Non-axial positioning gas turbine hollow blade preassembling method based on elastic support

Abstract

The invention discloses an axial-positioning-free gas turbine hollow blade preassembling method based on elastic supporting, relates to the technical field of gas turbine hollow blade preassembling, and aims to solve the problems that when an existing rotor wheel disc is adopted for replacing a preassembling wheel disc, a blade root is in a fir tree tooth shape, blades and the wheel disc are not provided with axial positioning and locking devices, and meanwhile a blade shroud ring is not provided with a pre-twisting angle; the problems that in the prior art, blades fall down in a wheel groove due to the influence of gravity during preassembling, the blades shake severely in the circumferential direction, the gap between adjacent blades is difficult to measure accurately, repeated adjustment is needed, and the efficiency is low during installation are solved, and the method comprises the steps that firstly, a locking piece is inserted into an air inlet side locking groove of a gas turbine rotor wheel disc; 2, the blades are sequentially inserted into wheel grooves of the gas turbine rotor wheel disc according to the frequency measurement sequence, and the air inlet sides of the blade roots of the blades abut against the end faces of the locking pieces; and thirdly, the air outlet side of the blade faces upwards, and a wedge-shaped supporting block is inserted into a gap between the end face of the blade root of the blade and the bottom face of the wheel groove of the rotor wheel disc.

Description

Technical Field

[0001] The present invention relates to the technical field of pre-assembly of hollow blades of gas turbines, and particularly relates to a method for pre-assembling hollow blades of gas turbines without axial positioning based on elastic support. Background Art

[0002] A gas turbine is a rotary thermal engine that uses continuously flowing gas as the working medium to convert the chemical energy of fuel into mechanical energy, provides power for other components of the gas turbine, and can also drive devices such as generators through a connecting shaft to convert mechanical energy into electrical energy. A gas turbine mainly consists of three major parts: a compressor, a combustion chamber, and a turbine. The compressor is used to compress air and increase the air pressure; in the combustion chamber, fuel is mixed with the compressed air and burned to generate high-temperature and high-pressure gas; the turbine uses the energy of the high-temperature and high-pressure gas to drive rotation and output mechanical energy. The turbine generally consists of a stator and a rotor, and a row of stator blades and a row of rotor moving blades form a stage of the turbine. After being compressed by the compressor, air enters the combustion chamber, mixes with the injected fuel and burns to generate high-temperature and high-pressure gas. The gas expands and does work in the turbine, driving the turbine blades to rotate. The turbine drives the compressor to rotate to maintain the air compression process, and at the same time outputs shaft power to drive generators, compressors or other devices.

[0003] After the blades are processed, they need to be assembled on the rotor for adjustment and grinding. However, when installing, the rotor disk is in a vertical state, and the blades tilt downward under the influence of gravity after installation, resulting in the inability to fix the gap between the intermediate body and the shroud. Therefore, during blade grinding, a horizontal pre-assembly method is usually adopted. After the blades are installed on the pre-assembly disk in a horizontal state, the blades are adjusted and ground. After the gap between the intermediate body and the shroud reaches the design value, the blades are removed from the pre-assembly disk and then assembled onto the turbine rotor. Therefore, when adjusting and grinding rotor blades of different specifications, corresponding pre-assembly disks need to be produced, resulting in additional processes and costs.

[0004] To save the production process of the pre-assembly disk, an existing rotor disk can be used to replace the pre-assembly disk. However, the first-stage moving blade of the high-pressure turbine of the gas turbine has a fir-tree root diamond structure, the inner cavity of the air passage is a hollow structure, and a plug is provided at the root end face of the blade, resulting in that the root end face and the plug are not in the same plane. Because the root is in the shape of fir-tree teeth and there is no axial positioning and locking device for the blade itself and the disk, and there is no pre-twist angle for the blade shroud, the blade sags in the wheel groove under the influence of gravity during pre-assembly, and the blade shakes severely circumferentially, making it difficult to accurately measure the gap between adjacent blades and requiring repeated adjustment, resulting in low installation efficiency. Summary of the Invention

