JP2013064368A - Gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas turbine that achieves high efficiency in heating or cooling of a turbine casing.SOLUTION: The gas turbine includes a turbine casing 7 provided with a protruded turbulence promoter 8 on an outer peripheral surface, an outer portion casing 11 encasing the turbine casing and having an inlet 9 where the fluid inflows from the outside, and a shell 13 which partitions a space formed by the turbine casing and the outer portion casing and which has a plurality of impingement holes formed therein.

Description

  The present invention relates to a turbine that is a component of a gas turbine, and more particularly to a structure of a casing.

  A gas turbine is a thermo-fluid machine, and high efficiency is important. In particular, since the gap between the rotating body and the stationary body is directly connected to the leakage of the working fluid, it is necessary to make it sufficiently small while giving priority to non-contact. In general, an initial gap is set between the turbine casing and the rotor blades when the engine is stopped, and the gap becomes minimum with the centrifugal elongation of the wheels and rotor blades until the casing sufficiently warms up after startup. As the turbine casing rises in temperature, the gap also shows a behavior of gradually opening. Therefore, the gap during rated operation depends on the minimum gap during startup.

  Conventionally, a method of minimizing the gap value by improving the accuracy of predicting the thermal deformation has been generally used. Further, as disclosed in Japanese Patent Application Laid-Open No. 2004-60544, the thermal fluid is circulated outside the turbine casing, so that the thermal deformation of the turbine casing is controlled to the expansion side at startup and to the contraction side at rating, thereby minimizing the gap. Structures such as actively performing have been proposed.

JP 2004-60544 A

  However, in the future, it is expected that further efficiency improvement, that is, gap minimization will be required, and it is expected that the handling itself will need to be made more efficient when using a thermal fluid.

  Accordingly, an object of the present invention is to provide a gas turbine in which heating or cooling of a turbine casing is made more efficient.

  In order to achieve the above object, a gas turbine according to the present invention includes a turbine casing provided with a convex turbulence promoter on an outer peripheral surface, and an outer partial casing that includes the turbine casing and has an inlet through which fluid flows from the outside. And a shell that defines a space formed by the turbine casing and the outer partial casing and that has a plurality of impingement holes.

  ADVANTAGE OF THE INVENTION According to this invention, the gas turbine which made heating or cooling of a turbine casing more efficient can be provided.

It is a figure which shows the structural example of a typical gas turbine. It is a figure which shows the structural example of the casing which has a typical deformation | transformation control rib. 1 is an overall structural cross-sectional view of a gas turbine. It is a figure which shows the structural example of the shell provided with the impingement hole. It is a modification of FIG. 2 and is a diagram showing an example in which the interval in the turbine rotation axis direction of the turbulence promoter is changed stepwise. FIG. 6 is a diagram showing a modification of FIG. 2 and showing an example in which the interval of the turbulence promoter in the turbine rotation axis direction is continuously changed. FIG. 6 is a diagram showing a modification of FIG. 2 and showing an example in which the interval in the turbine circumferential direction of the turbulence promoter is changed stepwise. FIG. 5 is a diagram showing a modification of FIG. 2 and showing an example in which the interval in the turbine circumferential direction of the turbulence promoter is continuously changed. FIG. 5 is a modification of FIG. 4 and shows an example in which the interval between the impingement holes in the turbine rotation axis direction is changed stepwise. FIG. 5 is a modification of FIG. 4 and shows an example in which the interval between the impingement holes in the turbine rotation axis direction is continuously changed. FIG. 5 is a modification of FIG. 4 and is a diagram illustrating an example in which the interval in the turbine circumferential direction of the impingement holes is continuously changed. FIG. 5 is a modification of FIG. 4 and is a diagram illustrating an example in which the interval in the turbine circumferential direction of the impingement holes is continuously changed. It is a figure which shows the other structural example of the casing which has the shell for impingement, and a deformation | transformation control rib. It is a figure which shows the example of the shape of a rib. It is another figure which shows the example which arrange | positions a rib combining a phase, and the thanks which arrange | positions alternately.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  Before describing the embodiments of the present invention, first, the overall structure of a gas turbine to which the present invention is directed will be described. FIG. 3 is a structural cross-sectional view of a general gas turbine. The gas turbine is roughly divided into a compressor 1, a combustor 2 and a turbine 3. The compressor 1 adiabatically compresses air sucked from the atmosphere as a working fluid, the combustor 2 mixes fuel with the compressed air supplied from the compressor 1 and burns to generate high-temperature and high-pressure gas, and the turbine 3. Generates rotational power when the combustion gas introduced from the combustor 2 expands. Exhaust gas from the turbine 3 is released into the atmosphere.

  In particular, the turbine blades 4 are generally arranged alternately with the stationary blades 5 and fixed to an implantation groove provided on the outer peripheral side of the wheel 6.

  FIG. 1 is a diagram illustrating a structure example of a gas turbine according to a first embodiment of the present invention. As shown in the figure, the gas turbine is composed of a turbine casing 7 having a convex turbulence promoter 8 on the outer peripheral surface, and further includes an inlet 9 into which the fluid from the outside flows in and an outlet from which the fluid flows from outside. 10, an outer partial casing 11, and a shell 13 which is located between the turbine casing 7 and the partial outer casing 11 and has impingement holes. The detailed structure of the shell 13 will be described later. The turbine casing 7 includes a stationary blade 4 fixed to the inner peripheral surface side and a moving blade 5 fixed to a wheel 6 (not shown).

  The fluid from the outside is sprayed from the space defined by the outer partial casing 11 and the shell 13 through the impingement hole 12 to the turbulence promoter 8 of the turbine casing 7, thereby heating and cooling the turbine casing 7 with high efficiency. The heating and cooling process itself can be expected to be performed with high efficiency.

