Method for determining end face gap of water guide mechanism of axial flow propeller unit

Abstract

The application discloses a kind of axial flow variable pitch unit water guide mechanism updating and reconstructing end face gap determination method, including before unit disassembly, the deformation disturbance F of force conversion after top cover is measured;Unit disassembly, the elevation difference A of seat ring upper plane to runner chamber base ring upper plane is measured using laser tracker, the actual height B of movable guide vane after repair is measured, movable guide vane end face gap design value is recorded as C, the thickness D of updated bottom ring is measured, the elevation difference E of top cover wear surface to the joint surface of top cover and seat ring is measured, the machining amount X of bottom ring is recorded, and the machining amount X of bottom ring is calculated as D+B+E+F+2C-A and the like steps.The application considers the deformation disturbance of supporting component when force conversion before unit disassembly, through the machining thickness reserved for bottom ring, can effectively control guide vane end face gap, avoid the problem that unit is installed after guide vane end face gap is unqualified, and unit peristalsis and guide vane refusal movement are generated.

Description

Technical Field

[0001] This invention belongs to the field of hydropower station generator set renovation technology, and specifically relates to a method for determining the end face clearance of the water guide mechanism of an axial-flow propeller turbine unit during renovation. Background Technology

[0002] A hydroelectric power station with an axial-flow propeller turbine unit has been in operation for nearly 40 years. The equipment is severely aged, and its hydraulic performance has deteriorated, necessitating the upgrading and renovation of the turbine runner chamber and guide vane mechanism. Due to prolonged operation, the flange surface on the bearing ring is severely corroded, exhibiting excessive waviness, requiring machining. For the upgrading and renovation of the turbine runner chamber and guide vane mechanism, the end face clearance must meet design requirements during unit operation to prevent the following problems: 1. Excessive guide vane end face clearance leads to leakage and turbine creep; 2. Insufficient guide vane end face clearance results in insufficient operating force and failure to move. Therefore, a new method for determining the end face clearance of the guide vane mechanism needs to be proposed. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies. As one aspect of this invention, a method for determining the end face clearance of the guide vane in the upgrading and renovation of an axial-flow propeller turbine unit is proposed. By controlling the installation elevation of the runner chamber and the machining thickness of the bottom ring, the end face clearance of the turbine guide vane is ensured to meet the design requirements, thereby ensuring the installation accuracy of the unit upgrade.

[0004] One aspect of the present invention provides a method for determining the end face clearance of the water guide mechanism in the upgrading and renovation of an axial-flow propeller turbine unit, comprising the following steps:

[0005] Before dismantling the S1 unit, the deformation deflection of the top cover after the force transformation was measured and recorded as F;

[0006] S2 uses a frame level and an optical level to check the levelness of the upper plane of the foundation ring and the seat ring to ensure that it meets the design requirements;

[0007] During the disassembly of Unit S3, the elevation difference between the upper plane of the seat ring and the upper plane of the foundation ring of the runner chamber was measured using a laser tracker and recorded as A.

[0008] After the S4 active guide vane was returned to the factory for repair, its actual height was measured and recorded as B.

[0009] According to the design requirements, the gap between the upper and lower end faces of the movable guide vane is equal. The design value is recorded as C. Therefore, the total gap between the upper and lower end faces of the movable guide vane is recorded as 2C.

[0010] After S6 assembles the new bottom ring, its thickness is measured, and the actual measured value is recorded as D.

[0011] S7 measures the elevation difference between the wear-resistant surface of the top cover and the mating surface between the top cover and the seat ring, and records it as E;

[0012] Let S8 denote the machining amount of the bottom ring as X. Then the thickness of the bottom ring after machining should be: DX = AEBF - 2C.

[0013] S9 calculates the bottom ring machining amount X = D + B + E + F + 2C - A 。 .

[0014] Preferably, in step S2, the accuracy of the optical level is preferably 0.02 mm / m.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] This invention provides a method for determining the end face clearance of the guide vane in the renovation of an axial-flow propeller turbine unit. This method takes into account the deformation deflection of the supporting components during the force transformation before the unit is disassembled. By reserving the machining thickness of the bottom ring, the end face clearance of the guide vane can be effectively controlled. It has strong operability and has been put into practice in the renovation of a hydropower station unit. It is completely feasible and has wide application value in the industry.

[0017] This invention provides a method for determining the end face clearance of the guide vane in the upgrading and renovation of an axial-flow propeller turbine unit. This method avoids the problems of unqualified guide vane end face clearance during unit reinstallation, which can cause unit creep and guide vane failure to move. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the turbine runner chamber of the axial-flow propeller-type hydro-generator unit in this invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] See Figure 1 , Figure 1 This is a schematic diagram of the turbine runner chamber of an axial-flow propeller-type hydro-generator unit according to an embodiment of the present invention.

