Method and system for performance evaluation of double-liner grooved water-lubricated stern bearing

Abstract

This invention relates to the field of ship propulsion shaft support and lubrication performance analysis, and provides a performance evaluation method and system for a double-lined grooved water-lubricated stern bearing. The method includes: establishing a three-dimensional geometric model of the double-lined grooved water-lubricated stern bearing; meshing the fluid and solid domains separately; establishing a layered joint calculation model for the fluid domain, a calculation model for the solid domain, and a journal dynamic model; establishing a fluid-structure interaction interface transfer model, creating a bidirectional fluid-structure interaction interface between the liquid film domain and the inner surface of the inner liner, whereby the fluid domain transfers liquid film pressure loads and wall shear stresses to the solid domain, and the solid domain feeds back interface displacement, velocity, and deformed boundary geometry information to the fluid domain; setting bidirectional fluid-structure interaction boundary conditions and a dynamic mesh update strategy; performing multi-condition performance calculations, impact load condition analysis, result output, and performance evaluation. The physical consistency and prediction accuracy of the calculation results are significantly improved by this invention.

Description

Technical Field

[0001] This invention relates to the field of support and lubrication performance analysis of ship propulsion shafting, and in particular to a performance evaluation method and system for a double-liner grooved water-lubricated stern bearing. Background Technology

[0002] Ship stern bearings are critical friction components that support propeller shafts, transmit complex alternating loads, and ensure the stable operation of the propulsion shafting. With the greening of ships and increasingly stringent environmental regulations, water-lubricated stern bearings have gradually become an important research subject in ship propulsion systems due to their advantages such as no oil pollution, convenient maintenance, and lower operating temperatures.

[0003] However, the viscosity of water as a medium is lower than that of traditional oil-lubricated media, resulting in a relatively limited ability to build up hydrodynamic film. Under complex operating conditions such as heavy loads, low speeds, eccentricity, and impacts, problems such as insufficient local lubrication, reduced load-bearing capacity, increased friction and wear, and deterioration of bearing stability can easily occur. To improve fluid supply, heat dissipation, and chip removal conditions, researchers typically incorporate groove structures on the bearing working surface. A reasonable groove shape, depth, width, number, and distribution can improve the local flow and pressure fields, enhance the lubricant renewal capacity, and to some extent improve load-bearing and friction-reducing performance. However, unreasonable groove parameters can disrupt the continuous convergent wedge effect, weaken the liquid film pressure-building capacity, lead to disordered pressure distribution, segmentation of the effective load-bearing area, and increased frictional losses.

[0004] Meanwhile, double- or multi-layer composite bearing structures can improve impact buffering capacity and load transfer characteristics to some extent through the synergistic deformation of materials with different stiffnesses. However, existing research mainly focuses on steady-state lubrication analysis or unidirectional coupling analysis, which makes it difficult to accurately describe the bidirectional coupling relationship between journal displacement, liquid film pressure field, liner deformation, and impact load simultaneously. Especially for double-layer grooved water-lubricated stern bearings, existing methods usually use a single Reynolds equation or a global averaging approach, which makes it difficult to accurately characterize key flow field features such as groove inlet pressure drop, groove internal backflow, groove outlet secondary throttling, and local pressure recovery. Therefore, there is still a lack of a unified calculation and evaluation method that can take into account both overall solution efficiency and accurate analysis of the local flow field in the groove. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by proposing a performance evaluation method and system for a double-lined grooved water-lubricated stern bearing, which significantly improves the physical consistency and prediction accuracy of the calculation results.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a performance evaluation method for a double-liner grooved water-lubricated stern bearing, comprising the following steps:

[0008] A three-dimensional geometric model of a double-lined grooved water-lubricated stern bearing was established. The fluid domain and solid domain were meshed separately, and a layered joint calculation model of the fluid domain, a calculation model of the solid domain, and a journal dynamic model were established.

[0009] A fluid-structure interaction interface transfer model is established, and a two-way fluid-structure interaction interface is established between the liquid film domain and the inner surface of the inner liner. The fluid domain transfers the liquid film pressure load and wall shear stress to the solid domain, and the solid domain feeds back the interface displacement, velocity and deformed boundary geometry information to the fluid domain.

[0010] We set up bidirectional fluid-structure interaction boundary conditions and dynamic mesh update strategies to perform multi-condition performance calculations, impact load condition analysis, result output, and performance evaluation.

[0011] In a second aspect, the present invention provides a performance evaluation system for a double-liner grooved water-lubricated stern bearing, comprising:

[0012] The three-dimensional geometric model building unit is used to: build a three-dimensional geometric model of a double-linerd grooved water-lubricated stern bearing;

[0013] Mesh generation cells are used to mesh the fluid domain and the solid domain separately.

[0014] The fluid domain hierarchical joint computation model establishment unit is used to: establish a fluid domain hierarchical joint computation model;

[0015] Solid domain computational model establishment unit, used for: establishing solid domain computational models;

[0016] Journal dynamics model establishment unit, used for: establishing journal dynamics model;

[0017] The fluid-structure interaction interface transfer model establishment unit is used to: establish a fluid-structure interaction interface transfer model.

[0018] The boundary and update settings unit is used to: set bidirectional fluid-structure interaction boundary conditions and dynamic mesh update strategies;

[0019] Multi-condition performance calculation unit, used for: performing multi-condition performance calculations;

[0020] The impact load condition analysis unit is used for: performing impact load condition analysis;

[0021] The evaluation unit is used to: output results and perform performance evaluation;

[0022] The three-dimensional geometric model establishment unit, mesh generation unit, fluid domain layered joint calculation model establishment unit, solid domain calculation model establishment unit, journal dynamics model establishment unit, fluid-structure interaction interface transfer model establishment unit, boundary and update setting unit, multi-condition performance calculation unit, impact load condition analysis unit, and evaluation unit sequentially establish the data flow connection.

[0023] Thirdly, the present invention provides an electronic device comprising: at least one processor, at least one memory, and a communication interface, wherein the processor, memory, and communication interface communicate with each other; the memory stores program instructions executable by the processor, and the processor invokes the program instructions to execute the performance evaluation method for the double-liner grooved water-lubricated stern bearing described in the first aspect.

