Patent Application
20090180865
The present invention relates to a vane tip clearance management structure for a gas turbine.
In general, a gas turbine is configured to obtain a drive force by injecting fuel into air which is compressed at a high temperature with a compressor, generating combustion gas by causing combustion inside a combustor, guiding this combustion gas to a turbine, and thereby rotating the turbine. Moreover, in the compressor and the turbine, a predetermined amount of clearance (tip clearance) is set in a space between tips of rotor vanes arranged in a circumferential direction and a casing provided so as to surround these rotor vanes.
Since the temperature inside the gas turbine becomes high, the difference between the inside and the outside temperatures becomes larger. As a result, the casing is thermally expanded in an axial direction and a circumferential direction thereof and is deformed into an oval shape. Meanwhile, the rotor vanes are also thermally expanded and deformed outward in a radial direction. When the casing and the rotor vanes are deformed as described above, there is a risk that the tips of the rotor vanes contact with the casing and are thereby damaged. Accordingly, the above-mentioned clearance is formed by estimating in advance amounts of thermal deformation of the casing and the rotor vanes at the time of operation. Meanwhile, if the clearance is made larger in order to prevent the contact attributable to the thermal deformation, performance of the entire gas turbine is degraded. Therefore, in view of improvement in performance and improvement in reliability, clearance management or positional management of the casing for forming a predetermined amount of this clearance has become extremely important in recent years.
Thus, conventionally provided are a structure configured to form a predetermined amount of clearance by sequentially stacking each step upward while setting a central shaft of a gas turbine to be perpendicular, or a structure configured to form a predetermined amount of clearance by use of an eccentric pin which is unaffected by the amount of displacement even if there is displacement between casings, or the like. Such conventional vane tip clearance management structures for a gas turbine are disclosed in cited documents 1 and 2, for example.
Patent Document 1: Japanese Patent Application Laid-open Publication No. 2001-200705
Patent Document 2: Japanese Patent Application Laid-open Publication No. 2004-162536
However, in a conventional vane tip management structure, a position to dispose the casing and a vane tip clearance are measured at the time of tentatively assembling a gas turbine. The vane clearance is adjusted based on a result of the measurement, and then reassembling is finally performed. Accordingly, it was not possible to check, after the final assembly, whether or not the position to dispose the casing and the vane tip clearance are set to a predetermined position and amount of the clearance. For this reason, it was not possible to surely prevent contact between tips of rotor vanes and the casing when operating the gas turbine.
Therefore, it is an object of the present invention to provide a vane tip clearance management structure for a gas turbine which allows a vane tip clearance to be easily checked at the time of assembly completion.
To solve the abovementioned problem, a vane tip clearance management structure for a gas turbine according to a first aspect of the present invention is characterized by including: an outer casing rotatably supporting a rotor; an inner casing provided so as to have a predetermined clearance from tips of rotor vanes which are fitted in multiple steps to the rotor on the inner side of the outer casing in the radial direction; penetrating means which penetrates the outer casing and the inner casing in the radial direction; and abutting means which abuts on the tip of the rotor vane by being moved in the radial direction of the outer casing and the inner casing by use of the penetrating means. Here, the clearance is calculated based on the amount of movement of the abutting means relative to the penetrating means.
To solve the problem, a vane tip clearance management structure for a gas turbine according to a second aspect of the present invention is characterized by including: an outer casing rotatably supporting a rotor; an inner casing provided so as to have a predetermined clearance from tips of rotor vanes which are fitted in multiple steps to the rotor on the inner side of the outer casing in the radial direction; a guide frame penetrating the outer casing and the inner casing in the radial direction and being supported by a supporting surface of the inner casing; and a rod being movably supported by the guide frame and abutting on the tip of the rotor vane. Here, the clearance is calculated based on the length of the guide frame, the length of the rod, the thickness of the inner casing, and the amount of movement of the rod relative to the guide frame.
To solve the problem, a vane tip clearance management structure for a gas turbine according to a third aspect of the present invention is characterized in that, in the vane tip clearance management structure for a gas turbine according to the second aspect, the clearance is calculated by subtracting a difference between the length from a tip of the guide frame to an inner peripheral surface of the inner casing obtained based on the supporting surface and the length from the guide frame to the rod, from the amount of movement of the rod relative to the guide frame.
