JP5281166B2 - Gas turbine with cooling insert - Google Patents

Description

  The present invention relates to a gas turbine. The gas turbine includes a plurality of rotor blades that are assembled in each case to form a plurality of rotor blade rows and disposed on a turbine shaft. The gas turbine further includes a plurality of rotor blades assembled in each case to form a plurality of rotor blade rows and secured on the turbine casing by a stator blade carrier. Air cooling holes.

  Gas turbines are used in many fields to drive generators or to drive machines. In this case, the energy content of the fuel is used to generate the rotational movement of the turbine shaft. For this purpose, the fuel is burned in the combustion chamber, and compressed air is supplied from the air compressor to the combustion chamber. The high-temperature and high-pressure working medium produced in the combustion chamber as a result of the combustion of the fuel is in this case guided to a turbine unit connected downstream of the combustion chamber and expanded by expansion in the turbine unit. Execute.

  A plurality of rotor blades are disposed on the turbine shaft to produce a rotational movement of the turbine shaft. The plurality of rotor blades are conventionally assembled to form a plurality of blade groups or a plurality of blade rows, and drive the turbine shaft by impact transferred from the working medium. Furthermore, a plurality of stator blades are conventionally arranged between adjacent rows of rotor blades for guiding the flow of the working medium through the turbine unit. The plurality of stator blades are connected to the turbine casing and are assembled so as to form a plurality of stator blade rows.

  The combustion chamber of the gas turbine can be configured as a so-called annular combustion chamber. A number of burners arranged around the turbine shaft in the circumferential direction of the turbine shaft are introduced into a common combustion chamber space. The common combustion chamber space is surrounded by a surrounding wall that is resistant to high temperatures. For this reason, the combustion chamber as a whole is configured as an annular structure. A number of combustion chambers can also be provided in addition to a single combustion chamber.

  The first stator blade row of the turbine unit is generally directly adjacent to the combustion chamber, and is directly adjacent to the subsequent rotor blade row as viewed from the flow direction of the working medium. . The first stator blade row of the turbine unit forms a first turbine stage of the turbine unit, and conventionally a plurality of further turbine stages are connected to the first turbine stage.

  In this case, the stator blades are fixed on the stator blade carrier of the turbine unit via blade bases (or blade roots), also called platforms, in each case. In this case, the stator blade carrier may comprise an insulating segment for securing the stator blade platform. In each case between the stator blade platforms of two adjacent stator blade rows, i.e. between the platforms spaced apart in the axial direction of the gas turbine, in each case the stator blade carrier of the turbine unit A guide ring is arranged on the top. Such a guide ring forms a related rotor blade row by a radial gap and is spaced a predetermined distance from each blade tip of a plurality of rotor blades fixed on the turbine shaft at the same axial position. . As a result, the stator blade platform and the plurality of guide rings that can be segmented in the circumferential direction of the gas turbine form a plurality of wall members of the turbine unit and constitute the outer limit of the working medium flow passage. .

  For example, in this case, the guide ring as known from US Pat. In Patent Document 1, the plurality of guide ring segments are hooked (hooked) to the stator blade carrier. A through hole for supplying cooling air to the guide ring is provided inside the wall of the guide ring segment. A pretension sleeve that presses the guide ring segment against the hook is screwed into the through hole. Cooling air flowing through the inside of the sleeve can flow through the opening into the rear space on the cooling gas side of the guide ring segment, and is used for cooling the guide ring segment. Patent document 2 has shown fixation and cooling of a guide ring segment as an alternative structure.

  Furthermore, a hole can be provided in the stator blade carrier, through which the measuring lance is guided. The measuring lance records the radial gap between the guide ring segment and the rotor blade tip. A cooled measuring lance is known from US Pat.

  In such a gas turbine configuration, in addition to the achievable power, a particularly high efficiency is customarily a configuration goal. In this case, an increase in efficiency can basically be obtained by increasing the outlet temperature at which the working medium is derived from the combustion chamber and flows into the turbine unit for thermodynamic reasons. Thus, temperatures of approximately 1200 ° C. to 1500 ° C. are targeted and are also obtained for such gas turbines.

  However, when the operating medium is at such a high temperature, components and parts that are exposed to such a high temperature operating medium are subject to a large heat load. Thus, among other things, gas turbine stator blade carriers are customarily made from cast steel. This is because it is suitable for withstanding the high temperature inside the gas turbine. Further, conventionally, cooling air holes are provided in the stator blade carrier. Through the cooling air holes, cooling air from the outside of the gas turbine flows into the inside to cool the stator blade carrier during the process. In this case, a plurality of cooling air reservoirs having different temperatures and different pressures are conventionally provided between the turbine casing and the stator blade carrier.

