Cavitation inhibition cone valve and inhibition method thereof

Abstract

The cavitation suppression conical valve comprises a flow guide shell, an inlet pipe and a water drainage pipe are installed at the two opposite ends of the flow guide shell in a communicating mode respectively, an annular valve seat is installed on the inner wall of the flow guide shell in a butt joint mode with the inlet pipe, and the end, close to the water drainage pipe, of the annular valve seat is connected with a flow guide cone through a flow guide plate. A cavitation suppression device is installed at the end, close to the drainage pipe, of the diversion cone and comprises an annular cavity formed in the end, close to the drainage pipe, of the diversion cone, a plurality of exhaust holes are formed in the side, facing the annular valve seat, of the annular cavity, and the annular cavity communicates with an air supply channel; and the air supply channel is used for introducing compressed air into the annular cavity. Through continuous gas injection of the annular cavity, the pressure gradient of the sudden expansion area of the diversion cone is dynamically balanced, cavitation nucleation is inhibited, and the collapse strength is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of cone valves, and in particular to a cavitation suppression cone valve and a cavitation suppression method thereof. Background Art

[0002] Due to its typical operating conditions of large flow rates and high pressure differentials, conical valves must have both anti-cavitation performance and efficient flow capacity. The flow field inside the conical valve has significant flow complexity: when the high-speed jet in the guide cone area enters the downstream sudden expansion structure, the streamlines are sharply deflected to form strong vortices, causing the local pressure to drop sharply below the saturated vapor pressure of the fluid. At this time, the pressure difference between the inside and outside of the microbubble nucleus in the fluid causes the bubbles to grow rapidly and form cavitation clusters. When the cavitation moves with the flow to the high-pressure area, it instantly collapses. This dynamic process is the cavitation phenomenon. The repeated impact of cavitation causes erosion of the surface material of the flow-through components, which not only reduces the hydrodynamic performance of the valve body, but also weakens the structural strength, threatening long-term operational safety. In engineering practice, an air supply device is usually used to inject air into the negative pressure area to increase the local pressure and suppress the formation and collapse intensity of cavitation. However, there is still a lack of systematic research on the optimization of the air supply form.

[0003] For example, Chinese patent document CN119022121A discloses a vibration and noise reduction device for fixing a conical valve. This device injects pressurized air into the air guide hood through an air supply pipe and air supply structure, effectively weakening cavitation, thereby effectively reducing the impact of cavitation and the vibration and noise it causes. However, because the air supply structure cannot evenly introduce pressurized air into the conical valve, the air supply area is concentrated and the airflow is unevenly distributed, resulting in insufficient coverage of the negative pressure area and limited cavitation suppression efficiency. Furthermore, this air supply method easily causes increased flow field disturbances, resulting in additional turbulent kinetic energy loss, resulting in poor actual performance.

[0004] Therefore, in-depth analysis of the conical valve cavitation evolution mechanism and its coupling with air replenishment measures is of great significance to improving valve reliability and engineering application efficiency. Summary of the Invention

[0005] The object of the present invention is to provide a cavitation suppression conical valve and a method for suppressing cavitation, so as to solve the problem that the air supply structure cannot uniformly introduce pressurized air into the conical valve, resulting in poor use effect.

[0006] To achieve the above-mentioned objectives, the present invention provides a cavitation suppression cone valve, comprising a guide shell, wherein the opposite ends of the guide shell are respectively installed with an inlet pipe and a drain pipe, an annular valve seat is installed on the inner wall of the guide shell that is connected to the inlet pipe, the annular valve seat is connected to a guide cone through a guide plate near one end of the drain pipe, a drainage gap is provided between the annular valve seat and the guide cone, a cavitation suppression device is installed at the end of the guide cone near the drain pipe, the cavitation suppression device comprises an annular cavity provided at one end of the guide cone near the drain pipe, a plurality of exhaust holes are provided on the side of the annular cavity facing the annular valve seat, the annular cavity is connected with an air supply channel, and the air supply channel is used to introduce compressed air into the annular cavity.

[0007] The guide cone is provided with an annular platform near one end of the drain pipe. The diameter of the annular platform is smaller than the diameter of the tail of the guide cone. The annular cavity is located in the annular tube. The exhaust hole is provided on the annular tube. The annular tube is fixed on the annular platform. The annular tube is tangent to or lower than the cone guide line. The air supply channel is connected to the annular tube.

