1333 results about "Fluid field" patented technology

The invention relates to the technical field of ship propulsion, and discloses an energy-saving control method for a pre-rotating guide wheel of a ship propulsion system and a fluid optimization system. According to the invention, through a multi-dimensional cooperative control strategy and fluid structure optimization, an integrated system with dynamic prerotation compensation, self-adaptive flow regulation and vortex suppression functions is constructed. The control method comprises a multi-physical field sensor array, a guide wheel angle dynamic compensation algorithm and an energy efficiency optimization decision model, a deep learning algorithm is adopted to establish a mapping relation between a propeller wake flow field and guide wheel parameters, and 0.1-second-level dynamic response is achieved. According to the fluid optimization system, an asymmetric variable-curvature guide vane structure is innovatively designed, the optimal space distribution of guide vanes is determined through three-dimensional flow field simulation, and a flow guide channel with the pressure gradient self-adaptive characteristic is formed. A real ship verifies that the propulsive energy consumption can be reduced by 10%-25%, the propulsive efficiency can be improved by 15%-30%, the cavitation effect is effectively restrained, vibration noise is reduced, and remarkable economic benefits and environmental protection values are achieved.

The invention relates to the technical field of high-pressure dredge pump simulation calculation, and discloses a construction and application method of a high-pressure efficient dredge pump simulation calculation model. A model is established based on dynamic fluid-solid coupling parameters (mud pulsating pressure, impeller dynamic stress and the like), soil multiphase rheological parameters (particle phase volume fraction, viscous resistance coefficient and the like) and pipeline transient resistance parameters (transient pressure drop gradient and the like), and factors such as rotating speed-power matching and the like are incorporated to calculate an operation envelope and a critical failure threshold. A multi-physics field coupling analysis system comprising parameter configuration, dynamic simulation (integrating a flow field and a structural vibration solver) and a safety evaluation module is developed, after actually measured data and self-defined parameters are input, dynamic flow velocity distribution, pressure pulsation characteristics and the like are obtained through fluid-solid bidirectional coupling calculation, and an optimal configuration scheme is generated. The system supports database management, multi-rheological model matching and three-dimensional visualization, the simulation precision and the engineering efficiency are improved, and support is provided for performance optimization and safety evaluation of the high-pressure working condition.

The invention belongs to the technical field of power systems, and particularly relates to a pressure sampler on-line unblocking control method and system, and the method comprises the steps: collecting the pressure difference fluctuation data of the inner wall of a pipeline in real time based on a quantum pressure difference sensor, associating historical flow field parameters through a pre-trained quantum neural network model, and dynamically predicting the multi-moment blocking risk level; a dynamic cleaning path is generated in combination with a quantum annealing algorithm, a genetic algorithm parameter library is called to match scene gene data, and cleaning priorities of a fourth pipe body and a seventh pipe body are determined; the control module generates an air cylinder driving instruction according to the cleaning path and the priority, and drives the spiral brush head to execute high-frequency inching unblocking operation, dynamic sensing and accurate cleaning of the blocking risk are achieved, and the data reliability and operation and maintenance safety of thermal power generation pressure measuring points are improved.

The invention discloses a bed load particle starting test method and device, and relates to the technical field of hydromechanics, the method comprises the following steps: laying sediment particles in a wave water tank, and adjusting the water flow rate through flow control until the bed surface shear stress is less than the critical shear stress; tracer particles are excited to emit fluorescence through a laser beam, and a camera array is used for synchronously collecting instantaneous flow velocity of a flow field and displacement data of sediment particles; analyzing spatial and temporal distribution characteristics of turbulence energy dissipation and pressure energy dissipation based on a turbulence burst process, and establishing a sediment particle starting mathematical model; experimental data and computational fluid mechanics numerical simulation are combined, and the mathematical model is verified and optimized. According to the technical scheme, the analysis precision and the experimental convergence speed of the sediment starting criterion under the complex hydrodynamic force condition can be remarkably improved, and full-chain efficient cooperation from micromechanical response to macroscopic engineering application is achieved.