  Thus, among other things, sufficient cooling of the stator blade carrier is required. Because of the extremely high temperature, the resulting extremely large temperature difference between the different states causes a thermal deformation of the stator blade carrier. This must be taken into account in the design of the gas turbine. In this case, in particular, the gap size of the radial gap between the rotor blade tip and the inner wall can compensate for variations induced as a result of the deformation of the stator blade carrier and can prevent damage to the gas turbine. Therefore, it must be chosen to be correspondingly large. However, increasing the gap leads to a reduction in gas turbine efficiency. As a result, sufficient cooling must therefore always be ensured so that the amount of deformation of the stator blade carrier can be reduced.

  On the other hand, strong cooling of the stator blade carrier also means a large consumption of cooling air flowing into the interior of the gas turbine. This lowers the temperature inside the gas turbine and, as a result, reduces the efficiency of the gas turbine.

US Pat. No. 3,864,056 GB 1 524 956 US Patent Application No. 2006/0140754 A1

  Accordingly, an object of the present invention is to disclose a gas turbine having particularly high efficiency while maintaining the reliability of operation as high as possible.

  The above object is achieved according to the invention by the feature that the cooling insert is provided in at least one air cooling hole for cooling the wall of the air cooling hole.

  The present invention is based on the viewpoint that in this case, particularly high efficiency can be achieved by increasing the temperature inside the gas turbine. This can be done by reducing the consumption of cooling air, ie by reducing the amount of cooling air introduced into the gas turbine. However, a reduction in the amount of cooling air causes an increase in the temperature of the stator blade carrier. This is because a smaller amount of air flows through the air cooling holes of the stator blade carrier and, as a result, a smaller amount of heat can be removed from the stator blade carrier. However, this can cause deformation of the stator blade carrier that must be taken into account in the manufacture of the gas turbine. Therefore, available cooling air should be used particularly effectively for cooling. That is, the maximum amount of heat should be taken away with the least amount of cooling air possible. Therefore, based on the knowledge that turbulent flow can conduct heat better than laminar flow, it can be considered to form a vortex in the air cooling hole for more effective wall cooling. This can be achieved by providing cooling inserts in the air cooling holes. More effective wall cooling can compensate for the reduced cooling of the stator blade carrier at the air cooling holes based on the reduced flow velocity of the cooling air.

  The cooling insert has a tube-like structure, and has a window-like wall opening on the tube wall. As a result, the cooling air flowing through the cooling insert can be brought into contact with the air cooling hole wall of the stator blade carrier, and heat energy can be taken from the air cooling hole of the stator blade carrier.

  In a particularly preferred embodiment, the wall openings are separated from each other by ribs over a large area. As a result, the cooling air can contact the wall of the air cooling hole over a large area.

  In an advantageous embodiment, each cooling insert comprises at least one stirrer. The stirrer is a small protrusion. That is, the obstacle has an overall surface that can convert laminar flow into turbulent flow. For example, the stirrer can be formed by a plurality of ribs, or can be formed in the form of a raised wire, in the form of a corner made of sheet metal, or in a similar manner. Even if the flow in the air cooling holes is already turbulent, these stirrers can carry out better heat transfer and thus the entire stator blade carrier with reduced consumption of cooling air. A better cooling can be achieved.

  The cooling insert can advantageously also be formed as an insert of the type that cools by impact. In this case, for example, the wall openings are formed as collision-type cooling holes distributed in a lattice shape. The cooling air flowing through the cooling insert can be discharged radially through the impingement type cooling holes, so that the cooling air impinges laterally against the wall of the stator blade carrier air cooling holes. can do. As a result, particularly efficient cooling of the blade carrier can be obtained.

  Each cooling insert advantageously has a thread-like structure. As a result of the screw-like structure, a vortex can be induced during the flow of cooling air inside the air cooling holes. Thereby, on the one hand, the degree of vortex flow can be reliably increased, and on the other hand, the residence time of the cooling air in the air cooling hole can be increased. As a result, better heat conduction from the material forming the stator blade carrier toward the flowing cooling air can be reliably performed.

  Each cooling insert is advantageously formed from the same material as the stator blade carrier. As a result, difficulties resulting from the selection of different materials for the cooling insert and the stator blade carrier can be avoided, for example difficulties such as differences in the degree of thermal expansion, and overall a fairly simple construction. Make it possible.

