Abstract:
A system according to an embodiment includes: a passive flow modulation device positioned within a turbine for modulating a flow of cooling air, the passive flow modulation device including a housing containing a temperature sensitive element; and a temperature sensor attached to the housing containing the temperature sensitive element, the temperature sensor providing temperature-related data.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is related to co-pending U.S. application Ser. No. ______, GE docket numbers 280848-1 and 283686-1, filed on ______. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The disclosure relates generally to turbomachines, and more particularly, to passive flow modulation of cooling flow with telemetry. 
         [0003]    Turbines are widely used in a variety of aviation, industrial, and power generation applications to perform work. Such turbines generally include alternating stages of peripherally mounted stator vanes and rotating blades. The stator vanes may be attached to a stationary component such as a casing that surrounds the turbine, and the rotating blades may be attached to a rotor located along an axial centerline of the turbine. A compressed working fluid, such as steam, combustion gases, or air, flows along a gas path through the turbine to produce work. The stator vanes accelerate and direct the compressed working fluid onto a subsequent stage of rotating blades to impart motion to the rotating blades, thus turning the rotor and performing work. 
         [0004]    Various components (e.g., blades, nozzles, shrouds, etc.) and areas (e.g., wheelspace between stator and rotor) of a turbine are typically cooled in some fashion to remove heat transferred by the hot gas path. A gas such as compressed air from an upstream compressor may be supplied through at least one cooling circuit including one or more cooling passages to cool the turbine. Further, various components and areas of a turbine may experience damaging conditions during operation of the turbine. Accurate measurements of these operating conditions, including temperature, may be required to take appropriate steps to correct or prevent any damage that may occur in the turbine and/or to optimize the operation of the turbine. One approach to obtaining temperature data in a turbine uses wired sensors, which often requires wiring between a rotating component and a stationary part of the turbine. However, a wired approach may be complex, expensive, and unreliable, due in part to the high temperatures in the turbine, as the electronic characteristics of the wiring may limit the range of temperatures over which a wired sensor may operate accurately. 
         [0005]    Due to the limitations of wired sensors, wired measurements may only be taken during testing of the turbine; during operation in the field, wired sensors may be impractical. However, monitoring these conditions over the entire lifespan of the turbine is desirable to ensure reliable operation of the turbine. Temperature measurements taken in the field may be correlated with control parameters to optimize field operation of the turbine. Change observed in these measurements over time may be also used to assess the health of the blades and other components of the turbine, allowing for appropriate maintenance scheduling. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0006]    A first aspect of the disclosure provides a system, comprising: a passive flow modulation device positioned within a turbine for modulating a flow of cooling air, the passive flow modulation device including a housing containing a temperature sensitive element; and a temperature sensor attached to the housing containing the temperature sensitive element, the temperature sensor providing temperature-related data. 
         [0007]    A second aspect of the disclosure provides a turbomachine, including: a gas turbine system including a compressor component, a combustor component, and a turbine component; a passive flow modulation device positioned within the turbine component for modulating a flow of cooling air, the passive flow modulation device including a housing containing a temperature sensitive element; and a temperature sensor attached to the housing containing the temperature sensitive element, the temperature sensor providing temperature-related data. 
         [0008]    A third aspect of the disclosure provides cooling system, including: a passive flow modulation device positioned within a turbine for modulating a flow of cooling air through an orifice into a wheelspace cavity, the passive flow modulation device including a housing containing a temperature sensitive element; a temperature sensor attached to the housing containing the temperature sensitive element, the temperature sensor providing temperature-related data; an interrogating system, located external to the turbine, for interrogating the temperature sensor and for receiving the temperature-related data from the temperature sensor; an analyzing system for determining a flow rate of the cooling air based on the temperature-related data; and a control system for adjusting at least one operational characteristics of the turbine based on the temperature-related data. 
         [0009]    The illustrative aspects of the present disclosure are designed to solve the problems herein described and/or other problems not discussed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    These and other features of this disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawing that depicts various embodiments of the disclosure. 
           [0011]      FIG. 1  is a schematic diagram of a gas turbine system according to embodiments. 
