Cone valve multi-mode air supply-energy dissipation synergistic cavitation reduction device and control method

Abstract

The invention relates to the technical field of cone valve multi-mode air supply-energy dissipation cooperative cavitation reduction devices and control methods, and discloses a fluid control device named'cone valve multi-mode air supply-energy dissipation cooperative cavitation reduction devices and control methods'. The conical valve aims to solve the problems that an existing conical valve is serious in cavitation under the working condition of high pressure difference, air supply and energy dissipation functions are separated, and response lags. The device is characterized by comprising three stages of energy dissipation perforated pipes which are arranged at the outlet end of a valve body in a gradient mode, negative pressure injection air supply pipes which are symmetrically arranged outside a flow guide cover and flow guide fins which are welded to the inner wall of a cone, and the three stages of energy dissipation perforated pipes, the negative pressure injection air supply pipes and the flow guide fins cooperate to achieve pressure gradient pressure relief, self-adaptive air supply and flow state stability; the control method dynamically adjusts the air supply intensity based on the opening degree, the pressure difference and the vibration signal. According to the technical scheme, cavitation inception and collapse impact are remarkably restrained, vibration noise is reduced, the service life of the valve is prolonged, an external air source is not needed, the system pressure drop is controllable, and the system is suitable for ultrahigh pressure difference and large-flow hydroelectric working conditions.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fluid machinery and valve control, and particularly relates to a conical valve multi-mode air supplement-energy dissipation collaborative air-cavitation reduction device and a control method. BACKGROUND

[0002] As a core control element for realizing flow regulation and energy dissipation in modern water conservancy and hydropower engineering, the conical valve has been widely used in key working conditions such as high water head flood discharge, tail water regulation of power stations, ecological release, etc. due to its compact structure, flexible opening and closing, reliable sealing and excellent flow characteristics. Especially under high pressure difference operating conditions, the conical valve forms a high-speed jet flow through local throttling, converts fluid potential energy into kinetic energy and finally dissipates it in the downstream water body, thereby realizing system pressure balance and energy management. However, the severe flow pattern change in this energy conversion process makes the valve body and outlet area extremely prone to cavitation phenomenon due to the sudden drop of local pressure below the saturated vapor pressure, and further causes cavitation damage. Cavitation not only directly erodes the metal matrix of the valve disc, valve seat and downstream pipe wall, leading to material peeling and dramatic increase of surface roughness, but also causes high-frequency pressure pulsation due to the collapse of air bubbles, inducing structural resonance and noise pollution, which seriously threatens the structural integrity and system stability of long-term operation of equipment, and has become a core bottleneck restricting the safe service of conical valves in super-high pressure and large flow conditions.

[0003] To solve the above problems, the prior art has attempted to intervene from two dimensions of air supplement and kinetic energy dissipation respectively, in order to alleviate the harm of cavitation. For example, the patent document with publication number CN119022121B proposes a technical solution of forcibly supplementing air into the cavity of the conical valve through an external pipeline, the core of which is to introduce air into the negative pressure area by using a first air supplement assembly and a plurality of second air supplement assemblies to fill the air bubble collapse space with gas phase, thereby weakening the cavitation intensity and inhibiting vibration noise. This scheme can indeed achieve local cavitation inhibition under certain working conditions, but its technical path essentially relies on external air source and complex flow guide structure, which not only significantly increases the system integration difficulty and on-site installation cost, but also causes air supplement lag, uneven distribution, and even local failure due to the influence of flow field disturbance on the gas delivery path under high flow rate or non-steady state conditions, resulting in significant working condition dependence and unpredictability of cavitation inhibition effect. At the same time, the patent with publication number CN110594484B focuses on outlet kinetic energy dissipation and proposes to set two-stage cyclone blades and conical flow guide plates downstream of the conical valve, which prolongs the fluid path and enhances turbulent energy dissipation by means of cyclone centrifugal effect, thereby indirectly reducing the probability of cavitation. Although this scheme realizes integrated integration with the valve body in structure, its energy dissipation mechanism is still essentially passive energy dissipation, and the efficiency of kinetic energy reduction in the core area of high-speed jet flow is limited, especially under super-high pressure difference conditions, the cyclone structure is difficult to fully break the main flow beam, resulting in residual kinetic energy still sufficient to induce local low pressure area; in addition, the blade surface protruding structure designed to enhance energy dissipation effect not only significantly improves the process difficulty of precision casting and surface treatment, but also easily forms local vortex shedding sources after long-term erosion and wear, which in turn aggravates flow state disorder and local cavitation risk.

[0004] However, as modern water conservancy projects evolve towards higher heads, larger flows, and more complex operating modes, the inherent "functional separation" and "response lag" characteristics of the two aforementioned technical approaches at the principle level are increasingly revealing their irreconcilable internal contradictions: while the air replenishment scheme can directly intervene in the cavitation dynamics process, it loses system robustness due to its reliance on external structures; while the energy dissipation scheme can reduce the overall energy level, its efficiency is limited because it cannot accurately target high-incidence areas of cavitation. At a deeper level, the two lack synergy in their physical mechanisms—air replenishment only acts on the already formed cavitation region, which is a "post-event intervention"; while energy dissipation can reduce the probability of cavitation, it cannot form an effective gas phase buffer in local low-pressure areas. This "separate" technical architecture often puts existing devices in a dilemma when facing transient operating condition switching, extreme pressure fluctuations, or asymmetric flow fields: "insufficient air replenishment leads to aggravated cavitation, while excessive energy dissipation leads to uncontrolled pressure drop." Experimental data also corroborate this contradiction: under the typical operating conditions of 120m simulated head and 30% opening, the cavitation index (σi) of a single air-injection structure can only be increased from 0.15 to 0.28, while a single vortex energy dissipation structure can reduce the outlet velocity by 18%, but the local minimum pressure is still 12kPa lower than the saturated vapor pressure, and the cavitation damage rate is not significantly improved; when the two are simply superimposed, the system pressure drop increases by 23% due to the blockage of the flow channel, resulting in increased energy consumption and decreased control accuracy.

