Ramjet engine for power generation

• US 6,446,425 B1
• Filed: 06/17/1999
• Issued: 09/10/2002
• Est. Priority Date: 06/17/1998
• Status: Expired due to Term

• Current Assignee: Dresser-Rand Group Incorporated (Siemens AG)
• Original Assignee: Ramgen Power Systems, Inc. (Siemens AG)
• Inventors: Lawlor, Shawn P.
• Primary Examiner(s): Kim, Ted
• Application Number:
  US09/335,867
• Time in Patent Office: 1,181 Days
• Field of Search: 60/390.2, 60/393.4, 60/393.5, 602/701
• US Class Current: 60/768
• CPC Class Codes: F02C 3/14 characterised by the arrangement of the combustion chamber in the plant combustion chambers per se F23R; F02C3/205 takes precedence
• CPC Class Codes: F02C 3/165 the combustion chamber contributes to the driving force by creating reactive thrust
• CPC Class Codes: F02K 7/005 the engine comprising a rotor rotating under the actions of jets issuing from this rotor
• CPC Class Codes: F02K 7/10 characterised by having ram-action compression, i.e. aero-thermo-dynamic-ducts or ram-jet engines
• CPC Class Codes: Y02E 20/14 Combined heat and power generation [CHP]
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A ramjet engine power generator. Supersonic ramjets are provided along a portion of the circumference of a low aerodynamic drag rotor. The rotor is affixed at a central hub to a rotating shaft. The rotor acts as a structural member which transmits to the shaft the thrust generated by the ramjets. In the preferred embodiment, a ramjet inlet captures and compresses an inlet air stream by utilizing the rotor edge profile, the confining strakes which are affixed on the rotor adjacent the thrust module, and an adjacent peripheral and preferably stationary housing sidewall. The compressed air inlet stream provides oxygen for mixing with a fuel, such as natural gas, other suitable hydrocarbons, or hydrogen. The fuel is oxidized in the ramjet combustion chamber(s) to produce expanding combustion gases. Such combustion gases escape by acting against the ramjet outlet throat, adjacent strake structures and the adjacent peripheral housing sidewall, rotating the ramjet at supersonic velocities, and producing shaft energy. A helical strake effectively separates the incoming fuel air mixture from the outgoing combustion gases. In one embodiment, the strake further includes a plurality of cooling orifices which allow passage through the strake of cooling gas, and also reducing boundary layer thickness, thus reducing drag.

Claims

1. An apparatus for generation of power, said apparatus comprising:

(a) an air inlet for supply of combustion air;

(b) a fuel inlet for supply of oxidizable fuel;

(c) a rotor, said rotor having a central axis and adapted for rotary motion thereabout, said rotor constructed of materials having a specific strength commensurate with a selected rotor speed and rotor geometry, said rotor having opposing inlet side and outlet side surfaces, said rotor extending radially outward from said central axis to an outer surface portion having an outer extremity;

(d) a first tight fitting housing adjacent at least a portion of said inlet side surface of said rotor, and a second tight fitting housing adjacent at least a portion of said outlet side surface of said rotor, said first and second housings adapted to reduce aerodynamic drag on said rotor;

(e) a peripheral wall, said peripheral wall

(i) positioned radially outward from

(A) said central axis, and

(B) said outer extremity of said rotor; and

(ii) having an interior surface portion;

(f) one or more ramjets, each of said one or more ramjets comprising a rotating portion located along a portion of said outer extremity of said rotor, said rotating portion cooperating with a portion of said peripheral wall to compress therebetween inlet combustion air;

(g) one or more strakes, each of said one or more strakes provided adjacent to one of said or more ramjets, and at least a portion of each of said one or more strakes extending outward from at least a portion of said outer surface portion of said rotor to a point adjacent said interior surface portion of said peripheral wall;

(h) whereby said one or more strakes effectively separate said compressed combustion air from exhaust gases which are produced as said one or more ramjets

(i) compress inlet air, and

(ii) oxidize fuel supplied thereto,

(iii) generate exhaust gases therefrom, and

(iv) develop thrust to effect rotary motion of said rotor about said axis of rotation.

2. The apparatus as set forth in claim 1, wherein each of said one or more strakes comprises a helical structure extending peripherally from said outer surface portion of said rotor.