[0024] Fourthly, the present invention provides a non-transitory computer-readable storage medium storing computer instructions that cause a computer to execute the performance evaluation method for a double-liner grooved water-lubricated stern bearing described in the first aspect.

[0025] Compared with existing technical solutions, the beneficial effects of the embodiments of the present invention are reflected in the following aspects:

[0026] (1) By establishing a two-way fluid-structure interaction model, the embodiment of the present invention realizes the two-way data transmission between liquid film pressure, journal displacement and double liner deformation, which can more realistically reflect the working state of the double-liner grooved water-lubricated stern bearing of the embodiment of the present invention under complex working conditions. Therefore, the physical consistency and prediction accuracy of the calculation results are higher.

[0027] (2) The embodiments of the present invention can uniformly analyze the combined effects of factors such as groove shape, number of grooves, groove distribution location, rotation speed, eccentricity and impact load on the lubrication performance and dynamic response of double-lined grooved water-lubricated stern bearings. Therefore, it is more suitable for engineering applications than analysis methods that only target single factors or steady-state conditions.

[0028] (3) The embodiments of the present invention can reveal the influence mechanism of the trench structure on the local secondary throttling effect, pressure field reconstruction, bearing area retention capacity and transient liquid replenishment capacity under impact conditions, thereby providing a direct basis for trench parameter optimization.

[0029] (4) The embodiments of the present invention introduce response analysis of double-layer structure, which can quantify the stress and deformation distribution law of inner and outer linings, and help with lining material selection, structural matching and impact resistance design.

[0030] (5) The embodiments of the present invention can output a variety of evaluation indicators such as maximum water film pressure, minimum film thickness, bearing capacity, friction coefficient, axial displacement, liner stress and deformation, which can provide systematic calculation support for improving the operational reliability and extending the service life of double-liner grooved water-lubricated stern bearings under complex working conditions. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart of a performance evaluation method for a double-linerd grooved water-lubricated stern bearing in an embodiment of the present invention.

[0033] Figure 2 This is a three-dimensional cross-sectional view of the double-liner grooved water-lubricated stern bearing in an embodiment of the present invention.

[0034] Figure 3 This is a schematic diagram of the radial cross-section of the double-liner grooved water-lubricated stern bearing in an embodiment of the present invention.

[0035] Figure 4 This is a schematic diagram of the bidirectional fluid-structure interaction data exchange process in an embodiment of the present invention.

[0036] Figure 5 This is a schematic diagram of a rectangular straight groove.

[0037] Figure 6 This is a schematic diagram of a rectangular spiral groove.

[0038] Figure 7 This is a schematic diagram of the U-shaped straight groove.

[0039] Figure 8 This is a waveform diagram of the impact load in an embodiment of the present invention.

[0040] Figure 9 This is a schematic diagram of the water film pressure under the rectangular straight groove parameters in an embodiment of the present invention.

[0041] Figure 10 This is a schematic diagram of the water film pressure under the parameters of the rectangular spiral groove in an embodiment of the present invention.

[0042] Figure 11 This is a schematic diagram of the water film pressure under the parameters of the U-shaped straight groove in an embodiment of the present invention.

[0043] Figure 12This is a schematic diagram of the distribution of trench pressure in an embodiment of the present invention.

[0044] Figure 13 This is a diagram illustrating the effect of secondary throttling in the trench according to an embodiment of the present invention.

[0045] Figure 14 This is a schematic diagram of the trajectory of the bearing shaft center after being impacted in an embodiment of the present invention.

[0046] Figure 15 This is a structural block diagram of the performance evaluation system for a double-lined grooved water-lubricated stern bearing in an embodiment of the present invention.

[0047] Reference numerals: 1-journal, 2-water film, 3-groove, 4-inner liner, 5-outer liner, 6-shell. Detailed Implementation

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0049] The embodiments of the present invention solve the following technical problems:

[0050] (1) Existing models cannot simultaneously consider the bidirectional coupling effect between journal displacement, liquid film pressure distribution and double-liner structure deformation, resulting in insufficient accuracy in predicting the performance of double-liner grooved water-lubricated stern bearings.

[0051] (2) Existing methods are difficult to uniformly analyze the comprehensive effect of groove shape, number of grooves, groove distribution location, rotational speed, eccentricity and impact load on bearing lubrication performance and dynamic response.

[0052] (3) Existing methods mostly use a single Reynolds equation or overall averaging, which makes it difficult to accurately characterize the fine flow field features such as local backflow, secondary flow, local pressure drop and pressure recovery in the trench region and near its boundary.

[0053] (4) Existing research lacks a clear quantitative characterization of the mechanism of action of groove structure in local secondary throttling, pressure field reconstruction, transient fluid replenishment and impact resistance improvement.

[0054] (5) There is a lack of a calculation method that can simultaneously output the local flow field characteristics of the groove, the overall lubrication performance parameters and the dynamic response parameters, and can directly serve the structural optimization design, working condition matching and impact resistance performance evaluation.

[0055] See Figure 1As shown, this embodiment of the invention provides a performance evaluation method for a double-liner grooved water-lubricated stern bearing, comprising the following steps:

[0056] Step S1: Establish a three-dimensional geometric model of the double-liner grooved water-lubricated stern bearing.

[0057] Figure 2 This is a three-dimensional cross-sectional view of the double-lined grooved water-lubricated stern bearing in an embodiment of the present invention. Figure 3 This is a schematic diagram of the radial cross-section of the double-lined grooved water-lubricated stern bearing in an embodiment of the present invention. Figure 2 and Figure 3 The spatial arrangement of the components of the double-liner grooved water-lubricated stern bearing in the axial direction is shown in the embodiments of the present invention. See [link / reference]. Figure 2 As shown, the bearing in this embodiment of the invention includes, from the inside out: journal 1, water film 2, inner liner 4 with groove 3, outer liner 5 and housing 6. The groove 3 is arranged along the bearing axial direction on the inner surface of the inner liner 4, and together with the water film 2 between the outer circular surface of the journal 1, it forms a lubrication channel. Figure 2 The three-dimensional sectional view intuitively reflects the assembly relationship and working position of groove 3, water film 2 and double liner structure in the overall bearing. Figure 3 The radial section diagram clearly shows the relative positions of journal 1, water film 2, groove 3, inner liner 4, outer liner 5, and shell 6 in the radial section. (See attached diagram.) Figure 3 As shown, journal 1 is offset inside the bearing, the bearing geometric center is O, the journal center is O1, and the distance e between them represents the journal eccentricity. A water film 2 lubrication gap is formed between the outer surface of journal 1 and the inner surface of the inner liner 4. Groove 3 is set on the inner surface of the inner liner 4 and communicates with the water film 2 area to improve the storage, replenishment and local pressure distribution of the lubricating medium.

