a speedy cooldown it has been decided to fill the vessel by spraying LN₂ in through a nozzle in the vessel top.
- Report Numbers:
- E 1.99:fermilab-d0-en-107
- Other Subject(s):
- Published through SciTech Connect.
- Funding Information:
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