Online measurement system and method for running clearance of guide bearing of water-turbine generator set

Abstract

The invention discloses an online measurement system and method for the running clearance of a guide bearing of a water-turbine generator set. The system comprises a guide bearing bush, a guide connecting pipe and a hydraulic testing device, a measuring hole penetrating along the thickness direction is formed in the loading area of the guide bearing bush and is externally connected with a hydraulic testing device; and the hydraulic testing device feeds the lubricating oil into the measuring hole at set pressure and outputs a gap value according to a preset flow-gap relationship. According to the invention, continuous online monitoring of the real thermal-state gap under the working condition of the rated rotating speed of the unit with the load is realized, and the problems of lagging of traditional shutdown static measurement and insufficient indirect monitoring precision are solved.

Description

Technical Field

[0001] This invention relates to the field of hydropower generation measurement technology, and in particular to an online measurement system and method for the operating clearance of the guide bearing of a hydropower generator set. Background Technology

[0002] The design of the guide bearing clearance value of a hydro-generator unit is a key link to ensure the safe, stable and efficient operation of the unit. It is a comprehensive result of multiple factors such as the unit's operational stability, structural parameters, thermal expansion, manufacturing errors and design specifications. The ultimate goal is to find a balance between "limiting the swing", "avoiding friction", "accommodating thermal expansion" and "ensuring lubrication" to ensure the long-term safe operation of the unit.

[0003] During the operation of a hydro-generator unit, measuring the guide bearing clearance is a crucial means of assessing bearing condition and evaluating unit stability. Currently, the primary method for measuring guide bearing clearance is static measurement after shutdown (when the unit is shut down, the main shaft is stationary and the temperature approaches normal, and the radial clearance between the bearing and the main shaft is measured directly), which can directly obtain accurate values. Dynamic monitoring during operation (monitoring parameters such as main shaft runout, vibration, and temperature to indirectly determine whether the clearance is abnormal) is used to assess the clearance change trend in real time. Combining both methods allows for the assessment of bearing condition.

[0004] After the unit starts operating, the guide bearings generate heat due to friction, causing the bearing collar / bearing temperature to rise. Thermal expansion reduces the guide bearing clearance. Since the rotating parts are in a rotating state during unit operation, directly measuring the clearance of the unit's guide bearings during operation is difficult. Static measurements during shutdown and dynamic monitoring during operation cannot accurately reflect the actual clearance of the guide bearings during the operation of the hydro-generator unit. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides an online measurement system and method for the operating clearance of guide bearings in hydro-generator sets, enabling precise measurement of guide bearing clearance during hydro-generator set operation.

[0006] This invention provides an online measurement system for the operating clearance of the guide bearing of a hydro-generator set, the specific technical solution of which is as follows: The system includes guide bearings, lead pipes, and a hydraulic testing device; The bearing bearing has a measuring hole that extends through the thickness direction in the load area. The measuring hole is connected to the outside of the bearing oil groove through the lead pipe. The bearing oil groove is connected to the hydraulic testing device through the connecting pipe. The hydraulic testing device includes an oil supply system, a pressure control module, a flow detection module, and a processor. The oil supply system draws lubricating oil from the guide bearing oil groove and delivers it to the measuring hole at a set output pressure. The flow detection module is located on the pipeline between the measuring hole and the pressure controller and transmits real-time flow data to the processor. The processor outputs the actual clearance value of the guide bearing based on the received flow rate.

[0007] This invention solves the problem that traditional static measurements during shutdown cannot reveal the true thermal clearance of the unit during operation. By converting the "clearance" into "leakage flow" for back calculation, an absolute clearance value that can be directly used for condition assessment can be obtained without shutting down the unit or damaging the oil film of the guide bearing. This enables continuous acquisition of the guide bearing clearance in online conditions.

[0008] Furthermore, the measuring hole forms a nozzle on one side of the bushing surface of the guide bearing, and the other side of the measuring hole extends from the side or back of the guide bearing.

[0009] The measuring hole outlet is designed as a nozzle and placed on the bushing surface, so that the lubricating oil flows out steadily in a predetermined direction, which not only creates a measurable leak but also keeps the bearing surface lubricated.

[0010] Furthermore, when the other side of the measuring hole extends from the back of the guide bearing, the axis of the measuring hole is perpendicular to the surface of the guide bearing.

[0011] With the axis perpendicular to the tile surface, the nozzle outlet flow field is symmetrical, and the leakage flow rate is only related to the gap height, thus improving accuracy.

[0012] Furthermore, the sealing quick connector is also provided at the opening on the other side of the measuring hole opposite to the nozzle and / or on the oil tank body, and the sealing quick connector is connected to the end of the lead pipe.