[0005] The present invention aims to solve the problem that when using an existing rotor disk to replace the pre-installed disk, since the blade root is of fir-tree tooth shape and there is no axial positioning and locking device for the blade itself and the disk, and there is no pre-twist angle for the blade shroud, when the blade is pre-installed, it sags in the wheel groove under the influence of gravity, and the circumferential sway of the blade is serious, making it difficult to accurately measure the gap between adjacent blades and requiring repeated adjustment, resulting in low installation efficiency. Furthermore, a pre-installation method for a hollow gas turbine blade without axial positioning based on elastic support is provided to solve the problems raised in the above background technology.

[0006] The technical solution of the present invention is as follows:

[0007] A pre-installation method for a hollow gas turbine blade without axial positioning based on elastic support, the method comprising the following steps:

[0008] Step 1, insert the locking piece into the intake-side locking groove of the gas turbine rotor disk;

[0009] Step 2, insert the blades into the wheel grooves of the gas turbine rotor disk in the order of frequency measurement, and make the intake side of the blade root abut against the end face of the locking piece;

[0010] Step 3, turn the outlet side of the blade upward, and insert a wedge-shaped support block into the gap between the end face of the blade root and the bottom surface of the wheel groove of the rotor disk, and use the wedge-shaped support block to lift the blade and put it in the working state;

[0011] Step 4, adjust the insertion position and depth of the wedge-shaped support block so that the working surface of the blade root teeth is in close contact with the working surface of the wheel groove teeth of the gas turbine rotor;

[0012] Step 5, adjust the axial height of the blade so that the outlet side of the blade root is flush with the outlet side of the wheel groove of the gas turbine rotor disk;

[0013] Step 6, measure and adjust the intermediate gap and shroud gap between adjacent blades. If the gap does not meet the requirements of the drawing, repeat steps 2 to 6 until the pre-installation of all blades is completed;

[0014] Further, the wedge-shaped support block is wedge-shaped.

[0015] Further, the wedge angle of the wedge-shaped support block is 3-10°.

[0016] Further, the wedge-shaped support block is made of an elastic material.

[0017] Further, the wedge-shaped support block is made of bamboo or wood.

[0018] Further, the surface of the wedge-shaped support block is provided with anti-slip lines with a depth of 0.1 mm.

[0019] Furthermore, the thickness of the wedge-shaped support block is 2-3 mm, and the thickness at the tip of the wedge-shaped support block is 0.5 mm.

[0020] Furthermore, in the fourth step, the clearance between the working surface of the blade root teeth and the working surface of the wheel groove teeth of the gas turbine rotor is less than 0.02 mm.

[0021] Furthermore, in the fifth step, the height difference between the outlet side of the blade root and the outlet side of the gas turbine rotor wheel disc is less than 0.02 mm.

[0022] Furthermore, in the sixth step, the intermediate clearance between adjacent blades is adjusted to 0.1-0.2 mm, and the shroud clearance between adjacent blades is adjusted to 0.14-0.16 mm.

[0023] The present invention has the following beneficial effects compared with the prior art:

[0024] 1. A pre-assembly method for hollow blades of a gas turbine without axial positioning based on elastic support. By using the rotor wheel disc to replace the pre-assembly wheel disc, the pre-assembly of the blades can be completed, and the blades can be ground and adjusted without manufacturing a new pre-assembly wheel disc, saving a large amount of tooling costs.

[0025] 2. Insert the locking piece into the inlet side locking groove of the gas turbine rotor wheel disc. The locking piece plays a limiting role for the blade. Using the locking piece as an axial temporary limiting device for the blade, the permanent locking piece is transformed into a temporary limiting tool without modifying the structure of the gas turbine rotor wheel disc, reducing the tooling cost.

[0026] 3. Insert a wedge-shaped support block into the gap between the end face of the blade root and the bottom surface of the rotor wheel groove. Use the wedge-shaped support block to lift the blade and put it in the working state, suppressing the blade shaking and facilitating the grinding and adjustment of the blade on the gas turbine rotor wheel disc.