           [0012]      FIG. 2  is a cross-sectional view of a rotor, stator, and a plurality of passive flow modulation (PFM) devices according to embodiments. 
           [0013]      FIG. 3  depicts a PFM device in a closed position according to embodiments. 
           [0014]      FIG. 4  depicts the PFM device of  FIG. 3  in an open position according to embodiments. 
           [0015]      FIG. 5  depicts a graph of the flow modulation provided by the PFM device of  FIGS. 3 and 4  according to embodiments. 
           [0016]      FIG. 6  depicts a PFM device in a reduced flow position according to embodiments. 
           [0017]      FIG. 7  depicts the PFM device of  FIG. 6  in a full flow position according to embodiments. 
           [0018]      FIG. 8  depicts a graph of the flow modulation provided by the PFM device of  FIGS. 6 and 7  according to embodiments. 
           [0019]      FIG. 9  depicts a telemetry system and turbine according to embodiments. 
       
    
    
       [0020]    It is noted that the drawing of the disclosure is not to scale. The drawing is intended to depict only typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the disclosure. In the drawing, like numbering represents like elements between the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    The disclosure relates generally to turbomachines, and more particularly, to passive flow modulation of cooling flow with telemetry. 
         [0022]    In the Figures, for example in  FIG. 1 , the “A” axis represents an axial orientation. As used herein, the terms “axial” and/or “axially” refer to the relative position/direction of objects along axis A, which is substantially parallel with the axis of rotation of the turbomachine (in particular, the rotor section). As further used herein, the terms “radial” and/or “radially” refer to the relative position/direction of objects along an axis (r), which is substantially perpendicular with axis A and intersects axis A at only one location. Additionally, the terms “circumferential” and/or “circumferentially” refer to the relative position/direction of objects along a circumference (c) which surrounds axis A but does not intersect the axis A at any location. 
         [0023]    Referring now to the drawings, in which like numerals refer to like elements throughout the several views,  FIG. 1  shows a schematic view of a gas turbine system  2  as may be used herein. The gas turbine system  2  may include a compressor  4 . The compressor  4  compresses an incoming flow of air  6 . 
         [0024]    The compressor  4  delivers a flow of compressed air  8  to a combustor  10 . The combustor  10  mixes the flow of compressed air  8  with a pressurized flow of fuel  12  and ignites the mixture to create a flow of combustion gases  14 . Although only a single combustor  10  is shown, the gas turbine system  2  may include any number of combustors  10 . The flow of combustion gases  14  is in turn delivered to a turbine  16 . The flow of combustion gases  14  drives the turbine  16  to produce mechanical work. The mechanical work produced in the turbine  16  drives the compressor  4  via a shaft  18 , and may be used to drive an external load  20 , such as an electrical generator and/or the like. 
         [0025]    A cross-sectional view of a turbine rotor  22  rotating within a stator  24  (e.g., along axis A) during operation of a gas turbine system  2  ( FIG. 1 ) is depicted in  FIG. 2 . A rotating flow of air  28  is produced in a wheelspace cavity  30  within the stator  24  during rotation of the rotor  22 . A plurality of orifices  34  are circumferentially positioned about the stator  24 . Cooling air  32  is tangentially injected via the plurality of orifices  34  into the wheelspace cavity  30  in a direction of rotation of the rotor  22 . The cooling air  32  may be generated for example by a compressor  4  of a gas turbine system  2  ( FIG. 1 ). The orifices  34  may be used, for example, as pre-swirl orifices and/or flow inducers in manner known in the art. According to embodiments, at least one of the plurality of orifices  34  is provided with a passive flow modulation (PFM) device  36  or  38  for selectively controlling the amount of cooling air  32  that is allowed to pass through the orifice  34  into the wheelspace cavity  30 . 