In the vane tip clearance management structure for a gas turbine of the first aspect of the invention, provided are: the outer casing rotatably supporting a rotor; the inner casing provided so as to have the predetermined clearance from the tips of the rotor vanes which are fitted in the multiple steps to the rotor on the inner side of the outer casing in the radial direction, the penetrating means which penetrates the outer casing and the inner casing in the radial direction, and the abutting means which abuts on the tip of the rotor vane by being moved in the radial direction of the outer casing and the inner casing by use of the penetrating means. Moreover, the clearance is calculated based on the amount of movement of the abutting means relative to the penetrating means. Accordingly, it is possible to check the vane tip clearance easily at the time of completing assembly.
In the vane tip clearance management structure for a gas turbine of the second aspect of the invention, provided are: the outer casing rotatably supporting a rotor; the inner casing provided so as to have the predetermined clearance from the tips of the rotor vanes which are fitted in multiple steps to the rotor on the inner side of the outer casing in the radial direction, the guide frame penetrating the outer casing and the inner casing in the radial direction and being supported by the supporting surface of the inner casing, and the rod being movably supported by the guide frame and abutting on the tip of the rotor vane. Moreover, the clearance is calculated based on the length of the guide frame, the length of the rod, the thickness of the inner casing, and the amount of movement of the rod relative to the guide frame. Accordingly, it is possible to check the vane tip clearance easily at the time of completing assembly.
According to the vane tip clearance management structure for a gas turbine of the third aspect of the invention, in the vane tip clearance management structure for a gas turbine of the second aspect of the invention, the clearance is calculated by subtracting the difference between the length from the tip of the guide frame to the inner peripheral surface of the inner casing obtained based on the supporting surface and the length from the guide frame to the rod, from the amount of movement of the rod relative to the guide frame. Accordingly, it is possible to calculate the vane tip clearance easily.
a) to 2(c) are views showing the vane tip management structure for a gas turbine according to the embodiment of the present invention, in which
a) is a schematic drawing of a rod and
Now, a vane tip clearance management structure for a gas turbine according to the present invention will be described below in detail with reference to the accompanying drawings.
As shown in
The compressor 5 is provided with stator vanes 9 and rotor vanes 10 which are alternately disposed at a given interval from the front side, and is also provided with a first stator vane retainer ring (an inner casing) 11, a second stator vane retainer ring (an inner casing) 12, and a third stator vane retainer ring (an inner casing) 13, which are in annular shapes and are supported concentrically with the casing 3. Moreover, base ends of the stator vanes 9 on respective steps are supported by a corresponding one of a rear end of the air intake 4, the casing 3, and the stator vane retainer rings 11, 12, and 13. A predetermined amount of clearance is formed between each of tips of the stator vanes 9 and the rotor 2. Meanwhile, base ends of the rotor vanes 10 on the respective steps are respectively supported by the rotor 2. A predetermined amount of a clearance C1 (see
In the meantime, the turbine 6 is provided with stator vanes 14 and rotor vanes 15 which are alternately disposed at a given interval from the front side, and is also provided with a turbine vane ring (an inner casing) 16 which is in an annular shape and is supported concentrically with the casing 3. Moreover, base ends of the stator vanes 14 on respective steps are respectively supported by the turbine vane ring 16. A predetermined amount of clearance is formed between each of tips of the stator vanes 14 and the rotor 2. Meanwhile, base ends of the rotor vanes 15 on the respective steps are respectively supported by the rotor 2. A predetermined amount of a clearance C2 (see
Accordingly, introduced air Ao that is introduced from the air intake 4 is compressed by the compressor 5, and the compressed air A thus compressed is guided to the cylinder 7. Then, the compressed air A introduced to the cylinder 7 flows into an upstream side of the combustor 8 and is mixed with liquid fuel F supplied into the combustor 8 to be combusted. Subsequently, combustion gas G generated by this combustion is guided from a downstream side of the combustor 8 to the turbine 6. The turbine 6 exerts a drive force by expanding this combustion gas G, and transmits the drive force to the compressor 5 and other unillustrated external devices such as a power generator.
