Modeling method of annular underwater magnetohydrodynamic thruster

Abstract

The present invention discloses a modeling method for an annular underwater magnetohydrodynamic thruster, and relates to the technical field of underwater thrusters. In order to solve the problem that in the prior art, modeling is mainly performed on the components of aircraft engines, the underwater environment will affect the performance of the thruster, and it is difficult to effectively predict the performance changes of the thruster under different working conditions due to the influence of the fluid-magnetic field coupling effect; the present invention realizes the performance prediction and optimization of the thruster in a complex underwater environment through refined fluid mechanics modeling, magnetic field analysis and fluid-magnetic field coupling process, and can effectively deal with influencing factors such as corrosion, wear and complex fluid dynamic characteristics, ensure accurate prediction and optimization of key performance parameters such as thrust and efficiency under different working conditions, and further improve the accuracy and reliability of the model through experimental verification and feedback optimization, meeting the dynamic response analysis and multi-condition performance evaluation needs of underwater thrusters in actual engineering applications.

Description

Technical Field

[0001] The invention relates to the technical field of underwater thrusters, and in particular to a modeling method for an annular underwater magnetofluid thruster. Background Art

[0002] Annular underwater magnetohydrodynamic thrusters have broad application prospects in underwater vehicles, underwater robots and other fields due to their high efficiency and quietness. For example, the patent application with the publication number of CN118551488A discloses a method for modeling the reliability of aircraft engines that considers multiple performance degradation data, and its steps include: S1, by analyzing the failure mechanism and performance degradation of important aircraft engine components, determine its key performance parameters and failure thresholds; S2, conduct aircraft engine test runs or model simulations to obtain performance degradation data; S3, establish Wiener process models with time scale transformation for performance parameters; S4, establish a multi-performance parameter degradation model based on Copula function, and select the optimal model according to the selection index; S5, combine the IFM method and the Markov Monte Carlo method to perform two-stage estimation of the parameters of the degradation model; S6, use the model to perform reliability analysis and remaining life prediction of aircraft engine components. This patent describes the degradation process of component performance based on the Wiener process, and uses the Copula function to describe the correlation between multiple performances.

[0003] However, although the above patents can effectively perform reliability analysis and remaining life prediction, the following problems still exist:

[0004] In the prior art, modeling is mainly performed on the components of aircraft engines. Factors such as corrosion, wear, and fluid dynamic characteristics in the underwater environment will affect the performance of the propeller, and the performance of the underwater magnetohydrodynamic propeller is not only affected by the influence between the components, but also by the fluid-magnetic field coupling effect. However, the above-mentioned patent model is mainly modeled for specific working conditions, and it is difficult to effectively predict the performance changes of the propeller under different working conditions. Summary of the invention

[0005] The purpose of the present invention is to provide a modeling method for an annular underwater magnetohydrodynamic thruster, to establish a comprehensive model of the thruster through fluid mechanics modeling, magnetic field analysis, fluid-magnetic field coupling and magnetofluid property modeling, to describe the fluid and magnetic field behavior, and to predict the performance of the thruster under different working conditions, so as to achieve optimization and reliable prediction of the thruster performance and solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The modeling method of an annular underwater magnetohydrodynamic thruster comprises the following steps:

[0008] Step 1: Fluid mechanics modeling: Based on the Navier-Stokes equations and fluid dynamics theory, determine the fluid characteristics inside the annular underwater magnetohydrodynamic thruster and establish a fluid mechanics model of the annular underwater magnetohydrodynamic thruster;

[0009] Step 2: Magnetic field analysis: Model the magnetic field of the annular underwater magnetohydrodynamic thruster, obtain the magnetic field parameters of the annular underwater magnetohydrodynamic thruster based on the magnetic field model, and analyze the spatial distribution of the magnetic field and the interaction information between the magnetic field and the thruster structure based on the magnetic field parameters;

[0010] Step 3: Fluid-magnetic field coupling: Couple the fluid mechanics model with the magnetic field model, simulate the interaction between the fluid and the magnetic field based on the coupling model, and analyze the dynamic response of the magnetic fluid under the action of the magnetic field;

[0011] Step 4: Magnetic fluid property modeling: Input the non-Newtonian fluid behavior and magnetic field response characteristics of the magnetic fluid into the coupling model to obtain a comprehensive model. Based on the comprehensive model, the dynamic behavior data of the magnetic fluid in the magnetic field are obtained, including dynamic behavior and flow characteristics.

[0012] Step 5: Performance parameter prediction: Based on the comprehensive model, the performance parameters of the annular underwater magnetohydrodynamic thruster are predicted and analyzed to evaluate the performance of the annular underwater magnetohydrodynamic thruster under different working conditions.

[0013] Furthermore, the step 1: fluid mechanics modeling specifically includes:

[0014] Determine the fluid domain boundary: set the fluid inflow and outflow boundaries according to the geometric structure of the propeller, and determine the boundary conditions of the fluid domain, including the inlet and outlet flow rates, pressure boundaries, and wall boundary conditions;

[0015] Establish control equations: Based on the Navier-Stokes equations, describe the mass conservation equations, momentum conservation equations, and energy conservation equations of the fluid inside the thruster;

[0016] Meshing: Determine the internal fluid domain of the annular underwater magnetohydrodynamic thruster based on the boundary conditions of the fluid domain, perform finite element meshing on the internal fluid domain of the annular underwater magnetohydrodynamic thruster, determine the key areas of the fluid domain, and perform high-density meshing on the key areas;

[0017] Definition of fluid properties: Based on the magnetic fluid characteristics of the annular underwater magnetic fluid thruster, set the physical parameters of the fluid;

[0018] Numerical solution and simulation: The Navier-Stokes equations are discretized and numerically solved to obtain the distribution characteristics of the fluid inside the annular underwater magnetohydrodynamic thruster.

