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Magnetocaloric Pumping of Liquid OxygenThe field-induced force density on a magnetic fluid is proportional to the magnetic susceptibility times the gradient of the magnetic field squared. The direction of the force is towards increasing magnetic field (positive gradient). Applying a magnetic field to a magnetic fluid will result in a force from all directions towards the location of peak field. Since the magnetic field is conservative and there are no magnetic monopoles, the net field-induced force on any fluid of constant susceptibly will be zero. The only manner to obtain a nonzero net field-induced force is to vary the susceptibility of the fluid. At the gas/liquid interface of liquid oxygen, the susceptibility varies drastically, and the exploitation of the resultant large net forces. An alternative method of varying the magnetic susceptibility is to vary the temperature of the fluid. The magnetic susceptibility of paramagnetic liquid oxygen obeys the Curie-Weiss law: it is inversely proportional to temperature. By applying a temperature gradient in the presence of a symmetric magnetic field, a nonzero net force results. Much of the theory of the so-called Magnetocaloric Effect has previously been developed for and applied to ferromagnetic fluids, or ferrofluids, but is readily applied to paramagnetic liquid oxygen.
Document ID
Acquisition Source
Kennedy Space Center
Document Type
Other - NASA Tech Brief
Immer, Christopher
(DYNACS Engineering Co., Inc. Cocoa Beach, FL, United States)
Kandula, Max
(DYNACS Engineering Co., Inc. Cocoa Beach, FL, United States)
Lane, John
(DYNACS Engineering Co., Inc. Cocoa Beach, FL, United States)
Youngquist, Robert
(NASA Kennedy Space Center Cocoa Beach, FL, United States)
Date Acquired
August 25, 2013
Publication Date
February 1, 2004
Publication Information
Publication: NASA Tech Briefs, February 2004
Subject Category
Physics (General)
Report/Patent Number
Distribution Limits
Public Use Permitted.
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