The invention provides a rock mass high-temperature deformation simulation method and system based on deep learning near-field dynamics, and relates to the field of rock mass thermal-mechanical coupling analysis and research, and the method comprises the steps: obtaining the parameter information of a to-be-simulated target rock mass, including the geometric shape of the rock mass and the physical attribute of the rock mass; dispersing the target rock mass into a plurality of material points according to the parameter information, and constructing a thermal-mechanical coupling model of the target rock mass; based on the initialized thermal-mechanical coupling model, time step iterative simulation of a solid mechanical field is conducted, and finally the crack propagation process and temperature distribution of the target rock mass are obtained; according to the method, a solid field near-field dynamics theory based on strain energy density is introduced, a fluid field near-field dynamics equation is combined, temperature distribution in a rock medium is predicted through a physical information neural network, a deep learning near-field dynamics framework of rock mass high-temperature deformation damage is formed, and therefore rock mass high-temperature deformation is efficiently and accurately simulated.

The invention provides a fluid-structure interaction vibration simulation and suppression method for a water-jet propeller, and belongs to the field of numerical simulation of computational fluid mechanics. The method comprises the following steps: establishing a finite element model of a water-jet propeller impeller-shafting coupling system; performing dry mode and wet mode comparative analysis on the finite element model by utilizing a finite element method, and verifying the effectiveness of the model; dividing finite element grids of a structural domain and a flow field domain; establishing a fluid-solid coupling model; on the basis of bidirectional fluid-solid coupling numerical calculation, the flow field speed and acting force are solved through CFD, the structure movement speed and displacement are updated, a flow field grid is further updated, flow numerical calculation continues to be conducted, and iteration is conducted till the simulation time ends; flow-induced vibration characteristics are analyzed through post-processing, and the vibration amplitude is restrained by adjusting the mass center position of the impeller airfoil. According to the method, the bidirectional fluid-solid coupling model of the impeller-shafting system of the water-jet propeller is constructed, structural deformation and transient flow field information are directly associated, and the hydrodynamic performance is improved.

The invention discloses an intelligent optimization system based on a self-adaptive control hydraulic cylinder, and relates to the technical field of hydraulic cylinder control, and the system comprises a monitoring data collection module which collects data of a flow field, a temperature field and a stress field in real time by means of various sensors arranged at different parts of the hydraulic cylinder, synchronously carries out the preprocessing and coding of the collected data, and transmits the data to a data processing module; the data is transmitted to the data processing and analyzing module in real time; detailed data of the hydraulic cylinder in different physical fields are acquired in real time through the monitoring data acquisition module, and the coupling coefficient is accurately calculated by using the multi-physical field coupling model, so that the system can deeply understand the specific influence of each physical field on the performance of the hydraulic cylinder; according to the method, the system can construct a more accurate hydraulic cylinder dynamic model in the model prediction control module, so that the future state of the hydraulic cylinder is accurately predicted, further, the system can obtain an optimal control input sequence through an objective function optimization algorithm, and the pertinence and effectiveness of a control strategy are remarkably improved.

The invention relates to the technical field of coal mine geological safety monitoring and disaster early warning, in particular to a coal mine disaster early warning method and system based on a geological model and a storage medium, and the method comprises the steps: firstly obtaining high fractal fracture information and monitoring data such as gas, hydrology and stress through chaotic wave excitation and fractal analysis; and a three-dimensional fractal grid with multi-level fracture representation is constructed. And discretizing a mechanical field and a fluid field by using a fractal partial differential equation operator, and globally solving a large-scale nonlinear equation through a quantum annealing mode or a quantum and classical combined annealing mode to form a quantum fractal coupling simulation result. And finally, integrating the grid units and monitoring data in the fuzzy hypergraph structure, carrying out fuzzy membership analysis on a multi-disaster element coupling sign, and outputting early warning information once the risk is judged to reach a threshold value. According to the invention, the precision and timeliness of coal mine geological disaster monitoring can be obviously improved.

The invention discloses a pipeline flow field remodeling method based on LAAF-PINN, and the method comprises the steps: collecting the flow field data of a pipeline measurement point; dividing the measuring points into monitoring points and testing points, and preprocessing the data sequence; constructing an LAAF-PINN, randomly selecting a matching point along a pipeline, and inputting a time-space sequence of the monitoring point and the matching point to obtain model output; calculating a data loss item according to the model output of the monitoring point, calculating a residual error according to the model output of the collocation point to obtain a partial differential equation loss item, and combining the two items to obtain total loss; after multiple rounds of iteration updating, a trained PINN model is obtained, a time-space sequence of a test set is input, and corresponding flow field information can be quickly and accurately reconstructed. According to the method, the LAAF-PINN is applied to pipeline hydraulic transient research, an existing flow field remodeling method is expanded, good robustness is achieved for data containing uncertain factors, and meanwhile the problem that the calculation precision is not high possibly existing in forward simulation is solved.