[0058] The fluid domain and the solid domain are meshed separately, and a hierarchical joint calculation model for the fluid domain, a calculation model for the solid domain, and a journal dynamics model are established.

[0059] Step S2: Establish a fluid-structure interaction interface transfer model. A two-way fluid-structure interaction interface is established between the liquid film domain and the inner surface of the inner liner. The fluid domain transfers the liquid film pressure load and wall shear stress to the solid domain, and the solid domain feeds back the interface displacement, velocity and deformed boundary geometry information to the fluid domain.

[0060] Figure 4 This is a schematic diagram illustrating the data transfer and dynamic mesh update process at the fluid-structure interaction interface in an embodiment of the present invention. Figure 4 This demonstrates the bidirectional coupling solution relationship between the fluid domain and the double-layered solid domain. See [link / reference]. Figure 4 As shown, the fluid solver calculates the pressure field. Velocity field and wall shear stress The liquid film pressure and wall shear stress are treated as interface loads and transferred to the solid domain. The displacement fields of the inner and outer lining layers are calculated in the solid domain by the structural solver. Stress field and strain field Simultaneously, the solid domain solution yields interface displacement, interface velocity, and deformed geometric information, which is fed back to the liquid film domain to correct the liquid film thickness and fluid boundary position. Because the bearing liner undergoes elastic deformation under load, the original fluid mesh needs to be dynamically updated based on the interface displacement, i.e., the... Step-flow mesh nodes According to the interface displacement increment Updated to the number Step grid node Mesh quality is maintained through spring smoothing, diffusion smoothing, or local reconstruction.

[0061] Figure 4 The second half further presents the iterative solution process for fluid-structure interaction:

[0062] First, fluid dynamics is solved. Then, load mapping and solid structure response calculations are performed. Next, structural displacements are fed back to the fluid domain, and the dynamic mesh is updated. This process continues until the pressure residual, displacement residual, and energy balance residual are all less than a set threshold. This workflow enables synchronous coupled calculations between liquid film pressure evolution, double-layer deformation, and fluid mesh updates.

[0063] Step S3: Set bidirectional fluid-structure interaction boundary conditions and dynamic mesh update strategy, perform multi-condition performance calculations, impact load condition analysis, result output, and performance evaluation.

[0064] Each step is described in detail below.

[0065] In step S1, a three-dimensional geometric model of a double-linerd, grooved, water-lubricated stern bearing is established. This model includes at least: a journal, a liquid film region, an inner liner, and an outer liner. A groove structure is provided on the inner surface of the bearing. Groove parameters include: groove shape, groove width, groove depth, number of grooves, and their distribution location. Groove shapes include: rectangular straight grooves, rectangular spiral grooves, U-shaped straight grooves, trapezoidal grooves, herringbone grooves, or other groove types with guiding and throttling functions. Figure 5-7 The structures of different groove-shaped water-lubricated bearings are shown. Figure 5 The structure of the rectangular straight groove is shown. Figure 6 The structure of the rectangular spiral groove is shown. Figure 7 The structure of the U-shaped straight groove is shown.

[0066] Mesh generation is performed separately for the fluid domain and the solid domain, including the following steps:

[0067] The fluid domain preferably uses a structured hexahedral mesh, combined with a block-based method to handle narrow-gap liquid film regions; the solid domain is meshed using finite element methods based on the material properties of the inner and outer liner layers; and the radial, circumferential, and axial mesh densities are determined through mesh independence analysis.

[0068] Establishing a hierarchical joint computational model for the fluid domain includes the following steps:

[0069] The fluid domain is divided into a non-groove main load-bearing region and a groove local fine solution region. In the non-groove main load-bearing region, the overall liquid film pressure distribution is solved using the modified Reynolds equation based on the two-dimensional thin film assumption. The groove local fine solution region includes the groove body, the groove leading edge, the groove trailing edge, and the high gradient transition region adjacent to the groove. The local flow field is solved using the three-dimensional Navier-Stokes equations. The Navier-Stokes equations (NS equations) are a set of nonlinear partial differential equations describing the motion of viscous fluids, which are derived based on the laws of conservation of mass, momentum, and energy.

[0070] The modified Reynolds equation under the assumption of two-dimensional thin films has the following calculation equation:

[0071] ,

[0072] In the formula, For the bearing circumferential coordinates, For the bearing axial coordinate, This is the circumferential flow correction factor. This is the axial flow correction factor. For liquid film thickness, For liquid film pressure, For lubricating hydrodynamic viscosity, For the bearing radius, The journal angular velocity, For time.

[0073] The aforementioned two-dimensional modified Reynolds equation describes the distribution of water film pressure along the circumferential and axial directions within the overall load-bearing region of a double-liner grooved water-lubricated bearing. It is used to solve for the overall water film pressure field, film thickness variation, and load-bearing capacity. Since the clearance of the water-lubricated bearing is much smaller than the bearing radius and axial length, the overall load-bearing region satisfies the thin-film lubrication assumption. Using the two-dimensional modified Reynolds equation avoids directly solving the three-dimensional Navier-Stokes equations for the entire bearing fluid domain, thus reducing the computational load.

[0074] The technical problem addressed by the two-dimensional modified Reynolds equation is that existing methods, which solve the entire fluid domain of the grooved bearing using a three-dimensional flow field, suffer from high computational costs, difficulty in iterative convergence, and are unsuitable for performance evaluation under multiple operating conditions. Conversely, using only the traditional averaged Reynolds equation makes it difficult to couple with the local three-dimensional flow characteristics of the groove. By employing the two-dimensional modified Reynolds equation in the overall region and the three-dimensional Navier-Stokes equation in the local groove region, and ensuring continuous pressure and flow transmission at the interface, a balance can be struck between the computational efficiency of the overall bearing performance and the detailed characterization of the local groove flow.

