Abstract:
A gas turbine inlet system includes a main inlet portion, wherein an airflow is introduced to the gas turbine inlet system. Also included is a silencer assembly. The silencer assembly includes a first silencing panel, wherein the first silencing panel is oriented substantially perpendicularly to the airflow, and wherein the first silencing panel includes a first plurality of airflow apertures. The silencer assembly also includes a second silencing panel, wherein the second silencing panel is oriented substantially perpendicularly to the airflow, and wherein the second silencing panel includes a second plurality of airflow apertures.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to gas turbine systems, and more particularly to inlet silencers of such systems. 
         [0002]    Often, a gas turbine inlet system includes a distinct duct to house 8-12 foot long baffles that function as silencers. The baffles are aligned longitudinally and in parallel with inlet airflow direction. The inlet airflow passes through gaps defined by the baffles and provide a direct line of sight for reverberating sound waves passing upstream through the gaps of the baffles. Therefore, the sound waves are permitted to travel in an uninterrupted manner toward a main inlet of the gas turbine inlet system. Furthermore, such an uninterrupted path within the gap allows for enhanced airflow velocity to result in an undesirably high pressure drop throughout the gas turbine inlet system. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0003]    According to another aspect of the invention, a gas turbine inlet system includes a main inlet portion, wherein an airflow is introduced to the gas turbine inlet system. Also included is a silencer assembly. The silencer assembly includes a first silencing panel, wherein the first silencing panel is oriented substantially perpendicularly to the airflow, and wherein the first silencing panel includes a first plurality of airflow apertures. The silencer assembly also includes a second silencing panel, wherein the second silencing panel is oriented substantially perpendicularly to the airflow, and wherein the second silencing panel includes a second plurality of airflow apertures. 
         [0004]    According to yet another aspect of the invention, a gas turbine inlet system includes a main inlet portion, wherein an airflow is introduced to the gas turbine inlet system. Also included is a first group of parallel silencing panels that are oriented substantially perpendicularly to the airflow, wherein the first group of parallel silencing panels include a first plurality of gaps therebetween. Further included is a second group of parallel silencing panels that are oriented substantially perpendicularly to the airflow, wherein the second group of parallel silencing panels includes a second plurality of gaps therebetween, wherein the first plurality of gaps is aligned in a first series of airflow planes and the second plurality of gaps is aligned in a distinct second series of airflow planes. 
         [0005]    According to one aspect of the invention, a gas turbine inlet system includes a main inlet portion, wherein an airflow is introduced to the gas turbine inlet system. The gas turbine inlet system also includes a silencer assembly including a first plurality of silencing panels having a first alignment and a second plurality of silencing panels having a second alignment. 
         [0006]    These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0007]    The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0008]      FIG. 1  is a side elevational view of a gas turbine inlet system; 
           [0009]      FIG. 2  is a side elevational view of a transition duct of the gas turbine inlet system; 
           [0010]      FIG. 3  is a side perspective view of first embodiment of a silencer panel system within the transition duct; 
           [0011]      FIG. 4  is a rear perspective view of the first embodiment of the silencer panel system; 
           [0012]      FIG. 5  is a front elevational view of the first embodiment of the silencer panel; 
           [0013]      FIG. 6  is an enlarged front elevational view of a portion of the first embodiment of the silencer panel of  FIG. 5 ; 
           [0014]      FIG. 7  is a cross-sectional view of the portion of the first embodiment of the silencer panel taken along line VII-VII of  FIG. 6 ; 
           [0015]      FIG. 8  is a side perspective view of a second embodiment of a silencer panel system within the transition duct; 
           [0016]      FIG. 9  is a side perspective view of the second embodiment of the silencer panel system; 
           [0017]      FIG. 10  is a side elevational schematic view of the second embodiment of the silencer panel system; 
           [0018]      FIG. 11  is a side elevational view of the second embodiment of the silencer panel system; and 
           [0019]      FIG. 12  is a side elevational view of a third embodiment of the silencer panel system. 
