Patent Number: 
Section: description

FIG. 1 illustrates an inlet annular passage assembly 10 which is provided upstream of a gas flow turbine 12. The assembly 10 includes an outer flow conduit 14 and an internal member 15. The outer flow conduit 14 preferably comprises a cylindrical duct having an internal superconducting magnetic member 16 and also includes means to generate an electron beam commonly referred to as an electron beam gun 22. The internal member 15 preferably comprises a cylinder also having an internal super conducting magnetic member 17 and an electron beam gun 18. In combination the duct and the internal member form an unobstructed cylindrical flow passageway 20. The inner diameter of the duct 14 substantially corresponds to the diameter of the flow passage at the inlet of the turbine 12. The internal and the external walls defining the annular passageway 20, both include opposing slots which direct the electron beams 24 preferably in a spiral path relative to the annular passageway 20. The effect of this configuration is to achieve a flat profile of the electron distribution across space like a electrically enhanced curtain of conductivity that spirals down the flow path similar to an auger, thread or a water screw. This enhanced curtain is the conductor through which current flows and interacts with a radial B-field, i.e., a radial magnetic field. A power extraction load 26 is put across the length of the annular passage assembly by means of a power extraction device. This device could include electrodes at the inlet and outlet of the flow conditioning assembly which pass a current through the spiral curtain of conductivity in the flow path. The pitch or slope of the electron beam spiral can vary. The thread angle should be from about 0.5 to about 5 degrees, and preferably about three degrees. The lower the angle, the more turns that would be achieved. Theoretically, the tighter the turns the higher the energy extraction that would be available. The interaction of the magnetic field and the current in the spiral curtain of conductivity, results in a retardation of the flow and in power extraction by the power extraction circuit. The current has a tangential Jtheta and a axial Jz component. Jtheta times B represents a force which retards the axial velocity. Jzxc3x97B causes a swirl in the flow. The MHD device of the present invention can be used with any standard turbine in order to increase the flight mach number range of the vehicle. The invention resides in the apparatus using spiral electron beam pathways (i.e. a helical curtain of electrons in the form of a helix) to induce conductivity in the gas flow, and subsequently to subject this to a magnetic field to condition the flow in a gas turbine. It is also novel to use this method to extract power and utilize it elsewhere in the system to increase the total power and engine efficiency. The electrical load can be tailored in order to vary the power which is extracted from the inlet flow. Thus, the method allows for a variable power extraction without requiring a variable inlet geometry. If the circuit is open the e-beam guns can still run without substantially affecting the flow energy. However the load can be varied to vary the amount of energy that is extracted without requiring the apparatus geometry to be changed. As shown in FIG. 2, the length of the extraction device 30 corresponds roughly to the diameter of the engine turbine 32, or is slightly smaller. For example, if the diameter of the turbine is around three feet, then the length of the extraction device is around 2-3 feet, preferably 2.5 feet assuming about a three-degree spiral that results in five winds. The inner diameter of the outer magnet plus the electron curtain generator corresponds to the outer diameter of the turbine flow path. The outer diameter of the inner magnet plus the electron curtain generator is close to the hub diameter of the turbine inlet. Suitable electron beam generators include those available from Kimball Physics, Inc, of Wilton, N.H. The magnets used in the extraction device are superconducting, lightweight magnets used for aircraft construction. A cryogenic fluid is used in order to provide for cooling of the magnet. The gas turbine inlet guide vanes typically comprise ferrous super alloys and are a standard configuration for flow straightening. A device 34 can be used for power management so as to reroute power extracted using the MHD extraction device 30 to an auxiliary power unit 36. MHD accelerators 38 can be used subsequent to the turbine engine or turbojet. An ionized gas generator 40 could also be subjected to the power management device 34. The power extraction electronics varies the amount of current, which will flow as a function of the impedance of the power extraction circuit. The impedance can be optimized to extract a optimum amount of power or to extract something less than that. The power extraction device in accordance with the present invention mounts to the inlet of the turbine and will add about 2.5 feet length. It is envisioned that it will be used at very high altitudes and high speeds. Another point of novelty of the invention is that it enables a turbine to be used in its customary configuration at low altitudes and/or low speeds. Thus, in particular for take-off and landing the device doesn""t need to be used to add power back in to the drive system. Use of the device can be limited to flight regimes where the temperature limitation of the turbine is reached. At this point, the device can be activated, and operation can be continued at a higher mach number. While in accordance with the patent statutes the best mode and preferred embodiment have been set forth, the scope of the invention is not limited thereto, but rather by the scope of the attached claims.