A bulb tubular turbine main shaft lubrication self-adapting water supply regulation system

Abstract

The present application relates to the technical field of water turbine control, and particularly relates to a bulb tubular turbine main shaft lubrication self-adaptive water supply control system, which comprises a water supply pipeline and a water distribution ring pipe, and further comprises a water inlet stationary guide cover and a water outlet stationary collector cover which are sleeved on the periphery of a runner ring and form a water inlet distribution ring cavity and a water outlet collector ring cavity respectively. Radial water inlet holes, radial water outlet holes and an internal valve cavity are arranged in the runner ring, a rotating speed response centrifugal slide valve assembly is arranged in the valve cavity, the rotating speed response centrifugal slide valve assembly comprises a valve core capable of radially sliding and a spring, and a water passing horizontal hole is arranged on the valve core. When the rotating speed is low, the spring drives the valve core to open the water path to supply water to the friction pair, and when the rotating speed is high, the centrifugal force drives the valve core to close the water path. An elastic bag type energy accumulator is connected in parallel to the water supply pipeline, and the elastic bag type energy accumulator stores energy when the water path is closed and releases energy when the water path is opened. The present application realizes pure mechanical self-adaptive water supply control without electrical signals, and improves the reliability of water film supply and the service life of the friction pair.

Description

Technical Field

[0001] This invention relates to the field of water turbine control technology, and in particular to an adaptive water supply regulation system for the main shaft lubrication of a bulb-type water turbine. Background Technology

[0002] Bulb-type turbine generator sets are widely used in low-head power plants due to their straight flow channels, high hydraulic efficiency, and compact structure, and often undertake peak and frequency regulation tasks in power grids. To protect the guide bearings and electrical equipment inside the turbine nacelle, a friction pair is installed between the main shaft and the turbine's fixed casing. Lubricating water is introduced to form a water film, which reduces friction and prevents water from entering the nacelle. The lubricating water is typically injected into the friction pair gap from the top supply point, spreading into a film under the action of water pressure and gravity.

[0003] However, during peak-shaving operation, the unit frequently operates under idling or no-load conditions. At this time, the guide vane opening is extremely small, while the runner maintains its rated speed. The centrifugal effect creates a strong low-pressure area or even a vacuum near the runner hub, drawing the top-supplied lubricating water directly into the flow channel. This prevents the formation of an effective water film at the friction pair interface, leading to dry friction and rapid component wear within a short time. Existing solutions often involve adding electric valves to the water supply pipeline for auxiliary water supply, but these still have the following shortcomings. First, electric valves rely on electrical signal control; if the electrical control system or signal line malfunctions, the valves cannot open or close correctly, and the reliability of the water supply is limited by electrical factors. Second, there is a response lag from vacuum formation to the establishment of auxiliary water supply; the water film is missing in the initial stage, and the friction pair still faces the risk of dry friction. In other words, the existing pipeline lacks energy storage capabilities and cannot pre-store water during normal unit operation, relying entirely on real-time water supply during idling, resulting in poor water supply continuity and anti-interference capabilities. Furthermore, in a bulb turbine for micro-hydropower generation in a water plant, published in CN103603763A, although the excess head in the water supply pipeline is effectively utilized for energy recovery, its focus is on optimizing the overall flow channel structure and power generation efficiency of the turbine, without addressing the lubrication and water supply control issues of the main shaft friction pair. When such turbines are applied to power grid peak shaving and frequency regulation conditions and need to frequently operate in idling or no-load states, the main shaft friction pair area also faces the risk of missing lubricating water film and dry friction damage to components due to vacuum on the flow channel side. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides an adaptive water supply control system for the main shaft lubrication of a bulb-type turbine.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An adaptive water supply control system for the main shaft lubrication of a bulb-type turbine includes a water supply pipeline and a water distribution ring pipe. The inlet end of the water supply pipeline is connected to the unit's lubrication water pipeline, and the water distribution ring pipe is connected to the horizontal outlet end of the turbine's fixed casing and friction pair area. It also includes an inlet static guide shroud and an outlet static collector shroud. The rotor collar is coaxially and fixedly sleeved on the main shaft of the unit, and rotates synchronously with the main shaft; The inlet static guide shroud is sleeved around the outer periphery of the impeller ring, and its inner wall and the outer circumferential surface of the impeller ring form an inlet water distribution ring cavity. The outlet end of the water supply pipeline is fixedly connected to the inlet static guide shroud and communicates with the inlet water distribution ring cavity. The outlet static collector shroud is sleeved around the outer periphery of the impeller ring, and its inner wall and the outer circumferential surface of the impeller ring form an outlet water collection ring cavity. The inlet end of the water distribution ring pipe is fixedly connected to the outlet static collector shroud and communicates with the outlet water collection ring cavity. The impeller collar has a radial water inlet hole, a radial water outlet hole, and an internal valve cavity connecting the two. The inlet of the radial water inlet hole is connected to the water inlet distribution ring cavity, and the outlet of the radial water outlet hole is connected to the water outlet collection ring cavity. A speed-responsive centrifugal slide valve assembly is installed in the internal valve cavity. The speed-responsive centrifugal slide valve assembly includes a valve core that can slide radially along the impeller collar and a spring that applies a radial inward restoring force to the valve core. A transverse water passage hole is formed on the valve core. When the unit speed is lower than the set threshold, the valve core is in the radially inner position under the action of the spring, and the water passage connects the radial water inlet and the radial water outlet, so that the water supply pipeline supplies water to the friction pair area. When the unit speed exceeds the set threshold, the valve core overcomes the spring force under the action of centrifugal force and slides radially outward, so that the water passage is misaligned with the radial water inlet and the radial water outlet to stop the water supply.