  By providing the cooling insert in the air cooling hole of the stator blade carrier, the cooling characteristics by the air cooling hole are changed. Only a smaller amount of cooling air is required to achieve the same cooling effect. Therefore, the cooling air supplied to the air cooling holes should advantageously be adapted to the cooling characteristics of the respective cooling insert. This means that the temperature and pressure of the introduced cooling air is optimized for the newly modified cooling characteristics by the cooling insert.

  Such a gas turbine is advantageously used in a turbine plant using gas and steam.

  An advantage associated with the present invention is that, in particular, by providing cooling inserts in the air cooling holes of the stator blade carrier, as a result of improving the cooling characteristics with a simultaneously reduced amount of cooling air, the advantages of the gas turbine. It is possible to achieve good efficiency. Furthermore, such inserts can be installed very easily, and can be installed relatively easily as a modification of an older gas turbine. The cooling insert can also be flexibly adapted to each requirement relating to cooling and each requirement relating to consumption of cooling air.

It is sectional drawing which shows a gas turbine. It is sectional drawing which shows the lower half of the insert for cooling. It is a top view which shows the insert for cooling.

  Exemplary embodiments of the present invention will be described in detail with reference to the drawings.

  Throughout the drawings, the same members are denoted by the same reference numerals.

  As shown in FIG. 1, the gas turbine 1 includes a compressor 2 for combustion air, a combustion chamber 4, a turbine unit 6 for driving the compressor 2, and a generator or drive machine (not shown). I have. In addition, the turbine unit 6 and the compressor 2 are installed on a common turbine shaft 8. The common turbine shaft 8 is also referred to as a turbine rotor, is connected to a generator or a drive machine, and is rotatable around the central axis 9. A combustion chamber 4 configured as an annular combustion chamber is provided with a plurality of burners 10 for burning liquid or gaseous fuel.

  The turbine unit 6 includes a plurality of rotatable rotor blades 12 connected to the turbine shaft 8. The rotor blades 12 are installed on the turbine shaft 8 in a ring-like manner and thus form a plurality of rotor blade rows. Furthermore, the turbine unit 6 includes a plurality of fixed stator blades 14. The plurality of stator blades 14 are also fixed in a ring manner on the stator blade carrier 16 of the turbine unit 6 to form a stator blade row. In this case, the plurality of rotor blades 12 function to drive the turbine shaft 8 as a result of impact force conversion from the working medium M flowing through the turbine unit 6. On the other hand, the plurality of stator blades 14 extend between two adjacent rotor blade rows or between two adjacent rotor blade rings when viewed along the flow direction of the working medium M. Function to guide the distribution of In this case, an adjacent pair of two stator blade 14 rings or stator blade rows and two rotor blade 12 rings or rotor blade rows is also referred to as a turbine stage.

  Each stator blade 14 has a platform 18. The platform 18 is installed as a wall member and functions to fix each stator blade 14 on the stator blade carrier 16 of the turbine unit 6. The platform 18 is in this case a component that is subjected to a very large thermal load and forms the outer limit of the hot gas path for the working medium M flowing through the turbine unit 6. Each rotor blade 12 is similarly fixed on the turbine shaft 8 via a platform 19, also referred to as a blade root.

  A guide ring 21 is installed on the stator blade carrier 16 of the turbine unit 6 between two spaced apart platforms 18 of the stator blades of two adjacent stator blade rows. In this case, the outer surface of each guide ring 21 also flows into the hot working medium M flowing through the turbine unit 6 in the radial direction as a result of a gap spaced from the outer end of the opposing rotor blade 12. Have been exposed. In this case, the guide ring 21 installed between adjacent stator blade rows, in particular, the hot working medium M flowing through the turbine 6 through the inner casing 16 or other components of the casing in the stator blade carrier. It functions as a cover member for protecting from excessive thermal stress as a result of the above.

  In a typical embodiment, the combustion chamber 4 is configured as a so-called annular combustion chamber. In this configuration, a number of burners 10 installed around the turbine shaft 8 in the peripheral direction are connected into a common combustion chamber space. For this purpose, the combustion chamber 4 is generally configured as an annular structure arranged around the turbine shaft 8.

  Because the stator blade carrier 16 is also heated as a result of the high temperature of the working medium M, a plurality of air cooling holes are formed in the stator blade carrier 16. Through the air cooling holes, different temperatures and pressures of cooling air are guided from various chambers outside the region of the stator blade carrier 16 through the stator blade carrier 16 and into the gas turbine 1. The cooling air can surely cool the stator blade carrier 16. Thereby, the thermal deformation of the stator blade carrier 16 can be reduced.