[0019] Furthermore, in the step 2, modeling the magnetic field of the annular underwater magnetic fluid thruster also includes:

[0020] Discretize the magnetic field, construct the magnetic field calculation grid, and divide the magnetic field domain of the annular underwater magnetohydrodynamic thruster into multiple finite element grids;

[0021] Establishing the control equation of the magnetic field based on the Maxwell equations, calculating the magnetic field distribution in each finite element grid based on the equations, and obtaining the spatial distribution characteristics and magnetic field parameters of the magnetic field;

[0022] Analyze the interaction between the magnetic field and the thruster structure, and determine the dynamic response characteristics of the magnetic field under different working conditions.

[0023] Furthermore, the magnetic field domain of the annular underwater magnetohydrodynamic thruster is divided into multiple finite element grids, including:

[0024] Extracting the operating parameters of the annular underwater magnetic fluid propeller; wherein the operating parameters include the temperature under standard working conditions and the actual working temperature of the annular underwater magnetic fluid propeller, the pressure under standard working conditions and the actual working pressure of the annular underwater magnetic fluid propeller, and the fluid viscosity corresponding to the annular underwater magnetic fluid propeller;

[0025] The reference coefficient is obtained by using the operating parameters of the annular underwater magnetic fluid thruster, wherein the reference coefficient is obtained by the following formula:

[0026]

[0027] Wherein, K represents the reference coefficient; f represents the preset constant coefficient, and the value range of the constant coefficient is 0.33-0.58; x represents the viscosity of the fluid; V ref represents the design volume of the annular underwater magnetohydrodynamic propulsor; V represents the actual calculation domain volume of the annular underwater magnetohydrodynamic propulsor; T ref It represents the temperature of the annular underwater magnetic fluid propulsion system under standard working conditions; T represents the actual working temperature; P ref represents the pressure under standard working conditions of the annular underwater magnetohydrodynamic thruster; P represents the actual working pressure; a, b and c represent the first coefficient, the second coefficient and the third coefficient respectively, and the value ranges of the first coefficient, the second coefficient and the third coefficient are 2.18-2.83, 1.34-1.77 and 0.82-1.53;

[0028] comparing the reference coefficient with a preset reference coefficient threshold;

[0029] When the reference coefficient does not exceed a preset reference coefficient threshold, the magnetic field domain of the annular underwater magnetohydrodynamic thruster is divided into a plurality of finite element grids according to a preset initial grid density;

[0030] When the reference coefficient exceeds a preset reference coefficient threshold, the grid density is set, and the magnetic field domain of the annular underwater magnetohydrodynamic thruster is divided into a plurality of finite element grids according to the set grid density.

[0031] Further, when the reference coefficient exceeds a preset reference coefficient threshold, the grid density is set, including:

[0032] When the reference coefficient exceeds a preset reference coefficient threshold, extracting a change gradient of the magnetic field intensity and a change gradient of the electric field intensity of the annular underwater magnetic fluid thruster as first parameter data;

[0033] Extracting the fluid density of the fluid corresponding to the annular underwater magnetic fluid propeller and the actual length of the annular underwater magnetic fluid propeller as second parameter data;

[0034] Retrieving the reference coefficient;

[0035] Obtaining a grid density using the first parameter data, the second parameter data and a reference coefficient;

[0036] The grid density is obtained by the following formula:

[0037]

[0038] Where D represents the grid density; D c represents the preset initial grid density; K represents the reference coefficient; M e and M b represents the modulus corresponding to the gradient of the change of magnetic field intensity and the gradient of the change of electric field intensity; F represents the sum of the external forces of the annular underwater magnetic fluid thruster; ρ represents the fluid density; x represents the fluid viscosity; E and B represent the gradient of the change of magnetic field intensity and the gradient of the change of electric field intensity; L c represents the preset length reference value; L represents the actual length of the annular underwater magnetohydrodynamic thruster.

[0039] Furthermore, in step three, coupling the fluid mechanics model with the magnetic field model specifically includes:

[0040] Define the coupling domain: determine the coupling area of ​​the annular underwater magnetohydrodynamic thruster, clarify the spatial range and boundary conditions of the fluid domain and the magnetic field domain, and spatially match the flow field domain in the fluid mechanics model with the magnetic field domain in the magnetic field model;

[0041] Coupling equation establishment: Based on the Navier-Stokes equation, the flow characteristics of magnetic fluid in the magnetic field are obtained, and based on the Maxwell equations, the intensity and spatial distribution of the magnetic field are obtained;

[0042] At the same time, the Lorentz force under the action of the magnetic field is superimposed on the Navier-Stokes equation to simulate the influence of the magnetic field on the movement of the magnetic fluid, and the relationship equation between the magnetization intensity and the magnetic field intensity is supplemented based on the simulation results;

[0043] Solve the coupled equations: Couple the Navier-Stokes equations with the Maxwell equations, establish the governing equations for fluid-magnetic field interaction, discretize the coupled equations, and calculate the Lorentz force distribution of the magnetic fluid under the action of the magnetic field and its influence on the fluid flow characteristics.

[0044] Furthermore, performance parameter prediction also includes:

[0045] Optimization design: Set optimization goals based on the performance prediction analysis results, and set optimization constraints based on the actual application requirements of the annular underwater magnetohydrodynamic thruster;

[0046] Parameter optimization is performed based on a multi-objective optimization algorithm to optimize the geometric structure, magnetic field distribution and material selection of the annular underwater magnetohydrodynamic thruster.

[0047] Furthermore, the performance of the annular underwater magnetohydrodynamic thruster under different working conditions is evaluated, specifically:

[0048] According to the application scenario types of annular underwater magnetohydrodynamic thrusters, simulation models under different working conditions are established, and based on the simulation models under various working conditions, the performance changes of the thrusters under different speeds, loads and environmental conditions are predicted;

[0049] Obtain key data under each working condition, analyze the changing rules of the annular underwater magnetohydrodynamic thruster under each working condition, compare the changing rules under each working condition, analyze the performance of the annular underwater magnetohydrodynamic thruster under different working conditions, and perform optimization feedback at the same time.

