초록 ▼

The invention relates to recirculation flow combustors having a generally curved recirculation chamber and unobstructed flow along the periphery of the boundary layer of the vortex flow in this chamber, and methods of operating such combustors. Such combustors further have a border interface area of

The invention relates to recirculation flow combustors having a generally curved recirculation chamber and unobstructed flow along the periphery of the boundary layer of the vortex flow in this chamber, and methods of operating such combustors. Such combustors further have a border interface area of low turbulence between the vortex flow and the main flow in the combustor, in which chemical reactions take place which are highly advantageous to the combustion process, and which promote a thermal nozzle effect within the combustor. A combustor of this type may be used for burning lean and super-lean fuel and air mixtures for use in gas turbine engines, jet and rocket engines and thermal plants such as boilers, heat exchanges plants, chemical reactors, and the like. The apparatus and methods of the invention may also be operated under conditions that favor fuel reformation rather than combustion, where such a reaction is desired.

대표청구항 ▼

The invention claimed is: 1. A combustor comprising: a reactor; an inlet for admitting a main flow of fluid to said reactor; an exit for discharging heated fluid from said reactor; said reactor positioned between said inlet and said exit and comprising a main flow zone, through which a majority o

The invention claimed is: 1. A combustor comprising: a reactor; an inlet for admitting a main flow of fluid to said reactor; an exit for discharging heated fluid from said reactor; said reactor positioned between said inlet and said exit and comprising a main flow zone, through which a majority of said main flow passes along a main flow path, and a recirculation zone, through which a lesser portion of said main flow passes; wherein said recirculation zone is defined in part by a wall having an interior surface curved in one direction in a substantially continuous manner and running from a take off point proximate to said exit to a return point proximate to said inlet, said interior surface being shaped and positioned with respect to said main flow path in such a manner as to divert part of the fluid in said main flow path at said take off point to form a recirculation vortex flow in said recirculation zone during the operation of said reactor; and wherein said interior surface is further characterized by a lack of discontinuities so as to cause substantially undisturbed movement of a boundary layer along the periphery of said recirculation vortex flow. 2. The combustor of claim 1, wherein the volume of said recirculation zone is no less then the volume of said main flow zone, in the operating mode in which said reactor functions as a combustion chamber. 3. The combustor of claim 1, wherein the volume of said recirculation zone is no less than the double volume of said main flow zone, in the operating mode in which said reactor functions as a reformer. 4. The combustor of claim 1, wherein the volume of fluid entering said recirculation zone compared to the fluid discharged at said exit is no less than seven percent in the operating mode in which said reactor functions as a combustion chamber. 5. The combustor of claim 1, wherein the volume of fluid entering said recirculation zone compared to the fluid discharged at said exit is no less then ten percent in the operating mode in which said reactor functions as a reformer. 6. The combustor of claim 1, wherein the fluid within said boundary layer has a degree of turbulence of less than 0.2. 7. The combustor of claim 6, wherein said degree of turbulence is between 0.008 and 0.01. 8. The combustor of claim 1, wherein the direction of said recirculation flow at said take off point is at an angle of between 15 and 100 degrees to the direction of said main flow path at said take off point. 9. The combustor of claim 1, wherein the direction of said recirculation flow at said return point is at an angle of between 85 and 175 degrees to the direction of said main flow path at said return point. 10. The combustor of claim 1, wherein the ratio of the velocity of said recirculation vortex flow in the area proximate said inlet but outside of said boundary layer to the velocity of said main flow entering said main flow zone is in the range of no less than 1.4:1, in the operating mode in which said reactor functions as a combustion chamber. 11. The combustor of claim 1, wherein the ratio of the velocity of said recirculation vortex flow in the area proximate said inlet but outside of said boundary layer to the velocity of said main flow entering said main flow zone is in the range of no less then 2:1, in the operating mode in which said reactor functions as a reformer. 12. The combustor of claim 1, wherein said boundary layer has a depth of approximately 1 mm when said heated fluid at said exit has a temperature of approximately 1100째 C. 13. The combustor of claim 1, wherein said boundary layer has a depth of approximately 2 mm when said heated fluid at said exit has a temperature of approximately 800째 C. 14. The combustor of claim 1, wherein said boundary layer has a depth greater than the diameter of the central core of recirculating fluid in said recirculation vortex flow when said heated fluid at said exit has a temperature in the range of 380-420째 C. 15. The combustor of claim 1, wherein the fluid within said recirculation vortex flow moves in layers and said layers are not substantially mixed radially within the vortex. 16. The combustor of claim 15, wherein heat energy is transferred from inner ones of said layers to outer ones of said layers. 