[0006] Furthermore, an accumulator is connected to the water supply pipeline. The accumulator stores water from the water supply pipeline when the speed-responsive centrifugal slide valve assembly closes the water supply path, and releases the stored water into the inlet distribution ring cavity when the speed-responsive centrifugal slide valve assembly opens the water supply path. During the high-speed operation of the unit connected to the grid and the water supply path is closed by the speed-responsive centrifugal slide valve assembly, the water pressure in the water supply pipeline increases, and pressurized water enters the accumulator for energy storage. When the unit enters an idling or low-speed, no-load state, and the water supply path is opened by the speed-responsive centrifugal slide valve assembly, the accumulator releases the stored water, compensating for the initial insufficient water supply caused by the lag in water pressure establishment in the water supply pipeline, ensuring that the friction pair interface still receives sufficient lubricating water during the strongest vacuum suction phase.

[0007] Furthermore, the accumulator is an elastic bladder-type accumulator, comprising a shell and an elastic bladder disposed within the shell. The elastic bladder divides the internal space of the shell into a water storage chamber and an air chamber. The air chamber is pre-filled with gas at a pressure lower than the rated working pressure of the water supply pipeline, so that when the speed-responsive centrifugal slide valve assembly is closed, the water pressure in the pipeline compresses the air chamber to store energy. When the speed-responsive centrifugal slide valve assembly closes the water circuit, pressurized water in the water supply pipeline enters the water storage chamber, squeezing the elastic bladder to expand and deform towards the air chamber, compressing the pre-filled gas in the air chamber, and converting the water pressure energy into the compressive potential energy of the gas for storage. When the speed-responsive centrifugal slide valve assembly opens the water circuit, the compressed gas in the air chamber expands, pushing the elastic bladder to squeeze the water in the water storage chamber out and release it into the water inlet distribution ring cavity. The elastic bladder structure achieves complete isolation between the water and the gas, preventing the gas from dissolving in the water or being carried into the water supply pipeline, ensuring the stability and continuity of the water release process.

[0008] Furthermore, a one-way valve is installed between the water supply pipeline and the accumulator. The one-way valve is directed towards the inlet water distribution ring cavity to prevent backflow into the unit's lubrication water pipeline when the accumulator releases water. When the accumulator releases the stored water when the centrifugal slide valve assembly is activated in response to the rotational speed, the one-way valve ensures that all the released water flows towards the inlet water distribution ring cavity and does not flow back along the water supply pipeline to the unit's lubrication water pipeline. This ensures that all the water stored in the accumulator is used for lubrication of the friction pair area, improving energy storage utilization efficiency.

[0009] Furthermore, an electrically controlled flow regulating valve is connected to the end of the accumulator furthest from the one-way valve. This valve is used to regulate the water release flow rate of the accumulator, extending the continuous water replenishment time during unit idling. By adjusting the opening of the electrically controlled flow regulating valve, the flow rate of water released by the accumulator can be controlled, allowing the stored water to be released slowly and continuously at a smaller flow rate, rather than being rapidly emptied all at once. This extends the effective water replenishment time to cover the entire idling or no-load phase, ensuring a stable water film supply to the friction pair area even when the unit is operating at low speed for extended periods.

[0010] Furthermore, a bypass venting valve is also connected to the accumulator, and an electrically controlled flow regulating valve is located between the bypass venting valve and the accumulator. The bypass venting valve is used to depressurize the accumulator. During scheduled unit maintenance or when the accumulator requires maintenance, the bypass venting valve can be opened to quickly release the water and pressure in the accumulator, facilitating depressurization operations.

[0011] Furthermore, multiple water distribution ring pipes are provided, evenly distributed along the circumference of the impeller ring 5, with the axis of each water distribution ring pipe parallel to the axis of the impeller ring. These multiple circumferentially distributed water distribution ring pipes can simultaneously supply water to the friction pair area from multiple directions, ensuring uniform water coverage of the entire circumference of both the working and maintenance seals. The parallelism between the axis of each water distribution ring pipe and the impeller ring axis ensures that the water outlet direction remains horizontal to the sealing surface. Under inertia, the water passes directly through the sealing gap, reaching the sealing lip and impeller ring even during vacuum suction on the flow channel side, forming a complete annular water film and preventing localized dry friction due to water supply deviation.

[0012] Furthermore, at least four speed-responsive centrifugal valve assemblies are evenly arranged along the circumference of the impeller ring, and are distributed symmetrically in an even number. The symmetrical arrangement of multiple speed-responsive centrifugal valve assemblies along the circumference of the impeller ring ensures a balanced mass distribution in all directions during high-speed rotation, preventing dynamic imbalance and additional vibration caused by uneven mass distribution on one side. Simultaneously, the even-numbered symmetrical distribution ensures that the centrifugal forces generated by each speed-responsive centrifugal valve assembly cancel each other out, preventing additional radial loads on the main shaft and ensuring the stability of the unit under high-speed grid-connected operation and extending bearing life.