[0050] Furthermore, the simulation models under different working conditions are established, including:

[0051] The key performance parameters of the annular underwater magnetohydrodynamic thruster are introduced into the simulation model, and the working conditions of the annular underwater magnetohydrodynamic thruster in actual application are simulated based on the simulation model;

[0052] The random loads are input into the fluid mechanics model and magnetic field model to calculate the stress distribution and deformation data of the annular underwater magnetohydrodynamic thruster under long-term action.

[0053] Predict the service life of annular underwater magnetohydrodynamic thrusters based on fatigue strength parameters and stress cycle numbers, evaluate the corrosion development process of annular underwater magnetohydrodynamic thrusters at different time points, and identify potential failure modes;

[0054] Conduct statistical analysis on the reliability distribution of thrusters under different working conditions, obtain key reliability indicators, generate reliability analysis reports, and perform optimization feedback based on the reliability analysis reports.

[0055] Furthermore, experimental verification is also included:

[0056] According to the optimized geometric structure and material properties of the annular underwater magnetohydrodynamic thruster, a physical prototype of the annular underwater magnetohydrodynamic thruster is manufactured;

[0057] Build an experimental platform to simulate the actual operating conditions under different working conditions based on the experimental platform, and fit the different working conditions in the simulation model;

[0058] Based on the experimental platform, the performance of the annular underwater magnetohydrodynamic thruster in actual operating conditions is tested, and the experimental data is compared with the simulation results to identify the deviation range of key performance parameters and determine the source of error;

[0059] The model parameters in the corresponding model are adjusted according to the comparison results, the adjusted model is re-simulated and re-verified with the experimental data to generate a test verification report for the annular underwater magnetohydrodynamic thruster.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] Through refined fluid mechanics modeling, magnetic field analysis and fluid-magnetic field coupling process, the performance prediction and optimization of the thruster in complex underwater environments are realized. It can effectively deal with influencing factors such as corrosion, wear and complex fluid dynamics characteristics, and ensure accurate prediction and optimization of key performance parameters such as thrust and efficiency under different working conditions. Through experimental verification and feedback optimization, the accuracy and reliability of the model are further improved, meeting the needs of dynamic response analysis and multi-condition performance evaluation of underwater thrusters in actual engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is a flow chart of the modeling method of the annular underwater magnetohydrodynamic thruster of the present invention. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] In order to solve the technical problem that the existing technology mainly models the components of aircraft engines, the underwater environment will affect the performance of the propeller, and it is difficult to effectively predict the performance changes of the propeller under different working conditions due to the influence of the fluid-magnetic field coupling effect, please refer to Figure 1 , this embodiment provides the following technical solutions:

[0065] The modeling method of an annular underwater magnetohydrodynamic thruster comprises the following steps:

[0066] Step 1: Fluid mechanics modeling: Based on the Navier-Stokes equations and fluid dynamics theory, determine the fluid characteristics inside the annular underwater magnetohydrodynamic thruster, establish a fluid mechanics model of the annular underwater magnetohydrodynamic thruster, and describe the velocity field, pressure distribution and flow characteristics of the fluid inside the thruster;

[0067] Step 2: Magnetic field analysis: Model the magnetic field of the annular underwater magnetohydrodynamic thruster, obtain the magnetic field parameters such as magnetic field strength, direction, and distribution characteristics of the annular underwater magnetohydrodynamic thruster based on the magnetic field model, and analyze the spatial distribution of the magnetic field and the interaction information between the magnetic field and the thruster structure based on the magnetic field parameters;

[0068] Step 3: Fluid-magnetic field coupling: Couple the fluid mechanics model with the magnetic field model, simulate the interaction between the fluid and the magnetic field based on the coupling model, analyze the dynamic response of the magnetic fluid under the action of the magnetic field, consider the Lorentz force between the magnetic fluid and the magnetic field, and ensure the accuracy of the model;

[0069] Step 4: Magnetic fluid property modeling: Input the non-Newtonian fluid behavior and magnetic field response characteristics such as viscosity, density, and magnetic susceptibility of the magnetic fluid into the coupling model to obtain a comprehensive model. Based on the comprehensive model, the dynamic behavior data of the magnetic fluid in the magnetic field are obtained, including dynamic behavior and flow characteristics;

[0070] Step 5: Performance parameter prediction: Based on the comprehensive model, the thrust, efficiency, velocity distribution, power consumption and other performance parameters of the annular underwater magnetohydrodynamic thruster are predicted and analyzed to evaluate the performance of the annular underwater magnetohydrodynamic thruster under different working conditions.

[0071] In this embodiment, through refined fluid mechanics modeling, magnetic field analysis and fluid-magnetic field coupling process, the performance prediction and optimization of the thruster in a complex underwater environment are realized, which can effectively deal with influencing factors such as corrosion, wear and complex fluid dynamics characteristics, and ensure the accurate prediction and optimization of key performance parameters such as thrust and efficiency under different working conditions. Through experimental verification and feedback optimization, the accuracy and reliability of the model are further improved, which meets the needs of dynamic response analysis and multi-condition performance evaluation of underwater thrusters in actual engineering applications, and has significant application and promotion value.