[0005] Fundamentally, existing technologies fail to address the root causes of fluid mechanics by constructing a proactive control mechanism that coordinates the pressure field, velocity field, and gas phase distribution field. This results in cavitation suppression remaining at the level of localized repair, unable to achieve a systematic solution that fundamentally reconstructs the flow field structure, dynamically matches energy dissipation during the process, and precisely injects buffer media at the end. Therefore, overcoming the functional barriers of traditional gas injection and energy dissipation technologies to construct a synergistic cavitation reduction device and intelligent control method capable of controllable pressure release across multi-level pressure gradients within the valve body, adaptive negative pressure ejection gas injection in key cavitation zones, and ensuring flow stability and manufacturing economy through integrated structural design has become a core technical challenge urgently needing to be overcome in this field. It is also a key breakthrough for driving the evolution of conical valves towards higher reliability, longer service life, and lower total lifespan costs. Summary of the Invention

[0006] To achieve the aforementioned objectives, this invention provides a "multi-mode gas replenishment-energy dissipation synergistic cavitation reduction device and control method for conical valves." It aims to construct a triple synergistic system within the conical valve through integrated structural design and an active flow field reconstruction mechanism. This system integrates controllable pressure gradient release, adaptive gas phase injection, and flow stabilization guidance, fundamentally resolving the core contradictions in existing technologies, such as the separation of gas replenishment and energy dissipation functions, lag response, poor adaptability to operating conditions, high manufacturing costs, and uncontrollable system pressure drop. The technical solution of this invention does not rely on an external gas source or complex flow guiding structure. Instead, it achieves a full-chain cavitation prevention and control mechanism by using a gradient pressure release structure with a three-stage energy dissipation porous pipe at the valve body outlet, symmetrically arranged negative pressure ejector gas replenishment pipes outside the flow guide shroud, and a flow stabilization structure with welded flow guiding ribs on the inner wall of the conical valve. This mechanism suppresses cavitation at its source, weakens cavitation collapse energy during the process, and buffers local low-pressure areas at the terminal, significantly improving the service reliability and system stability of the conical valve under ultra-high pressure differential, high flow rate, and transient operating conditions.

[0007] The multi-mode air replenishment-energy dissipation synergistic cavitation reduction device for conical valves described in this invention comprises a valve body, a cone, a sliding sleeve, a flow guide, a three-stage energy dissipation perforated pipe, an air replenishment pipe, a sealing ring, a sealing pressure plate, a transmission screw, a transmission nut, and a worm gear box. The valve body is welded from carbon steel or low-alloy high-strength steel, with a nominal inner diameter ranging from DN300 to DN1200. The wall thickness is determined based on finite element stress verification using a maximum working pressure of 16MPa to 42MPa, with a minimum wall thickness of not less than 28mm. The cone is integrally cast from ZG06Cr13Ni4Mo martensitic stainless steel, and after solution treatment and tempering, its hardness is controlled within the range of HB220 to HB260, with a surface roughness Ra≤0.8μm to resist erosion by high-speed sand-laden water flow. The sliding sleeve is made of 304 stainless steel sheet, rolled and welded. The clearance between the outer circle and the inner wall of the valve body is H8 / f7. The axial stroke is set from 150mm to 600mm according to the linear adjustment range of 0% to 100% of the valve opening. Its outer surface is mirror polished to reduce frictional resistance. The flow guide is made of 316L stainless steel sheet, stamped and formed. Its axial length is 1.2 to 1.8 times the valve body outlet diameter, and its radial thickness is 8mm to 15mm. The inner wall and the outer contour of the cone form a gradually narrowing flow channel with a contraction angle of 8° to 15° to guide the jet concentration and enhance the ejection effect.

[0008] At the valve body outlet end, a three-stage energy-dissipating perforated pipe is installed. Its structure consists of a first-stage energy-dissipating cylindrical perforated pipe, a second-stage energy-dissipating conical perforated pipe, and a third-stage energy-dissipating conical perforated pipe, arranged axially in series along the fluid flow direction. It is rigidly connected to the valve body outlet face via flanges or welding. The first-stage energy-dissipating cylindrical perforated pipe has a straight cylindrical structure with an outer diameter consistent with the valve body's inner diameter. The inner diameter is 0.6 to 0.75 times the valve body's inner diameter, and the pipe wall thickness is 12 mm to 20 mm. Perforations are evenly distributed along the circumference, with a hole diameter of 8 mm to 15 mm and a hole spacing of 2.5 to 4 times the hole diameter. The opening rate is 18% to 25%. The hole axis is perpendicular to the pipe axis, and the hole edges are chamfered to eliminate stress concentration. The secondary energy dissipation conical perforated pipe is a truncated cone structure with the cone angle facing upstream of the fluid. Its large end outer diameter is the same as that of the primary pipe, and the small end outer diameter is 0.8 times that of the large end. The cone angle is 10° to 20°. The pipe wall thickness gradually changes from 15mm to 10mm along the axial direction. The perforations are arranged in the conical area with a diameter of 6mm to 10mm. The hole spacing is 3 to 5 times the hole diameter, and the opening rate is 12% to 18%. The hole axis is arranged along the normal of the conical surface. The three-stage energy-dissipating perforated conical tube is a truncated cone structure with the cone angle facing downstream of the fluid. Its small-end outer diameter is the same as that of the second-stage tube, while the large-end outer diameter is 1.25 times that of the small end. The cone angle ranges from 15° to 25°, and the wall thickness gradually increases from 10mm to 18mm along the axial direction. Perforations are arranged in the conical region, with diameters ranging from 4mm to 8mm and a spacing of 4 to 6 times the diameter. The opening ratio is 8% to 12%, and the hole axes are arranged along the normal direction of the conical surface. The decreasing gradients in pore diameter, opening ratio, and structural form of the three-stage energy-dissipating perforated tube constitute a composite energy dissipation mechanism of progressive pressure release, progressive breakup, and progressive dissipation. This allows the high-speed jet to undergo three kinetic energy redistribution and pressure recovery processes as it passes through the three-stage structure, effectively preventing the persistence of local low-pressure zones.

[0009] On the outside of the fairing, a set of air supplement pipes are arranged symmetrically along the valve body axis, the number is 2 to 4, preferably 2, and is uniformly distributed at 90°. The air supplement pipe is bent from a 304 stainless steel seamless steel pipe, the outer diameter is 25mm to 40mm, the wall thickness is 3mm to 5mm, the air inlet end is located near the maximum outer diameter section of the cone, and is 5mm to 15mm away from the outer surface of the cone, the air outlet end penetrates the fairing wall and extends into the fairing cavity, the air outlet is located 50mm to 100mm upstream of the inlet of the first energy dissipation cylindrical punched pipe, and the angle between the air outlet axis and the valve body axis is 30° to 60°, so as to optimize the gas-liquid mixing angle. There is no valve or throttling element inside the air supplement pipe, and the gas flow depends on the high-speed jet suction; the air inlet is additionally provided with a Venturi tube (throat diameter 10mm) to enhance the low pressure area effect, and a bypass electromagnetic valve (normally closed type) is introduced to introduce auxiliary airflow when the opening is <10%, to ensure that the minimum negative pressure is 3kPa, the annular throttling gap formed between the cone and the valve seat generates a high-speed jet flow, and the flow rate can reach 25m / s to 60m / s. When the jet flow sweeps the air outlet of the air supplement pipe, a negative pressure area is formed in the pipe according to the Bernoulli principle, and the negative pressure value can reach 5kPa to 25kPa, which is sufficient to suck the external atmosphere into the valve through the air inlet and transport it to the cavitation high-occurrence area in the valve. On the inner wall of the cone, a plurality of flow guide ribs are welded in the circumferential direction, the number is 6 to 12, preferably 8, and is distributed at equal angles. The flow guide rib is cut and formed from a ZG06Cr13Ni4Mo steel plate of the same material as the cone, the thickness is 6mm to 10mm, the height is 5% to 8% of the inner diameter of the cone, and covers the full length of the working section of the cone in the axial direction. The cross section of the rib is a streamlined wing section, the front edge has a round corner radius of 2mm to 4mm, the back edge is sharp, and the attack angle is 0° to 5°, so as to minimize the flow resistance and suppress boundary layer separation. The function of the flow guide rib is to stabilize the flow field inside the cone, eliminate the asymmetric vortex caused by manufacturing tolerance or installation eccentricity, keep the jet core area axially symmetrical, and ensure that the air supplement pipe suction effect is uniform, the three-stage energy dissipation structure is balanced in stress, and the cavitation damage distribution is controllable. The rib and the cone are welded by argon arc welding process, the weld is qualified by 100% radiographic inspection, and stress relief annealing treatment is carried out after welding to prevent the heat affected zone from being brittle.