[0027] 4. The wedge-shaped support block is made of bamboo material, which has elasticity and wear resistance and can adapt to different tolerances, avoiding damage to the blade root end face and the blade root plug by hard tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of the blade pre-assembly state and the locking piece;

[0029] Figure 2 It is a cross-sectional view of the locking piece and the gas turbine rotor wheel disc;

[0030] Figure 3 It is a schematic structural diagram after the wedge-shaped support block is inserted;

[0031] Figure 4 It is a schematic structural diagram of the working surface of the blade root teeth and the working surface of the wheel groove teeth;

[0032] Figure 5Schematic diagram of the state where the outlet side of the blade root is flush with the outlet side of the rotor groove.

[0033] In the figure: 101, locking piece; 102, gas turbine rotor disc; 103, blade; 104, wedge-shaped support block; 105, intermediate body clearance; 106, shroud clearance; 102a, bottom surface of the rotor groove; 102b, working surface of the groove tooth; 103a, inlet side of the blade root; 103b, end face of the blade root; 103c, working surface of the blade root tooth; 103d, outlet side of the blade root; A, fixed position of the wedge-shaped support block. Specific implementation mode

[0034] Specific implementation mode one: Refer to Figures 1-5 As shown, a pre-assembly method for a hollow blade of a gas turbine without axial positioning based on elastic support, the method includes the following steps:

[0035] Step one, insert the locking piece 101 into the inlet side locking groove of the gas turbine rotor disc 102;

[0036] Step two, insert the blades 103 into the rotor grooves of the gas turbine rotor disc in the order of frequency measurement, and make the inlet side 103a of the blade root of the blade abut against the end face of the locking piece 101;

[0037] Step three, turn the outlet side of the blade 103 upwards, insert the wedge-shaped support block 104 into the gap between the end face 103b of the blade root and the bottom surface 102a of the rotor groove of the rotor disc, and use the wedge-shaped support block 104 to lift the blade 103 to the working state;

[0038] Step four, adjust the insertion position and depth of the wedge-shaped support block 104 so that the working surface 103c of the blade root tooth of the blade is in close contact with the working surface 102b of the rotor groove tooth of the gas turbine rotor;

[0039] Step five, adjust the axial height of the blade 103 so that the outlet side 103d of the blade root is flush with the outlet side 102c of the rotor groove of the gas turbine rotor disc;

[0040] Step six, measure and adjust the intermediate body clearance 105 and the shroud clearance 106 between adjacent blades. If the clearance does not meet the requirements of the drawing, repeat steps two to six until the pre-assembly of all blades 103 is completed.

[0041] Furthermore, in the middle rotor of the gas turbine, the locking piece 101 is a device for fixing the blade 103 in the gas turbine rotor disc 102. The locking piece 101 is of a fan-shaped structure. A single locking piece 101 can cover 3-4 blades 103 and provide axial support for the blades 103. Refer to Figure 2, two upper and lower locking grooves are provided on the gas turbine rotor disc 102. The upper locking groove is the locking groove on the air outlet side, and the lower locking groove is the locking groove on the air inlet side. In the present invention, it is only necessary to insert the locking piece 104 into the locking groove on the air inlet side. The locking piece 101 plays the role of lifting and supporting the blade 103 upward. The air outlet side of the gas turbine rotor disc 102 is the insertion end of the blade 103. When the blade 103 is inserted into the gas turbine rotor disc 102 and the blade 103 is in a non-working state, there is a certain gap between the blade root tooth working surface 103c and the wheel groove tooth working surface 102b of the gas turbine rotor. At this time, a wedge-shaped support block 104 is inserted into the gap between the blade root end surface 103b and the rotor wheel groove bottom surface 102a (A in the figure). As the wedge-shaped support block 104 is inserted, the wedge-shaped support block 104 pushes the blade 103 away from the center direction of the gas turbine rotor disc 102 ( Figure 2 Lift the blade 103 (to the left in the middle) to put it in working condition, suppress the shaking of the blade 103, and complete the initial fixation of the blade 103. Subsequently, adjust the insertion position and depth of the wedge-shaped support block 104 until the gap between the blade root tooth working surface 103c and the wheel groove tooth working surface 102b of the gas turbine rotor is less than 0.02mm. At this time, grind and adjust the blade 103 so that the intermediate body gap 105 and the shroud gap 106 of the blade 103 meet the design standards, and the fixation of the single blade is completed. Repeat the above steps until all blades 103 are ground and adjusted. Remove the blade 103, send it to the final assembly workshop, and install the blade 103 on the gas turbine rotor.

