Self-propulsion numerical simulation method, device and equipment of ship and medium

Abstract

The invention discloses a self-propulsion numerical simulation method, device and equipment of a ship and a medium, and belongs to the technical field of ship engineering. The method comprises the following steps: determining open water performance parameters of a propeller model according to a propeller model of a ship by using a transition model; performing self-propulsion numerical simulation calculation based on the three-dimensional model to obtain a self-propulsion numerical simulation result; obtaining open water performance parameters of the solid oar; and determining a self-propulsion factor of the ship according to the real oar open water performance parameter, the oar model open water performance parameter and the self-propulsion numerical simulation result. According to the technical scheme, the propeller model open water performance parameters are determined by using the transition model according to the propeller model, the flow near the blade surface of the propeller can be accurately simulated, so that the accuracy of self-propulsion numerical simulation is improved, and the ship self-propulsion factor is determined according to the real propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation result, so that the ship self-propulsion efficiency is improved. The complex hydrodynamic characteristics in the self-propulsion process of the ship can be truly restored, and reliable data support is provided for optimization design of the ship.

Description

Technical Field

[0001] The present application belongs to the field of ship engineering technology, and specifically relates to a method, device, equipment and medium for numerical simulation of self-propulsion of a ship. Background Art

[0002] Against the backdrop of the world actively promoting greenhouse gas emission reduction strategies and shipping companies pursuing fuel cost optimization, the speed of oil tankers has shown a continuous downward trend. The reduction in speed has directly led to a corresponding reduction in the propeller thrust required during the navigation of oil tankers. At the same time, the widespread use of new low-speed main engines has further reduced the operating speed of propellers. In addition, given that the cavitation problem faced by oil tanker propellers in actual operation is relatively mild, in order to improve propulsion efficiency, the disc ratio of newly designed oil tanker propellers has gradually decreased. The synergistic effect of the above-mentioned multiple factors has caused the Reynolds number of the oil tanker propeller model to continue to decrease in the self-propulsion test, and most areas of the blade surface are in a laminar flow or a transition state from laminar flow to turbulent flow.

[0003] However, current conventional computational fluid dynamics-based numerical simulation methods for self-propulsion mostly rely on two-equation turbulence models. These models, based on fully developed turbulence assumptions, struggle to accurately describe complex flow regimes such as laminar, transitional, and turbulent flows. When applied to the numerical simulation of self-propulsion oil tankers, these models exhibit significant errors in the calculation of propeller hydrodynamic performance, and can even result in relative rotational efficiency significantly deviating from actual values. This severely impacts the reliability of the numerical simulation results and the accuracy of actual ship performance predictions.

[0004] Therefore, how to break through the limitations of traditional turbulence models, construct a high-precision numerical simulation method suitable for current oil tankers, and improve the accuracy of self-propulsion numerical simulation results is an urgent problem that people in this field need to solve. Summary of the Invention

[0005] The embodiments of the present application provide a method, device, equipment and medium for numerical simulation of self-propulsion of a ship, the purpose of which is to accurately simulate the flow near the propeller blade surface, thereby improving the accuracy of the self-propulsion numerical simulation, and truly restoring the complex hydrodynamic characteristics of the ship during self-propulsion, providing reliable data support for the optimized design of the ship.

[0006] In a first aspect, an embodiment of the present application provides a method for numerically simulating self-propulsion of a ship, the method comprising:

[0007] Obtaining a three-dimensional model of the ship; wherein the three-dimensional model includes a propeller model, a hull model, and a rudder model;

[0008] Determining propeller model open water performance parameters based on the propeller model using a transition model;

[0009] Performing self-propulsion numerical simulation calculation based on the three-dimensional model to obtain self-propulsion numerical simulation results;

[0010] Obtain actual propeller open water performance parameters;

[0011] According to the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation results, the self-propulsion factor of the ship is determined; wherein the self-propulsion factor includes at least one of the thrust deduction fraction, the wake fraction and the relative rotation efficiency. In a second aspect, an embodiment of the present application provides a self-propulsion numerical simulation device for a ship, the device comprising:

[0012] A three-dimensional model acquisition module, configured to acquire a three-dimensional model of the ship; wherein the three-dimensional model includes a propeller model, a hull model, and a rudder model;

[0013] a propeller model open water determination module, configured to determine propeller model open water performance parameters according to the propeller model using a transition model;

[0014] A self-propulsion numerical simulation module, used to perform self-propulsion numerical simulation calculations based on the three-dimensional model to obtain self-propulsion numerical simulation results;

[0015] Actual propeller open water acquisition module, used to obtain actual propeller open water performance parameters;

[0016] A self-propulsion factor determination module is used to determine the self-propulsion factor of the ship based on the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation results; wherein the self-propulsion factor includes at least one of the thrust deduction fraction, the wake fraction and the relative rotation efficiency.

[0017] In a third aspect, an embodiment of the present application provides an electronic device comprising a processor, a memory, and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction, when executed by the processor, implements the steps of the method described in the first aspect.