[0008] The air supply channel is a pipe, which passes through the drain pipe and is connected to the annular pipe.

[0009] The side wall of the annular platform located on one side of the annular valve seat is provided with an air-guiding oblique annular surface, the angle a between the air-guiding oblique annular surface and the annular platform is between 120° and 130°, and the exhaust hole faces the air-guiding oblique annular surface.

[0010] There are multiple pipes, and the pipes are evenly distributed in a ring.

[0011] A sliding sleeve is movably mounted on the annular valve seat, and the position of the sliding sleeve on the annular valve seat can be adjusted to adjust the water flow gap between the sliding sleeve and the guide cone.

[0012] The guide shell is located at one end of the inlet pipe and is equipped with a push rod device. The telescopic end of the push rod device passes through the guide shell and is connected to the sliding sleeve.

[0013] The exhaust holes on the annular tube include an inner ring, an intermediate ring and an outer ring. The number of inner rings and outer rings is the same, and the intermediate rings are staggered with the inner ring and outer ring. The exhaust holes on the inner ring, intermediate ring and outer ring are arranged in parallel, and the diameter of the exhaust holes is 2 to 4 mm.

[0014] The central axis of the exhaust hole on the middle ring is close to the top of the gas guiding oblique annular surface, the central axis of the exhaust hole on the inner ring intersects with the gas guiding oblique annular surface, and the central axis of the exhaust hole on the outer ring is located above the gas guiding oblique annular surface.

[0015] A suppression method for suppressing cavitation nucleation inside a conical valve and reducing collapse strength, the suppression method employing the cavitation suppression conical valve, the suppression method comprising the following steps: S1. Install three vibration sensors on the outer wall of the guide shell to monitor the vibration of the guide shell in the X, Y, and Z directions in real time. When the vibration exceeds the threshold, compressed air is introduced into the air supply channel; S2, compressed air enters the annular cavity through the air supply channel and is evenly ejected from the exhaust holes arranged along the circumference of the annular cavity; S3, through feedback regulation, real-time control of compressed air pressure and flow, and control of compressed air to find the optimal air supply strategy under the current working conditions; S4. Compressed air increases the flow field pressure, reduces the fluid density, and increases the local pressure through gas-liquid mixing. Gas mixing destroys the strong vortex structure formed by the high-speed jet to reduce the flow velocity gradient.

[0016] Compared with the prior art, the present invention has the following technical effects: 1. Precise negative pressure control: Through continuous gas injection into the annular cavity, the pressure gradient in the expansion area of ​​the guide cone is dynamically balanced, suppressing cavitation nucleation and reducing collapse intensity.

[0017] 2. Enhanced flow field stability: Reduce the turbulent pulsation caused by the shearing effect between the supplementary air flow and the mainstream, alleviate the risk of eddy secondary cavitation caused by uneven air supply, and overcome the problem of aggravated outflow cavitation.

[0018] 3. Energy efficiency optimization: Based on the annular air supply coordinated flow channel rectification design, the energy dissipation caused by traditional air supply is reduced, the air supply volume requirement is reduced under the same cavitation suppression effect, and the linear constraint relationship between air supply volume and pressure drop is broken.

[0019] 4. Automatic control to optimize the air supply strategy: Based on the combination of fuzzy PID control and gain scheduling, the pressure and flow of the gas ejected from the annular pipe are adjusted in real time to keep the RMS values ​​of the vibration in the X, Y, and Z directions stable within the target range, achieving precise optimization of the air supply strategy and automatically reducing the effect of cavitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art.

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of the conical valve of the present invention.

[0022] Figure 2 It is a schematic diagram of the half-section structure of the conical valve of the present invention.

[0023] Figure 3 This is a schematic diagram of the structure of the cavitation suppression device installed in the present invention.

[0024] Figure 4 This is a schematic cross-sectional view of the installation of the cavitation suppression device of the present invention.

[0025] Figure 5 It is a structural schematic diagram of the connection between the annular valve seat and the guide cone of the present invention.

[0026] Figure 6 It is a schematic structural diagram of the exhaust hole on the annular tube of the present invention.

[0027] Figure 7 This is the velocity cloud diagram of the flow field after the pressurized air is introduced.

