JP2012041929A - Method and apparatus for air flow control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for air flow control.SOLUTION: An air flow control apparatus includes a guide vane to be positioned between an air inlet and a rotor of a turbomachine. Further, the guide vane includes a geometry configured to control an air flow incidence on the rotor, the guide vane further having a substantially constant aspect ratio. In addition, a body of the guide vane includes a shape memory material configured to change a geometry of the guide vane in response to energy provided by a power source.

Description

  The subject matter disclosed herein relates to gas turbines. More specifically, the present subject matter relates to guide vanes in gas turbines.

  In a gas turbine, a compressor adds kinetic energy to a fluid such as air by increasing its tangential momentum. The kinetic energy from the compressor and the thermal energy from the combustor are carried to the turbine by a fluid, often air, where the fluid energy is converted to mechanical energy. Several factors affect the efficiency of adding kinetic energy in the compressor. These factors can include air distribution within the compressor, pressure rise across the compressor, and loss loss in the compressor. One embodiment is a guide vane in a compressor that affects the distribution and magnitude of the air flow into the compressor. Guide vanes can be designed to be highly efficient at selected conditions of the turbine, such as full load, high power and / or fuel usage. The guide vanes control the air flow in the compressor, which determines the amount of kinetic energy that can be supplied to the rest of the gas turbine system. However, when operating at lower loads and lower power, airflow distribution and aerodynamic loading by the guide vanes results in lower efficiency of gas turbine performance.

US Pat. No. 7,498,839

  According to one aspect of the present invention, an air flow control device includes a guide vane disposed between a turbomachine inlet and a compressor rotor. Further, the guide vane includes a geometry configured to control air flow incidence on the rotor, and the guide vane further has a substantially constant aspect ratio. In addition, the body of the guide vane includes a shape memory material configured to change the geometry of the guide vane in response to energy supplied by the power source.

  According to another aspect of the present invention, a method of controlling air flow in a compressor includes flowing air from an inlet toward a guide vane and applying energy to the shape memory material in the guide vane to guide the guide. Changing the geometry of the vanes to control the distribution of air flow towards the rotor.

  According to yet another aspect of the present invention, a turbine compressor includes an intake port, a rotor disposed downstream of the intake port, and a guide vane disposed between the intake port and the rotor, the guide vane having shape memory. Contains materials. The compressor also includes a power source that is coupled to the shape memory material to cause a change in the guide vane geometry.

  These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.

  The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the claims appended hereto. The foregoing and other features and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings.

1 is a cross-sectional side view of an embodiment of a gas turbine including a compressor with a guide vane and a rotor. Sectional drawing of the guide vane of FIG. Sectional drawing of embodiment of a wing | blade-shaped guide vane. FIG. 6 is a perspective view of an embodiment of a guide vane in which the shape memory material changes the guide vane geometry.

  The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.

  FIG. 1 is a cross-sectional side view of an embodiment of a gas turbine 100 disposed about a central axis 102. Turbine 100 includes guide vanes 104 disposed within compressor 106. Air is pressurized in the compressor 106 and mixed with fuel, which are burned in the combustor and expanded in the turbine. The turbine then rotates in response to the expansion to drive the compressor 106 and produce a rotational output.

  A plurality of intake guide vanes 104 (one of which is shown) are disposed about the central axis 102 in front of one or more compressors 106. As shown, the compressor 106 includes an inner hub 108 and an outer hub 110 that form a flow path for air toward one or more combustors. The intake guide vane 104 guides the air from the intake port region 112 toward the first stage of the compressor 106 in the downstream direction as indicated by an arrow 114. In an aspect, the compressor 106 includes a plurality of stages. The first stage of the plurality of stages includes a rotor 116 and a stator 118. Similarly, the second stage includes a rotor 120 and a stator 122, and the third stage includes a rotor 124 and a stator 126. The air flow 114 flows in the downstream direction, in which case the guide vanes 104 form a flow distribution or flow field as indicated by flow arrows 128 through the plurality of compressor stages and into the combustor.