[0042] The present invention uses rotor disc 102 instead of pre-installed discs, enabling blade pre-installation, blade grinding, and adjustment without the need for new pre-installed discs, thus saving significant tooling costs. Locking plate 101 is used as a temporary axial limiter for blades 103, transforming the permanent locking plate 101 into a temporary limiter. This eliminates the need for structural modifications to the turbine rotor disc 102 and reduces tooling costs.

[0043] Specific implementation method 2: See Figure 1 and 3 As shown, the wedge-shaped support block 104 of this embodiment is wedge-shaped.

[0044] Specific implementation method three: see Figure 1 and 3 As shown, the wedge surface angle of the wedge-shaped support block 104 in this embodiment is 3-10°.

[0045] Furthermore, the wedge-shaped support block 104 is a wedge-shaped structure with a horizontal lower end and a wedge surface at its upper end. During installation, the lower end of the wedge-shaped support block 104 is inserted closely against the rotor wheel groove bottom surface 102a, and the upper wedge surface of the wedge-shaped support block 104 gradually lifts the blade root end surface 103b. The wedge shape of the wedge-shaped support block 104 allows for secure support of blades 103 of varying sizes, improving its applicability.

[0046] Specific implementation method four: see Figure 1 and 3 As shown, this embodiment is characterized in that: the wedge-shaped support block 104 is made of elastic material.

[0047] Specific implementation method five: see Figure 1 and 3 As shown, the characteristic of this embodiment is that the wedge-shaped support block 104 is made of bamboo.

[0048] Furthermore, the wedge-shaped support block 104 is made of bamboo or wood, etc., which has elasticity and wear resistance and can adapt to different tolerances, thereby preventing hard tools from damaging the blade root end surface 103b and the blade root plug.

[0049] Specific implementation method six: see Figure 1 and 3 As shown, this embodiment is characterized in that the surface of the wedge-shaped support block 104 is provided with anti-slip lines with a depth of 0.1 mm.

[0050] Furthermore, the wedge-shaped support block 104 is provided with anti-slip grooves, which can increase the friction between the wedge-shaped support block 104 and the blade root end surface 103b and the rotor wheel groove bottom surface 102a, so as to increase the stability of the blade 103 fixation.

[0051] Specific implementation method seven: See Figure 1 and 3 As shown, the thickness of the wedge-shaped support block 104 in this embodiment is 2-3 mm, and the thickness at the tip of the wedge-shaped support block 104 is 0.5 mm.

[0052] Furthermore, the thickness of the tip of the wedge-shaped support block 104 is 0.5 mm, which is convenient for insertion into the small gap between the blade root end face 103 b and the rotor wheel groove bottom face 102 a; the thickness of the wedge-shaped support block 104 is set to 2-3 mm, so that the maximum support height of the blade 103 reaches 2-3 mm.

[0053] Specific implementation method eight: see Figure 4 As shown, the gap between the blade root tooth working surface 103c of the blade and the wheel groove tooth working surface 102b of the combustion turbine rotor in this embodiment is less than 0.02 mm.

[0054] Specific implementation method nine: See Figure 5As shown, in the fifth step of this embodiment, the height difference between the outlet side 103d of the blade root and the outlet side 102c of the gas turbine rotor disk is less than 0.02 mm.

[0055] Specific Embodiment Ten: Refer to Figure 1 As shown, in the sixth step of this embodiment, the intermediate body gap 105 between adjacent blades 103 is adjusted to 0.1 - 0.2 mm, and the shroud gap 106 between adjacent blades is adjusted to 0.14 - 0.16 mm.