[0013] The guide bearing is inside the oil tank, while the hydraulic testing device is outside the oil tank. A convenient connection between the guide bearing measuring port and the oil tank outlet can be achieved through a sealed quick-connect pipe.

[0014] Furthermore, the measuring hole has a diameter of 1-5 mm.

[0015] Furthermore, the nozzle is flush with the tile surface and has rounded edges.

[0016] The rounded structure ensures geometric continuity between the nozzle and the bearing surface, resulting in a smooth transition of the lubricating oil film and no negative impact on the bearing's load-bearing capacity during the measurement process.

[0017] Furthermore, the system also includes a temperature detection module, which detects the real-time oil temperature of the lubricating oil and feeds it back to the processor.

[0018] The viscosity of lubricating oil changes significantly with operating temperature. If temperature is ignored, different flow rates will be corresponding to the same gap, affecting the accuracy of the measurement. After introducing a temperature detection module, the flow-temperature coupling variables are decoupled, so that the gap calculation results only reflect the real geometric changes and eliminate temperature interference.

[0019] This invention also provides an online measurement method for the operating clearance of a guide bearing in a hydro-generator unit. Based on the aforementioned online measurement system for the operating clearance of a guide bearing in a hydro-generator unit, the method includes: S1: When the hydro-generator unit is running at its rated speed and under load, start the hydraulic test device and use an oil pump to extract the lubricating oil from the guide bearing oil groove.

[0020] S2: After stabilizing the lubricating oil pressure at a preset value P that is the same as the calibration condition through the pressure control module, it is delivered to the measuring hole; S3: The flow detection module collects the flow rate Q of lubricating oil leaking through the gap between the nozzle and the shaft in real time and transmits it to the processor; S4: Based on the received flow signal and the pressure signal fed back by the pressure controller, the processor outputs the actual clearance value of the guide bearing according to the preset correspondence between leakage flow and clearance.

[0021] Existing measurement methods can only measure when the unit is shut down or indirectly calculate. This method can directly map the leakage flow of the hydro-generator unit into the gap during operation. Through constant pressure-flow measurement-back calculation, the absolute value of the gap can be output online under rated speed and load conditions, providing a data basis for subsequent trend analysis and early warning.

[0022] Furthermore, step S3 also includes: the temperature detection module synchronously collects the real-time oil temperature T of the lubricating oil and transmits it to the processor.

[0023] Furthermore, the processor uses a preset viscosity-temperature curve to provide feedback correction for the real-time detected flow rate.

[0024] Synchronous acquisition of oil temperature ensures that temperature is a known input rather than an unknown disturbance, and the viscosity-temperature curve completes flow correction to prevent gap values ​​from drifting with oil temperature.

[0025] The beneficial effects of this invention are as follows: 1. This invention opens a through measuring hole in the bearing area of ​​the guide shaft bearing and connects it to an external hydraulic testing device. The clearance is converted into the flow rate, pressure and temperature of the lubricating oil of the hydraulic testing device for online back calculation. Without stopping the machine or damaging the oil film, the absolute clearance value is directly output, realizing continuous monitoring of the clearance under the operating state.

[0026] 2. This invention obtains real-time oil temperature through a temperature detection module and corrects it using a viscosity-temperature curve, eliminating viscosity drift caused by oil temperature changes from the flow signal and improving measurement accuracy. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the system gap measurement connection structure of the present invention.

[0028] Figure 2 This is a schematic diagram of the method flow of the present invention.

[0029] Explanation of reference numerals in the attached drawings: 1-Guide bearing bush, 2-Inlet pipe, 3-Shaft collar, 4-Guide bearing oil groove. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention are clearly and completely described in the following description. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of the embodiments of the present invention, it should be noted that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is conventionally placed during use, or the orientation or positional relationship in which those skilled in the art conventionally understand it during use. This is only for the convenience of describing the present invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention. Furthermore, the terms "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0032] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0033] Example 1 Embodiment 1 of the present invention discloses an online measurement system for the operating clearance of the guide bearing of a hydro-generator set, such as... Figure 1 As shown, it includes a guide bearing 1, a guide pipe 2, and a hydraulic testing device; The load area of ​​the guide bearing 1 is provided with a measuring hole that extends through the thickness direction. The measuring hole is connected to the outside of the guide bearing oil groove 4 through the lead pipe 2. The guide bearing oil groove 4 is connected to the hydraulic testing device through the connecting pipe. In this embodiment, the guide pipe 2 is made of stainless steel pipes of equal length and inner diameter with consistent bending angles to eliminate systematic errors caused by differences in pipe resistance.

