Abstract:
A combustor includes a combustion chamber and a liner surrounding the combustion chamber. A ridge on top of the liner extends continuously around the liner. In alternate embodiments, a ridge extends continuously around the liner, and a groove extends continuously around the liner adjacent to the ridge, wherein both of the ridge and the groove are either substantially flat or curved.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally involves a combustor. Specifically, various embodiments of the present invention include a combustor having a liner with enhanced durability. 
       BACKGROUND OF THE INVENTION 
       [0002]    Combustors are known in the art for igniting fuel with air to produce combustion gases having high temperature and pressure. For example, gas turbine systems typically include multiple combustors that mix a compressed working fluid from a compressor with fuel and ignite the mixture to produce high temperature and pressure combustion gases. The combustion gases then flow to a turbine where they expand to produce work. 
         [0003]    Each combustor typically includes a liner that surrounds the combustion chamber to contain the working fluid and fuel during combustion. The temperatures associated with the combustion often exceed 3500° F., and the liner typically has a maximum operating temperature on the order of approximately 1500° F. Therefore, various systems and methods have been developed to cool the liner. For example, the working fluid may be directed over the external surface of the liner prior to flow into the combustion chamber to provide film or convective cooling to the liner. Alternately, or in addition, the thickness of the liner may be increased or thermal barrier coatings may be applied to the inside of the liner to protect the liner from excessive temperatures. Despite these and other measures, dynamic changes in pressure and power loads may cause plastic deformation, bulging, or creep to occur in the liner over time, resulting in additional maintenance, repairs, and unplanned outages. Therefore, an improved liner design with enhanced stiffness, rigidity, and/or cooling characteristics would be desirable. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0004]    Aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
         [0005]    One embodiment of the present invention is a combustor that includes a combustion chamber and a liner surrounding the combustion chamber. A ridge on top of the liner extends continuously around the liner. 
         [0006]    Another embodiment of the present invention is a combustor that includes a combustion chamber and a liner surrounding the combustion chamber. A ridge extends continuously around the liner, and a groove extends continuously around the liner adjacent to the ridge, wherein both of the ridge and the groove are either substantially flat or curved. 
         [0007]    A still further embodiment of the present invention is a combustor that includes a combustion chamber and a liner surrounding the combustion chamber. A radius extends continuously around the liner, and a substantially flat segment extends continuously around the liner and adjacent to the radius. The radius and the substantially flat segment define an outer circumference of the liner. The substantially flat segment has a first end and a second end, and the outer circumference of the liner at the first end is greater than the outer circumference of the liner at the second end. 
         [0008]    Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which: 
           [0010]      FIG. 1  is a simplified cross-section of a combustor according to one embodiment of the present invention; 
           [0011]      FIG. 2  is a side plan view of a liner according to a first embodiment of the present invention; 
           [0012]      FIG. 3  is a side plan view of a liner according to a second embodiment of the present invention; 
           [0013]      FIG. 4  is an enlarged view of a portion of the liner shown in  FIG. 2  or  3 ; 
           [0014]      FIG. 5  is a side plan view of a liner according to a third embodiment of the present invention; 
           [0015]      FIG. 6  is a side plan view of a liner according to a fourth embodiment of the present invention; 
           [0016]      FIG. 7  is an enlarged view of a portion of the liner shown in  FIG. 5  or  6 ; 
           [0017]      FIG. 8  is a side plan view of a liner according to a fifth embodiment of the present invention; 
           [0018]      FIG. 9  is a side plan view of a liner according to a sixth embodiment of the present invention; 
           [0019]      FIG. 10  is an enlarged view of a portion of the liner shown in  FIG. 8  or  9 ; 
           [0020]      FIG. 11  is a side plan view of a liner according to a seventh embodiment of the present invention; 
           [0021]      FIG. 12  is a side plan view of a liner according to an eighth embodiment of the present invention; and 
           [0022]      FIG. 13  is an enlarged view of a portion of the liner shown in  FIG. 8  or  9 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. 