[0018] In a fourth aspect, an embodiment of the present application provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of the method described in the first aspect are implemented.

[0019] In an embodiment of the present application, a three-dimensional model of a ship is obtained; wherein the three-dimensional model includes a propeller model, a hull model and a rudder model; a transition model is used to determine the propeller model open water performance parameters according to the propeller model; a self-propulsion numerical simulation calculation is performed based on the three-dimensional model to obtain a self-propulsion numerical simulation result; actual propeller open water performance parameters are obtained; and a self-propulsion factor of the ship is determined according to the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation result; wherein the self-propulsion factor includes at least one of a thrust reduction fraction, a wake fraction and a relative rotation efficiency. The above-mentioned method for self-propulsion numerical simulation of a ship can accurately simulate the flow near the propeller blade surface by using a transition model to determine the propeller model open water performance parameters according to the propeller model, thereby improving the accuracy of the self-propulsion numerical simulation. By determining the self-propulsion factor of the ship according to the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation result, the complex hydrodynamic characteristics of the ship during self-propulsion can be truly restored, providing reliable data support for the optimization design of the ship. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of a method for numerically simulating the self-propulsion of a ship provided in Example 1 of the present application;

[0021] Figure 2 1 is a flow chart of a method for numerically simulating the self-propulsion of a ship provided in Example 2 of the present application;

[0022] Figure 3 This is a comparative example diagram of the axial wake provided in Example 2 of the present application;

[0023] Figure 4 1 is a flow chart of a method for numerically simulating the self-propulsion of a ship provided in Example 3 of the present application;

[0024] Figure 5 This is a schematic structural diagram of a self-propulsion numerical simulation device for a ship provided in Example 4 of the present application;

[0025] Figure 6 This is a structural diagram of the electronic device provided in Example 5 of the present application. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present application clearer, the specific embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. It is understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. It should also be noted that, for ease of description, only parts related to the present application, not all of the contents, are shown in the accompanying drawings. Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe each operation (or step) as a sequential process, many of the operations therein can be implemented in parallel, concurrently or simultaneously. In addition, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but can also have additional steps not included in the accompanying drawings. The process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0027] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0028] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0029] The following, in conjunction with the accompanying drawings, describes in detail the method, device, equipment and medium for numerical simulation of self-propulsion of a ship provided in the embodiments of the present application through specific embodiments and their application scenarios.

[0030] Example 1

[0031] Figure 1 This is a flow chart of the numerical simulation method for self-propulsion of a ship provided in Example 1 of this application. Figure 1 As shown, the specific steps include:

[0032] S101, obtaining a three-dimensional model of a ship; wherein the three-dimensional model includes a propeller model, a hull model, and a rudder model;

[0033] First, this application is applicable to scenarios where self-propulsion numerical simulation of a ship is required to evaluate ship performance or optimize ship design. Specifically, the determination of propeller model open-water performance parameters, the acquisition of self-propulsion numerical simulation results, and the determination of the self-propulsion factor can be performed by an intelligent terminal. Based on the determined self-propulsion factor, the ship design can be optimized to achieve better self-propulsion performance.

[0034] Based on the above usage scenarios, it can be understood that the execution subject of this application can be the smart terminal, such as a desktop computer, a laptop computer, a mobile phone, a tablet computer, and an interactive multimedia device, etc., and no excessive restrictions are made here.

[0035] A ship is a navigable vehicle, generally used to transport people and goods and perform various specific tasks. In this scenario, a ship may specifically refer to a tanker. Specifically, a tanker may be a liquid cargo ship that transports crude oil or refined oil products, and may be powered by fuel oil, LNG (liquefied natural gas), methanol, or ammonia.

[0036] The three-dimensional model of a ship can refer to the digital modeling of the three-dimensional space of the ship using computer technology. The three-dimensional model of a ship can present the appearance, structure, geometric shape and other characteristics of the ship in a virtual form.

[0037] In this solution, the three-dimensional model of the ship may refer to a three-dimensional model of a physical ship model used for the self-propulsion numerical simulation test, wherein the physical ship model may refer to a physical model that is scaled down in proportion to the ship.

[0038] The three-dimensional model of the ship may include a propeller model, a hull model, and a rudder model.

[0039] A propeller is a vital propulsion device for ships. Its rotation converts engine power into thrust, driving the ship forward. A propeller model is a three-dimensional digital representation of a real propeller, detailing key parameters such as its shape, size, number of blades, pitch, and blade profile.

[0040] The hull is the main body of a ship, carrying cargo, personnel, and various equipment, and providing buoyancy to keep the ship afloat. A hull model is a three-dimensional representation of the hull's exterior and internal structure, including the bow, stern, sides, decks, and cabins.

[0041] The rudder is a key component in ship maneuvering, controlling the ship's direction by changing the direction of water flow. A rudder model is a three-dimensional simulation of the rudder, including parameters such as the shape and size of the rudder blade and the range of the rudder angle.

