46 results about "Cavitation flow" patented technology

The invention relates to the technical field of cleaning equipment, in particular to an underwater cavitation jet observation experiment device and method based on a triangular reflector, and the device comprises a jet control device, an impact observation device, a plurality of light source assemblies and a high-speed camera. The spraying control device comprises a nozzle, and external high-pressure water flow is sprayed out downwards from the nozzle after passing through the pump pipe; the impact observation device comprises a clamping device. The clamping device comprises a triangular prism reflector and a support used for placing the triangular prism reflector. A shot picture of the high-speed camera can simultaneously comprise a free jet flow area and a jet flow impact area reflected by the triangular prism reflector. According to the double-angle free cavitation jet flow observation device, the three-edged reflector is utilized, cavitation flow evolution of a free jet flow area of cavitation jet flow and a jet flow impact area reflected by the three-edged reflector can be observed at the same time, and double-angle free cavitation jet flow observation is achieved.

An underwater cleaning robot for the net of a cage, comprising a central robot frame, a thrust propeller, side thrust propellers, crawler wheels, an underwater camera, a tensioning wheel and a water jet cleaning mechanism. The water jet cleaning mechanism includes a cleaning disc, a regulator body, a water inlet pipe, a water spray pipe and a petal-shaped cavitation nozzle. The underwater camera collects the net shaking data, and after calculating the compensation thrust through feedback, the thrust propeller provides a compensation force to offset the net shaking. The tensioning wheel can tension the net, making the robot fit the net surface more effectively. During the walking process of the robot, an external high-pressure pump can pump high-pressure water into the regulator body through the water inlet pipe, and spray it out through the water spray pipe and the petal-shaped cavitation nozzle to achieve the cleaning of the net. The petal-shaped cavitation nozzles on both sides are inclined to different sides, and the petal-shaped cavitation fluid ejected can drive the regulator body to rotate, realizing rotary cleaning and improving the cleaning area range and cleanliness of the jet.

According to the BDIM-based propeller cavitation streaming simulation algorithm provided by the invention, the particularity of a propeller structure is considered, a hyperbolic tangent encryption function is introduced into a near-wall region of the propeller structure to carry out non-uniform grid division, and high-gradient flow and boundary layer development of a blade tip region can be effectively captured, so that the resolution of a cavitation source region and a vortex core is improved; in multi-phase interface tracking, a VOF method is adopted to carry out high-resolution reconstruction on fluctuation behaviors of a vapor-liquid interface, interface diffusion distortion can be avoided, interface definition and mass conservation can be taken into consideration in combination with double-field evolution of a volume fraction function and an intermediate velocity field, and the method is suitable for being applied to multi-phase interface tracking. The method is particularly suitable for dynamic capture of a cavitation primary area and a complex gas-liquid phase mixing area in a propeller wake, and the precision and reliability of simulation on the cavitation occurrence position, the time scale and the form can be improved.

The invention provides a cavitation flow field reconstruction method based on sparse perception and an unsupervised learning method, and the method comprises the steps: firstly, carrying out the numerical simulation of cavitation flow around a specific type of hydrofoil, considering the unique characteristics of a cavitation flow velocity field, executing the intrinsic orthogonal decomposition, and representing the intrinsic orthogonal decomposition as a representation form of the superposition of an average velocity field and a pulsation velocity field; a fluid velocity field modal library is constructed on the basis; and then an unsupervised clustering algorithm and sparse data sampling are executed to extract data samples, and fluid velocity field reconstruction is completed by using the velocity field modal library and a small number of data samples. Through verification and comparison of reconstruction effects under different sparse sampling strategies, high-fidelity reconstruction of a complex cavitation flow structure can be finally realized, and compared with the prior art, accuracy and robustness are remarkably improved.

