Table of Contents
Large-scale Cryogenics for Accelerators
Large-scale Cryogenics for Accelerators--Outline
The need for low temperatures on a large scale in accelerators
The need for cryogenic temperatures in cooling superconductors
Some possible refrigerants
Helium phase diagram (Steven W. VanSciver, Helium Cryogenics, p. 54)
The helium liquefaction process
Isothermal compression
Isentropic expansion
Ideal helium process
A real helium compressor
A real helium expander
A simplified real helium cycle Klaus D. Timmerhaus and Thomas M. Flynn, Cryogenic Process Engineering, p.126
A more typical modern helium cycle (but still simplified, from Linde Kryotechnik, AG)
Compressor losses from B. Ziegler, “Second Law Analysis of the Helium Refrigerators for the HERA Proton Magnet Ring,” in Advances in Cryogenic Engineering, Vol. 31, Plenum Press, 1986, p. 693
Cold box losses from B. Ziegler, “Second Law Analysis of the Helium Refrigerators for the HERA Proton Magnet Ring,” in Advances in Cryogenic Engineering, Vol. 31, Plenum Press, 1986, p. 693
Helium cycle efficiency
Getting KW of cooling below 4.2 K
Helium cycle with cold compressor
Heat transfer from the magnets and RF cavities
Cooling modes--surface heat flux
Types of large-scale cryogenic systems presently in operation
Pressurized versus pool boiling
Heat transport through channels--pressurized normal helium in SSC
Heat transport through channels--pressurized normal helium
Heat transport through channels--pressurized superfluid
Superfluid Heat Transport Function (Steven W. VanSciver, Helium Cryogenics, p. 144)
Comparison of apparent thermal conductivities of superfluid and Cu
LHC magnet cooling scheme
Heat transport through channels--superfluid versus forced flow
Pool boiling and 2-phase flow
More about 2-phase helium flow
Fermilab’s magnet cooling scheme
Fermilab’s cryogenic system
Losses during transfer from dewars
Safety issues in large cryosystems
ODH
ODH Analysis
Overpressurization
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Author: tom peterson
Email: tommy@fnal.gov
Home Page: http://tdpc02.fnal.gov/peterson/tom/refmenu.htm
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