[0010] The control method of the device comprises the following steps: based on real-time monitoring of three core parameters of valve opening, upstream and downstream pressure difference and vibration acceleration, a pre-set control algorithm is executed by a programmable logic controller (PLC) or an embedded microprocessor to dynamically adjust the air supplement pipe suction strength, and the equivalent opening rate change is realized by a step motor driving an adjustable aperture plate (aperture adjustment range 6-10mm) on the second energy dissipation conical punched pipe; specifically, the aperture plate is controlled by a connecting rod mechanism and linearly adjusts the opening area in response to the PLC signal. The control algorithm adopts a piecewise linear interpolation model, divides the valve opening into four intervals of 0%-20%, 20%-50%, 50%-80% and 80%-100%, and establishes a pressure difference ΔP and a target air supplement amount Q in each interval.air The mapping relationship is: when ΔP < 2 MPa, Q air = 0; when 2 MPa ≤ ΔP < 5 MPa, Q air = k1 x ΔP; when 5 MPa ≤ ΔP < 10 MPa, Q air = k2 x ΔP; and when ΔP ≥ 10 MPa, Q air = k3 x ΔP, wherein k1 = 0.3 L / (s MPa), k2 = 0.5 L / (s MPa), and k3 = 0.7 L / (s MPa). The mapping relationship is obtained by combining offline CFD simulation and bench test calibration, so as to ensure that the air supply amount matches the cavitation intensity under different pressure differences. The vibration acceleration signal is collected by a piezoelectric acceleration sensor installed on the outer wall of the valve body, the sampling frequency is 10 kHz, and the energy of the 0.5 kHz to 5 kHz frequency band is extracted after low-pass filtering as the cavitation intensity index. When the index exceeds the preset threshold value 0.5 g, the control algorithm automatically increases the Q air set value of the next control cycle to 10%, until the vibration falls back to the safe interval.

[0011] To verify the technical effect of the application, a full-size hydraulic test bench is built to simulate a water head range of 50 m to 200 m, a flow range of 0.5 m³ / s to 5.0 m³ / s, and a valve opening of 0% to 100% continuously adjustable. Under the baseline working condition (water head 120 m, opening 30%), the performance differences of the device of the application and the existing single air supply structure, single vortex energy dissipation structure, and simple superposition structure are compared and tested. The test results show that: the average outlet flow velocity of the device of the application is reduced from the baseline value of 42.3 m / s to 28.7 m / s, with a decrease of 32.2%; the local minimum pressure is raised from -12.5 kPa to +3.2 kPa, which is 15.7 kPa higher than the saturated steam pressure; the cavitation index σi is increased from 0.15 to 0.41; the root mean square value of the vibration acceleration is reduced from 1.8 g to 0.3 g; and the total pressure drop of the system is 0.85 MPa, which is 28.6% lower than that of the simple superposition structure. Under the extreme working condition (water head 180 m, opening 15%), the device of the application can still maintain the local minimum pressure 8.3 kPa higher than the saturated steam pressure, the cavitation index σi = 0.35, and the vibration acceleration 0.6 g, proving that it still has effective cavitation suppression capability under harsh working conditions of high pressure difference and small opening.

[0012] In terms of material adaptability, all over-flow components of the device can be upgraded in material according to the service environment. In seawater or high-chloride ion corrosion environment, the valve body, cone, sliding sleeve, flow guide cover, three-stage energy dissipation pipe and air supplement pipe are all made of duplex stainless steel 2205 or super duplex steel 2507, the PREN value is calculated according to PREN = %Cr + 3.3 × %Mo + 16 × %N, and ≥ 35; for example, UNS S32205 duplex stainless steel contains Cr22%, Mo3%, N0.18%, PREN = 22 + 3.3 × 3 + 16 × 0.18 = 36.5, no pitting occurs after 1000 hours of salt spray test. In low temperature environment (-40℃), the key pressure-bearing components are made of ASTM A352 LCB or LC3 cast steel with good low-temperature impact toughness, and the absorbed energy is ≥ 27J after Charpy V-notch impact test at -46℃. In the case of sand-containing water flow, the inner surface of the cone and the three-stage energy dissipation pipe can be stacked with stellite alloy or sprayed with tungsten carbide coating, the coating thickness is 0.3mm to 0.5mm, the microhardness HV is ≥ 1000, and the mass loss rate is ≤ 0.15g / m²·h after 200 hours of sand content 5kg / m³ erosion test.

[0013] In terms of economic benefits, the device prolongs the service life of key components significantly and reduces the total cycle maintenance cost. The traditional conical valve needs to be replaced every 3 years under the condition of 120m water head and 4000 hours of annual operation, and the single replacement cost is about 800,000 yuan; after using the device, the service life of the cone is prolonged to more than 8 years, and the service life of the valve seat is prolonged to more than 10 years, and the annual average maintenance cost is reduced by 62.5%. At the same time, without external air compressor, gas storage tank and complex pipeline system, the initial investment cost is reduced by 45% compared with the traditional forced air supplement scheme, the occupied area is reduced by 60%, and the installation and debugging period is shortened by 50%. In the application case of 100MW level hydropower station, the annual maintenance cost of a single conical valve is about 500,000 yuan, and the annual maintenance cost of four valves in the whole station is 2 million yuan, and the investment recovery period is less than 2 years.

[0014] As a preferred embodiment of the present application, the punched edge of the three-stage energy dissipation porous pipe can be additionally provided with a micro vortex generator, which is a semicircular protrusion with a height of 1mm to 2mm and a width of 2mm to 3mm, and 4 to 8 of which are uniformly distributed along the circumferential direction of the hole edge, for inducing controllable vortex at the hole, enhancing the jet breaking effect and promoting gas-liquid mixing. As another preferred embodiment of the present application, an adjustable guide vane can be arranged inside the air outlet of the air supplement pipe, the guide vane is driven by a micro stepping motor, the rotation angle is 0° to 90°, for increasing the entrainment negative pressure under low opening condition and reducing the air resistance under high opening condition, to realize active fine adjustment of the air supplement amount. As still another preferred embodiment of the present application, microscale grooves can be arranged on the surface of the guide rib, the groove depth is 50μm to 100μm, the groove width is 100μm to 200μm, the groove spacing is 200μm to 500μm, and the grooves are arranged along the flow direction, for suppressing near-wall turbulent pulsation and further reducing flow noise and vibration.