The invention relates to the technical field of oil exploitation, and provides a CFD-based electric submersible pump oil-gas-water three-phase flow adaptability analysis method and system, and the method comprises the steps: constructing a three-dimensional geometric model of an electric submersible pump, carrying out the initial grid division through CFD software, and optimizing the grid density through a self-adaptive grid refinement algorithm; setting oil well boundary conditions, a turbulence model and cavitation model parameters; steady-state and unsteady-state simulation calculation is carried out, and a flow field distribution diagram in the electric submersible pump is obtained; key performance parameters are extracted; simulating flow characteristics of oil-gas-water three-phase flow by adopting a turbulence model optimization algorithm based on multiphase flow coupling and combining a turbulence model, a multiphase flow model, an interphase turbulence correction term and an interphase interaction force model; and carrying out adaptability analysis on the oil-gas-water three-phase flow of the electric submersible pump. All-around technical support can be provided for design, operation and maintenance of the electric submersible pump, and technical progress and development of the oil exploitation industry are powerfully promoted.

The invention discloses an unsteady flow field dimension reduction and prediction method fusing physical modeling and deep learning, and belongs to the technical field of computer-aided fluid mechanics analysis. According to the method, firstly, a modal coefficient reflecting global dynamics is extracted from an unsteady flow field by using a DMD, and meanwhile, low-dimensional feature representation of a potential space is learned from a flow field snapshot through CVAE; the two types of features have complementarity in physical and statistical meanings, and the complex dynamic evolution law of the unsteady flow field is more effectively represented through the low-dimensional features constructed in a combined mode. On the basis, an LSTM model is used for carrying out time sequence modeling on the joint features, and high-precision prediction of future evolution of the flow field is achieved. The hybrid modeling method provided by the invention improves the dimensionality reduction efficiency and prediction precision of a high-dimensional nonlinear unsteady flow field while keeping physical consistency, and is suitable for intelligent simulation and rapid prediction tasks in a complex flow scene.

The invention relates to the technical field of ball valve design and simulation, in particular to a three-dimensional simulation design method and system for a ball valve. The method comprises the following steps: performing reference geometric construction based on a ball valve design specification, and performing geometric parameterization to obtain an initial geometric configuration; importing the initial geometric configuration into a finite element analysis platform, and endowing material attributes to obtain a finite element mesh model; performing ball valve working stress analysis on the finite element mesh model to obtain a stress-strain field; performing model fluid domain grid division according to the initial geometric configuration and the stress-strain field to obtain a fluid domain grid; valve opening change setting is conducted on the fluid domain grids, and a CFD calculation model is obtained; internal flow field transient simulation of the ball valve under different opening degrees is conducted on the CFD calculation model, and fluid dynamic parameters are obtained. The dynamic characteristics of the valve under the complex working conditions are accurately captured, and the working performance of the valve under different working conditions is improved.

The invention discloses a particle dynamic characteristic simulation method and device based on multi-scale fluid-solid coupling, and the method comprises the steps: generating a background grid according to a simulation flow field region, and generating a local grid according to the position of a target particle; inputting the solid domain parameter and the fluid domain parameter of the current time step into a fluid-solid coupling model, and outputting a target solid domain parameter and a target fluid domain parameter; judging whether a local grid needs to be regenerated or not; if yes, a new local grid is generated according to the target solid domain parameters, and solid domain parameters and fluid domain parameters of the new local grid are obtained to serve as input parameters of the next time step; if not, taking the target fluid domain parameter and the target solid domain parameter as input parameters of the next time step; and repeating the inputting and judging processes until the simulation duration is reached, and determining the dynamic characteristics of the solid particles according to the target solid domain parameters of each time step. According to the method, multi-scale fluid-solid coupling calculation can be accurately and efficiently carried out, so that dynamic characteristic simulation of target particles is effectively realized.