[0013] Furthermore, the valve core is equipped with a replaceable counterweight, which is used to calibrate the set threshold. By replacing the counterweight with one of different masses, the overall mass of the valve core is adjusted, thereby changing the magnitude of the centrifugal force on the valve core at the same rotational speed, thus calibrating the water supply opening and closing set threshold. When the actual operating parameters of the power plant change, or when it is necessary to adjust the switching point according to the rated speed characteristics of different units, it is not necessary to replace the entire valve core or spring; only the counterweight needs to be replaced to complete the threshold adjustment.

[0014] Furthermore, the rotor collar is provided with a receiving groove for accommodating the valve core and spring. A radial clearance groove is also connected to the internal valve cavity, and the clearance groove corresponds radially to the receiving groove. The valve core is movably disposed within the clearance groove. The receiving groove provides stable space for the spring, ensuring that the spring does not skew or twist during compression and release, and guaranteeing that the elastic force always acts radially on the valve core. The clearance groove provides sufficient radial space for the valve core to slide outward at high speeds, preventing interference between the valve core and the internal structure of the rotor collar. The maximum radial displacement of the valve core at high speeds is determined by the balance between centrifugal force and spring force. When the valve core slides outward to a position where the water passage hole is completely misaligned with the radial inlet and outlet holes, even if the speed continues to increase, the valve core will not slide further outward under the limiting action of the spring, ensuring a stable misalignment sealing effect between the holes in the closed state.

[0015] Furthermore, the inner wall of the inlet static flow guide shroud has an inlet annular groove in the area corresponding to the inlet water distribution annular cavity, and the inner wall of the outlet static flow collector shroud has an outlet annular groove in the area corresponding to the outlet water collection annular cavity. Both the radial inlet and radial outlet holes have outwardly protruding extensions at their ends. The extension of the radial inlet hole is located within the inlet annular groove, and the extension of the radial outlet hole is located within the outlet annular groove. The inlet annular groove forms a circumferentially connected water collection channel on the outer circumferential surface of the impeller ring. Regardless of the impeller ring's rotation angle, the water in the inlet water distribution annular cavity can enter the radial inlet hole through the inlet annular groove, preventing the inlet of the radial inlet hole from being blocked by the inner wall of the inlet static flow guide shroud due to the rotation of the impeller ring, thus avoiding flow interruption. The extended portion protrudes from the outer circumference of the impeller ring and extends into the corresponding ring groove, increasing the effective flow cross-sectional area of ​​the inlet and outlet, reducing local resistance loss when water flows in and out, and thus improving water supply efficiency.

[0016] Furthermore, the impeller collar is formed by axially joining a first half-ring and a second half-ring. The internal valve cavity, radial inlet hole, and radial outlet hole are all located in the area of ​​the joining surface to facilitate the assembly, disassembly, and maintenance of the speed-responsive centrifugal slide valve assembly. When the speed-responsive centrifugal slide valve assembly needs to be inspected, cleaned, or replaced, the first half-ring and the second half-ring can be separated axially to expose the internal valve cavity, radial inlet hole, and radial outlet hole, allowing operators to directly assemble and disassemble the speed-responsive centrifugal slide valve assembly.

[0017] Furthermore, the friction pair area includes a working seal and a maintenance seal. The working seal is a D-type polyurethane seal, and the maintenance seal is an L-type polyurethane seal. A bypass interface for an external flow indicator is also connected to the water supply pipeline. The working seal, as the main sealing element, has its D-shaped lip pressed against the impeller ring surface under the pressure of the flowing water. The maintenance seal, as an auxiliary sealing element, has an L-shaped cross-section used to block large particles of sediment and reduce the pressure of the incoming water in the flow channel. Together, they form a two-stage sealing protection. After connecting the external flow indicator to the bypass interface, the water flow status in the water supply pipeline can be monitored in real time. An alarm signal will be issued promptly when the water flow is interrupted or abnormal, allowing operators to monitor the working status of the auxiliary water supply device.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention integrates the speed-responsive centrifugal slide valve assembly inside the rotating collar, and uses the centrifugal force generated by the unit's own speed change to drive the valve core to slide radially, realizing pure mechanical adaptive control of automatically opening water supply at low speed and automatically shutting off water supply at high speed. It eliminates the dependence on electric valves and their electrical signals, avoids water supply interruption due to electrical control failure or signal abnormality, and greatly improves the system control reliability. 2. This invention connects an elastic bladder accumulator to the water supply pipeline. During the grid-connected operation phase when the centrifugal slide valve closes the water circuit, the accumulator stores water using the pipeline water pressure. During the idling or unloaded phase when the centrifugal slide valve opens the water circuit, the accumulator actively releases the stored water, forming a push-pull synergistic effect with the vacuum on the flow channel side, continuously replenishing water to the friction pair interface. This compensates for the insufficient water supply caused by the lag in pipeline water pressure establishment during the initial stage of water supply and extends the effective water film maintenance time. 3. This invention sets up an inlet static guide hood and an outlet static collector hood to form a water distribution ring cavity and a water collection ring cavity between the rotating collar and the stationary pipeline, respectively. With the help of the rotating isolation component, the dynamic-static conversion is realized, so that the water in the stationary pipeline can stably enter the interior of the high-speed rotating collar and flow back to the stationary water distribution ring pipe, ensuring the reliable operation of the speed response centrifugal slide valve assembly in the full speed range of the unit. Attached Figure Description