The invention discloses a low-temperature liquid cavitation numerical prediction method considering different-scale heat effects, and belongs to the field of low-temperature liquid cavitation numerical prediction. The implementation method comprises the steps that a corresponding fluid domain geometric model is established, grids are divided, a computational fluid mechanics model is established under the macro-scale, a separation vortex DES turbulence model is adopted, a fluid volume VOF model is used for capturing a macro-scale cavity interface, and convective heat transfer correction under the macro-scale is conducted on a cavitation model; establishing a cavitation kinetic equation considering heat conduction correction under the mesoscale, solving resistance, volume force, additional mass force, pressure gradient force and lift force suffered by the mesoscale discrete cavitation by using a DBM discrete phase model, and obtaining a movement track of the discrete cavitation in a cavitation flow field; and calculating the unsteady cavitation flow by taking a steady result as an initial value to obtain a flow field characteristic under a macroscale and a discrete cavitation dynamic evolution process under a mesoscale, thereby realizing quantitative description and high-precision numerical prediction of the unsteady cavitation flow.

The application discloses a kind of monitoring devices of pressure fluctuation frequency and amplitude in cavitation collapse process, including water tank, cavitation generator, magnetic fluid, magnetic field device, laser generator, optical splitter, laser probe and receiver;Optical splitter is emitted by single beam laser of laser generator and is divided into two beams, one is emitted as laser, frequency is f ;Another is as reference laser, frequency is f + f r ;Laser probe exports and irradiates on the tip of magnetic fluid by emitting laser, and reflection is formed to form reflected laser, and its frequency is f + f D ;Receiver, accept reflected laser, and it has reference laser inside by optical splitter, and its frequency is f + f r The application can master the whole dynamic data of quantized cavitation collapse by monitoring the frequency and amplitude of whole process pressure fluctuation caused by cavitation collapse in liquid environment through magnetic fluid magneto-rheological effect, tip surface effect and Doppler effect, which provides important technical means for single-cavity theory development and hydraulic machinery cavitation flow research.

The embodiment of the invention provides a drag reduction effect AI control method and system for a natural-ventilation mixed cavitation hydrofoil, and relates to the technical field of ship engineering. Executing a cavitation flow experiment to obtain an input data set and an output data set; performing feature extraction based on the input data set and the output data set to obtain a cavitation coverage area rate, a flow field instability feature parameter, an interface evolution stability index and a signal cavitation index, and integrating into a response data set; constructing a comprehensive data source set based on the input data set, the output data set and the response data set; and determining the influence level of the current ventilation behavior based on the response data set, and determining an optimal design scheme based on the influence level and the comprehensive data source set. The method overcomes the limitation that a traditional static black box model only depends on an input-output relation and lacks process feedback, and effectively distinguishes operation states which are temporarily low in resistance but about to be unstable from operation states which are really stable and efficient.

The invention relates to the technical field of state monitoring and fault diagnosis of ship power devices, and provides a noise data processing method based on cavitation flow characteristics of a propeller. According to the method, observable dynamic frequencies such as leaf frequency and cavitation bubble falling main frequency and statistical non-stationary quantities such as a frequency spectrum broadening factor, self-correlation time, broadband energy and kurtosis are unified in the same analysis framework, a mapping model of a cavitation state and signal processing parameters is constructed, analysis parameters such as FFT, STFT and CWT are adaptively configured, and the analysis parameters of the cavitation state and the signal processing parameters are analyzed. And multi-scale feature extraction of non-stationary pressure pulsation signals under different cavitation types and cavitation intensities is realized. According to the method, the cavitation state and type are identified and evaluated on the basis of the extracted multi-domain features, the threshold and mapping parameters are reversely updated according to the identification result, a closed loop of state judgment, parameter mapping, multi-domain analysis, feature output, cavitation identification and parameter updating is formed, and the precision and engineering applicability of propeller cavitation monitoring and diagnosis are improved.