  In an embodiment, the guide vane 104 (also “intake guide vane” or “IGV”) includes a shape memory material (or “shape memory alloy”) operatively connected to the guide vane 104, and the shape memory Changing the geometry of the guide vane 104 when energy is applied to the material. For example, the shape memory material is embedded in or forms a portion of the guide vane 104 inside and / or outside. The shape memory material can include a flexible composite material with conductors or wires embedded therein. The wire is operatively coupled to a power source 130, which energizes the wire and heats the wire in the form of an electric current. In one aspect, the power source 130 is coupled to the controller 132 to selectively apply current to the wires to change the geometry of the guide vane 104 based on turbine conditions. Conductive wire materials such as nickel titanium (NiTi) cause a large change in temperature when current is transferred. In an embodiment, a linear NiTi wire having a substantially linear shape is wound into a tight spiral configuration and embedded in the composite. When a selected level of current is applied to the wire, the wire is heated to maintain its previous approximately linear shape. Accordingly, the composite shape memory material changes from the first shape to the second shape because the conducting wire becomes linear. The power supply 130 provides a selected level of current to the wires from a direct current (DC) power source such as a battery, a transmission line based alternating current (AC) power source, or any other suitable power source. A shape memory material can be described as having shape memory properties such that the material stores a plurality of shapes based on conditions such as energy applied to the material. For example, the shape memory material is configured to have one shape at a low temperature and a second shape at a high temperature. A material that exhibits shape memory properties during both heating and cooling can be referred to as a two-way shape memory material. As illustrated, the guide vane 104 is an airfoil formed by a chord 134 and a length 136 dimension, in which case the aspect ratio (length / chord) represents a dimensional relationship. In embodiments, the aspect ratio of the guide vane 104 is substantially constant or fixed when the shape or geometry of the guide vane varies with the shape memory material.

  Continuing to refer to the embodiment of FIG. 1, the guide vane 104 geometry changes when a selected level of current is introduced for the buried wire. For example, the profile or geometry of the guide vane 104 is in the form of a first shape designed for full load and high power turbine conditions and a second shape designed for low load or turndown turbine conditions. . Full load conditions occur when high power is required from the turbine, and low loads or turndown conditions occur during off-peak hours when lower power is required. Thus, the first shape forms an air flow distribution that allows improved combustion efficiency and power generation at full load conditions. The second shape forms an air flow distribution that is most efficient at lower power conditions, such as during off-peak power demands. In an aspect, turbine combustion efficiency increases when the radial distribution of air flow has improved uniformity throughout the compressor. Specifically, overall efficiency is improved when the variable geometry of the guide vanes 104 results in a substantially uniform air flow incidence on the rotor blades at multiple turbine load conditions. Air flow incidence is the relationship or alignment of air flow from the guide vanes to the rotor blades. A substantially uniform air flow can be described as a radial distribution across the span of an airfoil (guide vane or rotor blade) that results in increased efficiency in accordance with turbine conditions. In an embodiment, the guide vane 104 changes the angle of the vane with respect to the air flow from the inlet depending on turbine conditions. In addition, efficiency is also affected by the amount of air flow through the compressor 106. The amount of air flow varies depending on the amount of fuel injected into the combustor and the associated turbine load conditions. In an aspect, different power and fuel usage scenarios result in different operating conditions in which the variable geometry of the guide vanes 104 is adjusted to improve turbine efficiency. In an embodiment, the guide vane 104 includes a single member or part. In other embodiments, the guide vane 104 includes a plurality of members.

  In some embodiments, the overall structure of the guide vane 104 includes a shape memory material in which wires are embedded throughout the composite-based structure. Such a structure allows the overall geometry of the guide vane 104 to change based on current conditions. In other embodiments, selected portions or regions of the guide vane 104 structure include a shape memory material. For example, the trailing edge of the guide vane 104 includes a shape memory material, thereby allowing the trailing edge profile or geometry to be selectively changed based on turbine conditions. In another embodiment, the leading edge changes geometry based on a current that is selectively applied to a shape memory material placed within the leading edge of the guide vane. In an aspect, the shape memory material of the guide vane 104 includes an alloy, a flexible carbon fiber composite, a conductive wire, and / or nanoparticles, where the shape memory material is the material or a selected portion of the material. The shape changes when energy is applied to the. The energy applied to the material can include current, voltage, electromagnetic waves, heat, or other suitable energy. Although the guide vanes 104 of this embodiment are shown for a particular type of gas turbine engine 100, the guide vanes are used with any known turbine engine type including, but not limited to, steam turbines, gas turbines and aeroderivative turbines. be able to. In some embodiments, the illustrated air flow through the compressor 106 includes any suitable fluid including air, oxygen, gaseous fuel, liquid fuel, or any combination thereof. Furthermore, the variable geometry guide vanes 104 can be placed between various stages of the compressor 106. As described herein, guide vanes 104 are also referred to as air flow control devices.

  FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1 and shows the profile of the guide vane 104 in the shape of the airfoil 200. The airfoil 200 includes a leading edge 202 and a trailing edge 204. The airfoil 200 includes a shape memory material such as a flexible composite that forms at least a portion of the airfoil wall 206. A conductor such as wire 208 is embedded in the airfoil wall 206. As shown, the wire 208 is embedded within the flexible composite wall 206 of the trailing edge 204, thus forming a trailing edge shape memory region. In an embodiment, the airfoil 200 is a generally hollow structure, in which case the cavity 210 is surrounded by the airfoil wall 206. As described above, the shape memory material including the composite wall 206 and the wire 208 changes the geometry of the trailing edge 204 when a current is applied to the wire 204. In some embodiments, the shape memory material and airfoil 200 change shape based on time, where time corresponds to the condition and predicted output. For example, a hypothetical turbine engine is subjected to low load conditions from 8PM to 8AM and full load conditions from 8AM to 8PM. Accordingly, the airfoil 200 has a first shape designed for improved efficiency at full load conditions and a second shape designed for improved efficiency at low load conditions, in which case The shape memory material allows for a change between the first and second shapes. In one embodiment, a controller, including a processor, memory, software, fanware, inputs and outputs, is coupled to the power source to accommodate scheduled or pre-programmed conditions such as those described above at low and full loads. Control geometry changes. In another embodiment, a feedback loop operates on the controller 132 that receives sensed turbine parameters, in which case the sensed turbine parameters are used to determine the geometry of the airfoil 200. For example, the sensor measures the temperature in the combustor and the amount of unwanted combustion by-products. Thus, the sensed temperature and by-product parameters are used to determine an improved airfoil and guide vane geometry for turbine output production at the sensing conditions and send a corresponding current level to the shape memory material. In embodiments, the shape memory material changes the airfoil 200 geometry in one or more dimensions or regions and / or the overall vane profile. For example, the shape memory material and the wire are configured to cause span and / or chordal expansion and contraction of the guide vane. In addition, the shape memory material is configured to cause rotation of at least a portion of the guide vane. For example, the wire can be embedded in the airfoil wall to cause a change in the span of the guide vane and rotation of the airfoil tip about the fixed root.

  FIG. 3 is a cross-sectional view of an embodiment of a guide vane in the shape of an airfoil 300. The airfoil 300 includes a leading edge 302 and a trailing edge 304. The airfoil 300 includes an airfoil wall 306, where at least a portion of the wall 306 includes a shape memory material. The shape memory material includes a leading edge wire 308 and a trailing edge wire 309 embedded within the flexible composite material of the airfoil wall 306. The airfoil 300 is generally hollow with a cavity 310 that provides flexibility to the airfoil. Thus, the airfoil 300 geometry changes when energy is applied to the wall flexible shape memory material. As shown, the leading edge wire 308 and trailing edge wire 309 are embedded in the wall 306 to store shape memory regions in both the leading and trailing edge portions 302, 304 of the airfoil 300. Accordingly, a selected current is applied to the leading edge wire 308 and / or the trailing edge wire 309 based on turbine conditions to cause a change in shape of the leading edge 302 and trailing edge 304, respectively. Accordingly, in some embodiments, the shape memory material in the guide vane 300 allows a substantially uniform air flow incidence on the rotor blades for multiple turbine load conditions. Nearly uniform incidence results in a uniform radial distribution of spanwise air flow across the rotor blades, where the near uniform incidence results in improved compressor and combustor efficiency at selected turbine load conditions. Let Further, the shape memory material in the guide vane 300 is designed such that the fixed guide vane geometry improves combustion and efficiency in one condition, but is less efficient in the second condition, Increases overall turbine efficiency.