17. The combustor of claim 1, wherein a high temperature relative to other temperatures within said reactor exists at the intersection of said peripheral vortex flow and said main flow passing through said inlet, and said peripheral vortex flow is moving in the same direction as said main flow after said main flow passes through said intersection, forming an interface layer between said peripheral vortex flow and said main flow, and wherein heat energy is transferred from the fluid in said peripheral vortex flow through said interface layer and into the fluid in said main flow zone. 18. The combustor of claim 17, wherein the fluid passing through said inlet, in the surface area of said fluid proximate to said interface layer, is fired by contact with said interface layer and acts as a pilot flame for the combustor. 19. The combustor of claim 17, wherein there is an absence of appreciable turbulent mixing between the fluid in said main flow and the fluid in said peripheral vortex flow. 20. The combustor of claim 17, wherein said interface layer causes a thermal nozzle to be established and maintained in said main flow zone. 21. The combustor of claim 17, wherein both combustion and fuel reformation take place within said interface layer where said interface layer meets with said main flow, and said combination of combustion and reformation is maintained during said operation of the combustor. 22. The combustor of claim 20, wherein the cross-sectional area of said exit is no more than 2.2 times the cross-sectional area of said inlet. 23. The combustor of claim 1, wherein, to change into the operating mode in which said reactor functions as a reformer, said inlet cross-sectional area is reduced relative to said inlet cross-sectional area employed in the operating mode in which said reactor operates as a combustion chamber. 24. A method of reacting fuel in a combustor, said combustor comprising a reactor; an inlet for admitting a main flow of fluid to said reactor; an exit for discharging heated fluid from said reactor; said reactor positioned between said inlet and said exit and comprising a main flow zone and a recirculation zone, said method comprising the steps of: passing a majority of said main flow in a path along said main flow zone; passing a lesser portion of said main flow in a path through said recirculation zone, so as to form a recirculating vortex flow that returns a portion of the fluid in said recirculation zone to an area proximate said inlet; causing a boundary layer of recirculating fluid to flow along the interior wall surface of said recirculation zone without substantial turbulence; causing the peripheral portion of said recirculating vortex flow to intersect said main flow in an area proximate said inlet, wherein, said peripheral flow has a higher velocity than said main flow; said peripheral flow, following the area of said intersection, is moving in approximately the same direction as said main flow; mixing said peripheral flow and said main flow by diffusion, and not by substantial mechanical mixing; thereby forming an interface layer between said main flow and said peripheral flow and causing a substantial transfer of heat energy from the fluid in said peripheral flow through said interface layer and into the fluid in said main flow zone. 25. The method of claim 24, wherein the volume of fluid entering said recirculation zone compared to the fluid discharged at said exit is no less than seven percent in the operating mode in which said reactor functions as a combustion chamber. 26. The method of claim 24, wherein the volume of fluid entering said recirculation zone compared to the fluid discharged at said exit is no less than ten percent in the operating mode in which said reactor functions as a reformer. 27. The method of claim 24, wherein said boundary layer of recirculating fluid flow along said interior wall surface of said recirculation zone has a degree of turbulence of less than 0.2. 28. The method of claim 27, wherein said boundary layer of recirculating fluid flow along said interior wall surface of said recirculation zone has a degree of turbulence of between 0.008 and 0.01. 29. The method of claim 24, wherein the ratio of said higher velocity of said peripheral vortex flow to the velocity of said main flow entering said main flow zone is in the range of no less than 1.4:1, in the operating mode in which said reactor functions as a combustion chamber. 30. The method of claim 24, wherein the ratio of said higher velocity of said peripheral vortex flow to the velocity of said main flow entering said main flow zone is in the range of no less than 2:1, in the operating mode in which said reactor functions as a reformer. 31. The method of claim 24 further comprising causing the fluid within said recirculation vortex flow to move in layers, wherein said layers are not substantially mixed radially within the vortex. 32. The method of claim 24, wherein heat energy is transferred from inner ones of said layers to outer ones of said layers. 33. The method of claim 24 further comprising causing the fluid entering through said inlet, in the surface area of said fluid proximate to said interface layer, to be fired by contact with said interface layer and thereby acting as a pilot flame for the combustor. 34. The method of claim 24 further comprising mixing the fluid in said main flow with the fluid in said peripheral vortex flow without causing appreciable turbulence. 35. The method of claim 24 further comprising causing a thermal nozzle to be established and maintained in said main flow zone. 36. The method of claim 24 further comprising causing both combustion and fuel reformation to take place within said interface layer, and maintaining said combination of combustion and reformation during the operation of the combustor. 37. The method of claim 24 further comprising changing the operating mode in which said reactor functions as a combustion chamber, to an operating mode in which said reactor functions as a reformer, by reducing the cross-sectional area of said inlet.