Abstract:
An annular fluid distribution device ( 20 ) for distributing fluid into a gaseous flow ( 14 ), that includes: a first fluid distribution manifold ( 30 ) having a first fluid inlet and first fluid outlets ( 24 ), wherein the first fluid outlets inject a first fluid into the gaseous flow; and a second fluid distribution manifold ( 32 ), having a second fluid inlet and second fluid outlets ( 26 ), wherein the second fluid outlets inject a second fluid into the gaseous flow. The second fluid manifold is isolated from the first fluid distribution manifold, and the first fluid outlets and the second fluid outlets are disposed on a common fluid outlet plane ( 43 ).

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates in general to turbine engines, and, more particularly, to a turbine fluid distribution ring for injecting fluid into a gaseous fluid flow in a manner that permits control of the fluid profile within the gaseous fluid in both the circumferential and radial directions. 
       BACKGROUND OF THE INVENTION 
       [0002]    Environmental regulations may limit the amount of NOx emitted from turbine engines. One known manner for reducing NOx emissions is to mix the compressed air used for combustion with fuel before the air enters the primary combustion zone. Such premixed fuel burns cleaner than combustion fuel that is not premixed so as to reduce the amount of NOx generated. In addition to the NOx reduction benefit, premixed combustion air can assist in the management of the dynamic forces during combustion. In particular, when the primary combustion zone is provided with a air/fuel premixture, a more stable, controlled and predictable combustion occurs. As a result, the potential for high frequency acoustic combustion forces and their associated dangers are minimized. 
         [0003]    A fuel injector assembly can be provided for distributing fuel into the compressed air flow upstream of the main combustor portion of the turbine. In one prior design, fuel is injected into the compressed air stream using a ring-type assembly as shown in  FIG. 1 . Such a fuel ring may be disposed within a turbine combustor at a location upstream in the gaseous fluid (i.e. airflow) from combustor burners, as shown in  FIG. 2 . While such fuel rings have permitted improved control of NOx production and dynamic forces when compared to earlier systems, the fuel rings permit only minimal control of the fuel profile within the gaseous fluid flow. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    The invention is explained in the following description in view of the drawings that show: 
           [0005]      FIG. 1  is an isometric view of a prior art fuel ring assembly. 
           [0006]      FIG. 2  is a cross-sectional view of the combustor section of a turbine engine showing the position of a fuel ring assembly. 
           [0007]      FIG. 3  is an isometric view of an annular fluid distribution device. 
           [0008]      FIG. 4  is cross section A-A of  FIG. 3 , showing two independent passageways and a fluid outlet leading from one of the independent passageways. 
           [0009]      FIG. 5  is cross section B-B of  FIG. 3 , showing two independent passageways and a fluid outlet leading from another independent passageway. 
           [0010]      FIG. 6  is a schematic view that depicts how outlets of the fuel ring of the present invention may be positioned to deliver fuel to associated burners. 
           [0011]      FIG. 7  is a cross section of a fuel ring depicting annular covers. 
           [0012]      FIG. 8  is a side view of a fuel ring showing an annular cover. 
           [0013]      FIG. 9  is a side view of a fuel ring showing a cover for each fluid outlet. 
           [0014]      FIG. 10  is a partial side elevational view of the embodiment of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    The inventors of the present invention have innovatively conceived of a structure that will permit greater control of the profile of a liquid injected into a gaseous fluid flow by permitting adjustment of the fuel both in the radial direction and in a circumferential direction, in order to reduce NOx emissions and combustion dynamics. 
         [0016]      FIG. 1  is a fuel ring  10  as known in the art.  FIG. 2  shows the position of the fuel ring  10  of  FIG. 1  in the combustor section  12  of a turbine engine. Arrows  14  depict the flow of gaseous fluid, typically compressed air, as it flows past the fuel ring  10 , reverses path and flows through burners  16  prior to entering a combustion chamber  18 . 
         [0017]      FIG. 3  is a view of an improved annular fluid distribution device  20 , and a characteristic annular axis  22  of the annular fluid distribution device  20 . The annular fluid distribution device  20  could be located in the combustor section  12  of a turbine engine in a manner similar to the fuel rings of the prior art. Attachment legs are known to those of ordinary skill in the art, as are ways to connect fluid supply lines to the fluid distribution device. For sake of clarity these are not shown. The annular distribution device includes first fluid outlet  24  and second fluid outlet  26 . These fluid outlets,  24 ,  26 , are the openings through the outer surface  28  of the annular fluid distribution device  20 . It can be seen in this embodiment that there are several fluid outlets,  24 ,  26 , and these outlets are through the surface toward the interior of the annular distribution device. 