[0028] Figure 8 This is the pressure cloud diagram of the flow field after the pressurized air is introduced.

[0029] Figure 9 This is a cross-sectional view of the steam volume distribution in the flow field after the pressurized air is introduced.

[0030] Figure 10 This is a three-dimensional diagram of steam volume distribution after pressurized air is introduced.

[0031] Figure 11 Velocity cloud diagram of the flow field without pressure air.

[0032] Figure 12 It is the pressure cloud diagram of the flow field without the introduction of pressurized air.

[0033] Figure 13 It is a cross-sectional diagram of the steam volume distribution in the flow field without the introduction of pressurized air.

[0034] Figure 14 This is a three-dimensional diagram of steam volume distribution without the introduction of pressurized air.

[0035] Figure 15 Comparison of peak sound pressure levels before and after the introduction of pressurized air.

[0036] Figure 16 This is the pressure cloud diagram after the pressurized air is introduced into the exhaust hole with a diameter of 2mm.

[0037] Figure 17 This is a cloud diagram of the steam volume fraction after the pressurized air is introduced into the exhaust hole with a diameter of 2mm.

[0038] Figure 18 This is the velocity cloud diagram after the pressurized air is introduced into the exhaust hole with a diameter of 2mm.

[0039] Figure 19 This is a three-dimensional diagram of the steam volume distribution after pressurized air is introduced into the exhaust hole with a diameter of 2mm.

[0040] Figure 20 This is the pressure cloud diagram after the pressurized air is introduced into the exhaust hole with a diameter of 3mm.

[0041] Figure 21 This is a cloud diagram of the steam volume fraction after the pressurized air is introduced into the exhaust hole with a diameter of 3mm.

[0042] Figure 22 This is the velocity cloud diagram after the pressurized air is introduced into the exhaust hole with a diameter of 3mm.

[0043] Figure 23 This is a three-dimensional diagram of the steam volume distribution after pressurized air is introduced into the exhaust hole with a diameter of 3mm.

[0044] Figure 24 This is the pressure cloud diagram after the pressurized air is introduced into the exhaust hole with a diameter of 4mm.

[0045] Figure 25 This is a cloud diagram of the steam volume fraction after the pressurized air is introduced into the exhaust hole with a diameter of 4mm.

[0046] Figure 26 This is the velocity cloud diagram after the pressurized air is introduced into the exhaust hole with a diameter of 4mm.

[0047] Figure 27 This is a three-dimensional diagram of the steam volume distribution after pressurized air is introduced into the exhaust hole with a diameter of 4mm.

[0048] Reference numerals Guide shell 10, inlet pipe 11, drain pipe 12, annular valve seat 13, guide cone 14, annular platform 141, air guide bevel annular surface 142, cone guide line 143, guide plate 15, sliding sleeve 16, drainage spacer 17, water flow gap 18; Cavitation suppression device 20, annular tube 21, annular cavity 211, pipe 22, exhaust hole 23, inner ring 231, middle ring 232, outer ring 233; Vibration sensor 30. DETAILED DESCRIPTION

[0049] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0050] Example 1: See also Figure 1-6A cavitation suppression cone valve includes a guide shell 10, and the opposite ends of the guide shell 10 are respectively installed with an inlet pipe 11 and a drain pipe 12. An annular valve seat 13 is installed on the inner wall of the guide shell 10 that is connected to the inlet pipe 11. The annular valve seat 13 is connected to a guide cone 14 through a guide plate 15 at one end near the drain pipe 12. A drainage gap 17 is provided between the annular valve seat 13 and the guide cone 14. A cavitation suppression device 20 is installed at the end of the guide cone 14 near the drain pipe 12. The cavitation suppression device 20 includes an annular cavity 211 provided at the end of the guide cone 14 near the drain pipe 12. The annular cavity 211 is provided with a plurality of exhaust holes 23 on the side facing the annular valve seat 13. The annular cavity 211 is connected to an air supply channel, and the air supply channel is used to pass compressed air into the annular cavity 211.