[0072] In this embodiment, the step 1: fluid mechanics modeling, specifically includes:

[0073] Determine the fluid domain boundary: set the fluid inflow and outflow boundaries according to the geometric structure of the propeller, and determine the boundary conditions of the fluid domain, including the inlet and outlet flow rates, pressure boundaries, and wall boundary conditions;

[0074] Establish control equations: Based on the Navier-Stokes equations, describe the mass conservation equations, momentum conservation equations, and energy conservation equations of the fluid inside the thruster;

[0075] In this embodiment, the mass conservation equation ensures that the mass of the fluid remains unchanged during the flow process; the momentum conservation equation considers the change in momentum of the fluid under the action of external forces, including the inertial force, viscous force and external pressure of the fluid; the energy conservation equation describes the change in internal energy of the fluid, especially considering energy loss in a high-pressure environment;

[0076] Meshing: Determine the internal fluid domain of the annular underwater magnetohydrodynamic thruster based on the boundary conditions of the fluid domain, perform finite element meshing on the internal fluid domain of the annular underwater magnetohydrodynamic thruster, determine the key areas of the fluid domain, such as the boundary layer, corners and narrow parts of the flow channel, and perform high-density meshing on the key areas;

[0077] Fluid property definition: Based on the magnetic fluid characteristics of the annular underwater magnetic fluid thruster, set the physical parameters of the fluid, including density, viscosity, compressibility, etc.;

[0078] Numerical solution and simulation: The Navier-Stokes equations are discretized and numerically solved to obtain the distribution characteristics of the fluid inside the annular underwater magnetohydrodynamic thruster.

[0079] In this embodiment, by setting the fluid inflow and outflow boundaries to ensure that the boundary conditions are consistent with the actual working conditions, the movement characteristics of the fluid in the thruster are accurately described. High-density grids are used in key areas to effectively improve the calculation accuracy, and physical parameters are set for the fluid properties to effectively ensure the accuracy of the model. A fluid mechanics model of the annular underwater magnetohydrodynamic thruster is systematically established to accurately describe the fluid characteristics inside the thruster, providing a reliable basis for subsequent magnetic field coupling analysis.

[0080] In this embodiment, in the step 2, modeling the magnetic field of the annular underwater magnetic fluid thruster also includes:

[0081] Discretize the magnetic field, construct the magnetic field calculation grid, and divide the magnetic field domain of the annular underwater magnetohydrodynamic thruster into multiple finite element grids;

[0082] The control equations of the magnetic field are established based on the Maxwell equations to describe the strength, direction and distribution characteristics of the magnetic field. The magnetic field distribution in each finite element grid is calculated based on the equations to obtain the spatial distribution characteristics and magnetic field parameters of the magnetic field, including magnetic induction intensity, magnetic field direction and magnetic flux density.

[0083] Analyze the interaction between the magnetic field and the thruster structure, and determine the dynamic response characteristics of the magnetic field under different working conditions to ensure the accuracy and reliability of the magnetic field model.

[0084] In this embodiment, the propeller structure mainly includes:

[0085] Annular channel structure: The annular flow channel inside the thruster through which the magnetic fluid is directed. This structure determines the fluid flow path and the area of ​​interaction with the magnetic field.

[0086] Magnetic field generating device: including electromagnetic coils, permanent magnets or other magnetic field generating elements. These components are responsible for generating a specific magnetic field distribution in the annular flow channel to form a magnetic field action area.

[0087] Guide components: The thruster may contain guide vanes or other auxiliary components to optimize the flow path of the magnetic fluid and control the flow rate and distribution.

[0088] Housing and support structure: The outer casing and support frame of the thruster provide mechanical strength and protect internal components, while also providing shielding or guiding effects on the distribution of the magnetic field.

[0089] Current supply system: The power supply system related to the magnetic field, which provides current to the electromagnetic coil and thus controls the strength and direction of the magnetic field.

[0090] Specifically, the magnetic field domain of the annular underwater magnetohydrodynamic thruster is divided into multiple finite element grids, including:

[0091] Extracting the operating parameters of the annular underwater magnetic fluid propeller; wherein the operating parameters include the temperature under standard working conditions and the actual working temperature of the annular underwater magnetic fluid propeller, the pressure under standard working conditions and the actual working pressure of the annular underwater magnetic fluid propeller, and the fluid viscosity corresponding to the annular underwater magnetic fluid propeller;

[0092] The reference coefficient is obtained by using the operating parameters of the annular underwater magnetic fluid thruster, wherein the reference coefficient is obtained by the following formula:

[0093]

[0094] Wherein, K represents the reference coefficient; f represents the preset constant coefficient, and the value range of the constant coefficient is 0.33-0.58; x represents the viscosity of the fluid; V refrepresents the design volume of the annular underwater magnetohydrodynamic propulsor; V represents the actual calculation domain volume of the annular underwater magnetohydrodynamic propulsor; T ref It represents the temperature of the annular underwater magnetic fluid propulsion system under standard working conditions; T represents the actual working temperature; P ref represents the pressure under standard working conditions of the annular underwater magnetohydrodynamic thruster; P represents the actual working pressure; a, b and c represent the first coefficient, the second coefficient and the third coefficient respectively, and the value ranges of the first coefficient, the second coefficient and the third coefficient are 2.18-2.83, 1.34-1.77 and 0.82-1.53;

[0095] comparing the reference coefficient with a preset reference coefficient threshold;

[0096] When the reference coefficient does not exceed a preset reference coefficient threshold, the magnetic field domain of the annular underwater magnetohydrodynamic thruster is divided into a plurality of finite element grids according to a preset initial grid density;

[0097] When the reference coefficient exceeds a preset reference coefficient threshold, the grid density is set, and the magnetic field domain of the annular underwater magnetohydrodynamic thruster is divided into a plurality of finite element grids according to the set grid density.

[0098] The technical effect of the above technical solution is: by extracting various operating parameters of the annular underwater magnetohydrodynamic thruster (such as temperature, pressure, fluid viscosity, etc.) and calculating the reference coefficient based on these parameters, the characteristics of the thruster in the actual working environment can be more accurately reflected. This accuracy is helpful for the subsequent finite element mesh division, ensuring that the mesh density can more accurately adapt to the actual working state of the thruster, thereby improving the accuracy of the magnetic field domain simulation or analysis.

