JP2014177937A - Casing for turbine engine having cooling unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inner shell and temperature controlling fluid conduits which make it possible to selectively control a clearance between tips of rotating turbine blades and surrounding shrouds of the turbine in order to prevent the tips of the turbine blades from rubbing the shrouds as the turbine blades rotate in a turbine engine.SOLUTION: A turbine inner shell 110 for a turbine engine includes one or more mounting grooves 120, each of which receives a fluid conduit 200. A temperature controlling fluid is circulated through the fluid conduit to selectively heat or cool surrounding portions of the turbine inner shell, to thereby control the thermal growth of those portions of the turbine inner shell.

Description

  The present invention relates to an inner shell and a temperature controlled fluid tube.

  An industrial turbine engine includes a compressor section, a combustor section, and a turbine section. In the turbine section, multiple rows of turbine blades (or buckets) attached to the rotor rotate between corresponding rows of stationary nozzles. A circumferential shroud is mounted on the turbine casing for each row of turbine blades, and the shroud is radially disposed just outside the tip of the turbine blade.

  A clearance must be maintained between the tip of the turbine blade and the shroud so that the tip of the turbine blade does not rub the shroud as the turbine blade rotates. However, it is desirable to keep the clearance as small as possible so that the working gas does not escape around the tip of the blade. Generally speaking, the smaller the clearance, the higher the efficiency of the turbine.

  During transient periods, such as when the turbine is starting up or when the turbine is increasing or decreasing the load or rotational speed, the temperature of the various elements within the turbine compartment may go up and down. Unfortunately, these various factors tend not to raise or lower the temperature at the same rate. For example, at start-up, turbine blades tend to rise in temperature more rapidly than turbine casings holding shrouds around the tips of the turbine blades. The turbine rotor blades are mounted on disks, and these disks are also heated to expand radially outward.

  When the temperature of one part of the turbine rises more rapidly than the other part, the part that is heated relatively quickly can undergo more rapid thermal expansion / growth than the part that is slowly rising in temperature. . At startup, if the temperature of the turbine blade increases more rapidly than the turbine casing holding the shroud, the turbine blade may experience more rapid thermal growth than the turbine casing.

  Also, different parts of the turbine are made of different materials having different coefficients of thermal expansion. Even if all elements rise in temperature at the same rate, different elements will grow in different amounts relative to each other due to differences in the coefficient of thermal expansion of the various materials.

  Another factor is the load on the various factors. The turbine rotor blade and the disk on which the turbine rotor blade is mounted are subjected to mechanical centripetal force because the rotor blade and the disk are rotating. This can also cause the disks and turbine blades to grow radially. At relatively low rotational speeds, this mechanical load results in relatively small growth. However, as the rotational speed increases, the moving blades and disks tend to grow longer. In contrast, the shroud surrounding the turbine blade does not rotate and does not undergo any growth due to centripetal force.

  When the designer determines the dimensional specifications for each element of the turbine, the factors described above should be used to ensure that the turbine blade does not grow long enough to begin to scratch the shroud at any given time point. All of this must be taken into account. However, designing turbine elements to ensure that the clearance between the turbine blade tip and the shroud is always guaranteed ensures that the clearance is greater than desired during steady-state operation, which increases turbine engine efficiency. Can have adverse effects.

  To address this problem, selected portions of the turbine casing can be heated and / or cooled during transient or steady state operation to control the position of the shroud radially. Then, the clearance between the tip of the turbine blade and the shroud is also controlled. By selectively heating or cooling portions of the turbine casing during the transition period, a clearance can be reliably maintained between the tip of the turbine blade and the shroud during the transition period. In addition, selective heating and / or cooling of the turbine casing during steady state operation can reduce the clearance between the tip of the turbine blade and the shroud to the minimum dimension desired, thereby reducing the turbine engine Efficiency can be maximized.

  Prior art attempts to selectively heat and / or cool the turbine casing have required that the coolant passage be formed at a selected location, such as just outside the shroud radially in the turbine casing. It was. Manufacturing turbine casings in this manner can be expensive and difficult. Also, it is impossible to incorporate such a design into an existing turbine engine. The turbine casing must be manufactured from the outset to include the coolant passage.