[0042] The three-dimensional model of the ship can be obtained by having the staff perform three-dimensional modeling based on the ship's design drawings, or by inputting the ship's design drawings into a pre-trained three-dimensional automatic modeling model, which then outputs the three-dimensional model of the ship.

[0043] S102, determining propeller model open water performance parameters according to the propeller model using a transition model;

[0044] Open water performance may refer to the operating performance of a propeller in a uniform flow field, and open water performance parameters may include thrust, torque, efficiency, and advance coefficient, etc. It is understood that the propeller model open water performance parameters are the open water performance parameters of the propeller model.

[0045] In fluid mechanics, transition refers to the process by which a fluid changes from one flow regime (e.g., laminar flow) to another (e.g., turbulent flow). Transition models are mathematical models used to describe and predict this flow regime transition.

[0046] The propeller model's open-water performance parameters can be determined using a transition model. This involves inputting the propeller model's geometric parameters and operating parameters (such as rotational speed and incoming flow velocity) into the transition model. By solving the governing equations in the transition model (e.g., the Reynolds-averaged Navier-Stokes equations combined with the transition model equations), the flow state on and around the propeller surface is simulated, and the propeller model's open-water performance parameters are calculated. The propeller model's immersion depth ratio must be consistent with that of the physical ship and its model. The calculation time step is limited to ensuring that the propeller model rotates no more than 1 degree per step.

[0047] In this technical solution, optionally, a transition model is used to determine the propeller model open water performance parameters according to the propeller model, including:

[0048] The propeller model open water performance parameters are determined based on the propeller model using the γ transition model.

[0049] The gamma transition model is used to predict the transition from laminar to turbulent flow in fluids. γ represents the probability that the flow at a point in space is turbulent, and its value range is 0 ≤ γ ≤ 1. A gamma value close to 0 indicates that the point is more likely to be in a laminar state, while a gamma value close to 1 indicates that the point is more likely to be in a turbulent state.

[0050] The γ transition model is used to determine the open water performance parameters of the propeller model based on the propeller model. The geometric parameters and operating condition parameters of the propeller model (such as rotation speed and incoming flow velocity, etc.) can be input into the computational fluid dynamics software, and the Reynolds-averaged Navier-Stokes equations are solved in combination with the γ transition model. The distribution of γ values on the propeller surface and the surrounding flow field is iteratively calculated, and the transition position and degree of the flow field from laminar flow to turbulent flow are analyzed. Finally, the open water performance parameters of the propeller model are determined based on the flow field calculation results.

[0051] The advantage of this scheme is that by using the γ transition model to determine the propeller model open water performance parameters according to the propeller model, the transition process from laminar flow to turbulent flow in the propeller surface and surrounding flow field can be captured more accurately, effectively avoiding the over-prediction or misjudgment of the propeller transition region by the traditional turbulence model, thereby obtaining the propeller model open water performance parameters that are more in line with the actual working conditions, and avoiding the γ-Re θ The transition model has the disadvantage of requiring artificial specification of the free stream boundary, which reduces uncertainty and at the same time reduces the sensitivity to the inlet turbulence intensity and the computational complexity.

[0052] In particular, the calculation of the propeller model open water performance parameters is exactly the same as that of the self-propulsion numerical simulation to ensure the consistency of the free surface and unsteady calculation methods and further reduce potential errors.

[0053] S103, performing self-propulsion numerical simulation calculation based on the three-dimensional model to obtain a self-propulsion numerical simulation result;

[0054] Self-propulsion numerical simulation is a technology that uses numerical methods to simulate the autonomous navigation of ships or other navigational objects in water on a computer. Self-propulsion numerical simulation simulates the ship's self-propulsion process by solving relevant fluid dynamics equations, taking into account the ship's motion, the changes in the surrounding flow field, and the interaction between them.

[0055] Self-propulsion numerical simulation results refer to the data and information obtained after self-propulsion numerical simulation calculations. Self-propulsion numerical simulation results can include ship motion parameters (such as speed, acceleration, and heading angle), flow field related information (such as pressure distribution on the hull surface and surrounding flow field, velocity vector distribution, vorticity distribution, and wake fraction), and parameters related to propulsion and resistance (such as propeller thrust and torque and the resistance of the hull).

[0056] The method of performing self-propulsion numerical simulation calculations based on the three-dimensional model and obtaining the self-propulsion numerical simulation results can be achieved by importing the three-dimensional model into computational fluid dynamics software, setting boundary conditions (such as incoming flow velocity, water depth, and ambient pressure, etc.) and initial conditions (such as the initial position, speed, and heading of the ship, etc.), and solving the control equations including the continuity equation, the momentum equation, and the two turbulence quantities in the two-equation turbulence model. The discretized equations are iteratively calculated using numerical methods such as the finite volume method or the finite element method. The motion parameters of the ship are updated in real time during the calculation process, and the interaction between the hull and the propeller and rudder as well as the fluid-solid coupling effect are considered until the calculation converges, and finally the self-propulsion numerical simulation results are obtained.