[0034] In a preferred embodiment, one end of the measuring hole is located on the mating surface between the guide bearing 1 and the journal, and an opening on one side of the bushing surface of the guide bearing 1 forms a nozzle. The other side of the measuring hole extends from the side or back of the guide bearing 1.

[0035] In a preferred embodiment, the nozzle is flush with the tile surface and has rounded edges.

[0036] In this embodiment, the guide bearing 1 is made of Babbitt alloy, and the rounded structure is a radius of 0.5mm. During the production of the guide bearing 1, the nozzle size of each guide bearing 1 is uniform, and the diameter deviation is required to be ≤0.01mm to ensure the consistency of measurement.

[0037] In a preferred embodiment, when the other side of the measuring hole extends from the back of the guide bearing, the axis of the measuring hole is perpendicular to the first surface of the guide bearing, and the diameter of the measuring hole is 1-5mm; in this embodiment, the measuring hole is 3mm.

[0038] In a preferred embodiment, the measuring hole is further provided with the sealing quick connector at the opening on the other side of the guide shaft bearing 1 opposite to the nozzle and / or on the oil tank body, and the sealing quick connector is connected to the end of the lead pipe 2; Specifically, the measuring hole is provided with a sealing quick connector at the opening on the other side of the guide shaft bearing 1 opposite to the nozzle and on the oil tank body. The lead pipe 2 is connected between the two sealing quick connectors to connect the measuring hole to the guide bearing oil tank 4.

[0039] The hydraulic testing device includes at least an oil supply system, a pressure control module, a flow detection module, a pressure detection module, a temperature detection module, and a processor; the oil supply system draws lubricating oil from the guide bearing oil groove 4 and delivers it to the measuring hole at a set output pressure; the oil supply system is connected to the guide bearing oil groove 4 and is connected to the measuring hole through a connecting pipe and the lead pipe 2; the pressure control module is connected to the oil supply system. Specifically, the oil pump inlet of the oil supply system is connected to the guide bearing oil groove 4, the oil outlet is connected to the inlet of the pressure control module through a pipeline, and the outlet of the pressure control module is connected to the measuring hole through a connecting pipe and a lead pipe 2.

[0040] The flow detection module and the pressure detection module are located on the pipeline between the measuring hole and the pressure control. They measure the flow rate and pressure of lubricating oil leaking through the gap between the nozzle of the guide bearing measuring hole and the bearing 3 in real time, and transmit the real-time flow and pressure data to the processor. The processor outputs the actual gap value of the guide bearing based on the received flow and pressure signals. The temperature detection module detects the real-time oil temperature of the lubricating oil and feeds it back to the processor; For every 10°C change in oil temperature, the viscosity of the hydraulic oil may change by 20%-30%, resulting in a 15%-25% change in flow rate for the same gap. The processor stores a temperature compensation algorithm, which monitors the oil temperature in real time through the temperature detection module. The algorithm corrects the flow rate for viscosity according to the μ-T curve. For example, if the oil temperature increases by 5°C and the viscosity decreases by 10%, the real-time flow rate needs to be multiplied by a correction factor of 0.9 before calculating the gap, thereby reducing the gap calculation error.

[0041] Specifically, the oil pump of the oil supply system is a gear pump with a rated flow rate of 10L / min; the pressure control module adopts an electro-hydraulic proportional pressure valve, which can control the pressure within the range of 0.5-2MPa with a control accuracy of ±0.05MPa; the flow detection module is a turbine flow meter with a measurement range of 0-5L / min and an accuracy of ±0.5%; the processor adopts a PLC control unit for data processing, storage, and output display.

[0042] Example 2 Embodiment 2 of the present invention discloses an online measurement method for the operating clearance of the guide bearing of a hydro-generator set, based on Embodiment 1 above. Figure 2 As shown, the details are as follows: S1: When the hydro-generator unit is running at its rated speed and under load, start the hydraulic test device and use the oil pump to extract the lubricating oil from the guide bearing oil groove 4. S2: After stabilizing the lubricating oil pressure at a preset value P that is the same as the calibration condition through the pressure control module, it is delivered to the measuring hole; S3: The flow detection module collects the lubricating oil flow rate Q leaking through the gap between the nozzle and the shaft collar 3 in real time, and simultaneously collects the real-time oil temperature T of the lubricating oil, and transmits the flow rate Q and oil temperature T to the processor. S4: The processor outputs the actual clearance value of the guide bearing based on the received flow signal and the pressure signal fed back by the pressure controller, according to the preset correspondence between leakage flow and clearance; at the same time, the processor also corrects the output flow of lubricating oil based on the preset viscosity-temperature curve.