[0019] Figure 1 This is a plan view of a bulb-type turbine unit; Figure 2 This is a schematic diagram of the planar structure of the present invention; Figure 3 This is a cross-sectional schematic diagram of the rotor collar; Figure 4 This is a schematic diagram of the planar structure of the rotating ring; Attached diagram labels: 1-Water supply pipe, 2-Water distribution ring pipe, 3-Inlet static guide shroud, 301-Inlet water distribution ring cavity, 4-Outlet static collector shroud, 401-Outlet water collection ring cavity, 5-Rotating ring, 501-Radial inlet hole, 502-Radial outlet hole, 503-Internal valve cavity, 6-Valve core, 7-Spring, 8-Passing horizontal hole, 9-Receiving groove, 10-Allowing groove, 11-Inlet ring groove, 12-Outlet ring groove, 13-Extension, 14 -Bypass interface, 15-Accumulator, 1501-Water storage chamber, 1502-Gas chamber, 16-Elastic bladder, 17-One-way valve, 18-Electrically controlled flow regulating valve, 19-Bypass discharge shut-off valve, 20-Bulb body, 21-Generator rotor, 22-Guide bearing, 23-Tube seat, 24-Maintenance shaft, 25-Lower support, 26-Modible guide vane, 27-Runner chamber, 28-Runner, 29-Tailpipe, 30-Concrete dam structure. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0021] Example 1, as Figures 2-4As shown, the present invention discloses an adaptive water supply control system for the main shaft lubrication of a bulb-type turbine, including a water supply pipeline 1 and a water distribution ring pipe 2. The inlet end of the water supply pipeline 1 is connected to the unit's lubrication water pipeline, and the water distribution ring pipe 2 is connected to the horizontal outlet end of the turbine's fixed housing and friction pair area. It also includes an inlet static guide shroud 3 and an outlet static collector shroud 4. The impeller collar 5 is coaxially fixedly sleeved on the main shaft of the unit and rotates synchronously with the main shaft. The water inlet static guide shroud 3 is sleeved on the outer periphery of the impeller collar 5, and its inner wall and the outer circumferential surface of the impeller collar 5 form an inlet water distribution ring cavity 301. The water outlet end of the water supply pipe 1 is fixedly connected to the water inlet static guide shroud 3 and communicates with the water inlet water distribution ring cavity 301. The water outlet static collector shroud 4 is sleeved on the outer periphery of the impeller collar 5, and its inner wall and the outer circumferential surface of the impeller collar 5 form an water outlet collecting ring cavity 401. The water inlet end of the water distribution ring pipe 2 is fixedly connected to the water outlet static collector shroud 4 and communicates with the water outlet collecting ring cavity 401. The impeller collar 5 has a radial water inlet hole 501, a radial water outlet hole 502, and an internal valve cavity 503 connecting the two. The inlet of the radial water inlet hole 501 communicates with the water inlet distribution ring cavity 301, and the outlet of the radial water outlet hole 502 communicates with the water outlet collection ring cavity 401. A speed-responsive centrifugal slide valve assembly is installed in the internal valve cavity 503. The speed-responsive centrifugal slide valve assembly includes a valve core 6 that can slide radially along the impeller collar 5 and a spring 7 that applies a radial inward restoring force to the valve core 6. A water-passing horizontal hole 8 is opened on the valve core 6. When the unit speed is lower than the set threshold, the valve core 6 is in the radially inner position under the action of the spring 7, and the water passage 8 connects the radial water inlet 501 and the radial water outlet 502, so that the water supply pipeline 1 supplies water to the friction pair area. When the unit speed exceeds the set threshold, the valve core 6 overcomes the elastic force of the spring 7 and slides radially outward under the action of centrifugal force, so that the water passage 8 is misaligned with the radial water inlet 501 and the radial water outlet 502 to stop the water supply.

[0022] Multiple water distribution ring pipes 2 are provided, and these multiple water distribution ring pipes 2 are evenly distributed along the circumference of the impeller ring 5, with the axis of each water distribution ring pipe 2 parallel to the axis of the impeller ring 5. Specifically, the multiple circumferentially distributed water distribution ring pipes 2 can simultaneously supply water to the friction pair area from multiple directions, ensuring that the water body evenly covers the entire circumference of the working seal and the maintenance seal. The axis of each water distribution ring pipe 2 is parallel to the axis of the impeller ring 5, so that the water outlet direction is kept horizontal with the sealing surface. Under the action of inertia, the water body passes directly through the sealing gap, and even when there is vacuum suction on the flow channel side, it can still reach the sealing lip and the impeller ring 5 to form a complete annular water film, avoiding local dry friction caused by water supply deviation.

[0023] At least four speed-responsive centrifugal valve assemblies are evenly arranged along the circumference of the impeller ring 5, and are distributed symmetrically in an even number. Specifically, the symmetrical arrangement of multiple speed-responsive centrifugal valve assemblies on the circumference of the impeller ring 5 ensures that the mass distribution in all directions of the impeller ring 5 remains balanced during high-speed rotation, avoiding dynamic imbalance and additional vibration caused by uneven mass distribution on one side. Simultaneously, the even-numbered symmetrical distribution ensures that the centrifugal forces generated by each speed-responsive centrifugal valve assembly cancel each other out, preventing additional radial loads on the main shaft and ensuring the stability of the unit under high-speed grid-connected operation and the service life of the bearings.