[0075] The technical effects achieved by the two-dimensional modified Reynolds equation are: while ensuring the accuracy of the calculation of the overall water film pressure field and bearing capacity, the calculation scale is significantly reduced, the efficiency of multi-condition lubrication performance evaluation is improved, and a stable overall pressure boundary is provided for local pressure recovery of the trench, secondary throttling effect and fluid-structure interaction deformation analysis.

[0076] For the strongly disturbed local regions of the trench, the three-dimensional complete Navier-Stokes equations can be used to describe the fluid mass and momentum conservation processes. For the layered joint calculation model, the Reynolds equations can be used in the overall region, while the Navier-Stokes equations can be used in the local regions of the trench. Interface coupling is achieved through pressure continuity and flow continuity conditions. The calculation equations are as follows:

[0077] mass conservation equation: In the formula: It is the Nabla operator, which is a vector differential operator. ,in, For fluid velocity vector, , , These are the components of the fluid velocity in the x, y, and z coordinate directions, where x, y, and z represent three mutually perpendicular directions in the spatial coordinate system. The x-direction represents the horizontal direction within the radial section of the bearing, the y-direction represents the vertical direction within the radial section of the bearing, and the axial direction is the z-direction.

[0078] Momentum conservation equation: ,

[0079] In the formula: For fluid density, For fluid velocity vector, For time, It is the Nabla operator, which is a vector differential operator. For liquid film pressure, For pressure gradient, For lubricating hydrodynamic viscosity, It is a volume force.

[0080] The Reynolds equation solution model for the overall bearing area is combined with the Navier-Stokes equation solution model for the local area of ​​the trench to form a layered coupled joint calculation formula. The calculation method is as follows:

[0081] Let the overall region be: ,in: For the overall computational domain of the fluid domain of a double-liner grooved water-lubricated bearing, The computational domain for the Reynolds equations is... This is the computational domain for the Navier-Stokes equations.

[0082] The following should be satisfied at the coupling interface:

[0083] Pressure continuity conditions: ,

[0084] in, The liquid film pressure obtained from the calculation domain of the Reynolds equation. The local fluid pressure obtained from the computational domain of the Navier–Stokes equations. It is a coupling interface between two regions;

[0085] Mass flow rate continuous condition: , , ,

[0086] in, The equivalent volumetric flux at the coupling interface for the Reynolds equation computational domain. For the Navier–Stokes equations, calculate the normal volumetric flux at the coupling interface of the domain. It is a two-region coupling interface. For pressure-flow factor, For liquid film thickness, For lubricating hydrodynamic viscosity, It is the Nabla operator, which is a vector differential operator. For liquid film pressure, For pressure gradient, The sliding speed of the journal surface relative to the bearing liner. For fluid velocity vector, For the interface normal vector, Let be the length of the infinitesimal element along the thickness direction of the water film.

[0087] Establishing a computational model for the solid domain includes the following steps:

[0088] Different material parameters, including elastic modulus, Poisson's ratio, density, and damping parameters, are assigned to the inner liner, outer liner, and journal respectively. A displacement response model of the double-liner structure and journal is established to solve the stress, strain, and deformation distribution under liquid film pressure and external load.

[0089] The solid domain is solved using dynamic equilibrium equations, geometric equations, and material constitutive equations. The material model can be either a linear elastic model, a viscoelastic model, or a nonlinear constitutive model.

[0090] The fluid domain and the solid domain satisfy displacement compatibility and stress equilibrium conditions at the coupling interface. Solid deformation feedback is used to update the liquid film thickness, thereby realizing bidirectional fluid-structure interaction iterative solution.

[0091] The dynamic equilibrium equations of the solid domain are:

[0092] ,

[0093] In the formula: The density of the inner lining material. The material density of the outer lining layer, The displacement vector of the inner lining layer. The displacement vector of the outer liner. For time, It is the Nabla operator, which is a vector differential operator. For the stress tensor of the lining layer, For the stress tensor of the outer liner, The volume force vector of the inner lining layer. This is the volume force vector of the outer liner.

[0094] Under the assumption of small deformation linear elasticity, the constitutive relation of the two-layer liner can be written as:

[0095] ,

[0096] In the formula: For the stress tensor of the lining layer, For the stress tensor of the outer liner, Let be the elastic stiffness tensor of the inner lining layer. Let the elastic stiffness tensor of the outer lining be... Let be the strain tensor of the inner lining layer. Let be the strain tensor of the outer liner.

[0097] Since the change in the lining during bearing operation is extremely small, the strain-displacement relationship can be expressed as:

[0098] ,

[0099] In the formula: Let be the strain tensor of the inner lining layer. For the strain tensor of the outer liner, It is the Nabla operator, which is a vector differential operator. The displacement vector of the inner lining layer. The displacement vector of the outer liner. Let be the displacement gradient tensor of the lining layer. Let be the displacement gradient tensor of the outer liner. This is the transpose of the displacement gradient tensor corresponding to the inner lining layer. This is the transpose of the displacement gradient tensor corresponding to the outer lining layer.

[0100] Establishing a journal dynamic model includes the following steps:

[0101] According to Newton's second law, the liquid film support force, friction force, gravity, and external load are introduced into the journal's motion equation to calculate the shaft center displacement trajectory and transient dynamic response. The x-direction represents the horizontal direction within the bearing's radial section, the y-direction represents the vertical direction within the bearing's radial section, and the axial direction is the z-direction. The journal's motion equations in the x and y directions are:

[0102] ,

[0103] in, For journal mass, Let x be the acceleration of the journal center in the x-direction. Let be the acceleration of the journal center in the y direction. This represents the x-component of the external dynamic load acting on the journal. Let y be the component of the external dynamic load acting on the journal. The component of friction in the x-direction. The component of friction in the y-direction. For gravity, Let x be the component of the external load in the x-direction. Let be the component of the external load in the y-direction.