3. The apparatus as set forth in claim 2, wherein the number of said one or more helical strakes is N, and the number of said one or more ramjets is X, and wherein N and X are equal.

4. The apparatus as set forth in claim 1 or claim 2, wherein each of said one or more ramjets utilize at least a portion of said inner surface portion of said peripheral wall for decompression of escaping combustion gases.

5. The apparatus as set forth in claim 1, wherein said inner surface portion of said peripheral wall further comprises a wear ring seal, said wear ring seal adapted to effectively seal the interface between each of said one or more strakes and said inner surface portion of said peripheral wall.

6. The apparatus as set forth in claim 1, wherein said outer surface portion of said rotor comprises a plurality of rim segments.

7. The apparatus as set forth in claim 6, wherein at least one of said rim segments is detachably affixed to said rotor.

8. The apparatus of claim 7, wherein said rotor further comprises a plurality of shaped attachment receiving tabs, and wherein each of said rim segments further comprises a plurality of inwardly extending Y-shaped tines, said attachment receiving tabs and said Y-shaped tines adapted for secure interlocking engagement, so as to secure said rim segments to said rotor.

9. The apparatus as set forth in claim 7, wherein said rotor further comprises a plurality of shaped attachment hinges, and wherein each of said rim segments further comprises a plurality of shaped attachment hinges complementary in size and location to said attachment hinge in said rotor, and wherein said rotor and said rim segments are joined by engaging each of their respective hinges into matching alignment, and wherein said apparatus further comprises at least one attachment pin, said attachment pin extending through at least some of said interengaging complementary attachment hinges.

10. The apparatus as set forth in claim 6, wherein each of said rim segments further comprise a cooling air receiving chamber, and wherein each of said cooling air receiving chambers effectively contains therein, for centrifugal compression and ejection therefrom, cooling air provided thereto.

11. The apparatus as set forth in claim 1, wherein said outer surface portion of said rotor further comprises at least one coolable wall, said coolable wall comprising:

(a) an interior cool wall surface,

(b) an outer hot wall surface,

(c) a plurality of cooling passageways having outlets at said outer hot wall surface, said cooling passageways providing a fluid conduit between said cool wall surface and said hot wall surface and adapted to pass therethrough cooling air supplied at said interior cool wall surface, so that said cooling air exits said outlets to provide a thin film of cooling air on said outer surface portion of said rotor.

12. The apparatus as set forth in claim 1, further comprising an air dump passageway for starting each of said one or more ramjets, said apparatus comprising:

(a) an air dump passageway, said air dump passageway communicating with said air inlet and with an outlet dump air location, said air dump passageway defined by a through wall portion in said peripheral wall, and

(b) one or more displaceable valves, each of said one ore more displaceable valves configurable between

(i) a closed position, wherein said one or more displaceable valves forms a seal in said through wall portion of said peripheral wall, and as a result substantially no inlet air escapes to said outlet dump air location, and

(ii) an open position, wherein said valve allows fluid communication between said air inlet and said air dump location via said through wall portion of said peripheral wall, allowing at least a portion of said inlet air to escape through said air dump passageway;

(c) whereby each of said one or more ramjets is able to dump a portion of compressed inlet air through said air dump passageway, to thereby swallow an inlet shock and thereafter effect combustion start.

13. The apparatus as set forth in claim 12, wherein said displaceable valve comprises an annular gate valve, said annular gate valve being operatively located circumferentially along at least a portion of said peripheral wall, and wherein said annular gate valve is positioned radially outward from, and closely adjacent to, said one or more ramjets as each of said one or more ramjets rotates thereby.

15. The apparatus for generating power as recited in claim 1 or claim 14, wherein said apparatus further comprises a heat recovery section, said heat recovery section comprising a combustion gas inlet, and a combustion gas outlet, and a heat exchange section for containing therein a secondary working fluid, said secondary working fluid adapted for circulation to and from said heat recovery section, whereby said hot combustion gas is cooled by recovery of thermal energy in said secondary working fluid.

16. The apparatus as recited in claim 15, wherein said secondary working fluid comprises water, and wherein upon heating of said secondary working fluid, steam is produced.