[0024] The valve core 6 is equipped with a replaceable counterweight, which is used to calibrate the set threshold. Specifically, by replacing the counterweight with one of different masses, the overall mass of the valve core 6 is adjusted, thereby changing the magnitude of the centrifugal force acting on the valve core 6 at the same rotational speed, thus calibrating the water supply opening and closing set threshold. When the actual operating parameters of the power plant change, or when it is necessary to adjust the switching point according to the rated speed characteristics of different units, it is not necessary to replace the entire valve core 6 or spring 7; only the counterweight needs to be replaced to complete the threshold adjustment, reducing the difficulty of commissioning and maintenance costs, and improving the adaptability of the device to operating conditions.

[0025] The rotating ring 5 has a receiving groove 9 inside to accommodate the valve core 6 and the spring 7. The internal valve cavity 503 is also connected to a radial clearance groove 10, which radially corresponds to the receiving groove 9. The valve core 6 is movably disposed within the clearance groove 10. Specifically, the receiving groove 9 provides stable space for the spring 7, ensuring that the spring 7 does not deflect or twist during compression and release, and guaranteeing that the elastic force always acts radially on the valve core 6. The clearance groove 10 provides sufficient radial space for the valve core 6 to slide outwards at high speeds, preventing interference between the valve core 6 and the internal structure of the rotating ring 5. The maximum radial displacement of valve core 6 at high speed is determined by the balance between centrifugal force and spring force 7. When valve core 6 slides outward to the position where the water passage hole 8 is completely misaligned with the radial water inlet hole 501 and the radial water outlet hole 502, even if the speed continues to increase, valve core 6 will no longer slide outward further under the limiting action of spring 7, ensuring that the misalignment sealing effect between each hole is stable in the closed state.

[0026] The inner wall of the inlet static flow guide shroud 3 has an inlet annular groove 11 in the area corresponding to the inlet water distribution annular cavity 301, and the inner wall of the outlet static flow collector shroud 4 has an outlet annular groove 12 in the area corresponding to the outlet water collection annular cavity 401. The ends of the radial inlet holes 501 and 502 both have outwardly protruding extensions 13. The extension of the radial inlet hole 501 is located within the inlet annular groove 11, and the extension of the radial outlet hole 502 is located within the outlet annular groove 12. Specifically, the inlet annular groove 11 forms a circumferentially connected water collection groove on the outer circumferential surface of the impeller ring 5. Regardless of the rotation angle of the impeller ring 5, the water in the inlet water distribution annular cavity 301 can enter the radial inlet hole 501 through the inlet annular groove 11, preventing the inlet of the radial inlet hole 501 from being blocked by the inner wall of the inlet static flow guide shroud 3 due to the rotation of the impeller ring 5, thus preventing flow interruption. The extension 13 protrudes from the outer circumference of the impeller ring 5 and extends into the corresponding ring groove, increasing the effective flow cross-sectional area of ​​the inlet and outlet, reducing the local resistance loss when water flows in and out, and thus improving the water supply efficiency.

[0027] The impeller collar 5 is formed by axially joining a first half-ring and a second half-ring. The internal valve cavity 503, radial inlet hole 501, and radial outlet hole 502 are all located in the area of ​​the joining surface, facilitating the assembly, disassembly, and maintenance of the speed-responsive centrifugal slide valve assembly. Specifically, when the speed-responsive centrifugal slide valve assembly needs to be inspected, cleaned, or replaced, the first half-ring and the second half-ring can be separated axially to expose the internal valve cavity 503, radial inlet hole 501, and radial outlet hole 502, allowing operators to directly assemble and disassemble the speed-responsive centrifugal slide valve assembly. This split structure significantly shortens maintenance time and reduces maintenance difficulty, making it particularly suitable for the confined space and limited maintenance conditions within the turbine nacelle of bulb turbine units.

[0028] The friction pair area includes a working seal and a maintenance seal. The working seal is a D-type polyurethane seal, and the maintenance seal is an L-type polyurethane seal. A bypass interface 14 for an external flow indicator is also connected to the water supply pipeline 1. Specifically, the working seal, as the main sealing element, has its D-shaped lip pressed against the surface of the impeller ring 5 under the pressure of the flowing water. The maintenance seal, as an auxiliary sealing element, has an L-shaped cross-section used to block large particles of sediment and reduce the pressure of the incoming water in the flowing channel. Together, they form a two-stage sealing protection. After the bypass interface 14 is connected to an external flow indicator, the water flow status in the water supply pipeline 1 can be monitored in real time. When the water flow is interrupted or the flow rate is abnormal, an alarm signal is issued promptly, allowing operators to monitor the working status of the auxiliary water supply device.

[0029] Example 2: Based on Example 1, this example proposes a spindle lubrication water supply control device with a water storage energy component. Its specific connection structure and principle are as follows.