The invention belongs to the technical field of electroplating process optimization, and particularly discloses a titanium alloy surface electroplating control method which comprises the following steps: dynamically generating a hanger posture configuration scheme based on workpiece three-dimensional contour data acquired in real time; a bubble distribution image and electroplating liquid flow field data are synchronously collected, and a bubble-flow field coupling feature set is generated through multi-modal fusion; performing real-time linkage adjustment on the rotation speed and the swing amplitude of the workpiece according to the coupling feature set; after electroplating is completed, plating thickness, edge integrity and surface defect data are collected, and a multi-source plating data set is formed by combining workpiece position information; historical data and real-time data are integrated to carry out hanger layout adjustment judgment, and hanger spacing dynamic reconstruction optimization is started when adjustment is needed. According to the method, multi-parameter cooperative control and closed-loop quality optimization in the electroplating process are achieved, the uniformity and integrity of a titanium alloy workpiece coating are remarkably improved, and generation of bubble related defects is effectively restrained.

The invention provides a centrifugal pump performance optimization method and device, computer equipment and a storage medium, and belongs to the field of centrifugal pump design. The method comprises the steps that a parameterized model of a centrifugal pump impeller is established to define the geometrical shape of the centrifugal pump impeller, a design space is determined, and a plurality of sample points are generated; for each sample point, performing computational fluid dynamics simulation, adjusting inlet pressure, monitoring a ratio of simulation lift to rated lift, determining critical cavitation pressure corresponding to the sample point, and storing flow field data to construct a data set; training an agent model by using the data set; the lift, the efficiency and the critical cavitation pressure serve as targets, design variables serve as optimization variables, performance is evaluated through an agent model, global optimization is conducted through a multi-target optimization algorithm, and a target design scheme is selected from a Pareto solution set obtained through optimization. Therefore, the centrifugal pump performance under different design variables can be quickly and accurately predicted, multiple targets are effectively balanced, and a comprehensive optimization solution is provided.

The invention discloses a well submersible pump hydraulic design data modeling method, which comprises five steps of sensing acquisition, hydraulic data enhancement, hydraulic performance prediction, intelligent material matching and modeling output, relates to the technical field of pump hydraulic modeling analysis, and particularly relates to a well submersible pump hydraulic design data modeling method and system. A physical information confrontation generative network is combined with a space-time Kriging interpolation algorithm to enhance three-dimensional flow field data; a multi-modal graph neural network fusing physical control loss is constructed, and dynamic prediction of performance indexes such as pump body efficiency, lift and net positive suction head is achieved; based on a corrosion-wear coupling model and a reinforcement learning algorithm, the service life, the cost and the machinability of candidate materials are evaluated, an optimal combination is intelligently recommended, and systematic support is provided for design of an efficient, low-cost and long-service-life submersible pump for a well.

The invention belongs to the field of aero-engines and turbines, and provides a quick prediction method, system and device for a two-dimensional viscous compressible flow field of a gas compressor and a medium, and the method comprises the steps: obtaining CFD simulation data of a two-dimensional blade profile of the gas compressor under multiple working conditions, and carrying out the preprocessing to obtain a standardized training data set; on the basis of the data set, constructing a hybrid neural network model which takes a blade profile geometric parameter and an operation condition parameter as input and takes a two-dimensional viscous compressible flow field as output; combining mean square error, gradient loss and physical consistency loss based on RANS equation residual error to construct a total loss function, and performing end-to-end training on the model; during reasoning, to-be-predicted parameters are input into the trained model according to the same preprocessing mode, and then a flow field prediction result can be rapidly output. According to the method, the problems of long consumed time, low precision and poor consistency of traditional CFD simulation can be solved, millisecond-level flow field prediction is achieved, high precision and high physical consistency are achieved, and the method is suitable for efficient optimization design of the blade profile of the gas compressor.