[0015] The manufacturing process of the device comprises the following key steps: the valve body is cut by numerical control plasma cutting, and the longitudinal seam is automatically welded by a plate rolling machine after rolling, and stress is eliminated by overall annealing after welding; the cone is cast by resin sand molding and vacuum pouring process, and is subjected to homogenization annealing + quenching + tempering heat treatment after casting; the three-stage energy dissipation porous pipe is punched by numerical control punch or laser cutting machine, the hole precision is ±0.1mm, and the hole diameter tolerance is ±0.05mm; the air supplement pipe is formed by numerical control pipe bending machine, the bending radius is ≥3 times the pipe diameter, and the inner wall is wrinkle-free after bending; the guide rib is processed by wire cutting to have an airfoil profile, and is automatically argon arc welded by a robot after being assembled with the cone, and the weld is continuous and pore-free; after the whole machine is assembled, water pressure strength test (1.5 times the design pressure for 30 minutes without leakage) and air tightness test (0.6MPa compressed air for 10 minutes, pressure drop ≤0.02MPa) are carried out.

[0016] The software implementation of the control method is based on a real-time operating system (RTOS), the control period is 100ms, the data acquisition module reads the pressure transmitter and acceleration sensor data through the RS485 bus, the control algorithm module performs segmented linear interpolation calculation and outputs a PWM signal to drive the stepping motor, and the human-computer interface module provides opening setting, parameter display and alarm recording functions. The system has self-diagnosis capability, and when it detects that the air supplement pipe is blocked or the vibration sensor is invalid, it automatically switches to a conservative control mode and issues a maintenance prompt.

[0017] The beneficial effects of the present application are embodied in the following aspects:

[0018] The technical scheme of the application realizes the fusion of air supplement and energy dissipation in structure, constructs the synergistic regulation mechanism of pressure field-velocity field-gas phase field in principle, realizes the adaptive adjustment based on working condition sensing in control, considers the process feasibility and economy in manufacturing, covers the multi-scene requirements from conventional water and electricity to ocean energy development in application, fundamentally breaks through the functional barriers and response lag defects of the traditional technical path, and provides a systematic solution for safe, efficient and long service life operation of the high-head conical valve. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Fig. 1 is a schematic diagram of the overall structure of the multi-mode air supplement-energy dissipation collaborative cavitation reduction device of the conical valve of the application;

[0020] Figure 2 Fig. 4 is a schematic diagram of the axial sectional structure of the three-stage energy dissipation perforated pipe, showing the gradient arrangement and hole type characteristics of the first-stage, second-stage and third-stage perforated pipes;

[0021] Figure 3 Fig. 6 is a top view schematic diagram of the spatial layout of the flow guide cover and the air supplement pipe, showing the symmetric distribution of the two air supplement pipes along the valve body axis and the position relationship of the air inlet and outlet;

[0022] Figure 4 Fig. 7 is a system block diagram of the control method, including sensor input, PLC control algorithm, actuator output and human-computer interaction module.

[0023] The reference signs are as follows: 1, valve body; 2, cone; 3, sliding sleeve; 4, flow guide cover; 5, first-stage energy dissipation cylindrical perforated pipe; 6, second-stage energy dissipation conical perforated pipe; 7, third-stage energy dissipation conical perforated pipe; 8, air supplement pipe; 9, sealing ring; 10, sealing plate; 11, drive screw; 12, drive nut; 13, worm gear box; 14, flow guide rib; 15, pressure transmitter; 16, acceleration sensor; 17, programmable logic controller; 18, stepper motor; 19, human-computer interface. DETAILED DESCRIPTION

[0024] Figures 1-3The overall implementation of the cone valve multi-mode air supplement-energy dissipation collaborative gas cavitation device and control method relies on a highly integrated mechanical structure and closed-loop feedback control system. The core is to realize the step-by-step energy dissipation of high-speed energy-containing jet flow, active filling of cavitation core area, and stability control of boundary layer flow through the physical coupling and dynamic collaboration between the three-level gradient pressure release structure at the outlet end of the valve body, the negative pressure induced air supplement system outside the fairing, and the flow stabilizing ribs on the inner wall of the cone. During the manufacturing process, the device strictly follows the engineering specifications of material selection, structure tolerance, welding process, assembly precision, etc., to ensure the structural integrity and functional effectiveness under extreme working conditions of maximum working pressure 42 MPa, flow rate 5.0 m³ / s, and water head 200 m. The control method is based on real-time acquisition of valve opening, upstream and downstream pressure difference, and vibration acceleration three types of sensing signals, and through the programmable logic controller to execute the segmented linear interpolation algorithm, to dynamically adjust the air supplement intensity and the equivalent opening rate of the energy dissipation structure, so as to maintain the optimal gas cavitation suppression effect in different operating intervals.

[0025] The valve body is made of Q345R low alloy high strength steel or ASTM A516 Gr.70 carbon steel, and its nominal inside diameter is selected as DN300, DN500, DN800 or DN1200 according to engineering requirements. The wall thickness is set as 28mm, 32mm, 36mm and 42mm respectively after finite element stress analysis, to meet the strength requirement of safety factor not less than 3.0 under 42MPa design pressure. The internal flow passage of the valve body is precisely machined by numerical control boring machine, with surface roughness Ra≤1.6μm to reduce flow friction loss. Standard flange interfaces are provided at both ends of the valve body, the RF type protruding surface structure is used for the flange sealing surface, and the bolt holes are arranged according to ASME B16.5 standard to ensure reliable connection with the upstream and downstream pipelines. The valve body has a pressure transmitter mounting interface reserved on the outer wall, which is 1 / 2"NPT, located at 5 times the pipe diameter upstream and 3 times the pipe diameter downstream of the valve body, for real-time monitoring of pressure difference signals. A drain screw plug is provided at the bottom of the valve body, with a size of M20×1.5, to facilitate emptying of internal water accumulation during shutdown maintenance.

[0026] The cone is integrally cast from ZG06Cr13Ni4Mo martensitic stainless steel, and the casting is formed by resin sand molding and vacuum pouring process, with pouring temperature controlled at 1520°C±10°C and cooling rate ≤50°C / h to avoid shrinkage and hot cracking defects. After casting, three heat treatments of homogenization annealing (980°C×4h air cooling) + quenching (1050°C×2h oil cooling) + tempering (620°C×4h air cooling) are carried out, and the final hardness is controlled in the range of HB220 to HB260, with tensile strength ≥750MPa, yield strength ≥550MPa, and elongation ≥15%. The outer contour of the cone is finished by a numerical control lathe, with surface roughness Ra≤0.8μm, and the taper angle is set to 8° to 15° according to the valve seat matching requirements, with taper run-out tolerance ≤0.05mm. Eight flow guide ribs are welded along the circumferential direction on the inner wall of the cone, with the same material as the cone, thickness of 8mm, height of 6% of the inner diameter of the cone, and axial length covering the full length of the working section of the cone. The cross section of the rib is in the shape of NACA 0012 airfoil profile, with front edge roundness radius of 3mm, rear edge thickness of 0.5mm, and attack angle set to 3° to stabilize the boundary layer at the minimum resistance cost. The rib and the cone are connected by automatic argon arc welding with robot, with welding wire brand ER410NiMo, welding current 180A to 220A, welding seam excess height ≤1mm, and after welding, 100% radiographic inspection (meeting the JB / T 4730.2-2005 II level qualified standard) and 580°C×2h stress relief annealing treatment are carried out.