[0030] An accumulator 15 is also connected to the water supply pipeline 1. The accumulator 15 stores water from the water supply pipeline 1 when the speed-responsive centrifugal slide valve assembly closes the water supply passage, and releases the stored water to the inlet distribution ring cavity 301 when the speed-responsive centrifugal slide valve assembly opens the water supply. Specifically, during the high-speed operation of the unit connected to the grid and the water supply path is closed by the speed-responsive centrifugal slide valve assembly, the water pressure in the water supply pipeline 1 increases, and pressurized water enters the accumulator 15 for energy storage. When the unit enters an idling or low-speed no-load state and the water supply path is opened by the speed-responsive centrifugal slide valve assembly, the accumulator 15 immediately releases the stored water, compensating for the insufficient initial water supply caused by the lag in water pressure establishment in the water supply pipeline 1. This ensures that the friction pair interface can still obtain sufficient lubricating water during the strongest vacuum suction stage, realizing an automatic cycle of energy storage and release without the need for additional control signals.

[0031] The accumulator 15 is an elastic bladder type accumulator, comprising a shell and an elastic bladder 16 disposed within the shell. The elastic bladder 16 divides the internal space of the shell into a water storage chamber 1501 and an air chamber 1502. The air chamber 1502 is pre-filled with gas at a pressure lower than the rated working pressure of the water supply pipeline 1, so that when the speed-responsive centrifugal slide valve assembly is closed, the water pressure in the pipeline compresses the air chamber 1502 to store energy. Specifically, when the speed-responsive centrifugal slide valve assembly closes the water circuit, pressurized water in the water supply pipeline 1 enters the water storage chamber 1501, squeezing the elastic bladder 16 to expand and deform towards the air chamber 1502, compressing the pre-filled gas in the air chamber 1502, and converting the water pressure energy into the compressive potential energy of the gas for storage. When the speed-responsive centrifugal slide valve assembly opens the water circuit, the compressed gas in the air chamber 1502 expands, pushing the elastic bladder 16 to squeeze the water in the water storage chamber 1501 out and release it into the water inlet distribution ring cavity 301. This elastic bladder structure achieves complete isolation between water and gas, preventing gas from dissolving in water or being carried into the water supply pipeline, thus ensuring the stability and continuity of the water release process.

[0032] A one-way valve 17 is installed between the water supply pipeline 1 and the accumulator 15. The one-way valve 17 is directed towards the inlet water distribution ring cavity 301 to prevent backflow into the unit's lubrication water pipeline when the accumulator 15 releases water. Specifically, when the accumulator 15 releases the stored water when the centrifugal slide valve assembly is activated in response to the rotational speed, the one-way valve 17 ensures that all the released water flows towards the inlet water distribution ring cavity 301 and does not flow back along the water supply pipeline 1 to the unit's lubrication water pipeline. This ensures that all the water stored in the accumulator 15 is used for lubrication of the friction pair area, improving energy storage utilization efficiency.

[0033] The end of the accumulator 15 furthest from the one-way valve 17 is connected to an electrically controlled flow regulating valve 18. This valve is used to regulate the water release flow rate of the accumulator, extending the continuous water replenishment time during unit idling. Specifically, by adjusting the opening of the electrically controlled flow regulating valve 18, the flow rate of water released by the accumulator 15 can be controlled, allowing the stored water to be released slowly and continuously at a smaller flow rate, rather than being rapidly emptied all at once. This extends the effective water replenishment time to cover the entire idling or no-load phase, ensuring a stable water film supply to the friction pair area even when the unit is operating at low speed for extended periods.

[0034] A bypass discharge valve 19 is also connected to the accumulator 15. An electrically controlled flow regulating valve 18 is positioned between the bypass discharge valve 19 and the accumulator 15. The bypass discharge valve 19 is used to depressurize the accumulator 15. Specifically, during scheduled unit maintenance or when the accumulator 15 requires maintenance, the bypass discharge valve 19 can be opened to release the water and pressure within the accumulator 15, facilitating depressurization. Preferably, a flushing water source can be connected to bypass the accumulator 1501 to perform reverse flushing and drainage, removing impurities that may have accumulated during long-term operation and extending the service life of the accumulator 15.

[0035] Example 3, based on Example 2, proposes a specific working principle of an adaptive water supply control system for the main shaft lubrication of a bulb-type axial-flow turbine.

[0036] When the bulb turbine is operating at high speed during grid-connected power generation, the main shaft drives the impeller ring 5 to rotate at the rated speed. The valve core 6 of the speed-responsive centrifugal slide valve assembly is subjected to a large centrifugal force, overcoming the elastic force of the spring 7 and sliding radially outward to the closed position. At this time, the water passage hole 8 on the valve core 6 is misaligned with the radial water inlet hole 501 and the radial water outlet hole 502, and the internal water passage is cut off. The water in the water supply pipe 1 cannot enter the water distribution ring pipe 2 through the impeller ring 5, and the auxiliary water supply is stopped. At the same time, because the speed-responsive centrifugal slide valve assembly has closed the water passage, the water pressure in the water supply pipe 1 rises to the rated working pressure. The pressurized water enters the water storage chamber 1501 of the accumulator 15 through the one-way valve 17, squeezing the elastic bladder 16 to expand towards the air chamber 1502, compressing the pre-charged gas in the air chamber 1502, and converting the water pressure energy into gas compression potential energy to complete energy storage. During this stage, the lubrication of the friction pair area is maintained by the top water supply point of the original unit's lubrication water pipe. Preferably, the accumulator 15 is equipped with a monitoring component for stopping the water supply from the water supply line 1 when the water storage chamber 1501 is full.