         [0018]      FIG. 4  is cross section A-A of the annular fluid distribution device  20  of  FIG. 3 , taken across the longitudinal axis  22 , at first fluid outlet  24 . A first distribution manifold  30  distributes fluid to all first fluid outlets  24 . A second distribution manifold  32  distributes fluid to all second fluid outlets  26  (shown in  FIG. 5 ). In this embodiment the first distribution manifold  30  and second distribution manifold  32  are separated by a common dividing wall  34 . A first fluid outlet duct  36  connects the first distribution manifold  30  to a first fluid outlet  24 . The first fluid outlet duct  36  may be made of a first fluid outlet duct inner section  38 , and a first fluid outlet duct outer portion  40 , where the first fluid outlet duct inner section  38  permits fluid to travel from the first distribution manifold  30  to the first fluid outlet duct outer section  40 , which in turn permits fluid communication to the first fluid outlet  24 . 
         [0019]    The centers  44  of the first fluid outlets  24  and the second fluid outlets  26  reside essentially on a common outlet plane, depicted by line  43 . A fluid traveling through the first fluid outlet duct outer portion  40  takes the shape of the first fluid outlet duct outer portion  40  through which it is traveling, and is characterized by a first fluid flow longitudinal axis  42  at the moment it passes through the center  44  of the first fluid outlet  24 . It is understood that the direction of the flow will subsequently change as the fluid is redirected by the gaseous flow into which it is injected. In this embodiment the first fluid outlet longitudinal axis  42  is depicted as being parallel to the fluid outlet plane  43 , and thus the outlet angle α between the first fluid flow longitudinal axis  42 , and common outlet plane  43 , is zero for every outlet  24 . However, a multitude of outlet angles α may be employed, depending on the requirements, and all angles are intended to be within the scope of this invention. Further, outlet angle α may vary from one first fluid outlet  24  to another first fluid outlet  24 . 
         [0020]      FIG. 5  is a cross section at B-B of the annular fluid distribution device  20  of  FIG. 3 , taken across the longitudinal axis  22 , at second fluid outlet  26 . A first distribution manifold  30  distributes fluid to all first fluid outlets  26  (as discussed above). A second distribution manifold  32  distributes fluid to all second fluid outlets  26 . Common dividing wall  34  separates the first distribution manifold  30  and the second distribution manifold  32 . The second fluid outlet  26  may comprise a second fluid outlet duct  46  that connects the second distribution manifold  32  to a second fluid outlet  26 . The second fluid outlet duct  46  may be made of a second fluid outlet duct inner section  48 , and a second fluid outlet duct outer portion  50 , where the second fluid outlet duct inner section  48  permits fluid to travel from the second distribution manifold  32  to the second fluid outlet duct outer section  50 , which in turn permits fluid communication to the second fluid outlet  26 . 
         [0021]    A fluid traveling through the second fluid outlet duct outer portion  50  takes the shape of the second fluid outlet duct outer portion  50  through which it is traveling, and is characterized by a second fluid flow longitudinal axis  52  at the moment it passes through the center  44  of the second fluid outlet  24 . In this embodiment the second fluid outlet longitudinal axis  52  is depicted as being parallel to a fluid outlet plane  42 , and thus the outlet angle β between the second fluid flow longitudinal axis  52 , and common outlet plane  43 , is zero for every outlet  24 . However, a multitude of outlet angles β may be employed, depending on the requirements, and all angles are intended to be within the scope of this invention. Further, outlet angle β may vary from one second fluid outlet  26  to another second fluid outlet  26 . 
         [0022]    The annular fluid distribution device  20  embodiment depicted in the figures shows two distribution manifolds. However, the inventors recognize that more than two distribution manifolds could be used, and annular fluid distribution devices with any number of distribution manifolds are envisioned, and intended to be within the scope of this disclosure, so long as there are at least two distribution manifolds. 