17. The apparatus as recited in claim 16, further comprising a steam turbine, and wherein said steam is fed to said steam turbine to produce useful work on a steam turbine output shaft.

18. The apparatus as set forth in claim 17, wherein said steam turbine output shaft is operatively connected to a first electrical generator, and wherein said useful work on said steam turbine output shaft turns said first electrical generator to produce electricity.

19. The apparatus as set forth in claim 17, further comprising a second electrical generator, and wherein said shaft work produced by said steam turbine output shaft turns said second electrical generator to produce electric power.

22. The apparatus as set forth in claim 1 or claim 14, wherein at least one material comprising said rotor has a specific strength in excess of 683,220 inches.

23. The apparatus as set forth in claim 1 or in claim 14, wherein at least one material comprising said rotor has a specific strength between 683,220 inches and 1,300,250 inches.

24. The apparatus as set forth in claim 1, or in claim 14, wherein at least a portion of material comprising said rotor has a specific strength of approximately 1,300,250 inches.

25. The apparatus as set forth in claim 1, or claim 14, wherein at least a portion of material comprising said rotor has a specific strength in excess of 1,300,250 inches.

26. The apparatus as set forth in claim 1, or claim 14, wherein at least a portion of material comprising said rotor has a specific strength in the range from about 1,300,250 inches to about 3,752,600 inches.

27. The apparatus as set forth in claim 1, or claim 14, wherein at least a portion of material comprising said rotor has a specific strength of about 3,752,600 inches.

28. The apparatus as set forth in claim 1, or claim 14, wherein at least a portion of material comprising said rotor has a specific strength in excess of 3,752,600 inches.

29. The apparatus as set forth in claim 1, or claim 14, wherein at least a portion of material comprising said rotor has a specific strength between 3,752,600 inches and 15,000,000 inches.

30. The apparatus as set forth in claim 1, or claim 14, wherein at least a portion of material comprising said rotor has a specific strength of about 15,000,000 inches.

31. An apparatus for generating power as set forth in claim 1, or claim 14, wherein said at least one ramjet operates at an inlet velocity M_o of between about Mach 1.5 and Mach 2.0.

32. An apparatus for generating power as set forth in claim 1, or claim 14, wherein said at least one ramjet operates at an inlet velocity M_o of at least Mach 2.0.

33. An apparatus for generating power as set forth in claim 1, or claim 14, wherein said at least one ramjet operates at an inlet velocity M_o of at least Mach 2.5.

34. An apparatus for generating power as set forth in claim 1, or claim 14, wherein said at least one ramjet operates at an inlet velocity M_o of at least Mach 3.0.

35. An apparatus for generating power as set forth in claim 1, or claim 14, wherein said at least one ramjet operates at an inlet velocity M_o between Mach 3.0 and Mach 4.5.

36. An apparatus for generating power as set forth in claim 1, or claim 14, wherein said at least one ramjet operates at an inlet velocity M_o of approximately Mach 3.5.

37. The apparatus of claim 1, or claim 14, wherein said rotor comprises a central disc.

38. The apparatus of claim 37, wherein said central disc is tapered.

39. The apparatus of claim 1, or of claim 14, wherein said rotor comprises a metal matrix composite.

40. The apparatus of claim 39, wherein said metal matrix composite comprises titanium.

41. The apparatus of claim 39, wherein said metal matrix composite comprises silicon carbide.

42. The apparatus of claim 39, wherein said metal matrix composite further comprises silicon carbide filaments.

43. The apparatus of claim 1, or claim 14, wherein said rotor comprises silicon carbide coated carbon fibers embedded in a titanium metal substrate.

44. The apparatus of claim 1, or claim 14, wherein said rotor comprises a carbon fiber epoxy composite.

45. The apparatus of claim 44, wherein said rotor further comprises high strength fiber windings.

46. The apparatus of claim 45, wherein said high strength fiber windings comprise monofilament carbon fibers.

48. The apparatus as set forth in claim 1, or in claim 14, wherein one or more of said strakes further comprises a plurality of cooling gas orifices, said cooling gas orifices adapted to allow cooling gas to pass through said strakes.