         [0024]    Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0025]    Various embodiments of the present invention provide a combustor with any one of several improved liner designs that enhance the stiffness and/or rigidity characteristics of the liner. For example, in particular embodiments, the liner may include one or more ridges and/or one or more grooves that extend around the liner in a spiral or parallel pattern. In other particular embodiments, the liner may include one or more radii and substantially flat segments that extend around the liner in a spiral or parallel pattern. In each embodiment, the combination of ridges, grooves, radii, and/or substantially flat segments have been designed to improve the liner&#39;s resistance to premature buckling, creep, or deformation that may be caused over time by dynamic pressure and load changes. In addition, the various embodiments have been designed to enhance film or convective cooling of the outside of the liner without increasing manufacturing costs or difficulty. 
         [0026]      FIG. 1  shows a simplified cross-section of a combustor  10  according to one embodiment of the present invention. As shown, the combustor  10  may include one or more nozzles  12  radially arranged in a top cap  14 . A casing  16  may surround the combustor  10  to contain the air or compressed working fluid exiting the compressor (not shown). An end cap  18  and a liner  20  generally surround a combustion chamber  22  downstream of the nozzles  12 . A flow sleeve  24  with flow holes  26  may surround the liner  20  to define an annular passage  28  between the flow sleeve  24  and the liner  20 . The compressed working fluid may pass through the flow holes  26  in the flow sleeve  24  to flow along the outside of the liner  20  to provide film or convective cooling to the liner  20 . The compressed working fluid then reverses direction to flow through the one or more nozzles  12  and into the combustion chamber  22  where it mixes with fuel and ignites to produce combustion gases having a high temperature and pressure. 
         [0027]      FIGS. 2 and 3  show side plan views of the liner  20  according to first and second embodiments of the present invention. In each particular embodiment shown in  FIGS. 2 and 3 , a ridge  30  on top of the liner  20  extends continuously around the circumference of the liner  20  to strengthen the liner  20 . The ridge  30  may extend axially along a portion or the entire length of the liner  20 , or a plurality of the ridges  30  may extend axially along some or all of the length of the liner  20 . As shown in  FIG. 2 , the ridge  30  may form a continuous substantially parallel spiral around the liner  20 . Alternately, as shown in the embodiment illustrated in  FIG. 3 , the liner  20  may include a plurality of the ridges  30 , with the ridges  30  forming substantially parallel circles or hoops around the circumference of the liner  20 . 
         [0028]      FIG. 4  provides an enlarged view of a portion of the liner  20  shown in  FIG. 2  or  3 . The ridge(s)  30  may be forged or cast with the liner  20  to facilitate ease of manufacturing, or the ridge(s)  30  may be added to the liner  20  by welding and subsequent machining, if desired. The dimensions and spacing of the ridge(s)  30  may be selected according to various design considerations to optimize the strength, stiffness, and/or rigidity of the liner  20 , as well as the cooling provided by the ridge(s)  30 . For example, the height  32  and width  34  of the ridge(s)  30 , as well as the distance  36  between adjacent ridge(s)  30  spiraling around or encircling the liner  20 , may be selected based on the thickness  38  of the liner  20 . In particular embodiments, the height  32  and/or width  34  of the ridge(s)  30  may be approximately 0.3-1.4 times the thickness  38  of the liner  20 , and the distance  36  between adjacent ridges  30  may be approximately 8-45 times the thickness  38  of the liner  20 . 
         [0029]    As shown in  FIG. 4 , each ridge  30  may comprise a base  40  proximate to the liner  20  and a distal end  42 . The base  40  may include a radius  44  along at least a portion of the base  40 . As used herein, the term “radius” includes any curved surface that reduces flow resistance across the outer surface of the liner  20 . The length of the radius  44  may be selected based on the thickness  38  of the liner  20 . For example, the radius  44  may have a curved length  49  of approximately 0.15-1 times the thickness  38  of the liner. The radius  44  may be forged or cast with the ridge(s)  30  during manufacture of the liner  20  or may be added separately, such as through lap welding and machining to produce a smooth, curved surface between the ridge(s)  30  and the liner  20 . As shown in  FIG. 4 , the distal end  42  may also include a radius  46  and/or terminate at a point  48  along at least a portion of the distal end  42 . 