[0051] Through the above structure, the present invention has the following characteristics: 1. Precise negative pressure control: Through continuous gas injection into the annular cavity 211, the pressure gradient in the sudden expansion area of ​​the guide cone 14 is dynamically balanced, suppressing cavitation nucleation and reducing collapse intensity; 2. Enhanced flow field stability: Reduces turbulent pulsation caused by the shearing effect between the supplementary air flow and the mainstream, alleviates the risk of secondary cavitation caused by uneven eddy currents, and overcomes the problem of aggravated outflow cavitation; 3. Energy efficiency optimization: Based on the annular air supply coordinated flow channel rectification design, the energy dissipation caused by traditional air supply is reduced, the air supply volume requirement is reduced under the same cavitation suppression effect, and the linear constraint relationship between air supply volume and pressure drop is broken.

[0052] In this embodiment, see Figure 2 、 4 The guide cone 14 is provided with an annular platform 141 at one end near the drain pipe 12. The diameter of the annular platform 141 is smaller than the diameter of the tail end of the guide cone 14. The annular cavity 211 is located within the annular tube 21. The exhaust hole 23 is provided on the annular tube 21. The annular tube 21 is welded and fixed to the annular platform 141. The annular tube 21 is tangent to or lower than the cone guide line 143. The air supply channel is connected to the annular tube 21. The cone guide line 143 is an extension of the inclined surface of the outer wall of the guide cone 14.

[0053] In this embodiment, the annular tube 21 has an outer diameter of 18 mm and an inner diameter of 14 mm.

[0054] In this embodiment, the air supply channel is a pipe 22 , which passes through the drain pipe 12 and is connected to the annular pipe 21 .

[0055] In order to make the gas supply more uniform, multiple pipes 22 are provided. Figure 5 In this embodiment, four pipes 22 are provided, and the plurality of pipes 22 are evenly distributed in a ring.

[0056] Further, in Figure 4In the embodiment, the side wall of the annular platform 141 located on the side of the annular valve seat 13 is provided with an air-guiding beveled annular surface 142. When the compressed air ejected from the exhaust holes 23 reaches the air-guiding beveled annular surface 142, the compressed air is blocked by the air-guiding beveled annular surface 142. The high-pressure air at the front end of the exhaust holes 23 is distributed toward the area between adjacent exhaust holes 23, so that the compressed air forms a conical closed air ring on the air-guiding beveled annular surface 142, thereby making the compressed air more stably combined with the flow field and reducing flow field disturbances.

[0057] See also Figure 7 The included angle a between the air guiding oblique annular surface 142 and the annular platform 141 is between 120° and 130°, and the exhaust hole 23 faces the air guiding oblique annular surface 142. The included angle a can be 120° or 130°. In this embodiment, the included angle a is 125°.

[0058] In this embodiment, see Figure 6 The exhaust holes 23 on the annular cavity 211 include an inner ring 231, an intermediate ring 232, and an outer ring 233. The inner rings 231 and outer rings 233 are identical in number, and the intermediate rings 232 are staggered with the inner and outer rings 231 and 233. The diameter of the exhaust holes 23 ranges from 2 to 4 mm. This annular layout achieves 360-degree continuous air supply coverage, overcoming the airflow concentration limitations of traditional single-point or discrete air supply modes. The spacing between the air supply holes is optimized based on flow field simulation, ensuring an overlap rate of over 80% between the airflow diffusion areas of adjacent air supply holes, eliminating air supply blind spots.

[0059] In this embodiment, see Figure 4 The central axis of the exhaust hole 23 on the middle ring 232 is close to the top of the air-guiding oblique annular surface 142, the central axis of the exhaust hole 23 on the inner ring 231 intersects with the air-guiding oblique annular surface 142, and the central axis of the exhaust hole 23 on the outer ring 233 is located above the air-guiding oblique annular surface 142, ensuring that the compressed air discharged from the exhaust hole 23 hits the air-guiding oblique annular surface 142 and the high-speed water jet from the outlet of the guide cone 14, thereby forming a uniform air film.

[0060] Example 2: Based on Example 1, see Figure 2 、 3 A sliding sleeve 16 is movably mounted on the annular valve seat 13 . The position of the sliding sleeve 16 on the annular valve seat 13 can be adjusted to adjust the water flow gap 18 between the sliding sleeve 16 and the guide cone 14 .

[0061] Specifically, a push rod device (not shown) is installed at one end of the guide housing 10 located at the inlet pipe 11. The telescopic end of the push rod device passes through the guide housing 10 and connects to the sliding sleeve 16. The push rod device drives the sliding sleeve 16 to slide, thereby adjusting the water flow gap 18 between the sliding sleeve 16 and the guide cone 14.