[0027] The sliding sleeve is formed by rolling and welding of 304 stainless steel (06Cr19Ni10) plate, with plate thickness selected as 6mm (DN300), 8mm (DN500), 10mm (DN800) or 12mm (DN1200) according to the valve body size, and after rolling, the longitudinal seam is welded by automatic submerged arc welding with welding wire brand H08Cr21Ni10 and welding speed 0.8m / min, and after welding, the outer circle is treated by straightening to make the outer circle roundness error ≤0.1mm. The outer circle of the sliding sleeve and the inner wall of the valve body are matched with an H8 / f7 gap, with matching gap 0.045mm to 0.125mm (depending on the nominal size change), and the outer surface is mirror polished to Ra≤0.4μm to reduce the sliding friction coefficient with the valve body to below 0.08. The axial stroke of the sliding sleeve is set according to the linear adjustment range of 0% to 100% of the valve opening, corresponding to 150mm for DN300 valve, 250mm for DN500 valve, 400mm for DN800 valve, and 600mm for DN1200 valve. The inner wall of the sleeve and the outer contour of the cone form an annular throttling passage, with the minimum cross-sectional area of the passage being 8% of the valve body cross-sectional area at 10% opening, 45% at 50% opening, and 98% at full opening.

[0028] The fairing is made of 316L stainless steel (022Cr17Ni12Mo2) plate material punched and formed, and the plate thickness is selected as 8 mm (DN300), 10 mm (DN500), 12 mm (DN800) or 15 mm (DN1200) according to the valve body size. The axial length of the fairing is 1.5 times the outlet diameter of the valve body, the inner wall profile and the outer profile of the cone form a converging flow passage, and the contraction angle is set to 12° to form a concentrated jet downstream of the cone and enhance the ejector effect. The outer wall of the fairing is symmetrically arranged with 2 air supplement pipes along the axis, the air supplement pipe is made of 304 stainless steel seamless steel pipe (GB / T 14976), the outer diameter is 32 mm, the wall thickness is 4 mm, the bending radius is 96 mm (3 times the pipe diameter), the inner wall of the elbow pipe is free of wrinkles, and the ovality is ≤5%. The air inlet end of the air supplement pipe is located 20 mm downstream of the maximum outer diameter section of the cone, 10 mm away from the outer surface of the cone, the air inlet is directed towards the valve axis, and there is no shielding structure. The air outlet end penetrates the fairing wall and extends into the inner cavity, the center of the air outlet is located 75 mm upstream of the inlet of the primary energy-saving cylindrical perforated pipe, the angle between the air outlet axis and the valve axis is 45°, the air outlet inner diameter is precisely bored to 30 mm±0.05 mm, and the edge chamfer C1.0 is used to eliminate stress concentration. There is no valve or throttling element inside the air supplement pipe, and the gas flow completely depends on the local negative pressure induced effect of the high-speed jet flow formed at the air outlet.

[0029] The three-stage energy dissipation perforated pipe is composed of a first-stage energy dissipation cylindrical perforated pipe, a second-stage energy dissipation conical perforated pipe and a third-stage energy dissipation conical perforated pipe which are connected in series along the axial direction, and the three are rigidly connected with the outlet end face of the valve body through flanges or welding. The outer diameter of the first-stage energy dissipation cylindrical perforated pipe is consistent with the inner diameter of the valve body, the inner diameter is 0.68 times the inner diameter of the valve body, the pipe wall thickness is 16 mm, and the length is 0.8 times the inner diameter of the valve body. The pipe wall is uniformly perforated in the circumferential direction, the hole diameter is 12 mm, the hole spacing is 3.2 times the hole diameter (38.4 mm), the hole opening rate is 21%, the hole axis is perpendicular to the pipe axis, and the hole edge is chamfered C0.5. The second-stage energy dissipation conical perforated pipe is a conical table structure with the conical angle facing the upstream, the large end outer diameter is consistent with the outer diameter of the first-stage pipe, the small end outer diameter is 0.82 times the large end outer diameter, the conical angle is 15°, the pipe wall thickness gradually changes from 15 mm at the large end to 10 mm at the small end, and the length is 0.6 times the inner diameter of the valve body. The perforation is arranged in the conical surface area, the hole diameter is 8 mm, the hole spacing is 4 times the hole diameter (32 mm), the hole opening rate is 15%, the hole axis is arranged along the normal direction of the conical surface, and the hole edge is chamfered C0.3. The third-stage energy dissipation conical perforated pipe is a conical table structure with the conical angle facing the downstream, the small end outer diameter is consistent with the small end outer diameter of the second-stage pipe, the large end outer diameter is 1.28 times the small end outer diameter, the conical angle is 20°, the pipe wall thickness gradually changes from 10 mm at the small end to 16 mm at the large end, and the length is 0.7 times the inner diameter of the valve body. The perforation is arranged in the conical surface area, the hole diameter is 6 mm, the hole spacing is 5 times the hole diameter (30 mm), the hole opening rate is 10%, the hole axis is arranged along the normal direction of the conical surface, and the hole edge is chamfered C0.2. The third-stage structure hole diameter gradient is 12 mm→8 mm→6 mm, and the hole opening rate gradient is 21%→15%→10%, thereby forming a composite energy dissipation mechanism of step-by-step pressure release, step-by-step crushing and step-by-step dissipation.

[0030] The sealing system is composed of a sealing ring and a sealing pressure plate. The sealing ring is molded by fluororubber (FKM) and has a Shore hardness of 75±5 and a compression permanent deformation rate of ≤15% (70℃×24h). The sealing ring is installed in an annular groove between the sliding sleeve and the valve body, the groove depth is 1.2 times the cross-sectional diameter of the sealing ring, and the groove width is 1.1 times the cross-sectional diameter. The sealing pressure plate is forged by 304 stainless steel and has a thickness of 12 mm. The sealing ring is compressed by an M16 internal hexagonal screw (12.9 grade), and the pre-tightening torque is set to 120 N·m to ensure no leakage under a pressure of 42 MPa. The transmission system is composed of a transmission screw, a transmission nut and a worm gear box. The transmission screw is made of 40Cr alloy steel and is quenched and tempered (HB280 to HB320), the thread specification is Tr80×12 (DN800 valve), and the thread pitch error is ≤0.02 mm / m. The transmission nut is made of ZCuAl10Fe3 aluminum bronze casting, and the inner thread clearance with the screw is 0.05 mm to 0.10 mm. The worm gear box is made of cast iron shell and has an internal worm gear transmission pair, the transmission ratio is 40:1, the efficiency is ≥85%, and the output shaft is connected with the transmission screw through an elastic coupling which can withstand a maximum torque of 8000 N·m.

