Abstract:
Aspects of the disclosure are directed to a system of an aircraft, comprising: at least one fairing, a liner, and an actuator configured to cause the at least one fairing to be translated relative to the liner in order to obtain a modulation of a metering area between the liner and the at least one fairing,

Description:
[0001]    This application claims priority to U.S. patent application Ser. No. 62/091,991 filed Dec. 15, 2014. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    This invention was made with government support under contract number FA8650-09-D-2932 awarded by the United States Air Force. The government has certain rights in the invention. 
     
    
     BACKGROUND 
       [0003]    In aircraft environments, an exhaust cooling environment typically includes a first area and a second area that is downstream from the first area. The first area may be referred to as a metering area and the second area may be referred to as a discharge/exit area. 
         [0004]    In conventional exhausting cooling environments, the metering area has a flat or consistent profile. Such a profile results in a loss of momentum in terms of a flow of air. This loss of momentum results in a degradation in terms of engine efficiency/performance. 
       BRIEF SUMMARY 
       [0005]    The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosure. The summary is not an extensive overview of the disclosure. It is neither intended to identify key or critical elements of the disclosure nor to delineate the scope of the disclosure. The following summary merely presents some concepts of the disclosure in a simplified form as a prelude to the description below. 
         [0006]    Aspects of the disclosure are directed to a system of an aircraft, comprising: at least one fairing, a liner, and an actuator configured to cause the at least one fairing to be translated relative to the liner in order to obtain a modulation of a metering area between the liner and the at least one fairing. In some embodiments, the at least one fairing comprises a plurality of fairings. In some embodiments, the at least one fairing comprises metal. In some embodiments, the system further comprises: a convergent flap and a divergent flap that define a throat associated with the system. In some embodiments, the metering area controls a radial dimension associated with the throat. In some embodiments, the metering area is based on a shape of the liner relative to a shape of the at least one fairing. In some embodiments, the metering area is based on a position of the liner relative to a position of the at least one fairing. In some embodiments, the metering area is based on a gap that exists between the liner and the at least one fairing. In some embodiments, the system is associated with an exhaust of an engine of the aircraft. In some embodiments, the metering area adjusts a first flow that flows through the engine relative to a second flow that bypasses the engine. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The present disclosure is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements. 
           [0008]      FIG. 1  illustrates a gas turbine engine. 
           [0009]      FIG. 2  illustrates an exemplary system for implementing a modulated metering area. 
           [0010]      FIGS. 3A-3C  illustrate a sequence in a change of a metering area relative to a nozzle throat area. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    It is noted that various connections are set forth between elements in the following description and in the drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities. 
         [0012]    In accordance with various aspects of the disclosure, apparatuses, systems and methods are described for modulating a metering area in relation to a nozzle throat area. The metering may be based on a relationship between a liner and one or more fairings. The modulated metering may be used to extract thrust in conjunction with one or more flows. 
         [0013]    Aspects of the disclosure may be applied in connection with a gas turbine engine. For example,  FIG. 1  is a side-sectional illustration of a gas turbine engine  10 . The engine  10  includes a compressor section  12 , a turbine section  14  and one or more engine hot sections. The engine hot sections may include, for example, a first engine hot section  16  configured as a combustor section and a second engine hot section  18  configured as an augmentor section. The compressor section  12 , the first engine hot section  16 , the turbine section  14  and the second engine hot section  18  may be sequentially aligned along an axial centerline  20  between a forward engine airflow inlet  22  and an aft engine airflow exhaust  24 . One skilled in the art would appreciate that in proximity to the exhaust  24  there may exist the nozzle throat area that is representative of an exhaust nozzle physical area. The nozzle throat area is described further below in connection with  FIG. 2  (reference character  250 ). 
         [0014]      FIG. 1  represents one possible configuration for an engine  10 . Aspects of the disclosure may be applied in connection with other engine configurations. 
         [0015]    One skilled in the art would appreciate that, in connection with the design and operation of an engine (e.g., engine  10 ), there may exist at least two flows. A first such flow, which may be referred to as a core flow  40 , may pass through the engine hardware and be subjected to combustion in, e.g., the first engine hot section  16 . A secondary flow, which may be referred to as a bypass flow  50 , bypasses the engine core. A bypass ratio may be established for denoting the ratio between the bypass flow  50  and the core flow  40 . 
         [0016]    Aspects of the disclosure may be used to adjust the bypass ratio. For example, aspects of the disclosure may be used to reduce the bypass flow or increase the core flow. An adjustment of the bypass ratio may be provided in order control or regulate engine performance/efficiency. In this respect, a metering of the flow(s) may be provided. 