       
    
    
       [0020]    The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Referring to  FIGS. 1 and 2 , a gas turbine inlet system  10  includes a main inlet portion  12  configured to receive an airflow  14  traveling predominantly in a first direction. The airflow  14  travels from the main inlet portion  12  through a transition duct  16  that narrows in a downstream direction and into various other portions of the gas turbine inlet system  10 . A silencer assembly  18  is disposed, at least in part, within the transition duct  16  and functions to dampen the sound associated with reverberating sound waves  20  that are generated by the gas turbine inlet system  10  and gas turbine itself as the airflow  14  passes through them. The sound waves  20  travel substantially opposite in direction to the airflow  14  and thereby interact with the silencer assembly  18  disposed within the transition duct  16 . In addition to functioning as a sound dampener, the presence of the silencer assembly  18  results in a flow rate of the airflow  14  that is higher than that of a flow rate produced in an inlet system that has silencers located in a smaller duct downstream of the transition duct  16 . 
         [0022]    Referring to  FIGS. 3 and 4 , a first embodiment of the silencer assembly  18  is illustrated. The silencer assembly  18  includes at least one, and typically a plurality of, silencer panels  22  that are arranged relatively parallel to each other. The illustrated silencer panels  22  have a relatively rectangular or square geometry that corresponds to an interior surface  23  of the transition duct  16 . It is also conceivable that various other geometries may be employed to suit the configuration of the transition duct  16 . The silencer panels  22  are disposed in series and each have an outer perimeter  24 . When disposed within the transition duct  16 , the outer perimeter  24  of the silencer panels  22  located downstream is smaller than that of the outer perimeter  24  of respective upstream silencer panels  22 . This is due to the narrowing of the transition duct  16  in the downstream direction. Although the silencer panels  22  are described as having smaller successive outer perimeters  24 , it should be appreciated that silencer panels  22  having relatively similar outer perimeters  24  may be employed in a housing conducive to such similar outer perimeters  24 . 
         [0023]    Referring now to  FIGS. 5-7 , a silencer panel  22  is illustrated. The silencer panel  22  is typically a planar sheet and may be formed of a durable material, such as stainless steel or any other stiff material, for example, and may include a plurality of perforations  26  therein. The perforations are lined with a sound dampening material, such as mineral wool. A plurality of airflow apertures  28  are imposed on the silencer panel  22  and may be formed by a punching process. The airflow apertures  28  may take on various geometric configurations including, but not limited to, circular, rectangular, squared, diamond-shaped, or oval. These are merely illustrative examples of numerous configurations that the airflow apertures  28  may take on. 
         [0024]    In operation, the plurality of airflow apertures  28  allow the airflow  14  to pass through the transition duct  16 , yet as a result of the staggered orientation of the silencer panels  22 , and therefore their respective airflow apertures  28 , fewer, if any, direct “sightlines” are present throughout the transition duct  16 . The term “sightlines” refers to an alignment of the airflow apertures  28  in a direction of airflow  14 . By reducing the number of sightlines, direct and uninterrupted travel of the reverberating sound waves  20  is substantially reduced, thereby resulting in a sound dampening effect on the overall gas turbine inlet system  10 . In addition to the advantageous dampening effect, the silencer assembly  18  also functions to reduce the pressure drop seen throughout the gas turbine inlet system  10 . This is a function of the reduction in flow velocity of the airflow  14 , as compared to a system having the silencers located in a smaller duct downstream of the transition duct  16 . 
         [0025]    Referring to  FIGS. 8 and 9 , a second embodiment of a silencer assembly  100  of the gas turbine inlet system  10  is illustrated. The silencer assembly includes a plurality of panel groups  102  that each comprise a plurality of panels  104 . The plurality of panel groups  102  are disposed, at least in part, within the transition duct  16  and the plurality of panels  104  are disposed relatively horizontally or vertically (horizontal with respect to illustration) and relatively perpendicular to the airflow  14 . The panels  104  of each panel group  102  are oriented relatively parallel to one another and are aligned in a relatively vertical or horizontal arrangement (vertical with respect to illustration). A plurality of gaps  106  are present within each panel group  102  and are defined by respective pairs of panels  104 . 