  However, because a large amount of cooling air reduces the temperature inside the gas turbine 1 and, as a result, reduces the efficiency of the gas turbine 1, the amount of cooling air used is: Should be as minimal as possible. However, in order to ensure sufficient cooling of the stator blade carrier 16, a cooling insert 22 is inserted into the air cooling hole. When the cooling insert 22 is formed as an insertion member that cools by collision, the outer diameter of the cooling insert 22 is slightly smaller than the diameter of the air cooling hole.

  A half cross section of such a cooling insert 22 is shown in FIG. The cooling insert 22 has a substantially cylindrical shape. Thereby, it can insert in the existing air cooling hole. In this way, the existing gas turbine can be modified to have such a cooling insert 22. Furthermore, the cooling insert can be of a tubular shape. In other words, the cooling insert can be exposed to axial flow along the entire axial direction. On the other hand, the cooling insert 22 is provided with a flange 23 for fixing in this case.

  On the tube wall having a circular cross-sectional shape, the cooling insert 22 has a plurality of window openings 25 like a window. The wall openings 25 can be arranged in a distributed manner along the axial direction and along the peripheral direction. The wall openings are of a fairly large area and are separated from each other by ribs 26. Such a cooling insert 22 has an outer diameter that matches the diameter of the air cooling hole, unlike a cooling insert that cools by collision.

  The ribs 26 extending in the peripheral direction of the cooling insert 22 are configured as a stirrer 24. The air flow is decomposed on the stirrer 24, and the laminar flow is converted into turbulent flow. In this case, the stirrer can have other shapes and arrangements. The turbulent flow contacts the wall of the stator blade carrier air cooling hole in the region of the wall opening 25, thereby cooling the stator blade carrier wall. As a result, better heat conduction from the material forming the stator blade carrier 16 toward the cooling air can be reliably performed. The ribs 26 and the stirrer 24 can also be installed in the form of threads. As a result, an additional swirling flow can be impacted against the cooling air, whereby the residence time and the degree of vortex flow in the air cooling hole can be further increased.

  FIG. 3 shows the air cooling insert 22 again in plan view. The flange 23 for fixing in the air cooling hole of the stator blade carrier 16 is again illustrated here. As a result of the cooling insert 22, due to the improved heat transfer from the material forming the stator blade carrier 16 to the cooling air in the air cooling holes, the cooling air supplied to the stator blade carrier 16 is: It should be compatible with the new cooling air characteristics. As a result, even better and more effective cooling of the stator blade carrier 16 can be achieved simultaneously with less cooling air consumption. Therefore, the efficiency of the gas turbine 1 can be improved as a whole.

DESCRIPTION OF SYMBOLS 1 Gas turbine 2 Compressor 4 Combustion chamber 6 Turbine unit 8 Turbine shaft 12 Rotor blade 14 Stator blade 16 Stator blade carrier 22 Cooling insert 24 Stirrer 26 Rib M Working medium

Claims (8)

A gas turbine (1),
This gas turbine (1)
A plurality of rotor blades (12) disposed on the turbine shaft (8) so as to form a plurality of rotor blade rows;
A plurality of stator blades (14) secured to the turbine casing by a stator blade carrier (16) so as to form a plurality of stator blade rows;
Comprising
The stator blade carrier (16) has a plurality of air cooling holes;
In such a gas turbine (1),
A cooling insert (22) is provided in the at least one air cooling hole for cooling the wall of the air cooling hole;
Said cooling insert (22) is a tube-like configuration,
The gas turbine according to claim 1, wherein the cooling insert (22) has a wall opening (25) provided in a tubular wall of the cooling insert (22). The gas turbine (1) according to claim 1, wherein
A gas turbine characterized in that the wall openings are separated from each other by ribs (26). Gas turbine (1) according to claim 1 or 2,
Each of the cooling inserts (22) has at least one stirrer (24). Gas turbine (1) according to claim 1 or 2 or 3,
The gas turbine according to claim 1, wherein the wall opening is formed as a hole for cooling by collision. In the gas turbine (1) according to any one of claims 1 to 4,
Each of the cooling inserts (22) has a screw-like structure. In the gas turbine (1) according to any one of claims 1 to 5,
Each of the cooling inserts (22) is made of the same material as the stator blade carrier (16). In the gas turbine (1) according to any one of claims 1 to 6,
A gas turbine characterized in that the cooling air supplied to the air cooling hole is adapted to the cooling characteristics of the cooling insert (22). A turbine plant using gas and steam,
A turbine plant comprising the gas turbine (1) according to any one of claims 1 to 7.

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