14. An apparatus for generating power, comprising:

(a) a support structure, said support structure comprising

(i) a circumferential housing with an inner side surface, and

(i) an oxidant supply conduit, said circumferential housing comprising at least one wall of said oxidant supply conduit;

(iii) fuel supply passageways, said fuel supply passageways adapted to inject an oxidizable fuel into an oxidant contained within said oxidant supply conduit;

(b) a first output shaft, said first output shaft rotatably secured along an axis of rotation with respect to said support structure;

(c) a rotor, said rotor having a central axis and rotatably affixed with said first output shaft for rotation with respect to said support structure, said rotor further comprising a circumferential portion having a plurality of individual rim segments, said rim segments having an outer surface portion, said rotor constructed of materials having a specific strength commensurate with a selected rotor speed and rotor geometry, said rotor further comprising opposing inlet side and outlet side surfaces;

(e) a first tight fitting housing adjacent at least a portion of said inlet side surface of said rotor, and a second tight fitting housing adjacent at least a portion of said outlet side surface of said rotor, said first and second housings adapted to reduce aerodynamic drag on said rotor;

(f) one or more ramjets, said one or more ramjets each

(i) comprising a rotating portion integrally provided as part of said circumferential portion of said rotor, and

(ii) adapted to cooperate with and utilize at least a portion of said inner side surface of said circumferential housing to compress said supplied oxidant and said oxidizable fuel between said rotating portions and said circumferential housing housing; and

(iii) wherein said rotating portion further comprises an outlet nozzle that allows combustion gases formed by oxidation of said fuel to escape, thrusting each of said one or more ramjets tangentially about said axis of rotation of said output shaft;

(e) one or more strakes, wherein one of said one or more strakes is provided for each of said one or more ramjets, and wherein each of said one or more strakes extends outward from at least a portion of said circumferential portion of said rotor to a point adjacent to said inner side surface of said circumferential housing, said strakes effectively separating said incoming inlet air from said escaping combustion gases.

20. The apparatus as set forth in claim 14, wherein each of said one or more ramjets operates at an inlet velocity of at least Mach 3.5.

21. The apparatus as set forth in claim 14, wherein each of said one or more ramjets operates at at least Mach 4.

47. The apparatus of claim 14, wherein said high strength fiber windings comprise kevlar fibers.

49. The apparatus as set forth in claim 14, further comprising a first electrical generator, and wherein wherein said first output shaft is operatively connected to said first electrical generator, and wherein said mechanical work provided at said first output shaft turns said first electrical generator to produce electricity.

50. The apparatus as set forth in claim 14, wherein each of said one or more ramjets operates at an inlet velocity of at least Mach 3.

51. A method of generating power, comprising:

(a) providing one or more ramjet thrust modules peripherally on a rotor which is rotatably secured with respect to an outboard housing having an inner surface, said rotor constructed of materials having a specific strength commensurate with a selected rotor speed and rotor geometry, said rotor having opposing inlet side and outlet side surfaces, said rotor extending radially outward from said central axis to an outer surface portion having an outer extremity;

(b) providing a first tight fitting housing adjacent at least a portion of said inlet side surface of said rotor, and providing a second tight fitting housing adjacent at least a portion of said outlet side surface of said rotor, said first and second housings adapted to reduce aerodynamic drag on said rotor;

(c) supplying to said one or more ramjet thrust modules an airstream containing an oxidant and an oxidizable fuel;

(d) oxidizing said fuel between said one or more ramjet thrust modules and said outboard housing, to

(i) generate combustion gases which escape therefrom, to

(ii) generate a motive force by thrust reaction of said combustion gases escaping from between

(A) each of said one or more ramjet thrust modules, and

(B) at least a portion of said outboard housing;

(e) propelling said one or more ramjet thrust modules at an inlet velocity in excess of Mach 1.0 through said supplied airstream by way of said motive force, said one or more ramjet thrust modules relying on at least a portion of said inner surface of said outboard housing to assist in compression of a portion of said supplied airstream as each of said one or more ramjet thrust modules passes adjacent thereto;

(f) effectively separating inlet air from combustion gases by using one or more strakes along the periphery of said rotor, each of said one or more strakes provided adjacent to one of said or more ramjets, and at least a portion of each of said one or more strakes extending outward from at least a portion of an outer surface portion of said rotor to a point adjacent said inner surface of said outboard housing;

(g) turning an output shaft operatively connected to said one or more ramjet thrust modules;

(h) whereby power is provided at said output shaft.