A hydrofoil cavitating flow control structure includes a hydrofoil. A primary protuberant stripe is disposed in a middle position of a suction side of the hydrofoil, a plurality of symmetrically-distributed secondary protuberant stripes are disposed obliquely at both sides of the primary protuberant stripe, and the plurality of secondary protuberant stripes are uniformly and equidistantly distributed along the length direction of the primary protuberant stripe. By changing geometric parameters such as an included angle between the primary protuberant stripe and the second protuberant stripe, a ratio of cross section diameters and a distribution spacing of the second protuberant stripes along a chord length direction of the hydrofoil and the like, the shedding of cloud cavitation on a hydrofoil surface is effectively suppressed, and cavitation erosion and pressure pulsation generated by cavitation collapse is reduced, thus improving the operation efficiency and the service life of hydraulic machinery.

A valve assembly includes a housing which has a liquid inlet and a liquid outlet, a cover affixed to the housing, a flow regulating assembly located in the housing, and an anti-cavitation flow diverter mounted in the housing. The anti-cavitation flow diverter includes an outer wall that surrounds an inner hollow portion. Sets of flow apertures are formed through the wall thickness of the outer wall. Each flow aperture is open to the inner hollow portion and extends at an angle along a non-radial path through the outer wall. Flows of liquid flowing through each set of the flow apertures impinge upon each other at meeting points which are spaced from inner surfaces of the housing.

The invention relates to a multi-phase flow closed-loop regulation and control experiment system for ventilation cavitation bubbles around a revolving body of a vertical water tunnel, and belongs to the field of cavitation water tunnel experiment technologies and equipment. Comprising a control system, a sensing system, a ventilation system, a rudder deflection system and an experimental model. The sensing system senses the state of the experimental model in real time; the control system is used for generating a rudder deflection control instruction and sending the rudder deflection control instruction to the rudder deflection system; a ventilation control instruction is generated and sent to a ventilation system; the rudder deflection system is used for adjusting rudder deflection parameters of the experimental model according to the rudder deflection control instruction, so that the attitude of the experimental model is adjusted, and the free pitching motion of the experimental model is realized; the ventilation system is used for adjusting ventilation parameters of the experimental model according to the ventilation control instruction so as to adjust the cavitation flow capacity of the experimental model; according to the invention, an experimental platform and a research basis are provided for research on flow phenomena such as cavitation falling and collapse and related large-scale and strongly-uncertain hydrodynamic characteristics under the flow direction gravity condition.

An acoustic energy tool comprising a crystal for generating acoustic energy when a volage is applied to the crystal, and a resonator. The resonator has a solid outer structure with the crystal being attached to the solid outer structure, with the resonator being comprised of a material that transmits the acoustic energy through the resonator. The tool includes a curved surface that focuses the acoustic energy being transmitted through the resonator and a fluid passageway that extends through the resonator for allowing a fluid to flow through the resonator. The acoustic energy being focused by the curved surface is concentrated in the fluid passageway so that it causes cavitation of the fluid in at least part of the fluid passageway. The cavitation of the fluid is used to break up clumps that form in the fluid or to generate reactive oxygen species.

This invention relates to the field of submerged cavitation water jets, specifically to a method for simulating the flow field load and ice-breaking of submerged water jets considering cavitation effects. The method includes obtaining an initial flow field-ice plate topology model; adjusting the fractal dimension of the mesh through a fractal growth mechanism, fusing a probabilistic model, and embedding a viscoelastic network stress transfer mechanism to obtain a fractal characteristic load field; converting the load generated by fractal iterative loading into the stress and strain of the ice plate, extracting dynamic damage evolution data of the ice plate and chaotic characteristic parameters from the fractal characteristic load field, and obtaining optimized submerged water jet parameters. This invention constructs coupling and correlation rules, clarifying the core coupling relationship between the cavitation-sensitive region and the ice plate load action region, ensuring that the cavitation load is accurately transferred to key areas of the ice layer. By adjusting the fractal dimension of the mesh in real time through a fractal growth mechanism to adapt to the dynamic evolution stage of cavitation bubbles, it solves the problem that traditional models cannot simultaneously capture the cavitation flow field morphology and ice plate damage.