[0057] S104, obtaining actual propeller open water performance parameters;

[0058] It is understood that the actual propeller open water performance parameters may refer to the actual propeller open water performance parameters. The actual propeller open water performance parameters can be obtained by using a propeller model open water test to obtain the actual propeller open water performance parameters, or by using a propeller model to perform an open water performance numerical simulation to obtain the actual propeller open water performance parameters.

[0059] S105, determining a self-propulsion factor of the vessel based on the actual propeller open water performance parameters, the propeller model open water performance parameters, and the self-propulsion numerical simulation results; wherein the self-propulsion factor includes at least one of a thrust deduction fraction, a wake fraction, and a relative rotation efficiency.

[0060] The self-propulsion factor is a set of parameters used to describe a vessel's self-propulsion performance, including thrust deduction fraction, wake fraction, and relative rotational efficiency. Specifically, the thrust deduction fraction refers to the ratio of the propeller's thrust used to overcome additional resistance, such as water disturbances around the hull, to the propeller's total thrust when the vessel is sailing. The wake fraction refers to the ratio of the difference between the average speed of the wake behind the hull and the ship's forward speed to the ship's forward speed. The relative rotational efficiency refers to the ratio of the propeller's rotational efficiency when operating near the hull to its rotational efficiency in open water.

[0061] The self-propulsion factor of the ship can be determined based on the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation results. The correction coefficient can be obtained by comparing the actual propeller open water performance parameters with the propeller model open water performance parameters. The initial self-propulsion factor can be calculated according to the self-propulsion numerical simulation results. The initial self-propulsion factor can be corrected based on the correction coefficient to obtain the self-propulsion factor of the ship.

[0062] In an embodiment of the present application, a three-dimensional model of a ship is obtained; wherein the three-dimensional model includes a propeller model, a hull model and a rudder model; a transition model is used to determine the propeller model open water performance parameters according to the propeller model; a self-propulsion numerical simulation calculation is performed based on the three-dimensional model to obtain a self-propulsion numerical simulation result; actual propeller open water performance parameters are obtained; and a self-propulsion factor of the ship is determined according to the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation result; wherein the self-propulsion factor includes at least one of a thrust reduction fraction, a wake fraction and a relative rotation efficiency. The above-mentioned method for self-propulsion numerical simulation of a ship can accurately simulate the flow near the propeller blade surface by using a transition model to determine the propeller model open water performance parameters according to the propeller model, thereby improving the accuracy of the self-propulsion numerical simulation. By determining the self-propulsion factor of the ship according to the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation result, the complex hydrodynamic characteristics of the ship during self-propulsion can be truly restored, providing reliable data support for the optimization design of the ship.

[0063] Example 2

[0064] Figure 2 This is a flow chart of the method for numerically simulating the self-propulsion of a ship provided in Example 2 of the present application. This solution makes a better improvement to the above-mentioned embodiment. Specifically, before using the transition model to determine the open-water performance parameters of the propeller model based on the propeller model, the method further includes: determining a computational domain based on the three-dimensional model; meshing the computational domain according to a preset meshing rule to obtain a computational grid; wherein the computational grid includes a propeller blade surface grid, a hull surface grid, and a rudder surface grid.

[0065] like Figure 2 As shown, the specific steps include:

[0066] S201, obtaining a three-dimensional model of a ship; wherein the three-dimensional model includes a propeller model, a hull model, and a rudder model;

[0067] S202, determining a calculation domain according to the three-dimensional model;

[0068] The computational domain refers to the spatial region selected for solving fluid flow problems during numerical simulation. Based on the 3D model, the computational domain can be determined by extending the propeller, hull, and rudder models in the 3D model to a certain distance in the fore-aft, left-right, and up-and-down directions to form a spatial range that fully encompasses the vessel and the surrounding flow field.

[0069] S203, meshing the computational domain according to a preset meshing rule to obtain a computational mesh; wherein the computational mesh includes a propeller blade mesh, a hull surface mesh, and a rudder surface mesh;

[0070] A computational grid is a discretized grid structure obtained by dividing the computational domain according to pre-set meshing rules. The computational grid is the foundation of numerical calculations. By discretizing the computational domain into small computational grids, continuous fluid flow problems can be transformed into numerical problems solved on these discrete computational grids. The quality of the computational grid directly affects the accuracy and stability of numerical simulations.

[0071] A preset meshing rule refers to a set of predefined criteria and methods used to divide the computational domain into computational grids. These rules take into account factors such as computational accuracy, efficiency, and mesh quality. For example, a finer mesh can be used near key areas such as the hull, rudder, and propeller to accurately capture the flow field's details; whereas a coarser mesh can be used in areas away from the hull, rudder, and propeller to reduce computational effort.

[0072] The propeller blade surface mesh is the surface division of the propeller blade within the computational mesh. Because propellers play a key role in ship propulsion, the flow field on their blade surfaces is complex. Therefore, a fine mesh is required to accurately calculate performance parameters such as thrust and torque generated by the propeller during rotation, as well as the pressure distribution and flow pattern changes around the blade surface.

