High-Magnetic-Field Research and Facilities [Final Report] (1979) / Chapter Skim
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APPLICATIONS
APPLICATIONS
Pages 38-54
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From page 38... ...
power generator in which a hot ionized plasma is passed through a magnetic field, generating power directly. The overall efficiency of such an MHD generator increases as the magnetic-field strength is raised.
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From page 39... ...
CONCLUSIONS We conclude that there are many important, currently developing technologies for which high magnetic fields, in excess of 2 T, are vital to success. In many of these applications, the range from 2 to 10 T has not yet been fully exploited; indeed, in several instances, the achievement of a large working volume is more of a problem at present than higher field strength per se.
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From page 40... ...
As electric power technology developed, it was found that the electric current used to excite the magnet coils could not be increased indefinitely because of resistive heating in the conductor. However, the magnetic field in the coil could be enhanced by inserting a strong magnetic material such as iron.
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From page 41... ...
It should be noted that problems of developing coils with larger volumes are at least as formidable as those connected with increasing field strength. Most current development work on superconducting magnets is funded as part of major technology programs such as fusion and MHD.
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From page 42... ...
The toroidal field is provided by D-shaped superconducting magnets with minor diameters typically one fourth of the major diameter. These machines are potentially capable of providing power plants of several gjgawatts at a competitive capital cost of about $1000/kW.
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From page 43... ...
Consequently, making use of conventional magnets would reduce the efficiency of MHD generators to a level that would render them unattractive for use in central station power generation. On the other hand, electromagnets making use of superconductors for their windings can readily generate magnetic fields in the range of 5-7 T and require hardly any electrical power to maintain these fields.
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From page 44... ...
The MHD combustion studies have indicated that the plant and process would be simplified if one could work with a combustion airstream enriched with oxygen. A possible approach to achieving such enrichment is to use the strong paramagnetism of the oxygen molecule, which enables it to be separated from nitrogen by a high magnetic field (perhaps the main MHD magnet field)
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From page 45... ...
The economic benefits of using superconductive high magnetic fields in central station generators are quite impressive. Not only are the generator losses reduced by 50 percent, but the higher magnetic field allows the frame size to be reduced, lowering the overall cost of the machine appreciably.
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From page 46... ...
has recently been exploring an interesting application of high magnetic fields to heat pumps, another field of energy use. This application is based on the principle of adiabatic demagnetization of paramagnetic materials, which has long been known to low-temperature physicists.
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From page 47... ...
The promise of higher fields has recently stimulated great interest in this subject, which is focused on magnetic separation of much more sophisticated mixtures than ever before. A promising energy application is the removal of pollutants from the cooling system of power plants and also from fossil fuels prior to combustion.
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From page 48... ...
. The improvements brought about by HGMS permit beneficiation of more weakly magnetic ores such as oxidized taconite iron ore and the separation of paramagnetic tourmaline from the tin mineral cassiterite, Sn02.
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From page 49... ...
DEFENSE TECHNOLOGY Ship Propulsion The British Navy substantially advanced superconducting machine technology by providing funds for the development of a 50-HP superconducting solidbrush-switched homopolar dc motor that operated successfully in 1965. The design was expanded to a 3250-HP pump motor that was demonstrated in 1971, and to a 1-MW land-based model of a ship power transmission system in the mid-1970's.
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From page 50... ...
Airborne Electric Power Future combat aircraft may require electrical power levels of tens of megawatts for periods of several seconds. To produce such power, chemical energy stored in propellants may be converted into electrical power by either turboalternators or MHD devices.
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From page 51... ...
36 Mm to = 3coc, X = 357 Mm 119 Mm 48 Mm 30 Mm 3. 57 Mm co = 4coc, X = 268 Mm 89 Mm 36 Mm 22 Mm 2.68 Mm such device is an electron resonance maser; this is an electron-beam tube operating in a uniform magnetic field and emitting coherent radiation at the electron cyclotron frequency, coc or eB/mec, and its harmonics.
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From page 52... ...
The detection of magnetic impurities in solids can be done with increasing sensitivity as the applied magnetic field is increased. So far, this technique has been of value chiefly as a means of studying weak magnetic materials in the laboratory; however, for the first time, the General Electric Company recently applied it in a manufacturing plant.
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From page 53... ...
A further advantage for large machines is that operating power costs can be reduced by using superconducting magnet windings. Accelerator engineers have been reluctant to convert to major superconducting systems until these were shown to be reliable and predictable from an engineering viewpoint.
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From page 54... ...
54 HIGH-MAGNETIC-FIELD RESEARCH AND FACILITIES accelerator unless high fields were used to bend the beams to within a manageable radius at a manageable cost. Finally, high-energy, high-current proton accelerators are being considered as a means of burning used fuel from nuclear reactors, breeding new fissile materials, and producing energy by inducing nuclear reactions on impact of the protons on the radioactive material.
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