  In a first aspect, the present invention can be embodied as an inner shell for a turbine section of a turbine engine, such that the inner shell forms a generally cylindrical inner shell. A plurality of arcuate casing portions configured to be attached to each other are included. Each arcuate casing portion has at least one shroud hook portion extending along the inside of the arcuate casing portion in the circumferential direction and at least extending along the arcuate casing portion in the circumferential direction. One mounting groove. Each at least one mounting groove is located adjacent to one of the at least one shroud hook portions. At least one tube having at least one internal passage for the temperature control fluid is mounted within one of the at least one mounting groove. At least one tube is configured to be slidably inserted into the mounting groove in the circumferential direction.

  In another aspect, the present invention may be embodied as a temperature controlled fluid tube that is configured to be attached to an arcuate portion of an inner shell of a turbine section of a turbine engine. The fluid tube includes an elongated arcuate body having an internal passage for temperature control fluid and at least one inlet opening configured to direct the flow of temperature control fluid into the internal passage.

FIG. 2 is a diagram illustrating an interface between a rotating turbine blade of a turbine section of a turbine engine and a surrounding portion of a turbine shell. It is a figure which shows the fluid pipe | tube currently slidingly inserted in the mounting groove of the turbine inner shell. It is a figure which shows the fluid pipe | tube completely installed in the mounting groove of the turbine inner shell. It is sectional drawing of 1st embodiment of the fluid pipe | tube installed in the mounting groove of the turbine inner shell. It is sectional drawing of 2nd embodiment of the fluid pipe | tube installed in the mounting groove of the turbine inner shell. 2 is a partial perspective view of a portion of a first embodiment of a temperature controlled fluid tube having a protrusion on the outer surface. FIG. FIG. 6 is a partial perspective view of a portion of a second embodiment of a temperature controlled fluid tube having a protrusion on the outer surface. It is sectional drawing of 3rd embodiment of the fluid pipe | tube installed in the mounting groove of the turbine inner shell.

  FIG. 1 is a diagram illustrating a portion of a turbine section of a turbine engine. FIG. 1 shows a turbine outer shell 100 and a turbine inner shell 110. The tips of two rows of turbine blades 122 and 124 are shown. These rows of turbine blades 122, 124 are mounted on a turbine rotor that rotates relative to the inner surface of the turbine inner shell 110. A row of stationary nozzles 130 is mounted between the two rows of turbine blades 122, 124 in the turbine inner shell 110.

  Circumferentially extending shrouds 142 and 144 are mounted at positions facing the tips of the turbine rotor blades 122 and 124 rotating in the turbine inner shell 110. Shrouds 142, 144 are attached to shroud hooks at turbine inner shell 110. As explained in the background section above, a clearance needs to be maintained between the tips of the rotating turbine blades 122, 124 and the stationary shrouds 142, 144. However, it is also desirable to minimize the clearance to maximize the efficiency of the turbine engine.

  FIG. 1 shows that temperature control fluid passages 150, 152 are formed in the turbine inner shell 110. Heated fluid can be circulated through the temperature control fluid passages 150, 152 to increase the temperature of the turbine inner shell, which causes the inner shell 110 to expand radially outward to provide shrouds 142, 144 and turbine blades. The clearance between the tips of 122 and 124 increases. At the same time, increasing the temperature of the shroud tends to cause thermal growth of the shroud, which tends to reduce the clearance. These factors must be balanced to ensure that the clearance is adjusted in the proper way using the correct temperature fluid.

  Conversely, to reduce the temperature of the turbine inner shell 110, cooling fluid can be circulated through the temperature control fluid passages 150, 152, causing the turbine inner shell 110 to contract radially inwardly and the shroud 142, The clearance between 144 and the tips of the turbine blades 122, 124 is reduced. At the same time, cooling the shroud tends to shrink the shroud, thereby increasing the clearance. Again, the fluid temperature must be carefully controlled to ensure proper clearance.