  FIG. 4 is a perspective view of an embodiment of a guide vane 400. Guide vane 400 is illustrated as a form of first shape 402 and second shape 404. As described above, the shape memory material in the guide vane 400 is capable of changing geometry when energy in the form of current is applied to the shape memory material. In an embodiment, the shape or geometry change causes the guide vane 400 to pivot as indicated by arrow 406. A vane root 408 or vane tip 410 is attached to the compressor to allow rotation. For example, if the vane root 408 is attached to the inner wall, hub or casing of the compressor, the vane tip 410 rotates 406 relative to the root 408 when current is applied to the shape-changing material. . As shown in FIG. 4, attaching either root 408 or tip 410 to the compressor allows relative rotation 406 of the root 408 and / or tip 410. The rotation of the guide vane 400 results in improved incidence of airflow onto the rotor at full load conditions of the first shape 402 and at low load conditions of the second shape 404. In the embodiment, the shape of the guide vane 400 is different from the airfoil. In embodiments with other guide vane shapes, the shape-changing material and guide vane 400 are configured to cause a geometry change based on conditions that improve turbine efficiency.

  Although the present invention has been described in detail only with respect to 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. Moreover, while various embodiments of the invention have been described, it is to be understood that aspects of the invention can include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is limited only by the scope of the claims.

100 Gas turbine 102 Axis 104 Guide vane 106 Compressor 108 Inner hub 110 Outer casing 112 Inlet region 114 Air flow 116 Rotor 118 Stator 120 Rotor 122 Stator 124 Rotor 126 Stator 128 Flow 130 Power supply 132 Controller 134 Blade chord 136 Length 200 airfoil 202 leading edge 204 trailing edge 206 airfoil wall 208 wire 210 cavity 300 airfoil 302 leading edge 304 trailing edge 306 airfoil wall 308 wire 310 cavity 400 guide vane 402 first shape 404 second Shape 406 Rotation 408 Vane root 410 Vane tip

Claims (10)

An air flow control device,
A guide vane (104) positionable between the inlet (112) of the turbomachine (100) and the rotor (116);
The guide vane (104) has a geometry configured to control air flow incidence on the rotor (116), the guide vane further having a substantially constant aspect ratio, and the guide vane ( 104) the apparatus wherein the body of 104) includes at least in part a shape memory material configured to change the geometry of the guide vane (104) in response to energy supplied by the power source (130).   The apparatus of claim 1, wherein the energy is applied to the shape memory material based on turbine load conditions.   The apparatus of claim 1 or claim 2, wherein the guide vane (104) comprises a unitary structure and the guide vane geometry comprises a leading edge (202) and a trailing edge (204).   The shape memory material includes a portion of the trailing edge (204) and is configured to change a shape of the trailing edge (204) to control air flow incidence on the rotor (116). Item 3. The apparatus according to Item 3.   The shape memory material includes a portion of the leading edge (202) and is configured to change the shape of the leading edge (202) to control air flow incidence on the rotor (116). The apparatus according to claim 3. A method for controlling air flow in a compressor (106) comprising:
Flowing air from the inlet (112) toward the guide vane (104);
Applying energy to the shape memory material in the guide vane (104) to change the geometry of the guide vane (104) to control the incidence of air flow onto the rotor (116). .   The method of claim 6, wherein applying the energy comprises changing a geometry of the guide vane (104) from a first shape to a second shape based on turbine load conditions.   8. The method of claim 6 or claim 7, wherein applying energy to the shape memory material comprises applying an electric current to a conductive wire embedded in a flexible composite.   The method of claim 6 or claim 7, wherein applying the energy includes causing a substantially uniform air flow incidence on the rotor (116) based on conditions.   The step of applying energy comprises causing movement of a root (408) or tip (410) of the guide vane (104) as the geometry of the guide vane (104) changes. 7. The method according to 7.