The application discloses a structure optimization method for inhibiting cavitation of a low-temperature stop valve, and comprises the following steps: S1, establishing a stop valve model and performing grid division; S2, performing a numerical calculation on the stop valve model after the grid division, obtaining a cavitation flow field cloud picture based on the calculation result, and determining a key position of cavitation occurrence; S3, optimizing the stop valve model, that is, setting a uniform grid-shaped flow guide plate at the key position of cavitation occurrence; S4, performing a second numerical calculation on the optimized stop valve model, obtaining an average gas phase volume and a flow coefficient based on the calculation result; S5, performing optimization judgment according to the average gas phase volume and the flow coefficient; and S6, repeating S4 and S5 until the average gas phase volume and the flow coefficient both meet the requirements, and outputting structure parameters of the optimized stop valve. The method can be widely applied to the design and optimization of stop valves in a low-temperature fluid conveying system, and has remarkable engineering application value.

An acoustic energy tool comprising a crystal for generating acoustic energy when a volage is applied to the crystal, and a resonator. The resonator has a solid outer structure with the crystal being attached to the solid outer structure, with the resonator being comprised of a material that transmits the acoustic energy through the resonator. The tool includes a curved surface that focuses the acoustic energy being transmitted through the resonator and a fluid passageway that extends through the resonator for allowing a fluid to flow through the resonator. The acoustic energy being focused by the curved surface is concentrated in the fluid passageway so that it causes cavitation of the fluid in at least part of the fluid passageway. The cavitation of the fluid is used to break up clumps that form in the fluid or to generate reactive oxygen species.

The utility model discloses a cavitation multiphase flow detection experiment system in the field of fluid testing, which comprises a liquid circulation pipeline module which comprises an inflow section, a gas-liquid mixing section, a testing section and a backflow section and is used for forming a liquid flowing loop and realizing the functions of controllable inflow conditions and outflow state recovery of main flow; the gas inlet and gas-liquid mixing pipeline module is communicated with the gas-liquid mixing section and is used for forming a gas-liquid two-phase fluid medium and realizing the controllability of the gas-phase medium; the cavitation flow experiment module is arranged corresponding to the test section and is used for forming a cavitation flow phenomenon and realizing a cavitation flow visualization function; and the multiphase flow test module is arranged corresponding to the cavitation flow experiment module and is used for detecting the characteristics of the cavitation multiphase flow field and realizing a non-intrusive test function. The gas-liquid two-phase flow state can be controlled, two-phase flow media under different gas-containing conditions can be obtained, cavitation flow states of different degrees can be formed, and cavitation flow characteristics under the influence of gas can be analyzed conveniently.

The present invention discloses an apparatus and method for efficiently removing chlorides from municipal solid waste incineration fly ash through hydrodynamic cavitation. The apparatus includes a fly ash silo, a stirring tank, a peristaltic pump, two cavitation tubes, a water storage tank, a filter press, and a wastewater recycling component. The method comprises the following steps: S1, preparation of fly ash slurry; S2, fitting of hydrodynamic cavitation parameters; S3, staged hydrodynamic cavitation: S3-1, determination of the optimal mass concentration; S3-2, determination of the optimal cavitation flow velocity; S4, continuous hydrodynamic cavitation; S5, post-treatment. Through hydrodynamic cavitation, the present invention can effectively promote the dissolution of soluble chlorides, greatly improve the removal rate of soluble chlorides, further reduce industrial water consumption, and the recycled water can be recycled, with low cost and good chloride removal effect. No chemical agents are used in the process of fly ash dechlorination, and environmental protection and efficient impurity removal of incineration fly ash can be achieved.

The invention relates to a cavitation erosion prediction method considering cavity collapse and an energy transport process thereof, and belongs to the technical field of hydrodynamic research. The cavitation prediction method comprises the following steps: solving a cavitation flow field for a to-be-predicted object; based on the physical characteristic change of cavity collapse, recognizing a collapse area and recording cavity collapse pressure; collapse energy is calculated according to the cavity collapse pressure; analyzing the transportation process of collapse energy radiation to the to-be-predicted position of the wall surface, calculating a transfer parameter and an attenuation parameter, and multiplying the transfer parameter and the attenuation parameter to obtain a transportation parameter; calculating the cavitation erosion load radiated to the wall surface by the collapse energy in combination with the collapse energy and the transportation parameters, and accumulating to obtain the accumulated cavitation erosion load of the current prediction position of the wall surface; and determining a cavitation erosion area according to the accumulated cavitation erosion load. According to the cavitation prediction method, the real physical process of cavity collapse is considered, the authenticity of collapse area identification is ensured, meanwhile, the transfer and dissipation processes in energy transportation are considered, and the accuracy of cavitation area prediction is ensured.