[0031] Figure 4 As shown in the figure, the hardware architecture of the control system includes a pressure transmitter, an acceleration sensor, a programmable logic controller, a stepper motor and a human-machine interface. The pressure transmitter is selected from Rosemount 3051 series, with a range of 0 to 50 MPa, an accuracy of ±0.075% FS, an output of 4 to 20 mA signal, and is installed on the upstream and downstream reserved interfaces of the valve body. The acceleration sensor is selected from PCBPiezotronics 352C33 type piezoelectric sensor, with a range of ±50g, a frequency response range of 0.5Hz to 10kHz, a sensitivity of 100mV / g, and is installed at the maximum vibration position of the outer wall of the valve body (determined by modal analysis), with a sampling frequency of 10kHz. The programmable logic controller is selected from Siemens S7-1200 series, with CPU model 1214C DC / DC / DC, built-in 16-bit A / D conversion module, and control period of 100ms. The stepper motor is selected from Dongfang Motor PKP series, with holding torque of 1.8N·m, step angle of 1.8°, and driver subdivision setting of 25600 steps / revolution, which is used to drive the adjustable guide vane inside the gas outlet of the air supply pipe. The human-machine interface is selected from WELON MT8102iE touch screen, with resolution of 800×480, supporting opening degree setting, real-time parameter display, historical data storage and alarm recording functions.

[0032] The control algorithm adopts a segmented linear interpolation model, which divides the valve opening into four intervals of 0%-20%, 20%-50%, 50%-80% and 80%-100%, and establishes a mapping relationship between the pressure difference ΔP and the target air supply quantity Q air in each interval: when ΔP<2MPa, Q air =0L / s; when 2MPa≤ΔP<5MPa, Q air =0.3×ΔP L / s; when 5MPa≤ΔP<10MPa, Q air =0.5×ΔP L / s; when ΔP≥10MPa, Q air =0.7×ΔP L / s. The control algorithm module determines the corresponding angle to which the micro stepper motor should drive the guide vane to rotate according to the calculated target air supply quantity Qair through the preset mapping curve or lookup table method, and outputs the corresponding PWM signal for accurate control. For example, when the Qair demand is high, the guide vane is rotated to 60° to increase the eduction negative pressure; when the Qair demand is low or the air resistance needs to be reduced, the guide vane is rotated to 15°. The mapping relationship is obtained based on CFD simulation and bench test joint calibration, ensuring that the air supply quantity matches the cavitation intensity. After low-pass filtering (cutoff frequency 5kHz), the energy E vib in the frequency band of 0.5kHz to 5kHz is extracted as the cavitation intensity index, and the calculation formula is , where a(t) is the acceleration time domain signal. vibWhen the corresponding root mean square acceleration exceeds 0.5g, the control algorithm automatically increases Q of the next control cycle air The set value is 10%, and the vibration is returned to the safe interval. The system has a self-diagnosis function. When it is detected that the negative pressure value of the air supply pipe is lower than 1kPa for 3 consecutive cycles (judged as blocked) or the output of the acceleration sensor is constant (judged as failure), the system automatically switches to the conservative control mode (Q air =0.5×ΔP L / s, ΔP≥5MPa) and triggers an audible and light alarm.

[0033] As a preferred embodiment of the present application, a micro vortex generator is added to the punched edge of the three-stage energy dissipation porous pipe. The generator is a semicircular protruding structure with a height of 1.5mm and a width of 2.5mm. Six generators are evenly distributed along the circumference of the hole edge. The generator is integrally formed with the pipe wall using laser cladding process, and the material is Stellite 6 alloy with a hardness of HRC58 to HRC62. The vortex generator induces controllable vortex at the hole, reduces the particle size of the jet from 8mm to 5mm under the reference working condition, and improves the gas-liquid mixing efficiency by 22%.

[0034] As another preferred embodiment of the present application, an adjustable guide vane is arranged inside the air outlet of the air supply pipe. The guide vane is a fan-shaped thin plate structure with a thickness of 2mm and an arc length of 1 / 4 of the pipe circumference. It is driven by a micro stepping motor to rotate around the shaft by 0° to 90°. When the valve opening is <20%, the guide vane is rotated to 60° to increase the suction negative pressure; when the opening is >60%, the guide vane is rotated to 15° to reduce the air resistance. Tests show that at 15% opening and 10MPa pressure difference, the guide vane at 60° position increases the air supply by 18%; at 80% opening and 5MPa pressure difference, the guide vane at 15° position reduces the system pressure drop by 0.15MPa.

[0035] As still another preferred embodiment of the present application, micron-level grooves are arranged on the surface of the guide rib. The grooves are processed by femtosecond laser with a depth of 80μm, a width of 150μm, and a pitch of 300μm, arranged along the flow direction, and account for 35% of the rib surface area. The groove structure reduces the near-wall turbulence intensity by 15%, reduces the flow noise (A-weighted) from 92dB to 85dB, and attenuates the high-frequency component (2kHz to 5kHz) of the vibration acceleration by 40%.

[0036] In the material adaptive embodiment, for seawater environment, the valve body, cone, sliding sleeve, fairing, three-stage energy dissipation pipe and air supply pipe are all made of UNS S32205 duplex stainless steel with PREN value of 36.5, and no pitting occurs after 1000 hours of neutral salt spray test (ASTM B117). For low temperature environment of-40℃, the key pressure-bearing components are made of ASTM A352 LCB cast steel with an average Charpy V-notch impact energy of 32J at-46℃. For sand-containing water flow conditions, the cone and the inner surface of the three-stage energy dissipation pipe are surfaced with Stellite No. 6 with a thickness of 0.4mm and a hardness of HRC55 to HRC58, and the mass loss rate is 0.12g / m²·h after 200 hours of sand content 5kg / m³ erosion test.

[0037] The key steps of the manufacturing process include: the valve body is cut by numerical control plasma cutting with a cutting speed of 800mm / min and a kerf width of 2.5mm; the edge rolling is performed by a four-roll plate rolling machine with a pre-bending length of ≥300mm; the longitudinal seam welding is performed by submerged arc automatic welding with welding flux SJ101 and a welding speed of 0.6m / min; and the whole post-welding annealing is performed at 620℃ for 8h with furnace cooling. The cone casting adopts vacuum suction casting process, four inner gates are set in the pouring system, and the post-casting heat treatment curve is strictly executed according to the process card. The three-stage energy dissipation perforated pipe punching adopts a fiber laser cutting machine with a laser power of 4000W and a cutting speed of 1.2m / min, and the hole position accuracy is ±0.08mm. The air supply pipe bending adopts a CNC pipe bender with a bending angle error of ≤0.5° and a springback compensation amount preset to 3°. The flow guiding rib wire cutting adopts a slow wire process with a molybdenum wire diameter of 0.2mm and a surface roughness Ra≤1.0μm. After the whole machine assembly, the water pressure strength test (63MPa pressure holding for 30 minutes without leakage) and the air tightness test (0.6MPa compressed air pressure holding for 10 minutes with a pressure drop of 0.015MPa) are performed.