The invention discloses a plasma sheath electromagnetic characteristic simulation method and system for a hypersonic flight vehicle, and the method comprises the steps: carrying out the fluid simulation according to the geometric shape and flight parameters of the hypersonic flight vehicle, so as to obtain the information of a flow field containing a plasma sheath region; according to the flow field information, simulation parameters of all positions of the plasma sheath space are determined, and the simulation parameters at least comprise electron density distribution and electron collision frequency distribution; based on the simulation parameters, a three-dimensional model of the plasma sheath is established, the three-dimensional model is layered according to electron density distribution, a layered three-dimensional model composed of a plurality of plasma layers is formed, and each plasma layer has the electron density within a preset range; based on the layered three-dimensional model, establishing a non-uniformly distributed electromagnetic simulation model of the plasma sheath; and carrying out grid division on the non-uniformly distributed electromagnetic simulation model, and carrying out numerical calculation by adopting a numerical solver so as to obtain the electromagnetic characteristics of the plasma sheath. According to the method, the problem of deviation between a simulation result and an actual situation of a traditional simulation model can be solved.

The invention discloses a method, a device, equipment and a medium for simulating migration of a proppant, and relates to the technical field of analogue simulation. Simulation is carried out through fluid dynamics and a discrete element analysis model, specifically, fluid parameters are obtained, a calculation model is constructed, and constraints are set; parameters are input for fluid and particle stress analysis, and particle displacement and grid updating are calculated; contact is judged through the particle collision sequence, boundary force is calculated, and the particle motion state is updated; and cyclically feeding back the flow field parameters to particle stress analysis until the number of iterations is met so as to obtain the void ratio, the flow velocity, the position and the momentum of the particles. According to the invention, the motion among particles can be captured and accurately calculated in a high-concentration particle flow or particle dominated collision system.

Disclosed is a design method for a large-size, wide-operating-condition, hypersonic, low-density contoured nozzle, relating to the field of low-density wind tunnel testing. During expansion of a low-density airflow in a nozzle, flow separation tends to occur between the airflow and the wall surface of the nozzle, and a thick boundary layer is formed midstream and downstream in the nozzle, suppressing airflow expansion and reducing the effective test area, resulting in a reduced effective test area and poor flow-field quality for conventional low-density nozzles. In the present invention, to address the difficulty of controlling low‑density hypersonic flow in the nozzle expansion section, and on the basis of different flow characteristics, a large-size, wide-operating-condition, low-density contoured nozzle can be changed into three different configurations, thus solving the problem of flow separation on the wall surface of the nozzle and effectively suppressing the growth of the boundary layer in the nozzle, while meeting wide-operating-condition requirements and reducing costs. The present invention significantly improves the flow-field quality of low-density contoured nozzles, expands the test area, and mitigates the problem of poor flow-field quality under off‑design conditions.

The invention discloses an injection-production regulation imbalance quantitative diagnosis method based on fluid potential energy, and the method comprises the steps: extracting a streamline track space coordinate sequence and corresponding point oil reservoir parameters based on a dynamic permeability field, a pressure field and an injection-production streamline field; constructing a three-dimensional fluid potential energy field model in the injection-production unit, and dividing dominant seepage, a retention zone and a transition zone based on the injection-production unit through potential energy gradient tensor; establishing a seepage potential index LS by taking the flow line penetrating pore volume as a stability weighting factor and combining the potential energy gradient intensity; on the basis of LS sorting, a potential energy-volume two-factor accumulation curve is constructed, the development non-equilibrium degree is represented through curve form parameterization, and the envelope area of the accumulation curve is calculated and used for representing the oil reservoir flow field development non-equilibrium degree and the development effect of each type of injection-production unit. According to the method, fluid potential energy and a two-factor cumulative distribution concept are introduced into computational logic, and unified and quantitative characterization of an oil reservoir flow field and an injection-production unit is realized in combination with a seepage mechanism of the injection-production unit.

The invention relates to the field of vacuum circuit breakers, in particular to a vacuum circuit breaker opening and closing dynamic characteristic calculation method, device and equipment and a medium. Establishing a three-dimensional geometric model of the pole-mounted vacuum circuit breaker arc extinguish chamber and the moving and static contacts; setting material attributes for each part in the three-dimensional geometric model; constructing a multi-physics field coupling system; the area where the moving contact is located is divided into movable grids, and the grid density of the moving contact and the grid density of the static contact dynamically change along with time; and performing multi-field coupling transient solution according to the three-dimensional geometric model, the multi-physical field coupling system and the movable grid to obtain the dynamic characteristics of the vacuum circuit breaker. The electromagnetic field, the thermal field, the fluid field, the structure field and the circuit are subjected to full coupling analysis, multi-physical field strong coupling dynamic simulation of the whole opening and closing process is achieved, and the dynamic characteristics of the whole opening and closing process can be accurately calculated.