The present application belongs to the technical field of intersection of computational fluid dynamics and artificial intelligence, and in particular to a high-precision prediction method for a hydrodynamic torque converter cavitation flow field. The method comprises the following steps: S1: obtaining transient CFD flow field simulation data inside the guide wheel flow passage of the hydrodynamic torque converter; S2: constructing a multi-task neural network model; S3: constructing a hybrid supervised loss function for optimizing the cavitation prediction sub-network; S4: training the neural network model by adopting a three-stage decoupling strategy; S5: constructing a physical residual loss term based on the law of conservation of fluid dynamics; and S6: inputting the space-time coordinates to be predicted into the trained neural network model. The present application improves the recognition accuracy of sparse cavitation features, enhances the training stability of complex multiphase flow fields, improves the physical consistency of the prediction results, and significantly improves the calculation efficiency of the cavitation flow field.

This invention provides a numerical simulation method and system for cavitation turbulence based on gas-liquid slip velocity correction, belonging to the field of cavitation numerical simulation technology. It obtains the gas phase volume fraction distribution and liquid phase velocity field distribution in a fluid pipe, establishes the density gradient field of the gas-liquid interface region, constructs a dynamic characteristic function of the gas-liquid interface including a coupled expression of interface curvature and local vorticity terms, and uses an adaptive gas-liquid slip velocity correction model to correct the relative gas-liquid velocities, solving for the turbulent characteristic parameters and pressure field distribution in the cavitation flow field. This significantly improves the accuracy and refinement of the gas-liquid interface dynamics description, enhances the adaptability of the slip velocity correction model to the nonlinear characteristics of the interface, and helps to more accurately simulate cavitation turbulence behavior, thereby improving the accuracy and reliability of cavitation turbulence numerical simulation and providing more scientific and effective technical support for cavitation prediction and control in complex engineering fields.

The present application relates to a kind of cavity erosion prediction method considering cavity collapse and its energy transport process, belong to the technical field of hydrodynamics research.The cavity erosion prediction method includes the following steps: solving cavitation flow field to the object to be predicted;Based on the physical property change of cavity collapse, identify collapse region and record cavity collapse pressure;According to cavity collapse pressure, calculate collapse energy;Analysis of the transport process of collapse energy radiated to the wall to be predicted position, calculate transfer parameter and attenuation parameter, and the transport parameter is obtained by multiplication;Combined with collapse energy and transport parameter, calculate the cavity erosion load of collapse energy radiated to the wall, and the cumulative cavity erosion load of the current predicted position of wall is obtained by accumulation;According to cumulative cavity erosion load, determine the cavity erosion region.The cavity erosion prediction method considers the real physical process of cavity collapse, ensures the authenticity of collapse region identification, and considers the transfer and dissipation process in energy transport, ensures the accuracy of cavity erosion region prediction.

The invention provides a cavitation turbulence numerical simulation method and system based on gas-liquid slippage velocity correction, and relates to the technical field of cavitation numerical simulation. Gas phase volume fraction distribution and liquid phase velocity field distribution in a fluid pipeline are obtained, and a density gradient field of a gas-liquid two-phase interface area is established; and constructing a gas-liquid interface dynamic characteristic function containing coupling expression of an interface curvature item and a local vorticity item, correcting the gas-liquid relative velocity by adopting a self-adaptive gas-liquid slippage velocity correction model, and solving turbulence characteristic parameters and pressure field distribution in the cavitation flow field. Thus, the accuracy and the refinement degree of gas-liquid interface dynamic description can be remarkably improved, the adaptability of a slip velocity correction model to interface nonlinear characteristics is enhanced, cavitation turbulence behaviors can be simulated more accurately, and therefore the accuracy and the reliability of cavitation turbulence numerical simulation are improved; and a more scientific and effective technical support is provided for cavitation prediction and control in the complex engineering field.