[0056] Furthermore, the intermediate body gap 105 between adjacent blades 103 is 0.1 - 0.2 mm; the shroud gap 106 between adjacent blades is 0.14 - 0.16 mm, preferably 0.15 mm, which is the standard dimension for the assembly of the blade 103 on the gas turbine rotor. The blade 103 is pre - installed on the gas turbine rotor disk 102 and undergoes grinding and adjustment to make the blade 103 reach the standard dimension for installation on the gas turbine rotor.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pre-assembly method for a hollow gas turbine blade without axial positioning based on elastic support, characterized in that: The method comprises the following steps: Step 1, insert the locking piece (101) into the locking groove on the air inlet side of the gas turbine rotor disk (102); Step 2, insert the blades (103) into the wheel grooves of the gas turbine rotor disk in the frequency measurement order successively, and make the air inlet side (103a) of the blade root abut against the end face of the locking piece (101); Step 3, turn the outlet side of the blade (103) upward, and insert a wedge-shaped support block (104) into the gap between the end face of the blade root (103b) and the bottom surface of the wheel groove of the rotor disk (102a), and use the wedge-shaped support block (104) to jack up the blade (103) to the working state; Step 4, adjust the insertion position and depth of the wedge-shaped support block (104) to make the working surface of the blade root teeth (103c) of the blade in close contact with the working surface of the wheel groove teeth (102b) of the gas turbine rotor; Step 5, adjust the axial height of the blade (103) to make the outlet side of the blade root (103d) of the blade flush with the outlet side (102c) of the gas turbine rotor disk; Step 6, measure and adjust the intermediate body gap (105) and shroud gap (106) between adjacent blades. If the gaps do not meet the requirements of the drawing, repeat steps 2 to 6 until the pre-assembly of all blades (103) is completed.

2. The pre-assembly method of the hollow gas turbine blade without axial positioning based on elastic support according to claim 1, characterized in that: The wedge-shaped support block (104) is wedge-shaped.

3. The pre-assembly method of the hollow gas turbine blade without axial positioning based on elastic support according to claim 2, wherein: The wedge angle of the wedge-shaped support block (104) is 3 - 10°.

4. The pre-assembly method of the hollow gas turbine blade without axial positioning based on elastic support according to claim 1, characterized in that: The wedge-shaped support block (104) is made of an elastic material.

5. The pre-assembly method of the hollow blade of a gas turbine without axial positioning based on elastic support according to claim 4, characterized in that: The wedge-shaped support block (104) is made of bamboo material.

6. The pre-assembly method of the hollow gas turbine blade without axial positioning based on elastic support according to claim 1, characterized in that: The surface of the wedge-shaped support block (104) is provided with anti-slip lines with a depth of 0.1 mm.

7. The pre - installation method of the hollow blade of a gas turbine without axial positioning based on elastic support according to claim 1, characterized in that: The thickness of the wedge-shaped support block (104) is 2 - 3 mm, and the thickness at the tip of the wedge-shaped support block (104) is 0.5 mm.

8. The pre-assembly method of the hollow blade of a gas turbine without axial positioning based on elastic support according to claim 1, characterized in that: In step 4, the gap between the working surface of the blade root teeth (103c) of the blade and the working surface of the wheel groove teeth (102b) of the gas turbine rotor is less than 0.02 mm.

9. The pre-assembly method of the hollow gas turbine blade without axial positioning based on elastic support according to claim 1, characterized in that: In step 5, the height difference between the outlet side of the blade root (103d) of the blade and the outlet side (102c) of the gas turbine rotor disk is less than 0.02 mm.

10. The pre-assembly method of the hollow gas turbine blade without axial positioning based on elastic support according to claim 1, wherein: In step 6, adjust the intermediate body gap (105) between adjacent blades to be 0.1 - 0.2 mm, and adjust the shroud gap (106) between adjacent blades to be 0.14 - 0.16 mm.

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