[0099] Optimize computational efficiency: The scheme dynamically adjusts the density of the finite element mesh according to the comparison result between the reference coefficient and the preset threshold. When the reference coefficient is low, a lower mesh density (i.e., the preset initial mesh density) is used to reduce the amount of calculation and improve the computational efficiency. When the reference coefficient is high, the mesh density is increased to ensure the accuracy of the calculation. This dynamic adjustment strategy helps to optimize the computational efficiency while maintaining the computational accuracy. Since the scheme takes into account a variety of variable factors (such as temperature, pressure, fluid viscosity, etc.) of the thruster in the actual working environment, it can adapt to different working environments and conditions more flexibly. This adaptability and flexibility make the scheme more robust and practical in dealing with complex and changeable actual application scenarios. By adjusting parameters such as the preset constant coefficient, the first coefficient, the second coefficient, and the third coefficient, as well as parameters such as the preset reference coefficient threshold and the initial mesh density, the scheme can support customized design of annular underwater magnetohydrodynamic thrusters for different models, specifications, and working environments. This customized design capability helps to meet the specific needs of different users and improve the market competitiveness of products.

[0100] In summary, this technical solution achieves the goal of improving calculation accuracy and optimizing calculation efficiency by comprehensively considering various operating parameters of the annular underwater magnetohydrodynamic thruster and dynamically adjusting the density of the finite element grid based on these parameters. At the same time, this solution also enhances adaptability and flexibility, supports customized design, and provides strong technical support for the research and development and application of annular underwater magnetohydrodynamic thrusters.

[0101] Specifically, when the reference coefficient exceeds a preset reference coefficient threshold, the grid density is set, including:

[0102] When the reference coefficient exceeds a preset reference coefficient threshold, extracting a change gradient of the magnetic field intensity and a change gradient of the electric field intensity of the annular underwater magnetic fluid thruster as first parameter data;

[0103] Extracting the fluid density of the fluid corresponding to the annular underwater magnetic fluid propeller and the actual length of the annular underwater magnetic fluid propeller as second parameter data;

[0104] Retrieving the reference coefficient;

[0105] Obtaining a grid density using the first parameter data, the second parameter data and a reference coefficient;

[0106] The grid density is obtained by the following formula:

[0107]

[0108] Where D represents the grid density; D c represents the preset initial grid density; K represents the reference coefficient; Me and M b represents the modulus corresponding to the gradient of the change of magnetic field intensity and the gradient of the change of electric field intensity; F represents the sum of the external forces of the annular underwater magnetic fluid thruster; ρ represents the fluid density; x represents the fluid viscosity; E and B represent the gradient of the change of magnetic field intensity and the gradient of the change of electric field intensity; L c represents the preset length reference value; L represents the actual length of the annular underwater magnetohydrodynamic thruster.

[0109] The technical effect of the above technical solution is: by extracting various operating parameters (such as temperature, pressure, fluid viscosity, etc.) of the annular underwater magnetohydrodynamic thruster and calculating the reference coefficient based on these parameters, the characteristics of the thruster in the actual working environment can be more accurately reflected. This accuracy helps the subsequent division of the finite element grid, ensuring that the grid density can more accurately adapt to the actual working state of the thruster, thereby improving the accuracy of the magnetic field domain simulation or analysis. The scheme dynamically adjusts the density of the finite element grid according to the comparison result between the reference coefficient and the preset threshold. When the reference coefficient is low, a lower grid density (that is, the preset initial grid density) is used to reduce the amount of calculation and improve the calculation efficiency. When the reference coefficient is high, the grid density is increased to ensure the accuracy of the calculation. This dynamic adjustment strategy helps to optimize the calculation efficiency while maintaining the calculation accuracy. Since the scheme takes into account various changing factors (such as temperature, pressure, fluid viscosity, etc.) of the thruster in the actual working environment, it can adapt to different working environments and conditions more flexibly. This adaptability and flexibility make the scheme more robust and practical in dealing with complex and changeable practical application scenarios. By adjusting the preset constant coefficient, first coefficient, second coefficient, third coefficient and other parameters, as well as the preset reference coefficient threshold and initial grid density, the solution can support customized design of annular underwater magnetohydrodynamic thrusters for different models, specifications and working environments. This customized design capability helps to meet the specific needs of different users and improve the market competitiveness of products.

[0110] In summary, this technical solution achieves the goal of improving calculation accuracy and optimizing calculation efficiency by comprehensively considering various operating parameters of the annular underwater magnetohydrodynamic thruster and dynamically adjusting the density of the finite element grid based on these parameters. At the same time, this solution also enhances adaptability and flexibility, supports customized design, and provides strong technical support for the research and development and application of annular underwater magnetohydrodynamic thrusters.

[0111] In this embodiment, the step three couples the fluid mechanics model with the magnetic field model, specifically including:

[0112] Define the coupling domain: determine the coupling area of ​​the annular underwater magnetohydrodynamic thruster, clarify the spatial range and boundary conditions of the fluid domain and the magnetic field domain, and spatially match the flow field domain in the fluid mechanics model with the magnetic field domain in the magnetic field model to ensure the consistency of the two in physical space;

[0113] The fluid domain refers to the flow area formed by the annular channel structure inside the thruster, and the magnetic field domain includes the action space generated by the magnetic field generating device (such as electromagnetic coil or permanent magnet);

[0114] Establishment of coupling equations: Based on the Navier-Stokes equations, the flow characteristics of magnetic fluid in the magnetic field are obtained, including the velocity field, pressure distribution and flow path. Based on the Maxwell equations, the intensity and spatial distribution of the magnetic field are obtained to describe the dynamic characteristics of the magnetic field under different working conditions.