[0038] The software implementation of the control system is based on the FreeRTOS real-time operating system, and the task priority allocation is as follows: data acquisition task (priority 5), control algorithm task (priority 4), actuator drive task (priority 3), human-computer interaction task (priority 2), and self-diagnosis task (priority 1). The data acquisition module reads the pressure and vibration data through the RS485 bus every 100ms, the control algorithm module performs interpolation calculation and outputs the PWM signal, and the stepper motor driver receives the 20kHz PWM signal to adjust the flow guiding piece angle. The historical data storage adopts the FAT32 file system, records a group of operating parameters every 10 minutes, and supports 30 days of continuous recording.

[0039] To verify the technical effect, a full-size hydraulic test bench is built, the test medium is clear water, the water temperature is 20 DEG C + 2 DEG C, the test pressure is 0 to 25 MPa adjustable, and the flow is 0 to 5.0 m3 / s continuously controllable. The comparative test objects include: A type (the device of the application), B type (only setting air supplement pipe without energy dissipation structure), C type (only setting three-stage energy dissipation pipe without air supplement), D type (air supplement pipe + energy dissipation pipe simple superposition without collaborative design). The test conditions are as follows: water head 120 m, opening 30%, flow 2.1 m3 / s, running time 100 hours. The test results are shown in the following table:

[0040]

[0041] In the economic benefit embodiment, taking a 100 MW level hydropower station as an example, a single conical valve runs 4000 hours per year, the traditional structure cone replacement cycle is 3 years, and the cost is 800,000 yuan; after using the application, the service life is extended to 8 years, and the annual cost is reduced from 26.7 to 10 million yuan. The traditional replacement cycle of the valve seat is 3 years, and the cost is 400,000 yuan; after using the application, it is extended to 10 years, and the annual cost is reduced from 13.3 to 4 million yuan. The total annual maintenance cost is reduced by 62.5%. In terms of initial investment, the unit price of the device of the application is 1.8 million yuan, the unit price of the traditional forced air supplement scheme (including air compressor, gas tank and pipeline) is 3.28 million yuan, and 45% is saved. The occupied area is reduced from 12 m2 to 4.8 m2, and the installation and commissioning period is shortened from 15 days to 7 days. A single valve saves 500,000 yuan in maintenance costs per year, and four valves in the whole station save 2 million yuan per year, with an investment recovery period of 1.8 years.

[0042] The device of the application is also verified in the marine energy development scene. In a certain tidal current power generation project, the device withstands bidirectional alternating flow (flow rate 4 m / s to 8 m / s, cycle 6 hours), and after running for 12 months, the cone surface is free of macroscopic cavitation damage, the three-stage energy dissipation pipe orifice is free of blockage, and the air supplement pipe injection function is normal, proving its long-term reliability under complex flow conditions. In the transient condition test of pumped storage power station, the valve is closed from full opening to 10% opening (for 5 seconds), and the control system adjusts the air supplement amount within 300 ms, the vibration peak value is suppressed below 0.8 g, and the protection shutdown is not triggered, which reflects its excellent dynamic response capability.

[0043] In summary, the conical valve multi-mode air supplement-energy dissipation collaborative cavitation erosion reduction device and control method realizes the systematic suppression of cavitation damage under super-high pressure difference, large flow and transient conditions through precise structure design, strict material control, optimized manufacturing process and intelligent closed-loop control, and the technical scheme has high engineering realizability, economic rationality and working condition adaptability, and can be widely applied to high-parameter fluid control scenes in the fields of hydropower, nuclear power, marine energy, petroleum and chemical industry, etc.

Claims

1. A cone-shaped valve multi-mode air supply-energy dissipation synergistic cavitation reduction device, characterized in that, The components include a valve body (1), a cone (2), a sliding sleeve (3), a flow guide (4), a three-stage energy dissipation multi-hole pipe, an air supply pipe (8), a sealing ring (9), a sealing pressure plate (10), a transmission screw (11), a transmission nut (12), and a worm gear box (13). The nominal inner diameter of the valve body (1) is DN300 to DN1200, and the wall thickness is determined by finite element stress verification based on the maximum working pressure of 16MPa to 42MPa, with a minimum of 28mm. The cone (2) is made of ZG06Cr13Ni4Mo Marble steel. The body is integrally cast in stainless steel and subjected to solution treatment and tempering. The surface hardness is controlled within the range of HB220 to HB260, and the surface roughness Ra≤0.8μm. The clearance fit tolerance between the outer circle of the sliding sleeve (3) and the inner wall of the valve body (1) is H8 / f7. The axial stroke is set to 150mm to 600mm according to the linear adjustment range of the valve opening from 0% to 100%. The outer surface is mirror polished. The axial length of the guide shroud (4) is 1.2 to 1.8 times the outlet diameter of the valve body (1), and the radial thickness is 8mm to 15mm. The inner wall and the outer contour of the cone (2) form a gradually narrowing flow channel with a contraction angle of 8° to 15°; the three-stage energy dissipation porous pipe is composed of a first-stage energy dissipation cylindrical perforated pipe (5), a second-stage energy dissipation conical perforated pipe (6) and a third-stage energy dissipation conical perforated pipe (7) connected axially in series along the fluid flow direction, and is rigidly connected to the outlet end face of the valve body (1) by flange or welding; the air supply pipe (8) is symmetrically arranged in 2 to 6 sections along the axis of the valve body (1), with the air inlet end located near the maximum outer diameter section of the cone (2) and 5 mm to 15 mm away from the outer surface of the cone (2), and the outlet end... The air outlet penetrates the wall of the guide shroud (4) and extends into its inner cavity. The air outlet is located 50mm to 100mm upstream of the inlet of the first-stage energy dissipation cylindrical perforated pipe (5). The angle between the axis of the air outlet and the axis of the valve body (1) is 30° to 60°. The inner wall of the cone (2) is welded with 6 to 12 guide ribs (14) along the circumferential direction. The cross-section of the rib is a streamlined airfoil with a front edge radius of 2mm to 4mm, a sharp rear edge, an angle of attack of 0° to 5°, a height of 5% to 8% of the inner diameter of the cone (2), and an axial length covering the entire working section of the cone (2). The secondary energy-dissipating conical punched tube (6) is provided with an adjustable aperture plate, which is driven by a stepper motor to achieve changes in the equivalent opening ratio; The three-stage energy dissipation porous pipe, the gas supply pipe (8) and the flow guide rib (14) are integrated to form a device for synergistically regulating the flow field to achieve multi-mode gas supply, gradient pressure relief and flow stability, thereby jointly suppressing cavitation.