The invention discloses a method for estimating the form of a ventilation supercavity under the action of tail jet flow. The method comprises the following steps: step 1, constructing a mathematical model; 2, on the basis of the mathematical model, boundary condition setting and mesh generation are carried out on the watershed of the aircraft, and a numerical calculation model is obtained; 3, verifying the numerical calculation model to obtain a ventilation supercavitation numerical calculation model suitable for the tail jet flow effect; and 4, based on the supercavitation numerical calculation model, performing simulation calculation on the ventilation supercavitation flow field under the action of the tail jet flow to obtain a simulation result. According to the method for estimating the ventilation supercavitation form under the action of the tail jet flow, the problems that the ventilation supercavitation flow is high in unsteady performance, and the ventilation supercavitation form under the action of the tail jet flow is difficult to calculate when the attack angle exists or not are solved.

The present invention provides a method and device for simulating the evolution process of cloud cavitation, which can effectively simulate the transformation from sheet cavitation to cloud cavitation and the growth and collapse processes of cloud cavitation in cavitating flows. The method for simulating the evolution process of cloud cavitation includes: Step 1, setting the initial calculation field; Step 2, calculating the interphase mass transfer rate during the cavitation process through a user-defined function (UDF), using a region to represent the region where sheet cavitation collapses into cloud cavitation, and exporting the grid node position coordinates of this region; Step 3, calculating the mass of non-condensable gas in the bubble and the bubble diameter when sheet cavitation is converted into cloud cavitation through the UDF; Step 4, generating a bubble injection file for the CFD-DPM coupling model through the UDF and setting relevant parameters; Step 5, incrementing the time step by 1, calculating the cloud cavitation flow under CFD-DPM coupling, and simultaneously solving the R-P equation through the UDF to control the change in bubble diameter; Step 6, repeating Steps 2 to 5 until the calculation duration requirement is met.

A high-speed projectile water entry supercavitation flow numerical value prediction method comprises the following steps: dividing a flow field computational domain by adopting an overlapped grid, realizing accurate capture of a motion boundary of a projectile through dynamic cutting, and executing a grid independence test; based on the computational domain, constructing a three-phase control equation based on a VOF model; on the basis of the established control equation, a flow field is solved through a Standard k-epsilon model and a Schnerr-Sauer cavitation model, and flow field pressure is output; predicting a projectile motion track by using a six-degree-of-freedom dynamic grid; according to the system, the equipment and the medium, numerical prediction of the high-speed projectile in-water super-cavitation flow process is realized based on the method; according to the method, the accuracy of the method is verified through grid independence test and experimental data comparison (the initial speed is 75.4-142.7 m / s), and finally, a Standard k-epsilon model is selected as an optimal turbulence model; the coupling problem of phase change, turbulent flow and cross-medium flow in the high-speed water entry process is solved, and a high-precision numerical prediction tool is provided for projectile design.

The present invention discloses a cavitation risk prediction method based on cavitation collapse potential energy, comprising the following steps: establishing a cavitation risk assessment method based on the potential energy contained in the cavitation collapse jet; S2, using modeling software to model the calculation domain and perform grid division on it; selecting corresponding turbulence models and cavitation models to solve the unsteady cavitation flow in the selected calculation domain; performing cavitation calculations, and when a more accurate cavitation morphology is obtained, starting to perform time averaging on the pressure to solve its average pressure field. Beneficial effects: The present invention predicts the cavitation distribution on the surface of a material based on the means of computational fluid dynamics, avoids a large number of tedious and difficult experimental explorations through numerical analysis, and saves experimental costs and time; quantitatively performing cavitation analysis on the model through the means of computational fluid dynamics, can more accurately and comprehensively predict the degree of cavitation damage in various areas of the model surface.