[0104] The formula for calculating the liquid film bearing capacity is: ,

[0105] The formula for calculating shear stress is: ,

[0106] The formula for calculating friction is: ,

[0107] in, This represents the x-component of the external dynamic load acting on the journal. Let L be the component of the external dynamic load acting on the journal in the y-direction, L be the axial length of the bearing, and π be pi. For liquid film pressure, For the bearing radius, These are the angular coordinates of the bearing's circumferential direction. For the bearing axial coordinate, For water film shear stress, For lubricating hydrodynamic viscosity, The sliding speed of the journal surface relative to the bearing liner. For liquid film thickness, Let x be the component of frictional force in the x-direction. Let y be the component of the frictional force in the y-direction.

[0108] Step S2: Establish a fluid-structure interaction interface transfer model. A two-way fluid-structure interaction interface is established between the liquid film domain and the inner surface of the liner. The fluid domain transfers liquid film pressure loads and wall shear stresses to the solid domain, while the solid domain feeds back interface displacement, velocity, and deformed boundary geometry information to the fluid domain. The fluid-structure interface satisfies the displacement compatibility condition, velocity continuity condition, and load balance condition.

[0109] Fluid-structure interface displacement compatibility conditions: ,

[0110] Velocity continuity condition at the fluid-structure interface: ,

[0111] Stress equilibrium conditions at the fluid-solid interface: ,

[0112] in, Let be the position vector of the fluid domain at the coupling interface. Let be the position vector of the solid domain at the coupling interface. For fluid interface velocity, For solid interface displacement, For time, For fluid-side stress tensor, Let be the unit normal vector of the coupling interface. Let be the solid side stress tensor.

[0113] Step S3 involves setting bidirectional fluid-structure interaction boundary conditions and a dynamic mesh update strategy, including the following steps:

[0114] The liquid film domain and the inner surface of the bearing are set as the main solid coupling interface, the liquid film domain and the journal surface are set as the relative motion boundary, the journal surface is set as the rotating wall surface, and its tangential velocity is determined by the rotational speed. The liquid film inlet and outlet are set as the pressure inlet and pressure outlet boundaries, respectively, and the outer surface of the outer liner is set as the fixed constraint boundary or the elastic support boundary.

[0115] To reflect the real-time feedback of the deformation of the double-layer structure on the liquid film thickness under liquid film pressure, the position of the boundary node of the fluid domain is updated according to the interface displacement obtained from the solid domain in each time step or each coupled iteration step, and the deformation correction of the liquid film domain is performed by a dynamic mesh method.

[0116] Fluid domain mesh updates satisfy: ,in, The coordinates of the fluid domain mesh nodes before the update. For the updated fluid domain mesh node coordinates, The displacement increment of the boundary node is obtained by displacement mapping of the fluid-structure interaction interface.

[0117] Preferably, dynamic mesh updates can employ spring smoothing, diffusion smoothing, local reconstruction, or combinations thereof to ensure mesh quality and solution stability in narrow-gap liquid film regions under deformation conditions.

[0118] A partitioned coupling iterative strategy is adopted to jointly solve the dynamic equations of the fluid domain, the solid domain, and the journal.

[0119] Within each time step, the liquid film pressure field and wall shear stress distribution are first solved by the fluid domain, and the pressure load and shear load are mapped to the surface of the inner liner.

[0120] Subsequently, the displacement, stress, and strain fields of the double-liner structure are solved in the solid domain, while the journal dynamic equations are used to update the axis trajectory, eccentricity, and offset angle.

[0121] The deformation of the inner liner and the journal displacement are then fed back to the fluid domain to correct the liquid film thickness distribution and boundary geometry, and the next iteration continues until each field variable meets the convergence criterion.

[0122] The preferred convergence criterion is:

[0123] ,

[0124] in, For liquid film pressure, This represents the number of coupling iteration steps. The liquid film pressure is obtained in the k-th iteration. The liquid film pressure is obtained in the (k+1)th iteration. The convergence tolerance of the liquid film pressure. The displacement vector of the liner is Let be the liner displacement vector obtained in the k-th iteration. The displacement vector of the liner obtained in the (k+1)th iteration is... This is the convergence tolerance for structural displacement. For liquid film thickness, The thickness of the liquid film obtained in the k-th iteration is... The thickness of the liquid film is obtained in the (k+1)th iteration. This is the convergence tolerance of the liquid film thickness.

[0125] To improve the stability of bidirectional coupled solutions, a relaxation factor can be introduced during the interface data transfer process.

[0126] ,in, The displacement vector of the liner is This represents the number of coupling iteration steps. As a relaxation factor, The displacement field is the iterative input to the solid solver. The displacement field is calculated by the solid solver.

[0127] Step S3 involves multi-condition performance calculations, including the following steps:

[0128] By setting different rotational speeds, eccentricities, groove parameters, and external load conditions, the maximum water film pressure, minimum water film pressure, minimum film thickness, bearing capacity, friction force, friction coefficient, axial displacement, maximum stress of inner and outer linings, and maximum deformation are calculated and compared.

[0129] Step S3 involves performing an impact load condition analysis, including the following steps:

[0130] The acceleration impact load spectrum is equivalently converted into a force impact load spectrum and applied to the journal dynamic model in the time domain. Positive triangular waves, negative triangular waves, or combined impact loads can be constructed according to standards such as BV043 / 85. Figure 8 This is a schematic diagram of the time history of impact load acceleration in an embodiment of the present invention. Figure 8 This demonstrates the equivalent loading form of external impact in the time domain; see [link / reference]. Figure 8 As shown, the horizontal axis The vertical axis represents the impact time. Indicates impact acceleration. The moment the impact began, To standardize the eigenvalues ​​of the isoacceleration spectrum in the corresponding direction in the impact spectrum, To standardize the isovelocity spectrum eigenvalues ​​in the corresponding directions of the impact spectrum, The equivalent velocity parameters used to construct the impact waveform, To standardize the eigenvalues ​​of the equidistribution spectrum in the corresponding direction in the impact spectrum. The moment when the positive impact acceleration reaches its peak. This is the moment when the positive impact acceleration decays to zero and the reverse impact phase begins. This is the moment when the reverse impact acceleration reaches its negative peak. For the moment when the reverse impact acceleration returns to zero and loading ends, see [reference needed]. Figure 8 As shown, by to A positive triangular impact pulse is formed by... to Forming a reverse triangular impact pulse, To construct the peak acceleration of the triangular wave in the positive triangular impact pulse phase of the impact acceleration time history, To construct the peak acceleration of the triangular wave in the reverse triangular impact pulse stage of the impact acceleration time history, , , The unit is , , The unit is , The unit is m.