[0115] At the same time, the Lorentz force under the action of the magnetic field is superimposed on the Navier-Stokes equation to simulate the influence of the magnetic field on the movement of the magnetic fluid, and the relationship equation between the magnetization intensity and the magnetic field intensity is supplemented based on the simulation results;

[0116] Solve the coupled equations: Couple the Navier-Stokes equations with the Maxwell equations, establish the governing equations for fluid-magnetic field interaction, discretize the coupled equations, and calculate the Lorentz force distribution of the magnetic fluid under the action of the magnetic field and its influence on the fluid flow characteristics.

[0117] In this embodiment, the performance parameter prediction further includes:

[0118] Optimization design: Set optimization goals based on the performance prediction analysis results, such as maximizing thrust, improving efficiency, and reducing power consumption, and set optimization constraints based on the actual application requirements of the annular underwater magnetohydrodynamic thruster, including structural size restrictions, material property requirements, and environmental adaptability;

[0119] Parameter optimization is performed based on a multi-objective optimization algorithm to optimize the geometric structure, magnetic field distribution and material selection of the annular underwater magnetohydrodynamic thruster. For example, the electromagnetic coil material or the guide component material is optimized to enhance the magnetic field stability and corrosion resistance, so as to improve the thrust, efficiency and other key performance indicators of the thruster.

[0120] In this embodiment, the annular channel structure of the thruster is optimized, the flow channel size, shape and layout of the guide components are adjusted to improve the fluid flow path and reduce energy loss, the configuration of the magnetic field generating device is adjusted, the magnetic field strength and spatial distribution are optimized, and the coupling effect of the magnetic field and the fluid is ensured to be optimal. Based on the characteristics of the magnetic fluid and the working environment requirements, materials with high magnetic permeability and low resistance loss are selected to improve the overall performance of the thruster.

[0121] In this embodiment, the performance of the annular underwater magnetic fluid thruster under different working conditions is evaluated, specifically:

[0122] According to the application scenario types of annular underwater magnetohydrodynamic thrusters, simulation models under different working conditions are established, and based on the simulation models under various working conditions, the performance changes of the thrusters under different speeds, loads and environmental conditions are predicted;

[0123] Obtain key data under each working condition, including fluid velocity field, pressure distribution, magnetic field intensity and Lorentz force distribution, analyze the changing laws of the annular underwater magnetohydrodynamic thruster under each working condition, compare the changing laws under each working condition, analyze the performance of the annular underwater magnetohydrodynamic thruster under different working conditions, such as the optimal operating range and potential performance bottlenecks, etc., and perform optimization feedback at the same time, feed the working condition prediction results back to the optimization design step, adjust the thruster's geometric structure, magnetic field configuration and material selection to improve performance under specific working conditions.

[0124] Specifically, the changing rules include: determining the thrust output and thrust stability under different speeds and loads, calculating the energy conversion efficiency of the thruster under different working conditions, identifying efficiency peaks and inefficiency areas, evaluating the flow stability of the fluid in the annular channel, analyzing potential eddy currents, boundary layer separation and other phenomena, analyzing the impact of changes in magnetic field intensity and distribution on fluid dynamic response, and ensuring that the magnetic field can remain effective under complex working conditions.

[0125] In this embodiment, different types of working conditions include: speed conditions, load conditions and environmental conditions. The simulation models under different working conditions include: speed change model: adjusting boundary conditions such as fluid inlet velocity and flow velocity distribution to simulate the performance of the propeller at different speeds; load change model: by setting different external load parameters, analyzing the thrust response and efficiency changes of the propeller; environmental change model: inputting different water temperature, density and pressure parameters to evaluate the impact of environmental changes on fluid flow characteristics and magnetic field distribution.

[0126] In this embodiment, establishing simulation models under different working conditions also includes:

[0127] The key performance parameters of the annular underwater magnetohydrodynamic thruster are introduced into the simulation model, including factors such as material properties, fatigue strength, and corrosion resistance. Based on the simulation model, the working conditions of the annular underwater magnetohydrodynamic thruster in actual applications are simulated, such as dynamic loads caused by waves and fluid pressure fluctuations.

[0128] The random loads are input into the fluid mechanics model and magnetic field model to calculate the stress distribution and deformation data of the annular underwater magnetohydrodynamic thruster under long-term action.

[0129] Predict the service life of annular underwater magnetohydrodynamic thrusters based on fatigue strength parameters and stress cycle numbers, evaluate the corrosion development process of annular underwater magnetohydrodynamic thrusters at different time points, and identify potential failure modes;

[0130] Conduct statistical analysis on the reliability distribution of thrusters under different working conditions, obtain key reliability indicators, generate reliability analysis reports such as failure rate and mean time between failures, and provide optimization feedback based on the reliability analysis reports.

[0131] In this embodiment, the geometric structure, magnetic field distribution and material selection of the thruster are adjusted through a multi-objective optimization algorithm to effectively improve the thrust and efficiency and reduce power consumption. The simulation models based on different working conditions are used to comprehensively analyze the performance of the thruster in a complex dynamic environment, identify potential performance bottlenecks and inefficient areas, evaluate the reliability of the thruster in long-term operation, predict the service life and identify failure modes, and ensure the performance stability and reliability of the thruster in a changing environment by optimizing the feedback loop, thereby greatly improving the actual application performance and durability of the thruster.

[0132] In this embodiment, experimental verification is also included:

[0133] According to the optimized geometric structure and material properties of the annular underwater magnetohydrodynamic thruster, a physical prototype of the annular underwater magnetohydrodynamic thruster is manufactured;

[0134] Build an experimental platform to simulate actual operating conditions under different working conditions, such as different water temperature, pressure and flow rate conditions, and fit the different working conditions in the simulation model;

[0135] Based on the experimental platform, the performance of the annular underwater magnetohydrodynamic thruster in actual operating conditions is tested, and the experimental data is compared with the simulation results to identify the deviation range of key performance parameters and determine the error sources, such as boundary condition setting errors or material parameter deviations.

