Patent US3736447A successfully refreshed from Google Patents.
US3736447A
Expired / Lapsed
US
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Uniform ionization means for mhd generators
Assignee: General Electric Co
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Filing: 1971-09-27
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Granted: 1973-05-29
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Expires: 1991-09-27
Abstract
Abstract Temperature limitations imposed by available materials require provision of other than purely thermal means for ionizing gas used in hot-gas magnetohydrodynamic (MHD) generators. Efficiency of such generators is markedly reduced by non-uniform ionization. Prior art ionization means, even when adequate, require use of appreciable fraction of length of expensive MHD channel to achieve high and uniform conductivity of gas plasma. Hot, cesiumseeded partially ionized gas passes through large-diameter conduit from source to nozzle feeding MHD channel. Magnetic field in pre-channel nozzle and conduit portions causes current flow in gas between short-circuited electrode pairs or pairs are fed repeated short high-voltage pulses continued by longer lower voltage pulses. Such current flow increases ionization everywhere in gas to desirable high and uniform level. Alternatively, gas not so seeded is ionized by irradiation from nuclear heat source; or gas not ionized is preionized by discharges between first pairs of electrodes, and then fully and uniformly ionized by discharges between later pairs of electrodes.
Inventors
- 👤 B Zauderer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:04
CPC Classifications
H; H02; H02K; H02K44/00; H02K44/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
290 words
In a magnetohydrodynamic generator comprising: a. a source of hot noble gas under pressure connected to b. a refractory insulating channel provided with c. a plurality of pairs of generator electrodes each consisting of a generator anode and a generator cathode located in opposition to each other in opposite walls of the channel, and having individual electrical connections extending through the channel wall to the outside of the channel, and d. a generator magnetic field extending transverse to the axis of flow through the channel and transverse to the line joining a generator anode and a generator cathode of a same pair, the improvement comprising: ionization enhancement means comprising e. a plurality of pairs of ionization electrodes, each pair consisting of a thermionically emissive cathode and an anode opposed to the cathode, forming a path between the anode and cathode for flow of ionized gas orthogonally to a line between the anode and cathode; f. connection means between the anode and the cathode, external to the gas flow path, forming a closed circuit for electron flow from the cathode through the gas to the anode, and back to the cathode through the connection means; g. a voltage source in the said closed circuit to cause the flow of current in the said closed circuit; h. the pairs of ionization electrodes being subdivided along the axis of flow of gas between them, and extending normally to the axis so that the portions of gas path between them extend across substantially the entire gas path, and extending downstream along the axis to a point immediately adjacent to the generator electrodes and extending upstream along the axis to a source of gas having an electron density of at least 1011 per cubic centimeter.
Claim 2
Dependent Claim
290 words
In a magnetohydrodynamic generator comprising: a. a source of hot noble gas under pressure connected to b. a refractory insulating channel provided with c. a plurality of pairs of generator electrodes each consisting of a generator anode and a generator cathode located in opposition to each other in opposite walls of the channel, and having individual electrical connections extending through the channel wall to the outside of the channel, and d. a generator magnetic field extending transverse to the axis of flow through the channel and transverse to the line joining a generator anode and a generator cathode of a same pair, the improvement comprising: ionization enhancement means comprising e. a plurality of pairs of ionization electrodes, each pair consisting of a thermionically emissive cathode and an anode opposed to the cathode, forming a path between the anode and cathode for flow of ionized gas orthogonally to a line between the anode and cathode; f. connection means between the anode and the cathode, external to the gas flow path, forming a closed circuit for electron flow from the cathode through the gas to the anode, and back to the cathode through the connection means; g. a voltage source in the said closed circuit to cause the flow of current in the said closed circuit; h. the pairs of ionization electrodes being subdivided along the axis of flow of gas between them, and extending normally to the axis so that the portions of gas path between them extend across substantially the entire gas path, and extending downstream along the axis to a point immediately adjacent to the generator electrodes and extending upstream along the axis to a source of gas having an electron density of at least 1011 per cubic centimeter.
Claim 3
Dependent Claim
105 words
The improvement claimed in claim 1, further comprising: i. an expansion nozzle having an entry portion and a throat and an expanding portion, j. the entry portion being connected to receive therein said hot noble gas under pressure having an electron density of at least 1011 per cubic centimeter; k. the therein said pairs of ionization electrodes are located in the walls of the entry portion and of the throat and of the expanding portion; and l. the length of the expansion nozzle is such that the time of passage of the said gas through it is less than the ionization relaxation of the gas.
Claim 4
Dependent Claim
77 words
The improvement claimed in claim 2 in which m. the therein said hot noble gas under pressure and having an electron density of at least 1011 per cubic centimeter is seeded with cesium; and n. the source of the herein said gas is connected with the entry portion of the said expansion nozzle by a thermally insulated duct of cross section sufficiently large that the velocity of gas flow through it is not greater than 0.1 Mach.
Claim 5
Dependent Claim
105 words
The improvement claimed in claim 1 in which o. the therein said source of hot noble gas under pressure provides gas having an electron density of less than 1011 per cubic centimeter; p. pairs of preionization electrodes identical with the pairs of ionization electrodes recited in h) of claim 1 are located upstream of the said pairs of ionization electrodes and q. there is applied to each pair of preionization electrodes and to each pair of ionization electrodes a cyclical potential of which one cycle consists of a high potential pulse followed by a lower potential pulse of longer duration than the high potential pulse.
Claim 6
Dependent Claim
62 words
The improvement claimed in claim 1 in which the therein said voltage source g) is provided by the interaction of the ionized gas moving between the ionizing cathode of an ionizing electrode pair and its associated ionizing cathode, wiTh a magnetic field component normal to the direction of motion of the gas and of a line joining the electrodes of a pair.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-28 | 1976-11-27 | 1977-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-28 | 1980-11-27 | 1981-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-28 | 1984-11-27 | 1985-05-29 | $7700.00 | Window Closed / Lapsed |