         [0017]    Referring to  FIG. 2 , a system  200  is shown. The system  200  may be associated with one or more portions of an engine (e.g., engine  10  of  FIG. 1 ), such as an exhaust (e.g., exhaust  24 ). The system  200  includes a number of components/devices that are described below. The system  200  may be used to provide for a modulated metering of one or more flows. 
         [0018]    Synchronization (sync) rings  202  are configured to move forward and aft (or left and right, respectively, in  FIG. 2 ), relative to a fixed/static structure  212 . The movement of the sync rings  202  serves to move or displace a convergent flap/seal  204 , a strut  206 , a divergent flap/seal  208 , and an external flap  210 . in some embodiments, one or more actuators  220  may be used to facilitate or provide for such translation. 
         [0019]    The system  200  may include a liner  230 . The liner  230 , which may be referred to as an augmented liner, may define a channel  232  that conveys at least a portion of the bypass flow. The sync rings  202 , a portion of the static structure  212 , and a portion of the bypass channel  232  may be representative of a modulated exhaust cooling (MEC) area  240 . The area  240  is referred to as being “modulated” due to the fact that its size/dimension may change based at least in part on a position of the liner  230  relative to one or more fairings as described further below. 
         [0020]    An axial translation of one or more of the components described above may serve to control a radial dimension of the nozzle throat area  250 , a portion of which is shown via a dashed line in  FIG. 2  for reference purposes. The translation may be provided by the actuator(s)  220 . The convergent flap  204  and the divergent flap  208  may define the nozzle throat area  250 . The MEC area  240  may be a function of the nozzle throat area  250 . 
         [0021]    The system  200  also includes a sync ring fairing  260  and a c-flap/c-seal fairing  262 . The role/function of such fairings  260  and  262  are described in further detail below. 
         [0022]    In some instances, a discharge area is (significantly) larger than a metering area. This may be inefficient from a perspective of aerodynamics and may result in a loss of flow momentum. To maximize/increase performance, it may be desirable for the metering area and the discharge area to he approximately the same, but capable of varying with the nozzle throat area. In doing so, momentum of the flow may be maintained and it may be possible to gain or extract some thrust from the flow. 
         [0023]    Referring now to  FIGS. 3A-3C , a system  300  (which may correspond to at least a portion of the system  200 ) is shown at various stages/sequences of operation. In particular,  FIGS. 3A-3C  illustrate an implementation that realizes a metering area  340  (which may correspond to the MEC area  240 ) as a function of a nozzle throat area (e.g., nozzle throat area  250 ).  FIG. 3A  corresponds to a minimum value for the nozzle throat area,  FIG. 3B  corresponds to an intermediate value for the nozzle throat area, and  FIG. 3C  corresponds to a maximum value for the nozzle throat area. 
         [0024]    In  FIGS. 3A-3C , a liner  330  (which may correspond to the liner  230  of  FIG. 2 ) and a convergent flap  304  (which may correspond to the convergent flap  204  of  FIG. 2 ) are shown as being coupled to one another via one or more fairings, such as fairings  350  and  352 . The fairing  350  may correspond to the fairing  260 , and the fairing  352  may correspond to fairing  262 . 
         [0025]    The fairings  350  and  352  may be made of one or more materials (e.g., metal, composite, etc.). The shape/geometry/form-factor of the fairings  350  and  352  may be selected in conjunction with the shape/geometry/form-factor of the liner  330  to obtain the particular metering area  340 . The metering area  340  may also be based on, or a function of, the position of the augmented liner  330  relative to the fairings  350  and  352 , and any gap that may exist between the augmented liner  330  and the fairings  350  and  352 . In this respect, a modulation of the metering area  340  may be obtained based on these input factors/conditions. The modulation of the metering area  340  may be stepped in the sense that the metering area  340  may take on discrete values. In some embodiments, the modulation of the metering area  340  may be continuous in the sense that the metering area  340  may assume a value within a continuous range of values. 
         [0026]    Technical effects and benefits of this disclosure include a realization of an exit flow that is approximately the same as a metering flow. In this manner, performance/efficiency may be increased/maximized by being able to extract thrust from the flow. Furthermore, such thrust may be obtained without a need to incorporate/implement a separate actuation mechanism, thereby maximizing/increasing reliability and minimizing/reducing complexity and weight. In this respect, a passive metering is provided as a function of the nozzle throat area. 
         [0027]    Aspects of the disclosure have been described in terms of illustrative embodiments thereof. Numerous other embodiments, modifications, and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure. For example, one of ordinary skill in the art will appreciate that the steps described in conjunction with the illustrative figures may be performed in other than the recited order, and that one or more steps illustrated may be optional in accordance with aspects of the disclosure.