         [0026]    The plurality of panel groups  102  are disposed in series and are each defined by an outer perimeter  124 . As is the case with the described first embodiment, when disposed within the transition duct  16 , the outer perimeter  124  of the plurality of panel groups  102  located downstream is smaller than that of the outer perimeter  124  of respective upstream plurality of panel groups  102 . Similarly, it should be appreciated that the panel groups  102  having relatively similar outer perimeters  124  may be employed in a housing conducive to such similar outer perimeters  124 . 
         [0027]    Referring now to  FIG. 10 , the orientation of the plurality of panel groups  102  is more closely illustrated. Typically, the plurality of panel groups  102  are arranged to reduce the number of “sightlines,” thereby reducing the ability of a sound wave  20  to propagate in an unimpeded manner through the silencer assembly  100 . The plurality of panels  104  are configured, such that downstream panels  104  substantially align with the upstream gaps  106 . As illustrated, a panel group disposed immediately downstream of another panel group is aligned such that the downstream panels effectively close out the upstream gaps, and may include a slight overlap with the upstream panels. Therefore, the silencer assembly  100  achieves a similar function as that of the first embodiment. Specifically, the silencer assembly  100  dampens sound by imposing impediments to reverberating sound waves  20  within the gas turbine inlet system  10 . It should be appreciated that numerous geometric configurations may be employed to form the panels  104 . Illustrative examples include oval and diamond shaped, however it is contemplated that any number of shapes may suit the application for its intended purpose. 
         [0028]    Referring now to  FIG. 11 , additional embodiments of the silencer assembly  100  are illustrated that employ the general concept of the previously described second embodiment. In each embodiment, the silencer assembly  100  includes the plurality of panel groups  102  that each comprise the plurality of panels  104  oriented at a desired angle to the airflow  14 . As with the second embodiment of the silencer assembly  100 , the downstream panels are positioned in line with the gaps  106  of the adjacent upstream panels at any desired angle to the airflow  14 . In addition to the plurality of panels  104 , the silencer assembly  100  may optionally include flow straighteners  108  that function to reduce swirling vortices that may be generated in the airflow  14  as a result of the passage through the plurality of panel groups  102 . The flow straighteners  108  impart a straightening effect on the airflow  14 , as swirling airflow may be undesirable. As previously described, such an alignment provides the aforementioned advantages, such as sound dampening and pressure drop reduction. The plurality of panels  104  may be formed in any number of shapes or geometries. Examples of such geometries include relatively diamond panels and teardrop panels. These are merely illustrative and should not be considered limiting, as numerous other geometries may be suitable. 
         [0029]    Referring to  FIG. 12 , additional embodiments of a silencer assembly  200  are illustrated. The silencer assembly  200  includes a plurality of panels  204  that extend longitudinally in the direction of the airflow  14 , with gaps  206  disposed between the plurality of panels  204 . The various embodiments illustrated each provide gaps  206  that do not consist of a path for the airflow that is parallel to the direction of incoming airflow  14  throughout the entire gap  206 . Specifically, the airflow  14  direction of travel must be altered in some manner as it passes through the silencer assembly  200 . Again, as with previously described embodiments, this reduces the presence of direct sightlines for sound waves  20  to reverberate back through. The plurality of gaps  206  may be angled, with respect to each other, or relatively parallel to one another, but formed in jagged or curved paths. The illustrated paths formed by the gaps  206  are merely exemplary and it is contemplated that numerous other gap paths may be employed. Irrespective of the path formed by the gaps  206 , the sound waves  20  are impeded from a direct line of reverberation back through the silencer assembly  200  and the velocity of the airflow  14  is reduced, resulting in an advantageous pressure drop reduction. 
         [0030]    While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.