[0037] When the unit receives a disconnection or shutdown command and transitions from grid-connected to idle or unloaded operation, the guide vane opening rapidly decreases, but the impeller 28 and impeller collar 5 maintain a relatively high speed. At this time, a low-pressure zone is formed near the hub of impeller 28 due to centrifugal and vortex effects, creating a vacuum on the flow channel side. Simultaneously, as the speed gradually decreases from the rated value, the centrifugal force on the valve core 6 decreases. When the speed drops below the set threshold, the restoring force of the spring 7 is greater than the centrifugal force, pushing the valve core 6 to slide radially inward to the open position. The water passage horizontal hole 8 is realigned with the radial water inlet hole 501 and the radial water outlet hole 502, and the internal water passage is opened. The compressed gas in the gas chamber 1502 inside the accumulator 15 pushes the elastic bladder 16 to squeeze out the water stored in the water storage chamber 1501, which flows into the water distribution ring pipe 2 through the opened internal water passage. At the initial moment of water release from accumulator 15, due to the suction effect of the vacuum on the flow channel side and the elastic compression effect of accumulator 15, a push-pull synergistic effect is formed, forcibly and evenly injecting water into the annular gap between the working seal and the maintenance seal. A lubricating water film is quickly formed between the sealing lip and the impeller ring 5, effectively resisting vacuum suction and preventing dry friction of the seal. The electrically controlled flow regulating valve 18 controls the water release flow rate of accumulator 15, ensuring that the water replenishment process continuously covers the entire idling or no-load stage.

[0038] When the unit is connected to the grid again and its speed increases to above the set threshold, the centrifugal slide valve assembly responds to the speed and shuts off the water circuit again. The accumulator 15 is then recharged and stored. This cycle repeats, achieving adaptive water supply control without the need for external electrical signals.

[0039] Example 4: Based on Example 1, this example proposes a spindle lubrication water supply control device for use in a bulb-type axial flow unit. The structure and principle of the bulb-type axial flow unit are as follows.

[0040] like Figure 1 As shown, the bulb turbine generator set includes a streamlined bulb body 20, which encapsulates the generator stator, generator rotor 21, and core power generation equipment such as guide bearings 22 and thrust bearings that support the rotation of the main shaft. In the middle section of the bulb body 20, there is a tubular base 23 for supporting the weight of the unit and the water thrust, as well as a vertically extending maintenance shaft 24 and a lower support column 25. Following the water flow direction, the rear section of the unit sequentially includes movable guide vanes 26 for controlling the water flow, a runner chamber 27 enclosing the rotating components, a runner 28 with propeller-shaped blades, and a tailrace pipe 29 at the end for guiding the water flow out smoothly.

[0041] The bulb turbine generator set is horizontally suspended in the center of the water passage. The bulb body 20 is anchored in the concrete dam structure 30 on the upper, lower, and side sides by the central tubular base 23, the top maintenance shaft 24, and the bottom support column 25. The maintenance shaft 24 directly connects the external space with the interior of the bulb body 20, serving as a passage for personnel access and cable routing. Internally, the generator stator is fixed to the inner shell of the bulb body 20, while the generator rotor 21 is mounted on a horizontal main shaft. The main shaft extends horizontally backward out of the bulb body 20, with its end cantilevered to the external runner 28. Movable guide vanes 26 are evenly arranged in a ring in the contraction channel between the tail of the bulb body 20 and the runner chamber 27. The runner 28 follows closely behind in the runner chamber 27 and connects to the gradually widening tailrace pipe 29.

[0042] Bulb turbine generator sets are mainly used in plain rivers with abundant flow, run-of-river hydropower stations, or tidal power stations. They are typically installed horizontally inside the dam body. Upstream water flows gently into the channel, circling the bulb body 20, and is then accelerated and swirled by the movable guide vanes 26 whose opening is adjusted in the central control room. Water flowing at a specific angle impacts the runner, causing it to rotate at high speed, converting water energy into mechanical energy. The runner 28 directly drives the generator rotor 21 inside the bulb body 20 to rotate within the generator stator via a horizontal main shaft, cutting magnetic field lines to generate electrical energy. The water, having lost energy after performing work, ultimately recovers some of its kinetic energy through the trumpet-shaped tailrace pipe 29 and is discharged into the downstream river channel.