         [0030]      FIGS. 5 and 6  provide side plan views of the liner  20  according to third and fourth embodiments of the present invention. In each particular embodiment shown in  FIGS. 5 and 6 , the ridge  30  again extends continuously around the circumference of the liner  20 ; however, the ridge  30  is substantially wider than in the embodiments shown in  FIGS. 2-4 . In addition, the particular embodiments shown in  FIGS. 5 and 6  further include a groove  50  that extends continuously around the liner  20  adjacent to the ridge  30 . A radius  52  between the ridge  30  and the groove  50  provides a smooth transition between the ridge  30  and the groove  50 . The ridge  30  and groove  50  may extend axially along a portion or the entire length of the liner  20 , or a plurality of the ridges  30  and/or the grooves  50  may extend axially along some or all of the length of the liner  20 . As shown in  FIG. 5 , the ridge  30  and groove  50  may form a continuous substantially parallel spiral around the liner  20 . Alternately, as shown in the embodiment illustrated in  FIG. 6 , the liner  20  may include a plurality of the ridges  30  and grooves  50 , with at least one groove  50  between adjacent ridges  30 . In this manner, the ridges  30  and grooves  50  form substantially parallel circles or hoops around the circumference of the liner  20 . 
         [0031]      FIG. 7  provides an enlarged view of a portion of the liner  20  shown in  FIG. 5  or  6 . The ridge(s)  30 , groove(s)  50 , and radii  52  may be forged or cast with the liner  20  to facilitate ease of manufacturing, or the liner  20  may be pressed or stamped to form the ridge(s)  30 , groove(s)  50 , and radii  52 , if desired. The dimensions and spacing of the ridge(s)  30 , groove(s)  50 , and radii  52  may be selected according to various design considerations to optimize the strength, stiffness, and/or rigidity of the liner  20 , as well as the cooling provided by the ridge(s)  30  and groove(s)  50 . For example, the height  54  and width  56  of the ridge(s)  30  and/or the groove(s)  50  continuously spiraling around or encircling the liner  20  may be selected based on the thickness  38  of the liner  20 . In particular embodiments, the height  54  of the ridge(s)  30  and/or groove(s)  50  may be approximately 1.1-2.5 times the thickness  38  of the liner  20 , and the width  56  of the ridge(s)  30  and/or the groove(s)  50  may be approximately 8-45 times the thickness  38  of the liner  20  for liner thicknesses greater than approximately 0.09 inches and approximately 16-90 times the thickness  38  of the liner  20  for liner thicknesses less than approximately 0.09 inches. Similarly, the radius  52  may have a curved length  58  of approximately 0.5-2.5 times the thickness  38  of the liner  20 . The ridge(s)  30  and/or the groove(s)  50  may be substantially flat with the same height  54  and width  56 , although such is not limitation of the present invention unless specifically recited in the claims. 
         [0032]      FIGS. 8 and 9  provide side plan views of the liner  20  according to fifth and sixth embodiments of the present invention. In each particular embodiment shown in  FIGS. 8 and 9 , the ridge  30  again extends continuously around the circumference of the liner  20 ; however, the ridge  30  is curved with the convex surface facing outward. In addition, the particular embodiments shown in  FIGS. 8 and 9  further include a groove  50  that extends continuously around the liner  20  adjacent to the ridge  30 . A smooth transition between the ridge  30  and the groove  50  produces a wavy surface on the outside of the liner  20 . The ridge  30  and groove  50  may extend axially along a portion or the entire length of the liner  20 , or a plurality of the ridges  30  and/or the grooves  50  may extend axially along some or all of the length of the liner  20 . As shown in  FIG. 8 , the ridge  30  and groove  50  may form a continuous substantially parallel spiral around the liner  20 . Alternately, as shown in the embodiment illustrated in  FIG. 9 , the liner  20  may include a plurality of the ridges  30  and grooves  50 , with at least one groove  50  between adjacent ridges  30 . In this manner, the ridges  30  and grooves  50  form substantially parallel circles or hoops around the circumference of the liner  20 . 