[0043] Specifically, the relationship between the leakage flow rate and the gap is obtained as follows: First, establish a precise benchmark correlation: prepare standard parts (taking a design gap of 0.33mm as an example): fabricate standard specimens with a gap of 0.33mm (accuracy must reach ±1μm), and at the same time match standard parts of similar size (such as 0.32mm, 0.31mm, 0.30mm, 0.29mm, 0.28mm...) to ensure coverage of 0.33mm and reasonable ranges above and below, and improve interpolation accuracy; Then, standardize the operating conditions: Under fixed conditions (e.g., inlet pressure 3MPa, outlet to atmosphere, oil temperature 40℃, and use of 32# hydraulic oil), introduce liquid into the gap of the standard test piece and record the data after the flow rate stabilizes; for example, 0.33mm corresponds to flow rate Q1, 0.32mm corresponds to Q2, 0.31mm corresponds to Q3, and so on.

[0044] Finally, fit the curve: plot the data as a gap-flow curve.

[0045] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. An online measurement system for the operating clearance of a guide bearing in a hydro-generator set, characterized in that, Includes guide bearings, lead pipes, and hydraulic testing equipment; The bearing bearing has a measuring hole that extends through the thickness direction in the load area. The measuring hole is connected to the outside of the bearing oil groove through the lead pipe. The bearing oil groove is connected to the hydraulic testing device through the connecting pipe. The hydraulic testing device includes an oil supply system, a pressure control module, a flow detection module, a pressure detection module, and a processor. The oil supply system draws lubricating oil from the guide bearing oil groove and delivers it to the measuring hole at a set output pressure. The flow detection module and the pressure detection module are located on the pipeline between the measuring hole and the pressure controller, and transmit real-time flow and pressure data to the processor. The processor outputs the actual clearance value of the guide bearing based on the received flow and pressure signals.

2. The online measurement system for the operating clearance of the guide bearing of a hydro-generator unit according to claim 1, characterized in that, The measuring hole forms a nozzle on one side of the bushing surface of the guide bearing, and the other side of the measuring hole extends from the side or back of the guide bearing.

3. The online measurement system for the operating clearance of the guide bearing of a hydro-generator unit according to claim 2, characterized in that, When the measuring hole extends from the back of the guide bearing on the other side, the axis of the measuring hole is perpendicular to the surface of the guide bearing.

4. The online measurement system for the operating clearance of the guide bearing of a hydro-generator unit according to claim 1, characterized in that, A sealing quick connector is also provided at the opening on the other side of the measuring hole opposite to the nozzle and / or on the oil tank body, and the sealing quick connector is connected to the end of the lead pipe.

5. The online measurement system for the operating clearance of the guide bearing of a hydro-generator unit according to claim 1, characterized in that, The diameter of the measuring hole is 1-5 mm.

6. The online measurement system for the operating clearance of the guide bearing of a hydro-generator unit according to claim 2, characterized in that, The nozzle is flush with the tile surface and has rounded edges.

7. The online measurement system for the operating clearance of the guide bearing of a hydro-generator unit according to any one of claims 1-6, characterized in that, The system also includes a temperature detection module, which detects the real-time oil temperature of the lubricating oil and feeds it back to the processor.

8. A method for online measurement of the operating clearance of a guide bearing in a hydro-generator set, characterized in that, Based on the online measurement system for the operating clearance of the guide bearing of a hydro-generator unit according to any one of claims 1-7, the method includes: S1: When the hydro-generator unit is running at its rated speed and under load, start the hydraulic test device and use the oil pump to extract the lubricating oil from the guide bearing oil groove. S2: After stabilizing the lubricating oil pressure at a preset value P that is the same as the calibration condition through the pressure control module, it is delivered to the measuring hole; S3: The flow detection module collects the flow rate Q of lubricating oil leaking through the gap between the nozzle and the shaft collar in real time and transmits it to the processor; S4: Based on the received flow signal and the pressure signal fed back by the pressure controller, the processor outputs the actual clearance value of the guide bearing according to the preset correspondence between leakage flow and clearance.

9. The method for online measurement of the operating clearance of the guide bearing of a hydro-generator unit according to claim 8, characterized in that, Step S3 also includes: the temperature detection module synchronously collects the real-time oil temperature T of the lubricating oil and transmits it to the processor.

10. The method for online measurement of the operating clearance of the guide bearing of a hydro-generator unit according to claim 9, characterized in that, The processor uses a preset viscosity-temperature curve to provide feedback correction for the detected real-time flow rate.

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