         [0023]    In a less uniform embodiment, the inventors envision an annular fluid distribution device  20  where all centers  44  are on the common outlet plane  43 . This leaves open the possibility that every outlet angle, whether α or β, is unique in the fluid distribution device  20 . Embodiments grow more uniform on the other end of the scale as the number of common outlet angles, whether α or β, grows. For example, if two first outlet angles α are the same, and all other outlet angles, whether α or β are different, then the outlet angles are more uniform. An even more uniform embodiment may provide for all first outlet angles α to be the same. As uniformity grows, an embodiment may provide for all first outlet angles α to be the same, and all second outlet angles β to be the same, though α and β may be different. The most uniform embodiment would provide for all outlet angles, α and β to be the same. 
         [0024]    In addition, in the embodiment shown it can be seen that the first fluid outlet longitudinal axes  42  and the second fluid outlet longitudinal axes  52  may merge at a common point  54  (see  FIG. 3 ). However, the present inventors envision a variety of embodiments. On the less uniform end are embodiments with no common point, such that each longitudinal axes  42 ,  52 , intersects no other longitudinal axis  42 ,  52 . There may be one common point  54 , where less than of all the longitudinal axes  42 ,  52  intersect. For example, there may be a common point where only two longitudinal axes intersect, and the rest of the longitudinal axes  42 ,  52 , intersect no other longitudinal axis  42 ,  52 . Embodiments may have multiple common points with varying number of longitudinal axes  42 ,  52  involved. For example, there may be two (or more) common points with two (or more) longitudinal axes  42 ,  52  per point, leaving the remaining axes  42 ,  52 , free of any common points. A very uniform embodiment, such as that depicted in the figures, depicts one common point  52 , where all axes  42 ,  52  intersect. Finally, this common point  52  may be within the common outlet plane  43 , as depicted in the figures. The common point  54  may be at the center of the annular fluid distribution device  20  as is depicted in the figures, or it may not be at the center, while still being in the common outlet plane  43 . The common point  54  may also not be disposed in the common outlet plane  43 , but may be at a point in the gaseous flow upstream or downstream of the common outlet plane  43 , and may or may not coincide with the center of the annular fluid distribution device  20 . 
         [0025]    The fluid outlets themselves can be disposed in an alternating pattern, (i.e.  24 ,  26 ,  24 ,  26  etc), or may be otherwise grouped. For example, there may be several first fluid outlets in order, and then several second fluid outlets in order, (i.e.  24 ,  24 ,  24 ,  24 ,  26 ,  26 ,  26 ,  26 ). Any number of patterns of outlets is possible, and all are intended to be within the scope of this invention. 
         [0026]    Further, any outlet angle is acceptable so long as it can be manufactured. For example, the outlet angle may inject the fluid into and against the gaseous flow direction, at any angle. It may inject the fluid into and with the gaseous flow direction, at any angle. Finally, it may inject the fluid into the gaseous flow perpendicular to the gaseous flow direction. Also, it is envisioned that some not all outlets inject fluid with, against, or perpendicular to the flow. For example, if the annular fluid distribution device  20  is not disposed perpendicular to the flow, but all longitudinal axes  42 ,  52 , point to a common point in the common outlet plane  43 , then some outlets may inject the fluid into and against the gaseous flow direction, some may inject the fluid into and with the gaseous flow direction, and some may inject the fluid perpendicular to the gaseous flow direction. Even more variations can be envisioned when the longitudinal axes  42 ,  52  do not point to a common point, such that each axis could inject into the gaseous flow at an angle different than all other axes, and all such embodiments are intended to be within the scope of the invention. 
         [0027]    As a result of the range of configurations available, it is clear that the depth of penetration of the first fluids into the gaseous fluid can be controlled independently, as can the depth of penetration of the second fluids into the gaseous fluid, using this annular fluid distribution device. The amount of penetration of the first fluid into the gaseous fluid determines where the first fluid will be disposed once the first fluid arrives at the combustor, and likewise with the second fluid. Thus, the annular fluid distribution device  20  can be designed to direct the fluids such that they will arrive at a desired location in the downstream combustor. In particular, the annular fluid distribution device  20  can be designed to direct the fluids to burners disposed in the combustor. 
         [0028]    For a given location and orientation of the fuel ring, the depth of penetration can be controlled on a per-outlet basis by configuring the angle α, β of the fluid outlet  24 ,  26 , the outlet diameter, and the pressure in the manifold  30 ,  33 . For example, it can be seen in  FIGS. 4 and 5  that a diameter of the first fluid outlet  24  is different than the diameter of the second fluid outlet  26 . As a result, given equal flow rates into the manifolds, first fluid exiting the first fluid outlet  24  would penetrate further into the gaseous flow than would a second fluid exiting from the second fluid outlet  26 . Another example would include increasing the pressure in one manifold over another, while keeping the diameters of the first fluid outlets  24  and second fluid outlets  26  the same. A final example could vary both the pressure in the manifolds as well as the outlet configurations. 