[0131] The impact process is caused by to The positive triangular acceleration pulse and to The reverse triangular acceleration pulses are used to characterize the dynamic loading process of a shaft system or bearing under impact, where it is first subjected to positive inertial excitation and then produces a reverse springback response. The transient support behavior, shaft displacement response, and liner deformation characteristics of the bearing under X-axis and Y-axis impact conditions are analyzed. The formula for the impact waveform function is:

[0132] ,

[0133] in, The moment the impact began, To standardize the eigenvalues ​​of the isoacceleration spectrum in the corresponding direction in the impact spectrum, To standardize the isovelocity spectrum eigenvalues ​​in the corresponding directions of the impact spectrum, The equivalent velocity parameters used to construct the impact waveform, To standardize the eigenvalues ​​of the equidistribution spectrum in the corresponding direction in the impact spectrum. The moment when the positive impact acceleration reaches its peak. This is the moment when the positive impact acceleration decays to zero and the reverse impact phase begins. This is the moment when the reverse impact acceleration reaches its negative peak. The moment when the reverse impact acceleration returns to zero and loading ends, by to A positive triangular impact pulse is formed by... to Forming a reverse triangular impact pulse, To construct the peak acceleration of the triangular wave in the positive triangular impact pulse phase of the impact acceleration time history, To construct the peak acceleration of the triangular wave in the reverse triangular impact pulse stage of the impact acceleration time history.

[0134] Step S3 involves outputting results and evaluating performance, including the following steps:

[0135] The system outputs parameters such as local velocity field, eddy field, pressure recovery zone, overall pressure distribution, minimum film thickness, bearing capacity, friction coefficient, liner stress, liner displacement, axial trajectory, and peak impact response of the trench, and comprehensively evaluates the role of the trench in film formation, bearing capacity, friction reduction, and impact resistance.

[0136] Figure 9-11 For pressure distribution contour maps of bearings with different grooves, Figure 9 This is a schematic diagram of the water film pressure under the parameters of a rectangular straight groove in an embodiment of the present invention. Figure 10 This is a schematic diagram of the water film pressure under the parameters of the rectangular spiral groove in an embodiment of the present invention. Figure 11 This is a schematic diagram of the water film pressure under the U-shaped straight groove parameters in an embodiment of the present invention. This set of figures is used to illustrate the ability of this method to solve for the water film pressure, and can be used to compare the influence of different groove shapes on the bearing's water film pressure build-up capability and pressure field continuity. Figure 9-11 The shades of color indicate the magnitude of the liquid film pressure. The high-pressure zone is mainly distributed in the converging wedge-shaped area formed after the journal is eccentric. The groove area will change the local water film thickness and flow channels, causing the pressure field to be redistributed near the groove inlet, groove outlet and high-pressure bearing area.

[0137] Figure 12 This diagram shows the circumferential pressure distribution at the bearing center. It demonstrates the accuracy of this method in solving for the water film and can be used to further quantify the pressure variation patterns reflected in the water film pressure cloud map. The horizontal axis represents the circumferential position of the bearing, and the vertical axis represents the liquid film pressure at the corresponding position. This curve allows comparison of pressure peaks, pressure growth zones, pressure decay zones, and the degree of pressure fluctuation, thereby determining whether the trench is conducive to forming a stable water film, improving load-bearing capacity, and suppressing local pressure surges.

[0138] Figure 13 This diagram illustrates the vortex distribution within different groove structures, demonstrating the method's ability to solve for local vortex, backflow, and shear flow characteristics of lubricating water in groove regions. The vortex distribution reflects the influence of the groove on the liquid film flow organization, including local fluid exchange, enhanced disturbance, and water film replenishment capacity. By comparing the vortex intensity and distribution range within different grooves, the impact of the groove structure on lubricating medium transport, local pressure recovery, and water film stability can be determined.

[0139] Figure 14 This diagram shows the trajectory of the shaft center position change after impact. It characterizes the transient motion response of the journal center under impact, which this method can solve. A smaller trajectory offset indicates a stronger ability of the bearing's water film and liner structure to suppress impact disturbances; a faster trajectory recovery speed indicates better dynamic stability and impact recovery capability of the bearing system. Figure 14This method can be used to evaluate the effects of bearings under impact loads on journal vibration, eccentricity changes, and motion stability.

[0140] The key innovations of this invention include:

[0141] (1) Construct a two-way fluid-structure interaction analysis framework that simultaneously considers journal displacement, liquid film pressure field, wall shear stress and double liner deformation;

[0142] (2) A method for data transfer and dynamic mesh update at the fluid-structure interaction interface is proposed to realize the transfer of liquid film load to the solid domain, the feedback of liner displacement to the fluid domain, and the real-time update of the fluid mesh after deformation.

[0143] (3) Establish a unified performance calculation process applicable to double-lined grooved water-lubricated stern bearings, which can simultaneously analyze steady-state lubrication performance and dynamic response under impact load;

[0144] (4) Reveal the mechanism by which the groove structure alters the bearing load, friction and impact resistance performance through local secondary throttling, pressure field reconstruction and transient fluid replenishment;

[0145] (5) It enables multi-factor coupled analysis of groove parameters, operating parameters, and impact loads, which can be directly used for parameter optimization, structural design, and performance evaluation of double-liner water-lubricated stern bearings. Optional alternatives to embodiments of the present invention include:

[0146] (1) For the solid domain, linear elastic model, viscoelastic model or material model containing nonlinear constitutive relations can be used;

[0147] (2) The groove configurations include: rectangular straight groove, U-shaped straight groove, rectangular spiral groove, and can also be expanded to: trapezoidal groove, herringbone groove, composite groove, etc.

[0148] (3) In addition to standard shock waves, impact loads can also be measured ship impact data or equivalent impact load sequences.

[0149] The technical effects of the embodiments of the present invention include:

[0150] (1) The embodiments of the present invention establish a two-way fluid-structure interaction model, which realizes the two-way data transmission between liquid film pressure, journal displacement and double liner deformation. This can more realistically reflect the working state of the double-liner grooved water-lubricated stern bearing under complex working conditions. Therefore, the physical consistency and prediction accuracy of the calculation results are higher.