The invention relates to the field of multiphase numerical simulation, and discloses a numerical simulation method for solid and liquid phases in a rotating flow channel based on multiple reference systems, which comprises the following steps of: firstly, acquiring a rotating flow field generated by a multiple reference system method, and extracting rotating domain information as well as particle information and fluid computational domain grid information in a current time step; secondly, particles in a rotation domain and particles outside the rotation domain are determined according to the rotation domain information and the particle information; in combination with the particle information and the fluid calculation domain grid information, the final flow field speed and the reconstructed porosity of the particles in the rotation domain and the particles outside the rotation domain are calculated respectively, and then the drag force is calculated according to the final flow field speed, the reconstructed porosity and the particle information; meanwhile, according to the particle information and the rotation domain information, the Korotkoff force and the centrifugal force of the particles in the rotation domain are calculated. Finally, drag force, Korotkoff force and centrifugal force are calculated through iteration, particle information and grid information of the next time step are obtained, and therefore numerical simulation calculation of particle motion in the rotating flow channel under the fixed grid is achieved.

The invention discloses a combustion chamber and turbine guider integrated composite flow channel outlet flow field uniformity evaluation method, and belongs to the technical field of gas turbine pneumatic design. The method comprises the steps that a geometric model of a combustion chamber and turbine guider integrated composite flow channel is built, a combustion chamber function section and a guider pneumatic section are fused through integral pneumatic modeling to form a continuous flow channel, a front section adopts a diffusion structure to form a low-speed combustion area, and a rear section adopts a gradually-shrinking channel to achieve gas accelerated expansion; performing three-dimensional cold-state flow field numerical simulation by adopting a structured grid division and delay separation vortex simulation technology; flow parameters including total pressure, Mach number, airflow angle and vorticity are extracted from the cross section of a flow channel outlet, conversion from a Cartesian coordinate system to a polar coordinate system is carried out, and a uniformly distributed aerodynamic parameter field is reconstructed by using an interpolation algorithm; the directional coupling degree is calculated based on the spatial correlation of the pressure gradient vector and the vorticity vector, and the vortex-pressure coupling entropy production index representing the overall aerodynamic loss of the flow channel is established in combination with the pressure pulsation intensity and the vorticity concentration ratio. According to the method, a three-dimensional evaluation system is constructed by integrating circumferential and radial non-uniformity and entropy production parameters, and accurate quantitative evaluation of flow characteristics and uniformity of the combustion chamber and turbine integrated structure is realized.

The invention discloses a method for determining structure information of a contraction section of water tunnel equipment and a related product, and is applied to the technical field of information processing. The method comprises the following steps: acquiring at least two candidate structural feature groups of a type of pipelines; according to the at least two candidate structural feature groups, determining flow field quality response information corresponding to each candidate structural feature group in the at least two candidate structural feature groups; according to the flow field quality response information corresponding to each candidate structural feature group in the at least two candidate structural feature groups, screening M types of target structural features from the N types of candidate structural features; and according to the M types of target structure features, determining water tunnel pipeline information of one type of pipelines. According to the method, the water tunnel pipeline information of one type of pipelines can be determined based on the accurately screened multiple types of target structure features, the performance optimization of the water tunnel equipment can be more efficiently and comprehensively realized, and the research process of the hydrodynamic characteristics of the underwater vehicle is accelerated.

The present invention relates to the technical field of steel metallurgy process simulation, and specifically relates to a simulation method for particle motion and interaction behavior within a continuous casting mold. The simulation method comprises the following steps: acquiring mold parameters and establishing a model; performing fluid domain volume extraction and structured mesh division on the model; importing the mesh model into simulation software and performing iterative solution; establishing injection points for argon bubbles and inclusions within the mold, compiling and calculating the flotation removal of argon bubbles and inclusions at a steel-slag interface, the capture thereof at a solidification front, and collision-aggregation, and performing coupled computation; and post-processing the simulation results to obtain the flow field, temperature field, solidified-shell distribution, and discrete-phase motion behavior within the mold at different time points. The method of the present invention enables analysis of the motion and interactions of discrete-phase particles such as argon bubbles and inclusions within the mold, thereby accurately predicting the distribution of the particles in the molten steel and the solidified shell.