[0062] Example 3: A method for suppressing cavitation nucleation inside a conical valve and reducing collapse strength, the method employing any one of the cavitation suppression conical valves of Examples 1 to 3, the method comprising the following steps: S1. Install three vibration sensors on the outer wall of the guide housing 10 to monitor the vibration of the guide housing 10 in the X, Y, and Z directions in real time. When the vibration exceeds a threshold, introduce compressed air into the air supply channel. S2: Compressed air enters the annular cavity 211 through the air supply channel and is evenly ejected from the exhaust holes 23 arranged along the circumference of the annular cavity 211; S3, through feedback regulation, real-time control of compressed air pressure and flow, and control of compressed air to find the optimal air supply strategy under the current working conditions; The system combines fuzzy PID control with gain scheduling to adjust the pressure and flow of compressed air in real time, keeping the RMS values ​​of vibration in the X, Y, and Z directions stable within the target range, achieving precise optimization of the air replenishment strategy and automatically reducing the effect of cavitation.

[0063] (1) Calculation of vibration error and error variation: ; ; Where: Indicates that the vibration sensor detects the root mean square value of vibration in real time; Indicates setting the expected root mean square value of vibration; Indicates the error amount at the current moment; Indicates the error amount of the previous time interval.

[0064] (2) Fuzzy PID gain scheduling: According to the fuzzy reasoning rules, the dynamic PID gain proportional gain is calculated , integral gain , differential gain .

[0065] If the error is large and the error change is positive (the error is increasing), increase the proportional gain , reduce the integral gain , reduce the differential gain .

[0066] If the error is small and the error change is negative (the error is decreasing), decrease the proportional gain. , increase the integral gain , increase the differential gain .

[0067] These fuzzy inference rules will output the corresponding PID gain adjustment to ensure that the vibration value quickly stabilizes to the target value.

[0068] (3) Control quantity calculation: Use PID control formula to calculate the intake volume adjustment : ; Where: Represents the proportional gain, Indicates the integral gain, represents the differential gain, The intake air volume adjustment amount.

[0069] Intake volume adjustment: Calculate the adjusted intake volume ; Where: is the adjusted intake volume, is the current air intake volume, The intake air volume adjustment amount.

[0070] (4) Threshold partition output control quantity: Through the gain scheduling algorithm, the PID gain is dynamically adjusted according to the actual control needs.

[0071] Threshold partition design: Normal area ( ): In this range, PID control operates normally, according to the vibration error and error variation Adjust the gain. Calculate the adjusted intake volume at this time:

[0072] Reverse warning zone ( ): If the intake volume exceeds the set safety threshold, it will enter the reverse warning zone. At this time, it is necessary to trigger the nonlinear compensation mechanism to reduce the intake volume. , to suppress the vibration increase:

[0073] Where: 𝛼 is the compensation coefficient, which determines the intensity of compensation.

[0074] And the air intake flow rate and the pressure difference before and after the air supply port satisfy the formula:

[0075] Where: is the gas volume flow rate, is the relative density of the gas, The pressure difference before and after the air supply port, is the flow coefficient.

[0076] In this way, the air intake The adjustment can be combined with the flow coefficient , and dynamically adjust according to different pressure differences and gas characteristics.

[0077] (5) Summary of automatic control process Real-time vibration monitoring → error calculation → fuzzy PID control → PID output calculation → air intake range determination: (Normal zone: adjust air intake to control vibration. Reverse warning zone: perform nonlinear compensation, reduce air intake to avoid increased vibration) → continuous system feedback and adjustment to ensure vibration remains within the target range, avoid frequent adjustments to extreme points, and stabilize the control system.

[0078] S4. Compressed air increases the flow field pressure, reduces the fluid density, and increases the local pressure through gas-liquid mixing. Gas mixing destroys the strong vortex structure formed by the high-speed jet to reduce the flow velocity gradient and reduce the probability of cavitation generation.

[0079] Example 5: See also Figure 7 is the velocity cloud of the flow field after the pressurized air is introduced. Figure 8 This is the pressure cloud diagram of the flow field after the pressurized air is introduced. Figure 9 This is a cross-sectional view of the steam volume distribution in the flow field after the pressurized air is introduced. Figure 10 This is a three-dimensional diagram of steam volume distribution after pressurized air is introduced.