[0136] According to the comparison results, the model parameters in the corresponding model are adjusted, including the viscosity, density and magnetic field intensity boundary conditions of the magnetic fluid, as well as the Lorentz force calculation and magnetization intensity relationship equation in the coupling model. The adjusted model is re-simulated and verified with the experimental data for a second time to ensure that the accuracy of the adjusted model meets expectations. The experimental verification results are fed back to the aforementioned optimization design steps to further optimize the thruster's geometric structure and magnetic field distribution, and generate a test verification report for the annular underwater magnetohydrodynamic thruster.

[0137] In this embodiment, a physical prototype is constructed and thrust tests, magnetic field measurements, and fluid visualization experiments are performed to verify the modeling and simulation results. The model parameters are optimized and adjusted in a targeted manner based on the experimental data to improve the accuracy and reliability of the model, thereby forming a highly reliable simulation model. This significantly improves the accuracy, stability, and reliability of the thruster under different working conditions, thereby ensuring the excellent performance of the annular underwater magnetohydrodynamic thruster in practical applications.

[0138] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A modeling method for an annular underwater magnetohydrodynamic thruster, characterized in that: The following steps are involved: Step 1: Fluid mechanics modeling: Based on the Navier-Stokes equations and fluid dynamics theory, determine the fluid characteristics inside the annular underwater magnetohydrodynamic thruster and establish a fluid mechanics model of the annular underwater magnetohydrodynamic thruster; Step 2: Magnetic field analysis: Model the magnetic field of the annular underwater magnetohydrodynamic thruster, obtain the magnetic field parameters of the annular underwater magnetohydrodynamic thruster based on the magnetic field model, and analyze the spatial distribution of the magnetic field and the interaction information between the magnetic field and the thruster structure based on the magnetic field parameters; Step 3: Fluid-magnetic field coupling: Couple the fluid mechanics model with the magnetic field model, simulate the interaction between the fluid and the magnetic field based on the coupling model, and analyze the dynamic response of the magnetic fluid under the action of the magnetic field; Step 4: Magnetic fluid property modeling: Input the non-Newtonian fluid behavior and magnetic field response characteristics of the magnetic fluid into the coupling model to obtain a comprehensive model. Based on the comprehensive model, the dynamic behavior data of the magnetic fluid in the magnetic field are obtained, including dynamic behavior and flow characteristics. Step 5: Performance parameter prediction: Based on the comprehensive model, the performance parameters of the annular underwater magnetohydrodynamic thruster are predicted and analyzed to evaluate the performance of the annular underwater magnetohydrodynamic thruster under different working conditions; In the step 2, the magnetic field of the annular underwater magnetic fluid thruster is modeled, and further includes: Discretize the magnetic field, construct the magnetic field calculation grid, and divide the magnetic field domain of the annular underwater magnetohydrodynamic thruster into multiple finite element grids; Establishing the control equation of the magnetic field based on the Maxwell equations, calculating the magnetic field distribution in each finite element grid based on the equations, and obtaining the spatial distribution characteristics and magnetic field parameters of the magnetic field; Analyze the interaction between the magnetic field and the thruster structure, and determine the dynamic response characteristics of the magnetic field under different operating conditions; The magnetic field domain of the annular underwater magnetohydrodynamic thruster is divided into multiple finite element grids, including: Extracting the operating parameters of the annular underwater magnetic fluid propeller; wherein the operating parameters include the temperature of the annular underwater magnetic fluid propeller under standard working conditions and the actual working temperature, the pressure of the annular underwater magnetic fluid propeller under standard working conditions and the actual working pressure, and the fluid viscosity corresponding to the annular underwater magnetic fluid propeller; Obtaining a reference coefficient using the operating parameters of the annular underwater magnetohydrodynamic thruster; comparing the reference coefficient with a preset reference coefficient threshold; When the reference coefficient does not exceed a preset reference coefficient threshold, the magnetic field domain of the annular underwater magnetohydrodynamic thruster is divided into a plurality of finite element grids according to a preset initial grid density; When the reference coefficient exceeds a preset reference coefficient threshold, the grid density is set, and the magnetic field domain of the annular underwater magnetohydrodynamic thruster is divided into a plurality of finite element grids according to the set grid density.

2. The annular underwater magnetic fluid thruster modeling method according to claim 1, characterized in that: The step 1: fluid mechanics modeling, specifically includes: Determine the fluid domain boundary: set the fluid inflow and outflow boundaries according to the geometric structure of the propeller, and determine the boundary conditions of the fluid domain, including the inlet and outlet flow rates, pressure boundaries, and wall boundary conditions; Establish control equations: Based on the Navier-Stokes equations, describe the mass conservation equations, momentum conservation equations, and energy conservation equations of the fluid inside the thruster; Meshing: Determine the internal fluid domain of the annular underwater magnetohydrodynamic thruster based on the boundary conditions of the fluid domain, perform finite element meshing on the internal fluid domain of the annular underwater magnetohydrodynamic thruster, determine the key areas of the fluid domain, and perform high-density meshing on the key areas; Definition of fluid properties: Based on the magnetic fluid characteristics of the annular underwater magnetic fluid thruster, set the physical parameters of the fluid; Numerical solution and simulation: The Navier-Stokes equations are discretized and numerically solved to obtain the distribution characteristics of the fluid inside the annular underwater magnetohydrodynamic thruster.