[0021] During unit operation, the weight of rotating parts is transferred to the thrust bearing, then through the thrust bracket, support cover, and top cover to the seat ring foundation. However, during unit installation, the top cover changes from a state without external axial load to a state under axial load after the rotating parts are installed. This causes a certain amount of sinking in the top cover, which is manifested at the lowest wear-resistant surface of the top cover. This sinking is an important factor affecting the end face clearance of the guide vanes. This sinking is equivalent to the deformation deflection of the top cover during disassembly. When reinstalling the unit after disassembly and modification, it needs to be taken into account to ensure the end face clearance of the moving guide vanes after the unit is reinstalled.

[0022] When reinstalling components of the generator set after upgrades and modifications, the installation sequence from bottom to top is as follows: lower ring of the runner chamber, middle ring of the runner chamber, foundation ring, bottom ring, movable guide vane, and top cover. Finally, the lower flange face of the outer side of the top cover is installed on the upper flange face of the seat ring. The bottom ring has a certain machining allowance. During unit reconfiguration, the end face of the bottom ring can be machined to adjust the end face clearance of the movable guide vane, ensuring optimal working conditions for the movable guide vane. Therefore, in the process of upgrading and modifying the water guide mechanism, the determination of its end face clearance directly reflects the determination of the machining allowance of the bottom ring. By optimizing the machining allowance of the bottom ring, the optimal working clearance of the movable guide vane, i.e., the end face clearance, is determined, ensuring the design requirements of the top cover's subsidence and the guide vane end face clearance after the unit's stress conversion.

[0023] Following this approach, as a preferred embodiment of the present invention, this embodiment provides a method for determining the end face clearance of the water guide mechanism for upgrading and modifying an axial-flow propeller turbine unit, comprising the following steps:

[0024] Before dismantling the S1 unit, the deformation deflection of the top cover after the force transformation was measured and recorded as F;

[0025] S2 uses a frame level and an optical level to check the levelness of the upper plane of the foundation ring and the seat ring to ensure that it meets the design requirements;

[0026] During the disassembly of Unit S3, the elevation difference between the upper plane of the seat ring and the upper plane of the foundation ring of the runner chamber was measured using a laser tracker and recorded as A.

[0027] After the S4 active guide vane was returned to the factory for repair, its actual height was measured and recorded as B.

[0028] According to the design requirements, the gap between the upper and lower end faces of the movable guide vane is equal. The design value is recorded as C. Therefore, the total gap between the upper and lower end faces of the movable guide vane is recorded as 2C.

[0029] After S6 assembles the new bottom ring, its thickness is measured, and the actual measured value is recorded as D.

[0030] S7 measures the elevation difference between the wear-resistant surface of the top cover and the mating surface between the top cover and the seat ring, and records it as E;

[0031] The purpose of this pre-installation of the water guiding mechanism is to effectively control the gap between the upper and lower end faces of the movable guide vane by machining the thickness reserved in the bottom ring. Therefore, the above measured values ​​are used to calculate the machining thickness of the bottom ring. The detailed calculation process is shown in steps 8 and 9.

[0032] Let S8 denote the machining amount of the bottom ring as X. Then the thickness of the bottom ring after machining should be: DX = AEBF - 2C.

[0033] S9 calculates the bottom ring machining amount X = D + B + E + F + 2C - A.

[0034] The above method takes into account the deformation deflection of the supporting components during the force transformation before the unit is dismantled. By reserving the machining thickness of the bottom ring, the clearance of the guide vane end face can be effectively controlled. It has strong operability and has been practiced in the renovation of a hydropower station unit. It has wide application value in the industry. Determining the end face clearance of the movable guide vane during the unit renovation and replacement according to the above method avoids the problems of unit creep and guide vane failure to move due to unqualified guide vane end face clearance.

[0035] In some preferred embodiments, in step S2, the accuracy of the optical level is preferably 0.02 mm / m.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for determining the face gap in a retrofit of a variable-pitch axial-flow unit guide vane mechanism, characterized in that The method comprises the following steps: S1 Before the unit is disassembled, the deformation degree of the top cover after force conversion is measured and recorded as F; S2 The horizontal degree of the upper plane of the foundation ring and the seat ring is checked by using a frame type level and an optical level, to ensure that it meets the design requirements; S3 The unit is disassembled, and the elevation difference between the upper plane of the seat ring and the upper plane of the runner chamber foundation ring is measured by using a laser tracker and recorded as A; S4 After the movable guide vane is repaired in the factory, the actual height of the body thereof is measured and recorded as B; S5 According to the design requirements, the upper and lower end surface gaps of the movable guide vane are equal, and the design value thereof is recorded as C, so that the total gap of the upper and lower end surfaces of the movable guide vane is 2C; S6 After the new bottom ring is assembled, the thickness thereof is measured, and the actual measured value is recorded as D; S7 The elevation difference between the top cover wear surface and the joint surface of the top cover and the seat ring is measured and recorded as E; S8 The machining amount of the bottom ring is X, and the thickness of the bottom ring after machining should be D-X=A-E-B-F-2C; S9 The machining amount X of the bottom ring is calculated as D+B+E+F+2C-A.

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