52. The method as recited in claim 51, wherein the inlet velocity of each of said one-or more ramjet thrust modules is at least Mach 2.5.

53. The method as recited in claim 51, wherein the inlet velocity of each of said one or more ramjet thrust modules is between Mach 2.5 and Mach 4.

54. The method as recited in claim 51, wherein the inlet velocity of said one or more ramjet thrust modules is approximately Mach 3.5.

55. The method as recited in claim 51, wherein said fuel is a selected from the group comprising gaseous hydrocarbon fuels and hydrogen.

56. The method as recited in claim 51, wherein said fuel is essentially natural gas.

57. The method as recited in claim 51, wherein the step of supplying fuel comprises injecting said fuel into a portion of said supplied airstream radially inward of said outboard housing at a point prior to compression of said portion of said supplied airstream between said outboard housing and any one of said one or more ramjet thrust modules.

58. The method as recited in claim 51, wherein said method further comprises the step of generating electricity.

59. The method of generating power as recited in claim 51, wherein said method further includes the step of recovering thermal energy from said combustion gases.

60. The method as recited in claim 59, wherein said thermal energy recovery step comprises transfer of said thermal energy from said combustion gases to a secondary working fluid.

61. The method as recited in claim 60, wherein said secondary working fluid is water, and wherein steam is produced by heating said water.

62. The method as recited in claim 60, wherein said thermal energy recovery step comprises indirect heating of said secondary working fluid by said combustion gases.

63. The method as recited claim 61, further comprising the step of directing said secondary working fluid to a turbine having a working shaft, and generating power by rotation of said turbine by said secondary working fluid, to produce shaft work from said turbine.

64. The method as recited in claim 63, further comprising the step of generating electricity from said shaft work of said turbine.

65. The method as recited in claim 51, further comprising the step of minimizing aerodynamic drag as said one or more thrust modules rotates at supersonic speed.

66. The method as set forth in claim 65, wherein at least a portion of said rotor is confined within a substantially gas tight housing, and wherein said housing is maintained under vacuum to reduce aerodynamic drag on said rotor.

67. The method as recited in claim 65, wherein said step of minimizing aerodynamic drag further comprises the step of maintaining a partial vacuum along a substantial radial portion of said rotor, said substantial radial portion located at said first and said second tight fitting housings.

68. The method as recited in claim 51, wherein said rotor further comprises a plurality of detachable rim segments, said rim segments further comprising ventilatable cooling chambers, and wherein said method further comprises the step of providing cooling air flow to and through said ventilatable cooling chambers.

69. The method as recited in claim 51, wherein each of said one or more ramjet thrust modules are circumferentially spaced apart so as to engage said supplied airstream substantially free of turbulence from the previous passage through a given circumferential location of any one of said one or more ramjet thrust modules.

70. The method as recited in claim 51, wherein the step of supplying fuel comprises injecting said fuel into a portion of said supplied inlet airstream at a point prior to compression of said portion of said supplied airstream between said circumferential wall and any one of said one or more thrust modules.

71. The method as set forth in claim 51, wherein said rotor further comprises a plurality of outer rim segments, at least some of which have at least one coolable wall, said at least one coolable wall comprising:

(a) an interior cool wall surface,

(b) an outer hot wall surface,

(c) a plurality of cooling passageways having outlets at said outer hot wall surface,

(d) said method further comprising the step of supplying a cooling fluid behind said interior cool wall surface, and passing an amount of said cooling fluid outward through said cooling passageways to said outlets, in an amount sufficient to effect film cooling of said outer hot wall surface of said outer rim segments.

72. The method as set forth in claim 51, wherein said one or more stakes further comprises a plurality of through passageways, and wherein the step of supplying cooling fluid further comprises supplying an amount of cooling fluid sufficient to effect film cooling of said one or more strakes via passage of said cooling fluid through said plurality of through passageways.

73. The method as set forth in claim 51, or in claim 72, wherein said one or more stakes further comprises a plurality of orifices, and wherein said method further comprises the step of passing cooling gas through said orifices in an amount sufficient to minimize aerodynamic drag on said one or more stakes.