The invention relates to the technical field of high-altitude environmental engineering, and discloses a cavitation flow numerical calculation key parameter correction method, system, equipment and medium aiming at high-altitude area environmental characteristics, and the method comprises the following steps: collecting atmospheric pressure measured data at different altitudes, establishing a segmented fitting relationship between atmospheric pressure and altitudes, and calculating a cavitation flow numerical calculation key parameter; acquiring an actual atmospheric pressure value of the current region of the power station; the method comprises the following steps: acquiring a water sample on site, measuring cavitation characteristic parameters, and combining sediment content analysis to obtain a corrected cavitation pressure value suitable for a local environment; measuring the distribution characteristics of gas nuclei in a local water body, and obtaining the corrected gas nucleus volume fraction and bubble initial radius; and the corrected parameters are substituted into a cavitation model based on a Rayleigh-Plesset equation, and cavitation flow numerical calculation is carried out. According to the method, the accuracy of cavitation flow calculation in the high-altitude area can be improved, and the rationality of cavitation calculation of a power station and a unit is guaranteed.

The present application relates to the technical field of fluid machinery computational fluid dynamics, in particular to a cavitation turbulent large eddy simulation method of nonlinear phase change viscosity correction, in the method, based on the local gas content, the effective dynamic viscosity of the fluid is updated by using a nonlinear hybrid dynamic viscosity empirical formula, the nonlinear hybrid dynamic viscosity empirical formula is used for characterizing additional dissipation generated in the gas-liquid mixing area due to interphase interaction; based on the updated flow field, the sub-grid stress is calculated, and a dynamic coefficient damping formula based on cavitation intensity is introduced to correct the core coefficient of the sub-grid model, and the corrected sub-grid turbulent viscosity is obtained. Through the construction of multiphase flow control equation, dynamic sub-grid modeling, nonlinear property updating and flux reconstruction technology, the simulation accuracy and numerical stability of complex cavitation flow are significantly improved, and a high-precision numerical simulation tool is provided for the design optimization and cavitation suppression of hydraulic machinery such as water turbines, water pumps and propellers.

The present invention discloses a cavitation intensity prediction method and system for coupling a multi-scale material model, relating to the field of engineering computational fluid dynamics technology. The method aims to address the problem that prior art cavitation assessments of hydraulic machinery flow pipes cannot consider the impact of material response. The method includes simulating cavitation flow to obtain a cavitation flow field, using a cavitation model to calculate the macroscopic evolution of cavitation bubbles in the cavitation flow field to obtain macroscopic evolution information of cavitation bubbles, and converting all small cavitation bubbles into single bubbles based on the macroscopic evolution information; calculating the microscopic dynamic process of the single bubbles to obtain microscopic dynamic information, calculating the impact load of the single bubble based on the microscopic dynamic information, and calculating the material cavitation incubation period of the flow pipe, i.e., the cavitation intensity, by integrating the impact loads of the single bubbles in all time steps. The present invention can simultaneously describe the dynamic evolution of large-scale and small-scale cavitation bubbles, achieving a leap from qualitative to quantitative prediction of cavitation intensity.

The application discloses a drag reduction effect AI control method and system of a natural-ventilation mixed cavitation hydrofoil, and relates to the technical field of ship engineering. A cavitation flow experiment is performed to obtain an input data set and an output data set; feature extraction is performed based on the input data set and the output data set to obtain a cavitation coverage area rate, a flow field instability characteristic parameter, an interface evolution stability index and a signal cavitation index, and the indexes are integrated into a response data set; a comprehensive data source set is constructed based on the input data set, the output data set and the response data set; and the influence level of a current ventilation behavior is determined based on the response data set, and an optimal design scheme is determined based on the influence level and the comprehensive data source set. The method overcomes the limitation of a traditional static black box model that only relies on an input-output relationship and lacks process feedback, and effectively distinguishes between a temporarily low-drag but soon-to-be unstable state and a truly stable and efficient operating state.