[0073] The hull surface mesh is the portion of the computational mesh that is specifically designed for the hull surface. The flow field on the hull surface significantly affects the ship's resistance and wake characteristics, so a reasonable hull surface mesh is required to accurately simulate the interaction between the hull and the surrounding fluid.

[0074] The rudder surface mesh is a mesh created within the computational mesh specifically for the rudder surface. The rudder controls the ship's course, and the flow field on its surface affects the rudder's maneuverability. Meshing the rudder surface allows numerical simulations to consider the effects of the rudder on the water flow at different angles, as well as the reaction force of the water flow on the rudder. This allows for analysis of the rudder's control effectiveness and the ship's maneuverability.

[0075] In the present technical solution, optionally, the dimensionless wall distance of the propeller blade surface grid is less than 1; and the change rate of each layer of the propeller blade surface grid is less than a preset change rate threshold.

[0076] Dimensionless wall distance y +It is a dimensionless parameter used in computational fluid dynamics to describe the distance between the mesh nodes near the wall and the wall. Where y represents the actual physical distance from the grid node to the wall; u r represents the friction velocity, which is an important parameter to characterize the turbulent flow characteristics near the wall; v represents the kinematic viscosity of the fluid, which reflects the viscous characteristics of the fluid.

[0077] Dimensionless wall distance y + Less than 1 means that the propeller blade mesh can finely analyze the flow within the boundary layer of the propeller blade and accurately capture the rapid changes in physical quantities such as speed and pressure, thereby providing accurate flow field information for calculating performance parameters such as propeller thrust and torque.

[0078] The change rate of each layer of the propeller blade grid can refer to the y between adjacent propeller blade grid layers. + The preset change rate threshold may be a pre-set standard value, such as 1.2, used to measure whether the change rate of each layer of the propeller blade grid is reasonable.

[0079] The change rate of each layer of the propeller blade surface grid is less than the preset change rate threshold in order to ensure that the distribution of the propeller blade surface grid near the propeller blade surface has a certain uniformity.

[0080] The advantage of this setting of the scheme is that the dimensionless wall distance of the propeller blade surface grid is less than 1, and the change rate of each layer of the propeller blade surface grid is less than the preset change rate threshold. It can accurately analyze the complex flow details in the propeller blade boundary layer, accurately capture the gradient changes of physical quantities such as velocity and pressure near the propeller blade surface, and improve the accuracy of the propeller model open water performance parameters and self-propulsion numerical simulation results.

[0081] In the present technical solution, optionally, the hull surface grid and the rudder surface grid adopt prismatic layer grids; and the dimensionless wall distance of the hull surface grid and the rudder surface grid exceeds a preset dimensionless wall distance threshold.

[0082] Prismatic layer meshes are a special type of mesh used to simulate flows near solid walls. Prismatic layer meshes are prismatic in shape and stacked along the wall normal, effectively conforming to the geometry of the solid wall.

[0083] The preset dimensionless wall distance threshold can be a pre-set lower limit for the dimensionless wall distance that can quickly trigger the turbulence model, such as 300. During actual ship navigation, the fluid near the hull and rudder surfaces is typically turbulent. Therefore, it is necessary to quickly trigger the turbulence model in the self-propulsion numerical simulation calculation to accurately restore the interaction between the hull, rudder, and the turbulent flow field. By setting the dimensionless wall distance of the hull surface mesh and the rudder surface mesh to exceed the preset dimensionless wall distance threshold, the turbulence model can be quickly triggered to take effect, improving the accuracy of the self-propulsion numerical simulation results.

[0084] In addition, the turbulence model can be quickly activated by adding a turbulence wire. The following is a diagram showing high y on the hull surface mesh and the rudder surface mesh. + , low y + and low y + Comparison table of some examples of self-propulsion numerical simulation results obtained with the rapid flow wire installed:

[0085]

[0086] Among them, high y + Indicates that the dimensionless wall distance of the hull surface mesh and the rudder surface mesh exceeds the preset dimensionless wall distance threshold, low y + Indicates that the dimensionless wall distance of the hull surface mesh and the rudder surface mesh is less than the preset dimensionless wall distance threshold.

[0087] Among them, resistance refers to the force exerted by water on a ship when it moves in the water, which hinders its forward movement; relative error can be the ratio of the absolute error obtained from the measurement to the true value of the measured value, generally expressed as a percentage; and the average wake fraction is a parameter that describes the uneven distribution of water velocity around the ship.

[0088] Based on the example comparison table, it can be seen that high y + Compared with low y + With low y + (with rapid flow wire), high y + It has smaller relative error and higher average wake score, and can more accurately restore the real physical state of the ship during self-propulsion.