         [0029]    Depth of penetration can also be controlled by group. For instance, groups of first fluid outlets may be configured together, and likewise with second fluid outlets. The embodiment depicted in the figures, where all α and β angles are zero, and there is a common point in common outlet plane  43  at the center of the annular fluid distribution device  20 , has proven to be especially advantageous to the inventors. As discussed in more detail below, such a configuration permits the first fluid from all first fluid outlets  24  to penetrate the gaseous flow a first depth, and the second fluid from all second fluid outlets  26  to penetrate the gaseous fluid a second different depth, all without the gaseous fluid seeing any new or changed structure from prior fuel ring configurations, and because there is no additional structure, there is advantageously no additional disturbance to the gaseous fluid flow. 
         [0030]    The inventive design further permits a great deal of flexibility in the design and operation of the gas turbine engine. For example, several different types of fluids can be injected into the gaseous fluid using this annular fluid distribution device. Fuel can be used, oil can be used, and steam can be used. Further, it is possible to use one fluid in the first distribution manifold  30 , and a different fluid in the second distribution manifold  32 . For example, when transitioning from fuel to oil, an operator could leave fuel in the first distribution manifold  30 , and transition the fluid in the second distribution manifold  32  from fuel to oil. As a result there would be a steady supply of fuel to the burners from the first fluid outlets  24 , while the fluid from the second fluid outlets  26  gradually transitions from fuel to oil. Then the fuel in the first distribution manifold  30  could likewise be transitioned from fuel to oil, such that the burners would, from beginning to end, see a gradual transition from fuel to oil. Even finer control of the transition is possible by controlling the pressure of the fluid in a manifold as the oil is introduced, for example, from low to high, such that the introduction of oil into the gaseous fluid is even more gradual. Other fluids, such as steam, could also be injected into the gaseous flow using this annular fluid distribution device. 
         [0031]    By varying the pressure and/or the fluid outlets themselves, the amount of penetration of the fluid into the gaseous stream can be controlled. The pressure ratios will determine the radial biasing of the fuel in the gaseous flow. For example, under relatively lower pressure, the fuel penetration may be limited, resulting in a rich mixture of fuel at locations radially outward in the gaseous flow, and a lean mixture at locations radially inward in the gaseous flow. Conversely, with higher relative pressures, fuel penetration into the gaseous stream can be increased, resulting in a richer mixture radially inward in the gaseous flow, and a lean mixture radially outward in the gaseous flow. Each group can be independently controlled, such that one group may penetrate the gaseous fluid further than another group. 
         [0032]    As also noted earlier, the fluid outlets may alternate, or may be grouped in any number of patterns. The pattern chosen will determine the circumferential biasing of the fuel in the gaseous flow. For example, several first fluid outlets may be grouped together, and the pressure in the first fluid manifold may be increased. As a result, more of the first fluid would be delivered to the gaseous fluid in the region of the first fluid outlets than would be delivered to the gaseous flow in the region of the second fluid outlets. This circumferential biasing, together with the radial fuel biasing permitted by this invention, allow control of the fuel profile in the gaseous flow to an extent not possible before. 
         [0033]    The inventors recognize advantages of several possible configurations of radial and circumferential biasing. Alternating the outlets and, for example, and varying the pressure in the manifolds, may result in a highly homogenous fuel profile in the gaseous flow.  FIG. 6  depicts a highly schematic view of a combustor configuration that specifically benefits from grouping several outlets from the same manifold together. In a combustor where, for example, burners are downstream in the gaseous fluid from the annular distribution ring, are grouped into stages, and disposed at the same radial distance from the combustor&#39;s longitudinal axis, for example stage A burners  56 , and stage B burners  58 , a number of first fluid outlets  24  can be grouped together into a first outlet group  60  and positioned in the gaseous flow upstream of the stage A burners  56 , and a number of second fluid outlets  26  can be grouped together into a second outlet group  62  and positioned in the gaseous flow upstream of the stage B burners  58 . There may be as many first fluid outlet groups  60  as there are stage A burners  56 , and each first fluid outlet group  60  may be associated with a specific stage A burner  56 . Likewise, there may be as many second fluid outlet groups  62  as there are stage B burners  58 , and each second fluid outlet group  62  may be associated with a specific stage A burner  58 . By positioning of the groups the inventors mean positioning of the outlet groups in whatever location is necessary in the gaseous flow to result in the fluid from an outlet group reaching the burner associated with that group. Such a location may require longitudinal and circumferential adjustment, so long as there is communication of the fluid between the fluid outlets and the burner associated with that outlet group. 