2. The cone valve multi-mode air supply-energy dissipation synergistic cavitation reduction device according to claim 1, characterized in that, The first-stage energy-dissipating cylindrical perforated pipe (5) has a straight cylindrical structure with an outer diameter consistent with the inner diameter of the valve body (1). The inner diameter is 0.6 to 0.75 times the inner diameter of the valve body (1), and the pipe wall thickness is 12 mm to 20 mm. Perforations are evenly distributed along the circumference, with a hole diameter of 8 mm to 15 mm and a hole spacing of 2.5 to 4 times the hole diameter. The opening rate is 18% to 25%, and the hole axis is perpendicular to the pipe axis. The hole edges are chamfered. The second-stage energy-dissipating conical perforated pipe (6) has a truncated cone structure with the cone angle facing upstream. The outer diameter of the large end is consistent with the outer diameter of the first-stage pipe, and the outer diameter of the small end is 0.8 times the outer diameter of the large end. The cone angle is 10° to 20°, and the pipe wall thickness is 1 mm to 20 mm along the axial direction. The diameter of the hole is 6mm to 10mm, the hole spacing is 3 to 5 times the hole diameter, the opening rate is 12% to 18%, and the hole axis is arranged along the normal direction of the conical surface. The three-stage energy dissipation conical punched pipe (7) is a truncated cone structure with the cone angle facing downstream. The outer diameter of the small end is consistent with the outer diameter of the small end of the secondary pipe, the outer diameter of the large end is 1.25 times the outer diameter of the small end, the cone angle is 15° to 25°, the pipe wall thickness gradually changes from 10mm to 18mm along the axial direction, the hole is arranged in the conical surface area, the hole diameter is 4mm to 8mm, the hole spacing is 4 to 6 times the hole diameter, the opening rate is 8% to 12%, and the hole axis is arranged along the normal direction of the conical surface.

3. The cone valve multi-mode air supply-energy dissipation synergistic cavitation reduction device according to claim 2, characterized in that, In the three-stage energy dissipation porous pipe, micro vortex generators are added to the edge of each stage of the perforation. The vortex generators are semi-circular protrusions with a height of 1 mm to 2 mm and a width of 2 mm to 3 mm, and 4 to 8 are evenly distributed along the circumference of the hole edge. They are used to induce controllable vortices at the hole opening to enhance the jet breaking effect and promote gas-liquid mixing.

4. The cone valve multi-mode air supply-energy dissipation synergistic cavitation reduction device according to claim 1, characterized in that, The gas supply pipe (8) is made of seamless 304 stainless steel pipe with an outer diameter of 25mm to 40mm and a wall thickness of 3mm to 5mm. Its gas flow depends entirely on the local negative pressure ejection effect formed by the high-speed jet at the outlet. The structural design of the gas supply pipe (8) enables the formation of a negative pressure sufficient to eject the external atmosphere inside the pipe when the valve opening is in the range of 10% to 80% and the flow velocity of the annular throttling gap is 25m / s to 60m / s.

5. The cone valve multi-mode air supply-energy dissipation synergistic cavitation reduction device according to claim 4, characterized in that, An adjustable guide vane is provided inside the air outlet of the air supply pipe (8). The guide vane is driven by a micro stepper motor (18) and rotates from 0° to 90°. It is used to increase the ejector negative pressure under low opening conditions and reduce the air resistance under high opening conditions, so as to realize the active fine adjustment of the air supply volume.

6. The cone valve multi-mode air replenishment-energy dissipation synergistic cavitation reduction device according to claim 1, characterized in that, The number of the flow guide ribs (14) is preferably 8, distributed at equal angles, and the material is the same as that of the cone (2), with a thickness of 6 mm to 10 mm. They are welded to the cone (2) by argon arc welding, and the welds are qualified by 100% radiographic testing and stress-relieving annealing. The surface of the flow guide ribs (14) is provided with micron-level grooves, with a depth of 50 μm to 100 μm, a width of 100 μm to 200 μm, and a spacing of 200 μm to 500 μm. They are arranged along the flow direction to suppress near-wall turbulent pulsation and reduce flow noise and vibration.

7. A control method for a cone valve multi-mode air supply-energy dissipation synergistic cavitation reduction device as described in any one of claims 1 to 6, characterized in that, Based on real-time monitoring of three core parameters—valve opening, upstream and downstream pressure difference ΔP, and vibration acceleration—a piecewise linear interpolation control algorithm is executed by a programmable logic controller (17) to dynamically adjust the gas supply intensity and the equivalent orifice ratio of the three-stage energy dissipation structure. The control algorithm divides the valve opening into four intervals: 0%-20%, 20%-50%, 50%-80%, and 80%-100%. Within each interval, a pressure difference ΔP and a target gas supply Q are established. air Mapping relationship: When ΔP < 2MPa, Q air =0; when 2MPa≤ΔP<5MPa, Q air =0.3×ΔP L / s; when 5MPa≤ΔP<10MPa, Q air =0.5×ΔP L / s; when ΔP≥10MPa, Q air =0.7×ΔP L / s.

8. The control method according to claim 7, characterized in that, The vibration acceleration signal is collected by a piezoelectric accelerometer (16) installed on the outer wall of the valve body (1), with a sampling frequency of 10kHz. After low-pass filtering, the energy in the 0.5kHz to 5kHz frequency band is extracted as the cavitation intensity index. When the root mean square acceleration corresponding to this index exceeds the preset threshold of 0.5g, the control algorithm automatically increases the Q of the next control cycle. air Set the value to 10% until the vibration returns to a safe range.

9. The control method according to claim 7, characterized in that, The control system has self-diagnostic capabilities: when the negative pressure value of the air supply pipe (8) is detected to be lower than 1 kPa for three consecutive control cycles, it is determined to be blocked; or when the output of the acceleration sensor (16) is constant and unchanged, it is determined to be faulty. The system automatically switches to conservative control mode, i.e., Q air =0.5×ΔP L / s (ΔP≥5MPa), and trigger an audible and visual alarm to prompt maintenance.

10. The cone valve multi-mode air supply-energy dissipation synergistic cavitation reduction device according to claim 1, characterized in that, All flow components are upgraded in terms of material according to the service environment: In seawater or high chloride ion corrosion environment, valve body (1), cone (2), sliding sleeve (3), flow guide (4), three-stage energy dissipation porous pipe and air supply pipe (8) are all made of duplex stainless steel 2205 or super duplex steel 2507 with PREN value ≥35; In the -40℃ low temperature environment, key pressure-bearing components are made of ASTM A352 LCB or LC3 cast steel, and absorb energy ≥27J after Charpy V-notch impact test at -46℃; In the case of sandy water flow, the inner surface of cone (2) and three-stage energy dissipation porous pipe is overlaid with Stellite alloy or sprayed with tungsten carbide coating, with a coating thickness of 0.3mm to 0.5mm and microhardness HV≥1000.

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