The invention provides a rotating mechanical system performance evaluation and optimization method and system based on system negentropy conversion rate, and the method comprises the following steps: carrying out the numerical simulation of a flow field of a rotating mechanical system through a computational fluid mechanics method, and obtaining the parameters of the flow field; calculating a viscous dissipation entropy yield, a turbulent dissipation entropy yield and a wall entropy yield in the fluid domain based on the flow field parameters; the total entropy yield of the system is obtained through the volume fraction and the wall area fraction of the whole fluid domain; converting the input power of the rotating machinery into an equivalent negentropy flow, and calculating the negentropy conversion rate of the system for evaluating the effective utilization degree of the input power; and evaluating the performance of the rotating machinery system based on the negentropy conversion rate, and identifying a key area of energy loss. According to the method, the negentropy conversion rate result is applied to structural design optimization, running state diagnosis and energy efficiency adjustment of the rotating machinery, and online calculation and dynamic visualization can be realized in combination with real-time monitoring data.

The present invention discloses a method and device for numerical simulation of near-wall single cavitation collapse coupled with boundary motion, comprising: step 1, introducing a physical model of a near-wall single cavitation into a pre-constructed external flow field to obtain a corresponding flow field physical model; step 2, meshing the flow field physical model; setting initial conditions and flow field boundary conditions, and setting a time step that meets the calculation requirements; step 3, setting specific calculation parameters for solving the flow field process, and introducing a fluid volume method to capture the gas-liquid interface; step 4, applying wall vibration in the form of a user-defined function to simulate the cavitation dynamics behavior under vibration impact. The present invention takes into account the influence of wall vibration in the numerical simulation process by coupling boundary motion, and realizes the simulation of the dynamics behavior of near-wall single cavitation under vibration impact conditions. On this basis, the influence of conditions such as vibration frequency on the cavitation collapse process can be further explored, providing theoretical guidance for optimized cavitation suppression design.

The invention discloses a simulation method for a corresponding relation between a baffle tongue position and a flow field of a semi-spiral suction chamber, and relates to the technical field of double suction pump design and numerical simulation. According to the method, a three-dimensional flow channel model of multiple groups of baffle tongue reference position parameters is constructed, multi-working-condition simulation and quantitative analysis are combined, a mapping relation model of baffle tongue positions and flow field characteristic parameters is established, and a baffle tongue region vortex generation rule, turbulence dissipation and pressure pulsation characteristics are accurately captured; the optimal baffle tongue parameter interval is determined by combining the flow field uniformity and energy loss minimization principle, the flow loss is effectively reduced, the vortex strength and energy dissipation are reduced, and the flow field uniformity is improved, so that the pump efficiency is improved, the vibration noise and the cavitation phenomenon are inhibited, and the optimal baffle tongue parameter interval is obtained by adopting adaptive grid encryption, a multiphase flow cavitation model and a test verification mechanism. The mapping model is corrected by combining measured data, so that the optimization result can directly guide the baffle tongue design under different working conditions, the research and development period is remarkably shortened, and the physical test cost is reduced.

The invention discloses a method for predicting fluid excitation characteristics of a propeller, and relates to the field of propeller simulation. The method comprises the following steps: modeling a propeller flow field according to attribute information corresponding to the propeller flow field to obtain a propeller flow field grid model; determining a propeller flow field control equation corresponding to the propeller flow field grid model, and discretizing the propeller flow field control equation by adopting a finite volume method to obtain a discretized propeller flow field control equation; performing propeller hydrodynamic numerical simulation on the discrete propeller flow field control equation based on a delay separation vortex simulation method to obtain speed spatial-temporal distribution and pressure spatial-temporal distribution, and performing decoupling processing on the speed spatial-temporal distribution and the pressure spatial-temporal distribution; and according to the whirling vibration data, the vortex motion data, the decoupled pressure field and the decoupled speed field, the exciting force of the propeller flow field is obtained. The method can accurately reflect the influence of different vortex motions on the excitation characteristics of the propeller and the fluctuation of the velocity field of the propeller.