[0043] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A bulb-type axial-flow turbine main shaft lubrication adaptive water supply control system, comprising a water supply pipeline (1) and a water distribution ring pipe (2), wherein the inlet end of the water supply pipeline (1) is connected to the unit lubrication water pipeline, and the water distribution ring pipe (2) is connected to the horizontal outlet end of the turbine fixed housing and the friction pair area, characterized in that: It also includes an inlet static flow guide hood (3) and an outlet static flow collector hood (4); The inlet static guide shroud (3) is sleeved on the outer periphery of the runner ring (5), and its inner wall and the outer circumferential surface of the runner ring (5) enclose to form an inlet water distribution ring cavity (301). The outlet end of the water supply pipeline (1) is fixedly connected to the inlet static guide shroud (3) and communicates with the inlet water distribution ring cavity (301). The outlet static collector shroud (4) is fixed on the turbine fixed housing and sleeved on the outer periphery of the runner ring (5), and its inner wall and the outer circumferential surface of the runner ring (5) enclose to form an outlet water collection ring cavity (401). The inlet end of the water distribution ring pipe (2) is fixedly connected to the outlet static collector shroud (4) and communicates with the outlet water collection ring cavity (401). The impeller collar (5) is provided with a radial water inlet hole (501), a radial water outlet hole (502), and an internal valve cavity (503) connecting the two. The inlet of the radial water inlet hole (501) is connected to the water inlet distribution ring cavity (301), and the outlet of the radial water outlet hole (502) is connected to the water outlet collection ring cavity (401). A speed-responsive centrifugal slide valve assembly is installed in the internal valve cavity (503). The speed-responsive centrifugal slide valve assembly includes a valve core (6) that can slide radially along the impeller collar (5) and a spring (7) that applies a radial inward restoring force to the valve core (6). A water-passing horizontal hole (8) is provided on the valve core (6). When the unit speed is lower than the set threshold, the valve core (6) is in the radial inner position under the action of the spring (7), and the water passage (8) connects the radial water inlet (501) and the radial water outlet (502) so that the water supply pipeline (1) supplies water to the friction pair area. When the unit speed exceeds the set threshold, the valve core (6) overcomes the elastic force of the spring (7) and slides radially outward under the action of centrifugal force, so that the water passage (8) is misaligned with the radial water inlet (501) and the radial water outlet (502) to stop the water supply.

2. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine as described in claim 1, characterized in that: An accumulator (15) is also connected to the water supply pipeline (1). The accumulator (15) stores water from the water supply pipeline (1) when the speed-responsive centrifugal slide valve assembly closes the water supply passage, and releases the stored water to the inlet water distribution ring cavity (301) when the speed-responsive centrifugal slide valve assembly opens the water supply.

3. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine according to claim 2, characterized in that: The accumulator (15) includes a housing and an elastic bladder (16) disposed within the housing. The elastic bladder (16) divides the internal space of the housing into a water storage chamber (1501) and an air chamber (1502). The air chamber (1502) is pre-filled with gas and the pressure is lower than the rated working pressure of the water supply pipeline (1), so that when the rotational speed responds to the centrifugal slide valve assembly being closed, the water pressure in the pipeline compresses the air chamber (1502) to store energy.

4. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine according to claim 2, characterized in that: A one-way valve (17) is provided between the water supply pipeline (1) and the accumulator (15). The one-way valve (17) is directed toward the water inlet distribution ring cavity (301) to prevent backflow into the unit lubricating water pipeline when the accumulator (15) releases water.

5. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine according to claim 4, characterized in that: The end of the accumulator (15) away from the one-way valve (17) is connected to an electrically controlled flow regulating valve (18), which is used to regulate the water release flow of the accumulator (15) and extend the continuous water replenishment time in the unit's idling state.

6. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine according to claim 5, characterized in that: A bypass discharge shut-off valve (19) is also connected to the accumulator (15). The electrically controlled flow regulating valve (18) is located between the bypass discharge shut-off valve (19) and the accumulator (15). The bypass discharge shut-off valve (19) is used to depressurize the accumulator (15).

7. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine according to claim 1, characterized in that: The water distribution ring pipe (2) is provided in multiple ways. The multiple water distribution ring pipes (2) are evenly distributed along the circumference of the rotating ring (5), and the axis of each water distribution ring pipe (2) is parallel to the axis of the rotating ring (5).

8. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine according to claim 1, characterized in that: The speed-response centrifugal slide valve assembly has at least 4 valves evenly arranged along the circumference of the rotor collar (5), and they are symmetrically distributed in an even number.

9. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine according to claim 1, characterized in that: The valve core (6) is provided with a replaceable counterweight, which is used to calibrate the set threshold.

10. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine according to claim 1, characterized in that: The rotating ring (5) is provided with a receiving groove (9) for accommodating the valve core (6) and the spring (7). The internal valve cavity (503) is also connected to a radial clearance groove (10). The clearance groove (10) is radially corresponding to the receiving groove (9). The valve core (6) is movably disposed in the clearance groove (10).

11. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine according to claim 1, characterized in that: The inner wall of the inlet static flow guide hood (3) is provided with an inlet ring groove (11) in the area corresponding to the inlet water distribution ring cavity (301), and the inner wall of the outlet static flow collector hood (4) is provided with an outlet ring groove (12) in the area corresponding to the outlet water collection ring cavity (401). The ends of the radial water inlet hole (501) and the radial water outlet hole (502) are provided with an extension portion (13) protruding outward. The extension portion of the radial water inlet hole (501) is located in the inlet ring groove (11), and the extension portion of the radial water outlet hole (502) is located in the outlet ring groove (12).

12. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine according to claim 1, characterized in that: The rotating ring (5) is formed by axially joining the first half-ring and the second half-ring. The internal valve cavity (503), the radial water inlet hole (501) and the radial water outlet hole (502) are all located in the area where the joint surface is located.

13. The adaptive water supply control system for main shaft lubrication of a bulb-type turbine according to claim 1, characterized in that: The friction pair area includes a working seal and a maintenance seal. The working seal is a type D polyurethane seal, and the maintenance seal is a type L polyurethane seal. The water supply pipeline (1) is also connected to a bypass interface (14) for an external flow indicator.

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