[0151] (2) The embodiments of the present invention can uniformly analyze the combined effects of factors such as groove shape, number of grooves, groove distribution location, rotational speed, eccentricity and impact load on bearing lubrication performance and dynamic response. Therefore, it is more suitable for engineering applications than analysis methods that only target single factors or steady-state conditions.

[0152] (3) The embodiments of the present invention can reveal the influence mechanism of the trench structure on the local secondary throttling effect, pressure field reconstruction, bearing area retention capacity and transient liquid replenishment capacity under impact conditions, thereby providing a direct basis for trench parameter optimization.

[0153] (4) The embodiments of the present invention introduce response analysis of double-layer structure, which can quantify the stress and deformation distribution law of inner and outer linings, and help with lining material selection, structural matching and impact resistance design.

[0154] (5) The embodiments of the present invention can output a variety of evaluation indicators such as maximum water film pressure, minimum film thickness, bearing capacity, friction coefficient, shaft displacement, liner stress and deformation, which can provide systematic calculation support for improving the operational reliability and extending the service life of water-lubricated stern bearings under complex working conditions.

[0155] The method of this invention embodiment is compared and analyzed with traditional overall averaging methods, unidirectional coupling methods, and conventional bidirectional fluid-structure interaction methods. The results show that, compared with existing methods, the method of this invention embodiment exhibits better consistency with high-precision benchmark results in predicting overall performance parameters such as maximum water film pressure, minimum film thickness, load-bearing capacity, and friction coefficient. This indicates that the method of this invention embodiment can more accurately reflect the actual working state of the double-liner grooved water-lubricated stern bearing under complex operating conditions.

[0156] Meanwhile, the embodiments of the present invention break through the limitations of traditional methods that mainly focus on overall performance characterization, and can further characterize the coupled influence of journal displacement and liner deformation on the local flow behavior of the trench, and output detailed results such as the local velocity field, eddy field, pressure recovery zone and transient liquid replenishment process of the water film trench region.

[0157] This invention provides a two-way fluid-structure interaction analysis method for precise analysis of the local flow field in trenches, overall lubrication performance evaluation, and dynamic response calculation under different rotational speeds, eccentricities, and impact loads. Particularly in key areas such as local pressure drop at the trench leading edge, pressure recovery at the trench trailing edge, and the evolution of the local recirculation zone, this invention provides clearer spatial distribution characteristics and variation patterns. This is more conducive to revealing the influence mechanism of the trench structure on local secondary throttling effects, pressure field reconstruction capabilities, and transient fluid replenishment behavior. The above results demonstrate that this invention has evolved from the existing analysis model that focuses on "overall performance evaluation" to a unified analysis method that considers both "local mechanism revelation" and "overall performance synergistic optimization." This provides a more reliable theoretical basis and computational support for trench parameter optimization design, double-liner structure matching, and performance prediction under complex impact conditions.

[0158] See Figure 15As shown, based on the same inventive concept, this embodiment of the invention also provides a performance evaluation system for a double-liner grooved water-lubricated stern bearing, comprising:

[0159] The three-dimensional geometric model building unit is used to: build a three-dimensional geometric model of a double-linerd grooved water-lubricated stern bearing;

[0160] Mesh generation cells are used to mesh the fluid domain and the solid domain separately.

[0161] The fluid domain hierarchical joint computation model establishment unit is used to: establish a fluid domain hierarchical joint computation model;

[0162] Solid domain computational model establishment unit, used for: establishing solid domain computational models;

[0163] Journal dynamics model establishment unit, used for: establishing journal dynamics model;

[0164] The fluid-structure interaction interface transfer model establishment unit is used to: establish a fluid-structure interaction interface transfer model.

[0165] The boundary and update settings unit is used to: set bidirectional fluid-structure interaction boundary conditions and dynamic mesh update strategies;

[0166] Multi-condition performance calculation unit, used for: performing multi-condition performance calculations;

[0167] The impact load condition analysis unit is used for: performing impact load condition analysis;

[0168] The evaluation unit is used to: output results and perform performance evaluation;

[0169] The data flow is sequentially established by the above-mentioned three-dimensional geometric model establishment unit, mesh generation unit, fluid domain layered joint calculation model establishment unit, solid domain calculation model establishment unit, journal dynamics model establishment unit, fluid-structure interaction interface transfer model establishment unit, boundary and update setting unit, multi-condition performance calculation unit, impact load condition analysis unit, and evaluation unit.

[0170] The specific functions of each unit in the performance evaluation system for the double-lined grooved water-lubricated stern bearing in this embodiment of the invention are described in detail below.

[0171] The three-dimensional geometric model building unit is used to: build a three-dimensional geometric model of a double-lined grooved water-lubricated stern bearing, wherein the three-dimensional geometric model of the double-lined grooved water-lubricated stern bearing includes at least: a journal, a liquid film region, an inner liner, and an outer liner, and the inner surface of the bearing is provided with a groove structure; the groove parameters include: groove shape, groove width, groove depth, number of grooves, and distribution position; the groove shape is a groove type with guiding and throttling functions, including: rectangular straight groove, rectangular spiral groove, U-shaped straight groove, trapezoidal groove, herringbone groove, and composite groove;

[0172] Mesh generation unit is used to: mesh the fluid domain and the solid domain separately. The fluid domain adopts a structured hexahedral mesh and combines a block method to handle the narrow gap liquid film region. The solid domain is meshed according to the material properties of the inner and outer liner layers, and the radial, circumferential and axial mesh densities are determined by mesh independence analysis.

[0173] The fluid domain hierarchical joint calculation model establishment unit is used to establish a fluid domain hierarchical joint calculation model: the fluid domain is divided into a non-groove main load-bearing region and a groove local fine solution region. In the non-groove main load-bearing region, the modified Reynolds equation based on the two-dimensional thin film assumption is used to solve the overall liquid film pressure distribution. The groove local fine solution region includes the groove body, the groove leading edge, the groove trailing edge, and the high gradient transition region adjacent to the groove. In the overall region, the Reynolds equation is used to solve the overall water film pressure distribution, film thickness distribution, and load-bearing capacity of the double-liner groove water-lubricated bearing. In the local region of the groove, the three-dimensional Navier-Stokes equation is used to solve the local flow field. The interface coupling is achieved through pressure continuity and flow continuity conditions. The mass conservation equation and momentum conservation equation are combined to form a hierarchical coupled joint calculation mode. The pressure continuity condition and the mass flow continuity condition are satisfied at the coupling interface.