[0089] Axial wake refers to a phenomenon of water flow velocity distribution along the axis of the ship (generally the bow and stern direction of the ship) during the navigation of the ship. Figure 3 This is a comparative example diagram of the axial wake provided in Example 2 of this application. Figure 3 As shown, (1) is high y + The corresponding axial wake diagram, (2) is low y + The corresponding axial wake diagram, (3) is low y+ (with the addition of a torrent wire) corresponding to the axial wake diagram; high y + Compared with low y + With low y + (with rapid flow wire), high y + The corresponding axial wake diagram shows a more uniform and reasonable velocity distribution.

[0090] The advantage of this setting is that the hull surface mesh and the rudder surface mesh use prismatic layer meshes, which can more accurately fit the complex curved surface shapes of the hull and rudder, and effectively capture the flow details in the boundary layer; the dimensionless wall distance of the hull surface mesh and the rudder surface mesh exceeds the preset dimensionless wall distance threshold, which can quickly stimulate the turbulence model, thereby providing a guarantee for the accurate simulation of the ship's self-propulsion performance.

[0091] S204, determining propeller model open water performance parameters according to the propeller model using a transition model;

[0092] S205, performing self-propulsion numerical simulation calculation based on the three-dimensional model to obtain a self-propulsion numerical simulation result;

[0093] S206, obtaining actual propeller open water performance parameters;

[0094] S207, determining a self-propulsion factor of the vessel based on the actual propeller open water performance parameters, the propeller model open water performance parameters, and the self-propulsion numerical simulation results; wherein the self-propulsion factor includes at least one of a thrust deduction fraction, a wake fraction, and a relative rotation efficiency.

[0095] The advantage of this setting is that by determining the calculation domain based on the three-dimensional model and dividing the calculation domain into grids according to the preset grid division rules to obtain the calculation grid, it can ensure that the numerical simulation covers the key flow field areas during the ship's self-propulsion process, improve the flow field calculation accuracy and optimize the allocation of computing resources.

[0096] Example 3

[0097] Figure 4 This is a flow chart of the method for numerically simulating the self-propulsion of a ship provided in Example 3 of the present application. This solution makes further improvements to the above-mentioned embodiments, specifically, obtaining the actual propeller open water performance parameters, including: obtaining the actual propeller open water performance parameters based on a propeller model open water test; or performing an open water performance numerical simulation based on the propeller model to obtain the actual propeller open water performance parameters.

[0098] like Figure 4 As shown, the specific steps include:

[0099] S401, obtaining a three-dimensional model of a ship; wherein the three-dimensional model includes a propeller model, a hull model, and a rudder model;

[0100] S402, determining propeller model open water performance parameters according to the propeller model using a transition model;

[0101] S403, performing self-propulsion numerical simulation calculation based on the three-dimensional model to obtain self-propulsion numerical simulation results;

[0102] S404, obtaining open water performance parameters of the actual propeller based on the propeller model open water test;

[0103] The method of obtaining the actual propeller open water performance parameters based on the propeller model open water test can be adopted. The propeller can be installed on the test shaft system in a dedicated propeller test water tank, and the propeller can be driven to rotate by a motor to simulate different rotation speeds and inlet flow speed conditions. The thrust and torque data generated by the propeller can be measured in real time using a high-precision force measuring device. At the same time, the flow field velocity distribution around the propeller is obtained through the flow velocity measuring equipment, and the actual propeller open water performance parameters are then calculated.

[0104] S405, performing open water performance numerical simulation based on the propeller model to obtain actual propeller open water performance parameters;

[0105] The open water performance parameters of the actual propeller can be obtained by performing a numerical simulation of the open water performance based on the propeller model. The scale ratio of the propeller model can be adjusted to a preset scale ratio to obtain a reduced propeller model, and the open water performance parameters of the actual propeller can be obtained by performing a numerical simulation of the open water performance based on the reduced propeller model. Alternatively, the open water performance parameters of the actual propeller can be obtained by performing a numerical simulation based on the propeller model and a preset rotation speed.

[0106] In this technical solution, optionally, open water performance numerical simulation is performed based on the propeller model to obtain actual propeller open water performance parameters, including:

[0107] Adjusting the scale ratio of the propeller model to a preset scale ratio to obtain a reduced propeller model;

[0108] Performing open water performance numerical simulation based on the scaled-down propeller model to obtain actual propeller open water performance parameters;

[0109] or,

[0110] Based on the propeller model and the preset rotation speed, an open water performance numerical simulation is performed to obtain the actual propeller open water performance parameters.

[0111] The scale ratio may refer to the ratio between the model size and the actual object size. The preset scale ratio may be a pre-set scale ratio that is smaller than the scale ratio of the propeller model. The reduced propeller model is a propeller model that is proportionally reduced to the preset scale ratio.

[0112] The rotational speed may refer to the number of revolutions of the propeller model around the axis per unit time. The preset rotational speed may be a predetermined rotational speed greater than the rotational speed used in determining the open water performance parameters of the propeller model based on the propeller model using the transition model.

[0113] It can be understood that the open water performance parameters of the actual propeller are obtained by performing numerical simulation of the open water performance based on the propeller model. Compared with determining the open water performance parameters of the propeller model according to the propeller model using the transition model, the scale ratio of the propeller model is reduced and / or the rotation speed is increased.