[0080] Figure 11 This is the velocity cloud diagram of the flow field without pressure air, Figure 12 This is the pressure cloud diagram of the flow field without pressure air. Figure 13 This is a cross-sectional diagram of the steam volume distribution in the flow field without the introduction of pressurized air. Figure 14 This is a three-dimensional diagram of steam volume distribution without the introduction of pressurized air. Figure 15 This is a comparison of the peak sound pressure levels before and after the introduction of pressurized air. The comparison shows that the present invention has achieved breakthrough improvements in the following four aspects: (1) Cavitation suppression performance is significantly enhanced Reduced cavitation risk: The steam volume ratio is significantly reduced, see Figure 10 、 Figure 14 Comparison chart of vapor volume distribution, cavitation intensity reduced by 90%.

[0081] Precise control of negative pressure area: the volume of negative pressure area (<0Pa) is reduced from 45% to 12%. Figure 8 、 Figure 12 The pressure diagram is compared, and the standard deviation of pressure distribution is reduced by 58%, eliminating the concentrated effect of cavitation collapse caused by local pressure mutation.

[0082] (2) Improved flow field stability and safety Vibration and noise suppression: After air replenishment, the turbulent pulsation intensity of the flow field is reduced by 40%, and the peak value of the measured sound pressure level is reduced from 176dB (without air replenishment) to 134dB (with air replenishment). Figure 15 .

[0083] (3) Energy efficiency and operation and maintenance cost optimization Reduced air supply volume requirement: Under the same cavitation suppression effect, the air supply volume requirement is reduced from 2.5m³ / s in the traditional design to 1.5m³ / s (a 40% reduction), and energy consumption is reduced by approximately 30%.

[0084] (4) Data verification and chart support Pressure distribution: The air supply pressure graph shows that the negative pressure area (blue area) has been significantly reduced, and the minimum pressure value has increased to (Original ),See Figure 8 、 Figure 12 Pressure map comparison.

[0085] Velocity field comparison: The high-speed area (red) in the air supply velocity diagram is reduced from 32% to 8%, and the mainstream flow velocity distribution is more uniform. Figure 7 、 Figure 11 Comparison of flow field velocity maps.

[0086] Cavitation area: The three-dimensional distribution diagram of the air-supplemented vapor volume shows that cavitation only exists in a small amount of the edge area (volume fraction <0.30), while the cavitation fills the entire sudden expansion area under the condition of no air-supplementation (volume fraction reaches 0.30), see Figure 10 、 Figure 14 Steam volume comparison.

[0087] Specifically, see Figure 16-27 By comparing the velocity nephograms, pressure nephograms and water vapor phase volume fractions of different exhaust hole diameters, the comprehensive advantages of different hole diameters in cavitation suppression, flow field stability and energy efficiency optimization can be fully verified. The specific summary is as follows: 1. Speed ​​cloud analysis No air supply working conditions: There is a significant high-speed jet (>50m / s) in the sudden expansion area downstream of the guide cone 14. The high-speed area accounts for 32% of the area. The velocity gradient is large, and the strong shear layer induces vortices and secondary cavitation.

[0088] Improvement after Qi replenishment: 3mm aperture: The high-speed zone area is compressed to 8%, the velocity distribution is the most uniform, and the gas-liquid mixing boundary layer effectively suppresses shear disturbances.

[0089] Compared with other apertures: 2mm aperture: The proportion of high-speed area dropped to 15%, and the insufficient air supply caused the velocity gradient to remain large.

[0090] 4mm aperture: The high-speed area accounts for about 10%, but the air supply flow causes local turbulence enhancement.

[0091] 2. Pressure cloud analysis No air supply working conditions: The minimum pressure in the sudden expansion area is (far below the saturated vapor pressure), the negative pressure area accounts for 45% of the volume, the pressure distribution standard deviation is high, and the cavitation risk is significant.

[0092] Improvement after Qi replenishment: 3mm aperture: minimum pressure increased to (higher than the saturated vapor pressure), the volume proportion of the negative pressure area is reduced to 12%, the standard deviation of the pressure distribution is reduced by 58%, and the gradient is gentle.

[0093] Compared with other apertures: 2mm aperture: lowest pressure , negative pressure areas account for about 20%, which is insufficient coverage.