         [0026]    According to embodiments, a PFM device  36 ,  38  may be used in series with an orifice  34  to variably control the flow of cooling air  32  passing through the orifice  34  into the wheelspace  30 . For example, the PFM device  36 ,  38  may initiate the flow of cooling air through the orifice  34 , and then increase and accelerate the flow of cooling air  32  exiting the orifice  34  into the wheelspace cavity  30  to or close to the speed of rotation of the rotor  22 . Each orifice  34  includes a defined effective throat area and exit angle a to provide a flow path such that the exit velocity and orientation of the air flow provides optimal heat transfer efficiency in the wheelspace cavity  30 . The PFM device  36 ,  38  provides cooling flow savings across the operating range of the turbine  16  and improves the output and efficiency of the turbine  16 . Although described herein for use in cooling air  32  passing into the wheelspace  30 , various embodiments of the present disclosure may be used, in general, in an turbine environment where there is a colder cavity at higher pressure and a hotter cavity at lower pressure requiring a modulated amount of cooling flow during specified turbine operating modes. 
         [0027]    One or more of the orifices  34  may provide a continuous flow of cooling air  32  into the wheelspace cavity  30 . Such an orifice  34  is depicted in the lower section of  FIG. 2 . 
         [0028]    The PFM device  36  according to embodiments is depicted in  FIGS. 3 and 4 . The PFM device  36  is in a closed position in  FIG. 3  and in an open position in  FIG. 4 . In embodiments, some of the components of the PFM device  36  are located outside the stator  24 , while other components are disposed within the wheelspace cavity  30 . 
         [0029]    The PFM device  36  includes a valve system  42  positioned on or near an exterior surface  44  of the stator  24 . The valve system  42  includes at least one gas inlet port  46  ( FIG. 4 ) and a gas outlet port  48 . A conduit  50  fluidly couples the gas outlet port  48  of the valve system  42  to the orifice  34 . A seal  52  prevents cooling air from passing directly from an exterior of the stator  24  into the orifice  34  and wheelspace cavity  30 . 
         [0030]    A temperature sensitive element  54  disposed within the wheelspace cavity  30  may be used for actuating the PFM device  36 . In embodiments, the temperature sensitive element  54  may include a housing  56  containing a thermally expandable material  58 . The thermally expandable material  58  may include, for example, a silicon heat transfer fluid or any other suitable thermally expandable material that is stable at the operating temperatures of the turbine  16  (e.g., up to 1300° F.). In other embodiments, the temperature sensitive element  54  may include, for example, a bimetallic element or other type of arrangement that changes size and/or shape in response to a change in temperature. 
         [0031]    The thermally expandable material  58  within the housing  56  engages a head  59  of a piston  60 , which extends through the stator  24 . In embodiments, the valve system  42  includes a valve disc  62  that is attached to a distal end of the piston  60 . Opposing outer side surfaces  64  ( FIG. 4 ) of the valve disc  62  are configured to mate with corresponding surfaces of a valve seat  66  of the valve system  42 . In further embodiments, other valve mechanisms such as, for example, a spring-loaded pintle, a ball and stopper, a butterfly plate valve, and/or the like may be used. 
         [0032]    The PFM device  36  is shown in a closed configuration in  FIG. 3 . That is, in the closed configuration, at least a portion of the outer side surfaces  64  of the valve disc  62  engage the valve seat  66  of the valve system  42 . In the closed configuration, cooling air  32  is prevented from flowing from a colder area, outside of the stator  24 , through the conduit  50  and the orifice  34  into the hotter wheelspace cavity  30 . 
         [0033]    Referring now to  FIG. 4 , an increase in temperature in the wheelspace cavity  30  causes an enlargement of the thermally expandable material  58  within the housing  56 . As a result, the thermally expandable material  58  expands and forces the head  59  of the piston  60  downward. The displacement of the piston  60  forces the valve disc  62  attached to the end of the piston  60  away from the valve seat  66  as indicated by arrow  70 . When the outer side surfaces  64  of the valve disc  62  no longer contact the valve seat  66 , a flow of cooling air  32  begins to flow from the gas inlet port  46  through the gas outlet port  48 , conduit  50 , and orifice  34 , into the wheelspace cavity  30  as indicated by arrow  72 . The flow of cooling air  32  increases as the valve disc  62  moves farther away from the valve seat  66  (as the temperature increases further) as more flow area is provided between the outer side surfaces  64  of the valve disc  62  and the valve seat  66 . 