Next, the vane tip management structure and a vane tip management method for a gas turbine, according to the embodiment of the present invention will be described with reference to
Firstly, the vane tip management structure will be described. As shown in
As shown in
Moreover, in the vane tip management structure of this embodiment, a rod 25 and a guide frame 26 are provided as shown in
Specifically, in a space between the casing 3 and the stator vane retainer ring 11, 12 or 13, the guide frame 26 is disposed so as to penetrate the outer hole 17, 18 or 19 and the inner hole 21, 22 or 23. At this time, the lower surface of the flange portion 26e abuts on the stepped portion 21a, 22a or 23a. Accordingly, it is possible to restrict movement of the guide frame 26 inward in the radial direction (toward the rotor 2). Moreover, it is possible to insert the rod 25 to the through hole 26c by supporting the guide frame 26 as described above. In the meantime, in a space between the casing 3 and the turbine vane ring 16, the guide frame 26 is disposed so as to penetrate the outer hole 20 and the inner hole 24. At this time, the lower surface of the flange portion 26e abuts on the stepped portion 24a. Accordingly, it is possible to restrict movement of the guide frame 26 inward in the radial direction (toward the rotor 2). Moreover, it is possible to insert the rod 25 to the through hole 26c by supporting the guide frame 26 as described above.
Next, the vane tip management method, that is, a method of measuring the clearances C1 and C2 will be described. First, after final assembly of the gas turbine 1 (shaft center alignment of the casing 3, the stator vane retainer rings 11, 12, and 13, and the turbine vane ring 16), the rotor 2 is rotated such that the hole positions of the outer holes 17, 18, 19, and 20 as well as the inner holes 21, 22, 23, and 24 in the radial direction coincide with the phases of the rotor vanes 10 and 15. Then, as shown in
C1=L1−(M1−B)−(J−K) (1)
Similarly, as shown in
C2=L2−(M2−B)−(J−K) (2)
That is, the length from the tip of the guide frame 26 to any of the inner peripheral surfaces of the stator vane retainer rings 11, 12, and 13 as well as the inner peripheral surface of the turbine vane ring 16 (amounts of projection of the rods 25) is calculated by (M1-B) or (M2-B), and a difference between the lengths of the rod 25 and the guide frame 26 is calculated by (J-K) Then, it is possible to calculate the clearance C1 or C2 by subtracting both of the above calculated figures from the length L1 or L2 indicating the length from the base end of the guide frame 26 to the base end of the rod 25, that is, the sinking amount (the amount of movement) of the rod 25 toward the rotator vane 10 or 15. Therefore, by applying the above-described configuration, it is possible to confirm the clearances C1 and C2 easily after completing the assembly of the gas turbine by geometrically calculating the formulas (1) and (2).
Thus, according to the vane tip clearance management structure for a gas turbine of the present invention, provided are: the casing 3 configured to support the rotor 2 rotatably; the stator vane retainer rings 11, 12, and 13, as well as the turbine vane ring 16 provided with predetermined amounts of clearances from the tips of the rotor vanes 10 and 15 fitted in multiple steps to the rotor 2, on the inner side of the casing 3 in the radial direction; the guide frames 26 which penetrate the casing 3, the stator vane retainer rings 11, 12, and 13, and the turbine vane ring 16 in the radial direction and are supported by the stepped portions 21a, 22a, 23a, and 24a; and the rods 25 which are movably supported by the guide frames 26 and which abut on the tips of the rotor vanes 10 and 15. Here, the clearances C1 and C2 are each measured by subtracting the length (M1-B) or (M2-B) and also subtracting the length difference (J-K) between the rod 25 and the guide frame 26, from the amount of movement L1 or L2 of the rod 25 relative to the guide frame 26. Here, the lengths (M1-B) and (M2-B) indicate the lengths from the tips of the guide frames 26 to the inner peripheral surfaces of the stator vane retainer rings 11, 12, and 13 as well as the turbine vane ring 16, the lengths calculated by using the stepped portions 21a, 22a, 23a and 24a as a basis. In this way, it is possible to confirm the vane tip clearances easily at the time of completing the assembly of the gas turbine.
The present invention is applicable to management of clearance between a rotor and a stationary body which is supported so as to cover an outer periphery of this rotor.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-266358 | Sep 2005 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2006/317981 | 9/11/2006 | WO | 00 | 3/13/2008 |