3. The annular underwater magnetic fluid thruster modeling method according to claim 1, characterized in that: The reference coefficient is obtained by the following formula: Wherein, K represents the reference coefficient; f represents the preset constant coefficient, and the value range of the constant coefficient is 0.33-0.58; x represents the viscosity of the fluid; V ref represents the design volume of the annular underwater magnetohydrodynamic propulsor; V represents the actual calculation domain volume of the annular underwater magnetohydrodynamic propulsor; T ref It represents the temperature of the annular underwater magnetic fluid propulsion system under standard working conditions; T represents the actual working temperature; P ref represents the pressure under standard working conditions of the annular underwater magnetohydrodynamic thruster; P represents the actual working pressure; a, b and c represent the first coefficient, the second coefficient and the third coefficient respectively, and the value ranges of the first coefficient, the second coefficient and the third coefficient are 2.18-2.83, 1.34-1.77 and 0.82-1.

53.

4. The annular underwater magnetic fluid thruster modeling method according to claim 1, characterized in that: When the reference coefficient exceeds a preset reference coefficient threshold, the grid density is set, including: When the reference coefficient exceeds a preset reference coefficient threshold, extracting a change gradient of the magnetic field intensity and a change gradient of the electric field intensity of the annular underwater magnetic fluid thruster as first parameter data; Extracting the fluid density of the fluid corresponding to the annular underwater magnetic fluid propeller and the actual length of the annular underwater magnetic fluid propeller as second parameter data; Retrieving the reference coefficient; Obtaining a grid density using the first parameter data, the second parameter data and a reference coefficient; The grid density is obtained by the following formula: Where D represents the grid density; D c represents the preset initial grid density; K represents the reference coefficient; M e and M b represents the modulus corresponding to the gradient of the change of magnetic field intensity and the gradient of the change of electric field intensity; F represents the sum of the external forces of the annular underwater magnetic fluid thruster; ρ represents the fluid density; x represents the fluid viscosity; E and B represent the gradient of the change of magnetic field intensity and the gradient of the change of electric field intensity; L c represents the preset length reference value; L represents the actual length of the annular underwater magnetohydrodynamic thruster.

5. The annular underwater magnetic fluid thruster modeling method according to claim 1, characterized in that: The step three couples the fluid mechanics model with the magnetic field model, specifically including: Define the coupling domain: determine the coupling area of ​​the annular underwater magnetohydrodynamic thruster, clarify the spatial range and boundary conditions of the fluid domain and the magnetic field domain, and spatially match the flow field domain in the fluid mechanics model with the magnetic field domain in the magnetic field model; Coupling equation establishment: Based on the Navier-Stokes equation, the flow characteristics of magnetic fluid in the magnetic field are obtained, and based on the Maxwell equations, the intensity and spatial distribution of the magnetic field are obtained; At the same time, the Lorentz force under the action of the magnetic field is superimposed on the Navier-Stokes equation to simulate the influence of the magnetic field on the movement of the magnetic fluid, and the relationship equation between the magnetization intensity and the magnetic field intensity is supplemented based on the simulation results; Solve the coupled equations: Couple the Navier-Stokes equations with the Maxwell equations, establish the governing equations for fluid-magnetic field interaction, discretize the coupled equations, and calculate the Lorentz force distribution of the magnetic fluid under the action of the magnetic field and its influence on the fluid flow characteristics.

6. The annular underwater magnetic fluid thruster modeling method according to claim 5, characterized in that: Performance parameter prediction, including: Optimization design: Set optimization goals based on the performance prediction analysis results, and set optimization constraints based on the actual application requirements of the annular underwater magnetohydrodynamic thruster; Parameter optimization is performed based on a multi-objective optimization algorithm to optimize the geometric structure, magnetic field distribution and material selection of the annular underwater magnetohydrodynamic thruster.

7. The annular underwater magnetic fluid thruster modeling method according to claim 1, characterized in that: Evaluate the performance of annular underwater magnetohydrodynamic thrusters under different operating conditions, specifically: According to the application scenario types of annular underwater magnetohydrodynamic thrusters, simulation models under different working conditions are established, and based on the simulation models under various working conditions, the performance changes of the thrusters under different speeds, loads and environmental conditions are predicted; Obtain key data under each working condition, analyze the changing rules of the annular underwater magnetohydrodynamic thruster under each working condition, compare the changing rules under each working condition, analyze the performance of the annular underwater magnetohydrodynamic thruster under different working conditions, and perform optimization feedback at the same time.

8. The annular underwater magnetic fluid thruster modeling method according to claim 7, characterized in that: Establish simulation models under different working conditions, including: The key performance parameters of the annular underwater magnetohydrodynamic thruster are introduced into the simulation model, and the working conditions of the annular underwater magnetohydrodynamic thruster in actual application are simulated based on the simulation model; The random loads are input into the fluid mechanics model and magnetic field model to calculate the stress distribution and deformation data of the annular underwater magnetohydrodynamic thruster under long-term action. Predict the service life of annular underwater magnetohydrodynamic thrusters based on fatigue strength parameters and stress cycle numbers, evaluate the corrosion development process of annular underwater magnetohydrodynamic thrusters at different time points, and identify potential failure modes; Conduct statistical analysis on the reliability distribution of thrusters under different working conditions, obtain key reliability indicators, generate reliability analysis reports, and perform optimization feedback based on the reliability analysis reports.

9. The annular underwater magnetic fluid thruster modeling method according to claim 1, characterized in that: Also includes experimental verification: According to the optimized geometric structure and material properties of the annular underwater magnetohydrodynamic thruster, a physical prototype of the annular underwater magnetohydrodynamic thruster is manufactured; Build an experimental platform to simulate the actual operating conditions under different working conditions based on the experimental platform, and fit the different working conditions in the simulation model; Based on the experimental platform, the performance of the annular underwater magnetohydrodynamic thruster in actual operating conditions is tested, and the experimental data is compared with the simulation results to identify the deviation range of key performance parameters and determine the source of error; The model parameters in the corresponding model are adjusted according to the comparison results, the adjusted model is re-simulated and re-verified with the experimental data to generate a test verification report for the annular underwater magnetohydrodynamic thruster.

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