         [0034]    A graph of the flow modulation provided by the PFM device  36  is illustrated in  FIG. 5 . As shown, the ratio of the pressure (P 3 ) in the orifice  34  and the pressure (P 2 ) in the wheelspace cavity  30 , as well as the air mass flow (qm) through the orifice  34 , increases as the temperature (T 1 ) and turbine load (GT load) increase. Arrow  74  indicates a target pressure ratio (P 3 /P 2 ) and air mass flow (qm) for optimized cooling efficiency for an illustrative turbine (e.g., turbine  16 ). As indicated by arrow  76 , the PFM device  36  provides a substantial cooling flow savings across much of the operating range of the turbine as compared to a fixed flow, which improves the output and efficiency of the turbine. 
         [0035]    The PFM device  38  according to embodiments is depicted in  FIGS. 6 and 7 . The PFM device  38  is in a reduced flow position in  FIG. 6  and in a full flow position in  FIG. 6 . In embodiments, the PFM device  38  is disposed within the wheelspace cavity  30 . 
         [0036]    The PFM device  38  includes a temperature sensitive element  78  disposed within the wheelspace cavity  30 . In embodiments, the temperature sensitive element  78  includes a housing  80  partially filled with a thermally expandable material  84 . The thermally expandable material  84  may include, for example, a silicon heat transfer fluid or any other suitable thermally expandable material that is stable at the operating temperatures of the turbine  16 . In other embodiments, the temperature sensitive element  78  may include, for example, a bimetallic element or other type of arrangement that changes size and/or shape in response to a change in temperature. 
         [0037]    A piston  86  is coupled to a movable shelf  88 . A head  90  of the piston  86  extends at least partially over an exit  92  of an orifice  34 . The distal end surface  94  of the head  90  of the piston  86  may have an angled configuration corresponding to the flow angle a of cooling air  32  through the orifice  34  into the wheelspace cavity  30 . The angled configuration of the distal end surface  94  of the head  90  of the piston  86  helps to direct the flow of, and maintain the exit angle of, cooling air  32  into the wheelspace cavity  30 . Other configurations of the end surface  94  of the head  90  of the piston  86  (e.g., perpendicular to the displacement direction of the piston  86 ) may also be used. 
         [0038]    A biasing member  96  (e.g., a spring) biases the movable shelf  88  and piston  86  towards the exit  92  of the orifice  34  as indicated by arrow  98 . In the configuration depicted in  FIG. 6 , the head  90  of the piston  86  extends at least partially over the exit  92  of the orifice  34 . This reduces the flow of cooling air  32  that can pass through the orifice  34  into the wheelspace cavity  30 . 
         [0039]    Referring now to  FIG. 7 , an increase in temperature in the wheelspace cavity  30  causes an expansion of the thermally expandable material  84  within the housing  80  and a corresponding displacement of the piston  86  in direction  100 . The force applied by the piston  86  counteracts the biasing force applied by the biasing member  96  and forces the movable shelf  88  and piston  86  in direction  100 . As indicated by arrow  102 , the expansion of the thermally expandable material  84  displaces the head  90  of the piston  86  away from the exit  92  of the orifice  34 . Since the head  90  of the piston  86  is now blocking less of the exit  92  of the orifice  34 , a larger flow of cooling air  32  can pass through the orifice  34  into the wheelspace cavity  30 . The flow of cooling air  32  continues to increase as the temperature within the wheelspace cavity  30  increases, which causes additional displacement of the head  90  of the piston  86  away from the exit  92  of the orifice  34 . In  FIG. 7 , the exit  92  of the orifice  34  is fully open. 
         [0040]    A graph of the flow modulation provided by a PFM device  38  is illustrated in  FIG. 8 . As shown, the effective flow area (Ae) and the air mass flow (qm) of the cooling air  32  through the orifice  34  increase as the temperature (T 1 ) and turbine load (GT load) increase. Arrow  174  indicates a target effective flow area (Ae) and air mass flow (qm) for optimized cooling efficiency for an illustrative turbine (e.g., turbine  16 ). As indicated by arrow  176 , the PFM device  38  provides a substantial cooling flow savings across much of the operating range of the turbine as compared to a fixed flow, which improves the output and efficiency of the turbine. 