         [0033]      FIG. 10  provides an enlarged view of a portion of the liner  20  shown in  FIG. 8  or  9 . The ridge(s)  30  and groove(s)  50  may be forged or cast with the liner  20  to facilitate ease of manufacturing, or the liner  20  may be pressed or stamped to form the ridge(s)  30  and groove(s)  50 , if desired. The dimensions and spacing of the ridge(s)  30  and groove(s)  50  may be selected according to various design considerations to optimize the strength, stiffness, and/or rigidity of the liner  20 , as well as the cooling provided by the ridge(s)  30  and groove(s)  50 . For example, the height  54  and width  56  of the ridge(s)  30  and/or the groove(s)  50  continuously spiraling around or encircling the liner  20  may be selected based on the thickness  38  of the liner  20 . In particular embodiments, the height  54  of the ridge(s)  30  and/or groove(s)  50  may be approximately 1.1-5 times the thickness  38  of the liner  20 , and the width  56  of the ridge(s)  30  and/or groove(s)  50  may be approximately 8-45 times the thickness  38  of the liner  20  for liner thicknesses greater than approximately 0.09 inches and approximately 16-90 times the thickness  38  of the liner  20  for liner thicknesses less than approximately 0.09 inches. 
         [0034]      FIGS. 11 and 12  provide side plan views of the liner  20  according to seventh and eighth embodiments of the present invention. Each particular embodiment shown in  FIGS. 11 and 12  may include a corrugated surface  60  with a radius  62  and a substantially flat segment  64  adjacent to the radius  62 . The radius  62  and segment  64  extend continuously around the liner  20  to define an outer circumference of the liner  20 . The segment  64  has a first end  66  and a second end  68 , and the outer circumference of the liner  20  at the first end  66  is greater than the outer circumference of the liner  20  at the second end  68  to provide the corrugated surface  60 . The direction of the corrugated surface  60  may vary according to particular embodiments. For example, in the embodiment shown in  FIG. 11 , the first end  66  is upstream from the second end  68 , and in the embodiment shown in  FIG. 12 , the first and  66  is downstream from the second end  68 . 
         [0035]    The radius  62  and segment  64  may extend axially along a portion or the entire length of the liner  20 , or a plurality of the radii  62  and/or the segments  64  may extend axially along some or all of the length of the liner  20 . As shown in  FIG. 11 , the radius  62  and the segment  64  may form a continuous substantially parallel spiral around the liner  20 . Alternately, as shown in the embodiment illustrated in  FIG. 12 , the liner  20  may include a plurality of the continuous radii  62  and segments  64 , with at least one segment  64  between adjacent radii  62 . In this manner, the radii  62  and segments  64  form substantially parallel circles or hoops around the circumference of the liner  20 . 
         [0036]      FIG. 13  provides an enlarged view of a portion of the liner  20  shown in  FIG. 11  or  12 . The radii  62  and segments  64  may be forged or cast with the liner  20  to facilitate ease of manufacturing, or the liner  20  may be pressed or stamped to form the radii  62  and segments  64 , if desired. The dimensions and spacing of the radii  62  and segments  64  may be selected according to various design considerations to optimize the strength, stiffness, and/or rigidity of the liner  20 , as well as the cooling provided by the radii  62  and segments  64 . For example, the slope  70  of the segments  64  may be approximately 2-8 degrees with respect to the axis of the liner  20 . The height  72  of the corrugated surface  60  and the distance  74  between adjacent radii  62  or adjacent segments  64  continuously spiraling around or encircling the liner  20  may be selected based on the thickness  38  of the liner  20 . In particular embodiments, the height  72  of the corrugated surface  60  may be approximately 1.1-3.0 times the thickness  38  of the liner  20 . The distance  74  between adjacent radii  62  or adjacent segments  64  may be approximately 8-45 times the thickness  38  of the liner  20  for liner thicknesses greater than approximately 0.09 inches and approximately 16-90 times the thickness  38  of the liner  20  for liner thicknesses less than approximately 0.09 inches. Similarly, the radii  62  may have a curved length  76  of approximately 0.5-2.5 times the thickness  38  of the liner  20 . 
         [0037]    It is believed that the various embodiments described and illustrated in  FIGS. 2-13  will provide increased stiffness and rigidity to the liner without increasing manufacturing difficulty or costs. In addition, the ridges, grooves, radii, and or flat segments will function as turbulators to enhance film or convection cooling of the liner. As a result, it is anticipated that the useful life of the liners may be extended, and maintenance, repairs, and/or unplanned outages may be produced. 
         [0038]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other and examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.