[0094] 4mm aperture: lowest pressure , but the standard deviation of pressure fluctuation is only reduced by 35%.

[0095] 3. Water vapor phase volume fraction analysis No air supply working conditions: The vapor volume in the cavitation area is 0.0003299587 m³, and the cavitation phenomenon is serious.

[0096] Improvement after Qi replenishment: 3mm pore size: The vapor volume is sharply reduced to 4.1829807e-05 m³, and the suppression effect is improved by about 87%, which is the optimal value.

[0097] Compared with other apertures: 2mm pore size: vapor volume is reduced to 0.00014203208 m³ (57% inhibition), with limited effect.

[0098] 4mm pore size: Vapor volume 5.0888676e-05 m³ (85% suppression), slightly lower than 3mm, possibly due to disturbance leading to decreased efficiency.

[0099] The specific data is organized into the following table:

[0100] Overall conclusion: Cavitation suppression performance: After air replenishment with a 3mm aperture, the vapor volume is the smallest (4.18e-05 m³), ​​the negative pressure zone is compressed most significantly (12% by volume), and the high-speed zone area is the smallest (8%). The three data consistently indicate that its cavitation suppression effect is the best.

[0101] Flow field stability: The velocity cloud map shows the most uniform velocity distribution, and the pressure cloud map shows the most gentle pressure gradient, verifying its ability to suppress vortex secondary cavitation and turbulent pulsation (peak sound pressure level reduced by 42dB).

[0102] Engineering suggestion: Use 3mm aperture as the standard design of the annular air supply device, taking into account both performance and energy efficiency; under extreme working conditions, explore the optimization of multi-aperture combinations to further improve dynamic control capabilities.

[0103] (2) Dynamic pressure gradient matching mechanism The air supply cavity can monitor the local pressure of the sudden expansion area downstream of the guide cone in real time by setting a pressure sensor at the outlet (see Figure 4 ), when the system has a negative pressure value close to the saturated vapor pressure of the fluid (such as , corresponding to the non-air supply condition), the air supply cavity will automatically increase the air supply volume and raise the minimum pressure to , which is significantly higher than the saturated vapor pressure of water (about ), effectively inhibiting cavitation nucleation.

[0104] (3) Flow field collaborative rectification design High-speed jet shear suppression: The supplemental airflow is injected circumferentially, forming a gas-liquid mixing boundary layer and reducing the shear intensity of the mainstream flow. After the supplemental airflow, the high-speed zone (>50m / s) is reduced from 32% to 8%.

[0105] Eddy current secondary cavitation control: By destroying the strong eddy current structure through gas mixing, the steam volume area is significantly reduced, and the volume of the cavitation area is reduced by 90%.

[0106] Compared with the prior art, the annular air supply device of the present invention achieves breakthrough improvements in the following four aspects: (1) Cavitation suppression performance is significantly enhanced Reduced cavitation risk: The steam volume ratio is significantly reduced, see the steam volume distribution comparison chart, and the cavitation intensity is reduced by 90%.

[0107] Precise control of negative pressure areas: The volume of negative pressure areas (<0Pa) is reduced from 45% to 12%, as shown in the pressure diagram. Furthermore, the standard deviation of pressure distribution is reduced by 58%, eliminating the concentrated effect of cavitation collapse caused by local pressure changes.

[0108] (2) Improved flow field stability and safety Vibration and noise suppression: After air replenishment, the turbulent pulsation intensity of the flow field is reduced by 40%, and the measured peak sound pressure level is reduced from 176dB (without air replenishment) to 134dB (with air replenishment).

[0109] The present invention systematically solves technical problems such as uneven air supply, low cavitation suppression efficiency and high energy consumption of fixed conical valves through the design of an annular air supply channel, dynamic pressure matching mechanism and coordinated optimization of flow field, providing an innovative solution for the anti-cavitation design of high pressure difference and large flow valves in water conservancy and hydropower projects.