  It may be advantageous to increase or decrease the clearance using fluids of appropriate temperature at different times. However, the design shown in FIG. 1 requires that fluid passages be formed in the turbine inner shell and can be expensive.

  FIG. 2 shows a design embodying the invention for a turbine engine's turbine inner shell 110 that includes a fluid tube 200 that can carry a flow of temperature controlled fluid. The turbine inner shell of a turbine engine is typically comprised of two or more arc-shaped sections that are bolted together to form a generally cylindrical turbine inner shell. FIG. 2 shows a portion of one arc-shaped section of the turbine inner shell 110. FIG. 2 also shows that several shroud hooks 114 are formed on the radially inner surface of the turbine inner shell 110. A shroud facing the tip of the rotating turbine blade is attached to the shroud hook 114.

  A mounting groove 120 is formed in the turbine inner shell 110 at a position immediately adjacent to one radially outer side of the set of shroud mounting hooks 114. An elongated arc-shaped tube 200 is mounted in the mounting groove 120. FIG. 2 shows that the fluid pipe 200 is partially inserted into the mounting groove 120. FIG. 3 shows the fluid tube 200 fully inserted into the mounting groove 120. 2 and 3 also show that when the fluid tube 200 is fully inserted into the turbine inner shell 110, the mounting block portion 240 provided on the fluid tube is aligned with the mounting block portion 112 of the turbine inner shell 110. Show.

  FIG. 4 shows a cross-sectional view of the first embodiment of the fluid pipe 200 mounted in the mounting groove 120 of the turbine inner shell 110. The fluid tube 200 has a lower surface portion 210 that abuts a wall 116 that separates the mounting groove 120 from a position where the shroud is mounted on the shroud mounting hook 114.

  The fluid tube 200 has a stepped shape and includes an upper portion 230 having a small cross-sectional area that encloses the first internal passage 232 and a lower portion having a large cross-section that encloses the second internal passage 220. A partition wall 222 provided with a plurality of openings 234 separates the first internal passage 232 from the second internal passage 220.

  The upper portion 230 also provides bending and torsional stiffness to the structure, helping the lower portion maintain its shape. This also helps to prevent any deformation of the lower part from affecting the shape and position of the underlying shroud.

  A supply pipe 250 is attached to the upper part 230 of the fluid pipe 200. Supply pipe 250 feeds the flow of temperature control fluid into first internal passage 232. The temperature control fluid can flow circumferentially along the first internal passage 232. The temperature control fluid can also enter the second internal passage 220 through the opening 234 in the septum 222. The partition wall 222 provided with the opening 234 allows the flow of the temperature control fluid fed into the first internal passage 232 to pass through the turbine inner shell 110 before the temperature control fluid enters the second internal passage 220 through the opening 234. To be evenly distributed in the circumferential direction around

  The flow of the temperature control fluid that has entered the second internal passage 220 flows out of the fluid pipe 200 through a plurality of openings 212 that pass through the lower wall 210 of the fluid pipe 200. As will be described in detail later, the outer wall of the fluid pipe 200 is separated from the inner wall of the mounting groove 120. As a result, the temperature control fluid passes along the gap between the outer wall of the fluid tube 200 and the inner wall of the mounting groove 120 and eventually exits to a position radially outward of the turbine inner shell 110. The arrows in FIG. 4 indicate the flow of the temperature control fluid, which flows from the supply pipe 250 into the first internal passage 232 and from the first internal passage 232 to the second internal passage 220. , Exits aperture 212, travels around the outside of fluid tube 200, and exits to a location radially outside of turbine inner shell 110.

  In alternative embodiments, the fluid circulating through the first and second internal passages does not necessarily have to be delivered to a position radially outward of the inner shell 110. Alternatively, the fluid may be collected and used for other purposes within the turbine inner shell 110.

  With the configuration shown in FIG. 4, the temperature control fluid impinges on the wall 116 adjacent to the shroud mounting hook 114. As a result, the temperature control fluid can heat or cool the portions of the turbine inner shell and the shroud directly opposite the rotating turbine blade tips. This provides a quick and effective control over the thermal growth of these parts of the turbine and thus the clearance between the turbine blade and the shroud.