[0114] The Reynolds number can be increased by reducing the scale ratio of the propeller model and / or increasing the rotation speed. The Reynolds number is a dimensionless number used to characterize the state of fluid flow and reflects the relative magnitude of the fluid's inertial and viscous forces.

[0115] By increasing the Reynolds number, the flow field characteristics in the numerical simulation can be made closer to the flow state of the actual propeller under real working conditions, effectively reducing the calculation error caused by scale effect and flow state difference, so as to obtain accurate real propeller open water performance parameters.

[0116] The advantage of this arrangement of the present scheme is that by reducing the scale ratio of the propeller model and / or increasing the rotation speed, a numerical simulation of the open water performance is performed to obtain the open water performance parameters of the actual propeller, which can effectively improve the Reynolds number in the simulation process and make the flow field state closer to the actual situation of the actual propeller under actual navigation conditions, thereby improving the accuracy of the obtained open water performance parameters of the actual propeller.

[0117] S406, determining the self-propulsion factor of the ship based on the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation results; wherein the self-propulsion factor includes at least one of a thrust deduction fraction, a wake fraction and a relative rotation efficiency.

[0118] The advantage of this arrangement of the scheme is that by obtaining the actual propeller open water performance parameters based on the propeller model open water test, some complex physical phenomena during the actual operation of the propeller can be reflected, providing intuitive and real data support for the actual propeller performance evaluation; the actual propeller open water performance parameters are obtained by performing open water performance numerical simulation based on the propeller model, which has the advantages of strong repeatability, low cost and the ability to quickly obtain a large amount of data, and various parameters can be flexibly adjusted to perform multi-working condition simulation analysis.

[0119] Example 4

[0120] Figure 5 This is a schematic diagram of the structure of the self-propulsion numerical simulation device for a ship provided in Example 4 of this application. Figure 5 As shown, the device includes:

[0121] A three-dimensional model acquisition module 510 is used to acquire a three-dimensional model of the ship; wherein the three-dimensional model includes a propeller model, a hull model, and a rudder model;

[0122] a propeller model open water determination module 520 for determining propeller model open water performance parameters based on the propeller model using a transition model;

[0123] A self-propulsion numerical simulation module 530 is used to perform self-propulsion numerical simulation calculations based on the three-dimensional model to obtain self-propulsion numerical simulation results;

[0124] The actual propeller open water acquisition module 540 is used to obtain actual propeller open water performance parameters;

[0125] The self-propulsion factor determination module 550 is used to determine the self-propulsion factor of the ship based on the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation results; wherein the self-propulsion factor includes at least one of the thrust deduction fraction, the wake fraction and the relative rotation efficiency.

[0126] In an embodiment of the present application, a three-dimensional model acquisition module is used to obtain a three-dimensional model of a ship; wherein the three-dimensional model includes a propeller model, a hull model and a rudder model; a propeller model open water determination module is used to determine the propeller model open water performance parameters according to the propeller model using a transition model; a self-propulsion numerical simulation module is used to perform self-propulsion numerical simulation calculations based on the three-dimensional model to obtain self-propulsion numerical simulation results; a real propeller open water acquisition module is used to obtain real propeller open water performance parameters; a self-propulsion factor determination module is used to determine the self-propulsion factor of the ship according to the real propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation results; wherein the self-propulsion factor includes at least one of thrust deduction fraction, wake fraction and relative rotation efficiency. The above-mentioned ship's self-propulsion numerical simulation device can accurately simulate the flow near the propeller blade surface by using the transition model to determine the propeller model open water performance parameters according to the propeller model, thereby improving the accuracy of the self-propulsion numerical simulation. By determining the ship's self-propulsion factor based on the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation results, the complex hydrodynamic characteristics of the ship during self-propulsion can be truly restored, providing reliable data support for the optimized design of the ship.

[0127] The self-propulsion numerical simulation device for a ship in the embodiments of the present application can be a device, or a component, integrated circuit, or chip in a terminal. The device can be a mobile electronic device or a non-mobile electronic device. For example, the mobile electronic device can be a mobile phone, a tablet computer, a laptop computer, a PDA, an in-vehicle electronic device, a wearable device, an ultra-mobile personal computer (UMPC), a netbook, or a personal digital assistant (PDA), etc. The non-mobile electronic device can be a server, a network attached storage (NAS), a personal computer (PC), a television (TV), an ATM, or an kiosks, etc., which are not specifically limited in the embodiments of the present application.

[0128] The self-propulsion numerical simulation device for a ship in the embodiment of the present application may be a device having an operating system. The operating system may be an Android operating system, an iOS operating system, or other possible operating systems, which are not specifically limited in the embodiment of the present application.

[0129] The self-propulsion numerical simulation device for a ship provided in the embodiment of the present application can realize each process implemented in the above-mentioned embodiments one to three. To avoid repetition, they will not be described here.