Claims

1. A cavitation suppression cone valve, comprising a guide housing (10), wherein opposite ends of the guide housing (10) are respectively connected to an inlet pipe (11) and a drain pipe (12), an annular valve seat (13) is installed on the inner wall of the guide housing (10) where it is connected to the inlet pipe (11), an end of the annular valve seat (13) close to the drain pipe (12) is connected to a guide cone (14) through a guide plate (15), and a drainage gap (17) is provided between the annular valve seat (13) and the guide cone (14), characterized in that: The guide cone (14) is provided with a cavitation suppression device (20) at one end close to the drain pipe (12). The cavitation suppression device (20) comprises an annular cavity (211) provided at one end of the guide cone (14) close to the drain pipe (12). The annular cavity (211) is provided with a plurality of exhaust holes (23) on a side facing the annular valve seat (13). The annular cavity (211) is communicated with an air supply channel, and the air supply channel is used to introduce compressed air into the annular cavity (211).

2. The cavitation suppression cone valve according to claim 1, characterized in that: The guide cone (14) is provided with an annular platform (141) at one end close to the drain pipe (12); the diameter of the annular platform (141) is smaller than the diameter of the tail of the guide cone (14); the annular cavity (211) is located in the annular tube (21); the exhaust hole (23) is provided on the annular tube (21); the annular tube (21) is fixedly mounted on the annular platform (141); the annular tube (21) is tangent to or lower than the cone guide line (143); and the air supply channel is connected to the annular tube (21).

3. The cavitation suppression cone valve according to claim 2, characterized in that: The air supply channel is a pipe (22), which passes through the drain pipe (12) and is then communicated with the annular pipe (21).

4. The cavitation suppression cone valve according to claim 2, characterized in that: The side wall of the annular platform (141) located on one side of the annular valve seat (13) is provided with an air-guiding oblique annular surface (142), the angle a between the air-guiding oblique annular surface (142) and the annular platform (141) is between 120° and 130°, and the exhaust hole (23) faces the air-guiding oblique annular surface (142).

5. The cavitation suppression cone valve according to claim 3, characterized in that: A plurality of the pipes (22) are provided, and the plurality of the pipes (22) are evenly distributed in a ring shape.

6. The cavitation suppression cone valve according to claim 1, characterized in that: A sliding sleeve (16) is movably mounted on the annular valve seat (13), and the position of the sliding sleeve (16) on the annular valve seat (13) can be adjusted to adjust a water flow gap (18) between the sliding sleeve (16) and the guide cone (14).

7. The cavitation suppression cone valve according to claim 6, characterized in that: A push rod device is installed at one end of the guide housing (10) located at the inlet pipe (11), and the telescopic end of the push rod device passes through the guide housing (10) and is connected to the sliding sleeve (16).

8. The cavitation suppression cone valve according to claim 4, characterized in that: The exhaust holes (23) on the annular tube (21) include an inner ring (231), an intermediate ring (232), and an outer ring (233). The number of the inner rings (231) and the outer rings (233) is the same, and the intermediate rings (232) are staggered with the inner rings (231) and the outer rings (233). The exhaust holes (23) on the inner ring (231), the intermediate ring (232), and the outer ring (233) are arranged in parallel. The diameter of the exhaust holes (23) is 2 to 4 mm.

9. The cavitation suppression cone valve according to claim 8, characterized in that: The central axis of the exhaust hole (23) on the middle ring (232) is close to the top of the gas-guiding oblique annular surface (142), the central axis of the exhaust hole (23) on the inner ring (231) intersects with the gas-guiding oblique annular surface (142), and the central axis of the exhaust hole (23) on the outer ring (233) is located above the gas-guiding oblique annular surface (142).

10. A method of suppression, characterized in that: The invention is used to inhibit cavitation nucleation inside a conical valve and reduce collapse strength. The inhibition method adopts a cavitation suppression conical valve according to any one of claims 1 to 9, and is characterized in that the inhibition method comprises the following steps: S1. Install three vibration sensors (30) on the outer wall of the guide shell (10) to monitor the vibration of the guide shell (10) in the XYZ directions in real time. When the vibration is greater than a threshold value, introduce compressed air into the air supply channel; S2, compressed air enters the annular cavity (211) through the air supply channel and is evenly ejected from the exhaust holes (23) arranged circumferentially along the annular cavity (211); S3, through feedback regulation, real-time control of compressed air pressure and flow, and control of compressed air to find the optimal air supply strategy under the current working conditions; S4. Compressed air increases the flow field pressure, reduces the fluid density, and increases the local pressure through gas-liquid mixing. Gas mixing destroys the strong vortex structure formed by the high-speed jet to reduce the flow velocity gradient.

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