         [0034]    As a result, fluid exiting from first fluid outlet groups  60  would enter the gaseous flow and be carried in the gaseous flow until the fluid reaches the stage A burners  56 . Likewise, fluid exiting from second fluid outlet groups  62  would enter the gaseous flow and be carried in the gaseous flow until the fluid reaches stage B burners  58 . This way, the desired amount of fluid in the gaseous airflow, i.e. the premix ratio, can be tailored per stage of burners. This improved tailoring of the fuel profile greatly improves the designer&#39;s and operator&#39;s ability to reduce NOx emissions and combustion dynamics. The inventors envision that an annular fluid distribution device with more outlet manifolds could be configured to tailor the amount of fluid delivered to more downstream burner stages, or to individual burners within a stage. All such variations are meant to be within the scope of this invention. 
         [0035]    In another embodiment, if downstream burners are not disposed at the same radial distance from the combustor longitudinal axis, first outlet groups may be configured to deliver first fluids to the outer burners, while second outlet groups may be configured to deliver second fluids to the inner burners. This may be accomplished by increasing the pressure in the second manifold over the pressure in the first manifold, thereby increasing the penetration of the second fluids into the gaseous flow, such that they will reach the inner burners. The inventors envision groups being configured to deliver fluids to any number of burners at any number or radial distances from the combustor&#39;s longitudinal axis. All such variations are meant to be within the scope of this invention. 
         [0036]    The inventors of the annular fluid distribution ring  20  have also innovatively devised at least two different ways in which the embodiment in the figures can be manufactured. In one embodiment, shown in  FIG. 7 , the first distribution manifold  30  is formed in part by a first distribution manifold cover  64  which is welded in place with welds  66 . Likewise, the second distribution manifold  32  is formed in part by a second distribution manifold cover  68 . The covers are one-piece, annular covers, and are installed after the fluid outlet duct inner sections  38 ,  48  are drilled. In an inner duct drilling operation  72 , the drilling operation  72  forms the fluid outlet duct inner sections  38 ,  48 , and then the distribution manifold covers  64 ,  68  are welded into place. Fluid outlet duct outer section  40 ,  50  may be formed by an outer duct drilling operation  74 . This can occur before or after the inner duct drilling operation  72 .  FIG. 8  shows manifold cover  64  as positioned in the annular fluid distribution ring  20 , and manifold cover  68  prior to being welded into position in the annular fluid distribution ring  20 . 
         [0037]    In an alternate embodiment, shown in  FIG. 9 , each fluid outlet  24 ,  26 , may have a discrete cover associated with it. For example, a first fluid outlet  24  may have a first fluid outlet cover  74  associated with it. The cover may be a separate piece of circular material. When the first fluid outlet cover  74  is not in place, as shown in  FIG. 9 , an inner duct drilling operation  72  can be performed, because the drilling operation can access the interior of the fluid distribution chambers  30 ,  32 , as can be seen in  FIG. 10 . After the inner duct drilling operation  72 , the first fluid outlet cover  74  is welded into place, as also shown in  FIG. 9 . Likewise, a second fluid outlet  26  may have a second fluid outlet cover  76  associated with it, which may be welded into place once the inner duct drilling operation  72  is performed. In yet another embodiment, the inner duct drilling operation  72  may be performed through the annular fluid distribution ring  20  wall, and the remaining hole may be covered (i.e. filled) by weld material (not shown). 
         [0038]    The inventors have innovatively devised an annular structure that permits circumferential and radial biasing of fuel flow into a gaseous fluid, thus permitting a wide variety of fuel profiles in the gaseous fluid not seen in the prior art annular structures. With this greater flexibility comes reduced NOx emissions, and greater control of combustion, resulting in fewer combustion instabilities. All this can be accomplished using an annular fluid distribution device that is relatively simple and inexpensive to manufacture, given the greatly improved control and flexibility resulting from its use. 
         [0039]    While various embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions may be made without departing from the invention herein. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.