[0130] Example 5

[0131] like Figure 6 As shown, an embodiment of the present application also provides an electronic device 600, including a processor 601, a memory 602, and a program or instruction stored in the memory 602 and executable on the processor 601. When the program or instruction is executed by the processor 601, each process of the above-mentioned embodiment of the self-propulsion numerical simulation method of a ship is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0132] It should be noted that the electronic devices in the embodiments of the present application include the mobile electronic devices and non-mobile electronic devices mentioned above.

[0133] Example 6

[0134] An embodiment of the present application also provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, each process of the above-mentioned embodiment of the self-propulsion numerical simulation method of a ship is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0135] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer-readable storage medium, such as a computer read-only memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk.

[0136] Example 7

[0137] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned embodiment of the self-propulsion numerical simulation method of a ship, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0138] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0139] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be noted that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0140] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), including a number of instructions for enabling a terminal (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0141] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

[0142] The above are only preferred embodiments of the present application and the technical principles employed. The present application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions that are possible for those skilled in the art will not depart from the scope of protection of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments and may include more other equivalent embodiments without departing from the concept of the present application. The scope of the present application is determined by the scope of the claims.

Claims

1. A method for simulating the self-propulsion of a ship, characterized in that: The method comprises: Obtaining a three-dimensional model of the ship; wherein the three-dimensional model includes a propeller model, a hull model, and a rudder model; Determining propeller model open water performance parameters based on the propeller model using a transition model; Performing self-propulsion numerical simulation calculation based on the three-dimensional model to obtain self-propulsion numerical simulation results; Obtain actual propeller open water performance parameters; The self-propulsion factor of the ship is determined based on the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation results; wherein the self-propulsion factor includes at least one of the thrust deduction fraction, the wake fraction and the relative rotation efficiency.

2. The method for numerical simulation of self-propulsion of a ship according to claim 1, characterized in that: The propeller model is used to determine open water performance parameters of the propeller model, including: The propeller model open water performance parameters are determined based on the propeller model using the γ transition model.

3. The method for numerical simulation of self-propulsion of a ship according to claim 1, characterized in that: Before determining the propeller model open water performance parameters based on the propeller model using the transition model, the method further includes: determining a calculation domain according to the three-dimensional model; The computational domain is meshed according to a preset meshing rule to obtain a computational mesh; wherein the computational mesh includes a propeller blade mesh, a hull surface mesh, and a rudder surface mesh.

4. The method for numerical simulation of self-propulsion of a ship according to claim 3, characterized in that: The dimensionless wall distance of the propeller blade surface grid is less than 1; and the change rate of each layer of the propeller blade surface grid is less than a preset change rate threshold.

5. The method for numerical simulation of self-propulsion of a ship according to claim 3, characterized in that: The hull surface grid and the rudder surface grid adopt prismatic layer grids; the dimensionless wall distance of the hull surface grid and the rudder surface grid exceeds a preset dimensionless wall distance threshold.

6. The method for numerical simulation of self-propulsion of a ship according to claim 1, characterized in that: Obtain actual propeller open water performance parameters, including: Obtaining actual propeller open water performance parameters based on propeller model open water tests; or, Based on the propeller model, open water performance numerical simulation is performed to obtain the actual propeller open water performance parameters.

7. The method for numerical simulation of self-propulsion of a ship according to claim 6, characterized in that: Based on the propeller model, open water performance numerical simulation is performed to obtain the actual propeller open water performance parameters, including: Adjusting the scale ratio of the propeller model to a preset scale ratio to obtain a reduced propeller model; Performing open water performance numerical simulation based on the scaled-down propeller model to obtain actual propeller open water performance parameters; or, Based on the propeller model and the preset rotation speed, an open water performance numerical simulation is performed to obtain the actual propeller open water performance parameters.

8. A self-propelled ship simulation device, characterized in that: The device comprises: A three-dimensional model acquisition module, configured to acquire a three-dimensional model of the ship; wherein the three-dimensional model includes a propeller model, a hull model, and a rudder model; a propeller model open water determination module, configured to determine propeller model open water performance parameters according to the propeller model using a transition model; A self-propulsion numerical simulation module, used to perform self-propulsion numerical simulation calculations based on the three-dimensional model to obtain self-propulsion numerical simulation results; Actual propeller open water acquisition module, used to obtain actual propeller open water performance parameters; A self-propulsion factor determination module is used to determine the self-propulsion factor of the ship based on the actual propeller open water performance parameters, the propeller model open water performance parameters and the self-propulsion numerical simulation results; wherein the self-propulsion factor includes at least one of the thrust deduction fraction, the wake fraction and the relative rotation efficiency.

9. An electronic device, characterized in that: The method comprises a processor, a memory, and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction, when executed by the processor, implements the steps of the method for numerical simulation of self-propulsion of a ship as described in any one of claims 1 to 7.

10. A readable storage medium, characterized in that: The readable storage medium stores a program or instruction, and when the program or instruction is executed by the processor, the steps of the method for numerical simulation of self-propulsion of a ship according to any one of claims 1 to 7 are implemented.

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