  The step shape of the mounting groove 120 and the corresponding step shape of the fluid tube 200 allow the fluid tube 200 to be easily mounted to the turbine inner shell 110. A staircase shape such that the radially outer portion has a smaller cross-sectional shape than the radially inner portion ensures that the fluid tube is captured by the turbine inner shell 110 without the use of fittings. Other shapes for the mounting groove 120 and the fluid tube 200 may perform the same function. For example, the mounting groove 120 and the fluid tube 200 may have a trapezoidal or triangular shape, with the radially outer portion having a smaller dimension than the radially inner portion. Further, in some embodiments, the shape of the mounting groove does not necessarily match the shape of the fluid pipe.

  FIG. 5 shows an alternative configuration of the fluid tube 200. In this embodiment, no partition is provided between the first fluid passage 232 and the second fluid passage 220. This embodiment may be advantageous in embodiments where it is not important that the temperature control fluid is reliably distributed circumferentially. Without a partition, flow constraints are reduced.

  FIG. 6 illustrates that a plurality of protrusions 242, 244, 246 may be formed on the outer wall of the fluid tube 200 embodying the invention. The protrusions 242, 244 and 246 are for separating the outer wall of the fluid pipe 200 from the inner wall of the mounting groove 120 in the turbine inner shell 110. By maintaining the distance, as shown in FIGS. 4 and 5, the temperature control fluid can pass along the space between the outer wall of the fluid pipe 200 and the inner wall of the mounting groove 120. Although not shown in FIG. 6, similar protrusions may be formed on the bottom wall of the fluid pipe 200.

  In the embodiment shown in FIG. 6, the protrusions 242, 244, 246 extend in the length direction of the fluid pipe 200. Further, the front edge and the rear edge of the protrusion are tapered. The tapered elongated shape of the protrusions 242, 244, 246 is designed to facilitate sliding mounting of the fluid tube 200 into the mounting groove 120 of the turbine inner shell 110.

  FIG. 7 shows an alternative embodiment of the fluid tube 200. In this embodiment, the protrusion is formed as a ridge 248 that extends around the outer wall of the fluid tube 200. Although only a single ridge 248 is shown in FIG. 7, multiple ridges 248 may be located along the length of the fluid tube 200. Ridge 248 extends in essentially the same direction as temperature control fluid flows along the outside of fluid tube 200. In this way, the ridge 248 does not interfere with the flow and can help direct the flow of the temperature control fluid.

  FIG. 8 illustrates another embodiment of a fluid tube 300 mounted in a mounting groove 320 of the turbine inner shell 110. In this embodiment, no protrusion is formed on the outer wall of the fluid pipe 300. As a result, the bottom wall 310 and the side outer wall of the fluid pipe 300 can be in direct contact with the inner wall of the mounting groove 320.

  When a fluid tube embodiment such as that shown in FIG. 8 is used in the turbine inner shell 110, the incoming flow of temperature control fluid is used using one or more of the pipes coupled to the internal passage 320 of the fluid tube 300. One or more of the pipes that feed into and are coupled to the internal passage 320 take out the flow of temperature control fluid. The pipes used to feed the incoming flow and the pipes used to draw the outgoing flow are arranged around the fluid pipe so as to produce a predetermined flow pattern through the internal passage 320 of the fluid pipe 300. .

  A fluid tube as described above can be easily attached to the turbine inner shell to help control the clearance between the tip of the turbine blade and the surrounding shroud. The fluid lines can be easily inserted and removed from the corresponding mounting grooves when the sections of the turbine inner shell are separated for maintenance and repair. The mounting groove for the fluid pipe described above can also be machined into an existing turbine inner shell, providing a way to actively control the clearance between the tip of the turbine blade and the surrounding shroud. It makes it possible to incorporate such fluid pipes into existing turbines that do not have.