  Here, the turbulence promoter 8 provided in the turbine casing 7 is processed on the outer peripheral surface as shown in FIG. In this processing method, the casting may be performed on the mold when the turbine casing 7 is cast, or may be performed by machining, laser processing, or the like after casting.

  The shell 13 is shown in FIG. The shell 13 has a sealing wall 14 for partitioning a space in which the fluid flowing in from the inlet 9 of the outer partial casing 11 is temporarily held, and an impingement hole 13. The fluid ejected from the impingement hole 13 collides with a convex turbulence promoter 8 formed on the outer peripheral surface of the turbine casing 7.

  FIG. 5 to FIG. 8 show examples of arrangement of the convex turbulence promoter 8. The convex turbulence promoter 8 does not need to be arranged at equal intervals in the axial direction 17 of the turbine casing 7 and may be provided with a density stepwise from the upstream side to the downstream side as shown in FIG. The axial clearance 17 of the turbulence promoter 8 <the downstream axial clearance 17 '). This is because the turbulence promoter 8 is densely packed in a portion corresponding to the tip of the first stage rotor blade for which the gap is to be controlled to the minimum, so that the fluid does not need to flow into the partial outer casing 11 more than necessary. As shown in FIG. 6, the axial spacing 17 may be continuous (the axial clearance 17 of the turbulence promoter 8 on the upstream side <the axial clearance 17 ′ of the intermediate portion <the axial clearance 17 ″ on the downstream side). ).

  Further, as shown in FIG. 7, the density may be provided stepwise with respect to the circumferential interval 18 of the turbine casing 7. This is because the turbine casing 7 does not have a uniform structure in the circumferential direction. In addition, as shown in FIG. 8, the density of the circumferential interval 18 may be continuous.

  Next, FIG. 9 to FIG. 12 show arrangement examples of the impingement holes 12 formed in the shell 13. As shown in FIG. 9, the impingement holes 12 provided in the shell 13 do not need to have the axial intervals 17 evenly arranged, and may be provided with a density stepwise as shown in the figure. In addition, as shown in FIG. 10, the density of the axial interval 17 may be continuous.

  Further, as shown in FIG. 11, the density may be provided stepwise with respect to the circumferential interval 18 of the shell 13. In addition, as shown in FIG. 12, the density of the circumferential interval 18 may be continuous.

  FIG. 13 is a diagram illustrating a structure example of a gas turbine that is Embodiment 2 of the present invention. As shown in the figure, a turbine casing 7 having a convex turbulence promoter 8 on the outer peripheral surface, further including a turbine casing 7 and having an inlet 10 through which an external fluid flows in and an outlet 11 through which the fluid flows out. The outer casing 11 is located between the turbine casing 7 and the partial outer casing 11 and is formed of a shell 13 having an impingement hole 12.

  Here, the partial outer casing 11 in this embodiment is composed of two cylinders 15 and 15 ′ having different diameters, and is characterized by comprising a hollow disc 16 connecting these cylinders 15 and 15 ′. . In the case of FIG. 13, a cylinder 15 having a large diameter is arranged on the upstream side. Further, the radial heights (levels on the turbine rotating shaft side) of the cylinder 15 'and the shell 13 are aligned at the same position. In FIG. 14, the example of the cross-sectional shape of the turbulence promoter 8 is shown. The shape may be a circle, a polygon, a V shape, or the like.

  FIG. 15 shows an example of the arrangement of the turbulence promoter 8. The arrangement may be parallel or staggered.

  By adopting the means described in the above-described embodiments, the fluid from the outside is blown to the turbulence promoter of the turbine casing through the impingement hole, so that the turbine casing is heated and cooled with high efficiency. Thus, heating and cooling itself can be performed with high efficiency. Further, by providing the arrangement of the impingement holes or the turbulence promoters in a coarse and dense manner, it becomes possible to perform the heating and cooling of the portion facing the first stage rotor blade where the gap is to be minimized most efficiently.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Combustor 3 Turbine 4 Rotor blade 5 Stator blade 6 Wheel 7 Turbine casing 8 Turbulence promoter 9 Inlet 10 Outlet 11 Partial outer casing 12 Impingement hole 13 Shell 14 Sealing wall 15 Tube 16 Hollow disc W
17 Axial spacing 18 Circumferential spacing

Claims (9)

A turbine casing provided with a convex turbulence promoter on the outer peripheral surface;
An outer partial casing containing the turbine casing and having an inlet through which fluid flows from the outside;
A gas turbine, comprising: a shell that defines a space formed by the turbine casing and the outer partial casing and has a plurality of impingement holes formed therein.   The gas turbine according to claim 1, wherein the outer partial casing includes two cylindrical portions having different diameters and includes a hollow disc that connects the cylindrical portions.   3. The gas turbine according to claim 1, wherein the turbulence promoter provided in the turbine casing is formed by processing a mold for casting the turbine casing.   3. The gas turbine according to claim 1, wherein the turbulence promoter provided in the turbine casing is formed by machining or laser processing after casting.   5. The gas turbine according to claim 1, wherein the shell includes a sealing wall for partitioning the space and an impingement hole.   6. The gas turbine according to claim 1, wherein the convex turbulence promoter is disposed so as to be dense and dense with respect to an axial direction of the turbine casing. 7.   7. The gas turbine according to claim 1, wherein the convex turbulence promoter is disposed so as to be dense with respect to a circumferential direction of the turbine casing.   8. The gas turbine according to claim 1, wherein the impingement holes provided in the shell are arranged so as to be dense in the axial direction.   9. The gas turbine according to claim 1, wherein the impingement holes provided in the shell are arranged so as to be dense and dense in a circumferential direction.