         [0041]    A PFM device is often used in a high temperature (e.g., in a range of about 500° C. to about 600° C., or more generally, at a temperature greater than about 500° C.) operating environment of a turbine, such as in a wheelspace cavity, making it difficult to determine real time operating conditions (e.g., temperature, cooling flow consumption, etc.) of the PFM device. According to embodiments, a temperature sensor  200  ( FIGS. 3, 4, 6, 7, 9 ) may be attached to an outer surface of the housing in the PFM device containing the supply of thermally expandable material. The temperature sensor  200  may directly measure in real time the temperature at the outer surface of the housing or may output a signal that can be used in the calculation of the temperature at the outer surface of the housing. Regardless, once the temperature is known, a flow rate of the cooling air through the PFM device can be determined, for example, using an empirical relationship between the surface temperature of the housing containing the temperature sensitive element and the cooling flow thru the PFM device. Such a relationship is presented, for example, in the graphs depicted in  FIGS. 5 and 8 . Further, the temperature measurements obtained during operation of the turbine (e.g., in the field) may be correlated with control parameters and other turbine data to optimize operation of the turbine. 
         [0042]    A telemetry system  210  according to embodiments is depicted in FIG.  9 . The telemetry system  210  includes a temperature sensor  200  attached to a PFM device  202  located within the turbine  16 . In embodiments, the temperature sensor  200  may comprises a wireless temperature sensor. In other embodiments, the temperature sensor  200  may comprise a wired temperature sensor. As disclosed above, the temperature sensor  200  may be attached to an outer surface of a housing of the PFM device  202  containing a supply of thermally expandable material. In general, the PFM device  202  is not physically accessible during operation of the turbine  16 . In  FIGS. 3 and 4 , for example, the temperature sensor  200  is attached to an outer surface of the housing  56  containing a supply of thermally expandable material  58 . In  FIGS. 6 and 7 , the temperature sensor  200  is attached to an outer surface of the housing  80  containing a supply of thermally expandable material  84 . 
         [0043]    A wireless temperature sensor  200  may comprise, for example, a surface acoustic wave (SAW) sensor, a printed direct write conformal sensor, or other suitable sensor that can withstand the high temperature environment within an operating turbine  16  and that can be wirelessly interrogated (e.g., via an RF interrogating system).  FIG. 9 , for example, depicts an RF interrogating system  204  interrogating  206  and receiving  208  data from a wireless temperature sensor  200 . 
         [0044]    The data received by interrogating system  204  is provided to an analyzing system  212 . As described above, the data may include, for example, temperature data measured by the temperature sensor  200  itself, or a signal that can be used to in the calculation of the temperature data. In the latter case, the analyzing system  212  may be configured to perform the temperature calculation. In addition, the analyzing system  212  may be configured to determine, based on the temperature data, a flow rate of the cooling air through the PFM device  202  (e.g., based on the associated flow versus temperature graphs depicted in  FIGS. 5 and 8 ). A turbine control system  214  receives the output of the analyzing system  212  and, based on the received data, sends control signals  216  to one or more components of the gas turbine system  2  to adjust one or more operational characteristics (e.g., cooling gas flow) of the gas turbine system  2  (e.g., for firing curve correction). 
         [0045]    A wired temperature sensor  200  may comprise, for example, a thermocouple, a resistive temperature detector, or other suitable wired temperature sensor that can withstand the high temperature environment within an operating turbine  16 . In this case, as shown in  FIG. 9 , wiring  220  is provided for coupling the wired temperature sensor  200  to an interrogating system  222 , which is coupled to the analyzing system  212 . The analyzing system  212  operates as detailed above. 
         [0046]    In various embodiments, components described as being “coupled” to one another can be joined along one or more interfaces. In some embodiments, these interfaces can include junctions between distinct components, and in other cases, these interfaces can include a solidly and/or integrally formed interconnection. That is, in some cases, components that are “coupled” to one another can be simultaneously formed to define a single continuous member. However, in other embodiments, these coupled components can be formed as separate members and be subsequently joined through known processes (e.g., fastening, ultrasonic welding, bonding). 
         [0047]    When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element, it may be directly on, engaged, connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
         [0048]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof 
         [0049]    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 examples are intended to be within the scope of the claims if they have 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.