  Although the invention has been described with respect to what is considered to be the most practical and preferred embodiment at present, the present invention is not limited to the disclosed embodiment, and conversely, is included in the spirit and scope of the claims. It is intended to cover various modifications and equivalent configurations.

110: inner shell 112, 240: block portion 114: shroud hook 116: wall 120, 320: mounting groove 122, 124: turbine blade 130: stationary nozzle 142, 144: shroud 150, 152: fluid passage 200, 300: Fluid pipe 210: Lower wall 220, 232, 320: Internal passage 222: Partition 230: Upper part 234: Opening 242, 244, 246: Projection 248: Ridge 250: Supply pipe 310: Bottom wall

Claims (19)

An inner shell for a turbine section of a turbine engine having a plurality of arcuate casing portions configured to be attached to each other to form a generally cylindrical inner shell, each circle The arcuate casing part is
At least one shroud hook portion extending circumferentially along the inside of the arcuate casing portion;
At least one mounting groove extending along the arcuate casing portion in the circumferential direction, each at least one mounting groove being located adjacent to one of the at least one shroud hook portion. Including at least one mounting groove;
At least one tube has at least one internal passage for temperature control fluid, each tube being mounted within one of the at least one mounting groove, the at least one tube being mounted An inner shell configured to be inserted into the groove.   The inner shell of claim 1, wherein a radially inner side of the at least one mounting groove has a width greater than a radially outer side of the at least one mounting groove.   The inner shell of claim 1, wherein each at least one mounting groove is located radially outward of one of the at least one shroud hook portions.   The inner shell of claim 1, wherein the internal passage of each at least one tube extends along the length of the tube.   The inner shell of claim 4, wherein each at least one tube includes a plurality of openings extending from the internal passage to the outside of the tube.   The inner shell of claim 5, wherein the plurality of openings are formed on a side of the tube facing the at least one shroud hook portion.   6. The inner shell of claim 5, wherein each at least one tube includes a plurality of protrusions formed on the outer surface of the tube.   The inner shell of claim 7, wherein the plurality of protrusions are configured to separate an outer surface of the tube from an inner surface of the at least one mounting groove. Each at least one tube
A first internal passage extending in the length direction of the tube;
A second internal passage extending in the longitudinal direction of the tube, wherein the first internal passage is located radially outward of the second internal passage; and
The inner shell of claim 1, comprising a plurality of radially extending openings extending between the first and second internal passages.   The inner shell of claim 1, wherein each at least one tube further includes at least one inlet opening configured to direct a flow of temperature control fluid into the internal passage.   The inner shell of claim 1, wherein the at least one tube is configured to be slidably inserted into the mounting groove in a circumferential direction. A temperature controlled fluid conduit configured to be attached to an arcuate portion of an inner shell of a turbine section of a turbine engine,
An elongated arc-shaped body having an internal passage for the temperature control fluid;
A temperature control fluid tube comprising at least one inlet opening configured to direct a flow of temperature control fluid into the internal passage.   The temperature controlled fluid conduit according to claim 12, wherein a radially inner side of the elongated body has a greater width than a radially outer side of the elongated body.   The temperature controlled fluid conduit according to claim 12, wherein the at least one inlet opening is located radially outward of the elongated arcuate body.   The temperature control fluid pipe according to claim 12, wherein the internal passage extends in a length direction of the elongated arc-shaped main body.   The temperature controlled fluid tube of claim 15, wherein a plurality of openings extend from the internal passage through the elongated arcuate body to the exterior of the body.   The temperature control fluid pipe according to claim 16, wherein the plurality of openings are formed radially inward of the elongated arcuate body.   The temperature control fluid pipe according to claim 16, wherein a plurality of protrusions are formed on at least one outer surface of the elongated arcuate body. The internal passage is
A first internal passage extending in the length direction of the elongated arc-shaped body;
A second internal passage extending in the longitudinal direction of the elongated arc-shaped body, wherein the first internal passage is located radially outward of the second internal passage; An internal passage,
The temperature controlled fluid conduit of claim 12, including a plurality of radially extending openings extending between the first and second internal passages.