[0174] The solid domain computational model building unit is used to establish the solid domain computational model: different material parameters are assigned to the inner liner, outer liner, and journal, including elastic modulus, Poisson's ratio, density, and damping parameters, to establish a displacement response model of the double-liner structure and journal, in order to solve for the stress, strain, and deformation distribution under liquid film pressure and external loads; the solid domain is solved using dynamic equilibrium equations, geometric equations, and material constitutive equations, and the material model is selected as: linear elastic model, viscoelastic model, or nonlinear constitutive model; the fluid domain and solid domain satisfy displacement compatibility and stress balance conditions at the coupling interface, and solid deformation feedback is used to update the liquid film thickness, realizing bidirectional fluid-structure interaction iterative solution;

[0175] The journal dynamic model establishment unit is used to establish the journal dynamic model: the liquid film support force, friction force, gravity and external load are introduced into the journal motion equation, the motion equations of the axis displacement trajectory and transient dynamic response in the x and y directions are calculated, and the liquid film bearing capacity, shear stress and friction force are calculated.

[0176] The fluid-structure interaction interface transfer model establishment unit is used to establish a fluid-structure interaction interface transfer model: a two-way fluid-structure interaction interface is established between the liquid film domain and the inner surface of the inner liner. The fluid domain transfers the liquid film pressure load and wall shear stress to the solid domain, and the solid domain feeds back the interface displacement, velocity and deformed boundary geometry information to the fluid domain.

[0177] The boundary and update setting unit is used to set the bidirectional fluid-structure interaction boundary conditions and dynamic mesh update strategy: the liquid film domain and the inner surface of the bearing are set as the main fluid-structure interaction interface; the liquid film domain and the journal surface are set as the relative motion boundary; the journal surface is set as a rotating wall surface, and its tangential velocity is determined by the rotational speed; the liquid film inlet and outlet are set as pressure inlet and pressure outlet boundaries, respectively; and the outer surface of the outer liner is set as a fixed constraint boundary or an elastic support boundary. In each time step or each coupling iteration step, the boundary node positions of the fluid domain are updated based on the interface displacement obtained from the solid domain. A dynamic mesh method is used to correct the deformation of the liquid film domain. The dynamic mesh update employs... The method employs spring smoothing, diffusion smoothing, local reconstruction, or combinations thereof; a partitioned coupled iterative strategy is used to jointly solve the fluid domain, solid domain, and journal dynamics equations: within each time step, the fluid domain solves for the liquid film pressure field and wall shear stress distribution, mapping the pressure load and shear load to the inner liner surface; the solid domain solves for the displacement field, stress field, and strain field of the double-liner structure, updating the axis trajectory, eccentricity, and offset angle using the journal dynamics equations; the inner liner deformation and journal displacement are fed back to the fluid domain to correct the liquid film thickness distribution and boundary geometry, proceeding to the next iteration until all field variables satisfy the convergence criterion;

[0178] The multi-condition performance calculation unit is used to perform multi-condition performance calculations: setting different rotational speeds, eccentricities, groove parameters and external load conditions, and calculating and comparing the maximum water film pressure, minimum water film pressure, minimum film thickness, bearing capacity, friction force, friction coefficient, axial displacement, maximum stress and maximum deformation of inner and outer linings;

[0179] The impact load condition analysis unit is used to perform impact load condition analysis: the acceleration impact load spectrum is equivalently converted into the force impact load spectrum, and applied to the journal dynamic model in a time domain manner to construct positive triangular wave, negative triangular wave or combined impact load, and analyze the transient support behavior, shaft displacement response and liner deformation characteristics of the bearing under X-axis impact and Y-axis impact conditions.

[0180] The evaluation unit is used for result output and performance evaluation. Output parameters include: local velocity field of the trench, eddy field, pressure recovery zone, overall pressure distribution, minimum film thickness, bearing capacity, friction coefficient, liner stress, liner displacement, axial trajectory and peak impact response. It comprehensively evaluates the role of the trench in film formation, bearing capacity, friction reduction and impact resistance.

[0181] Based on the same inventive concept, embodiments of the present invention also provide an electronic device, including: at least one processor, at least one memory, and a communication interface, wherein the processor, memory, and communication interface communicate with each other; the memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the performance evaluation method for double-liner grooved water-lubricated stern bearings in embodiments of the present invention.

[0182] Based on the same inventive concept, embodiments of the present invention also provide a non-transitory computer-readable storage medium storing computer instructions that cause a computer to execute the performance evaluation method for a double-liner grooved water-lubricated stern bearing according to embodiments of the present invention.

[0183] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for evaluating the performance of a double-liner grooved water-lubricated stern bearing, characterized in that, Includes the following steps: A three-dimensional geometric model of a double-lined grooved water-lubricated stern bearing is established. This three-dimensional geometric model includes at least: journal, liquid film region, inner liner and outer liner. The inner surface of the bearing is provided with a groove structure. The groove parameters include: groove shape, groove width, groove depth, number of grooves and distribution position. The groove shape is a groove type with guiding and throttling functions, including: rectangular straight groove, rectangular spiral groove, U-shaped straight groove, trapezoidal groove, herringbone groove and composite groove. Mesh generation is performed separately for the fluid domain and the solid domain: the fluid domain uses a structured hexahedral mesh, combined with a block method to handle narrow gap liquid film regions; the solid domain is meshed using finite element methods based on the material properties of the inner and outer lining layers, and the radial, circumferential, and axial mesh densities are determined through mesh independence analysis. Establish a hierarchical joint calculation model for the fluid domain, a calculation model for the solid domain, and a dynamic model for the journal. A fluid-structure interaction interface transfer model is established, and a two-way fluid-structure interaction interface is established between the liquid film domain and the inner surface of the inner liner. The fluid domain transfers the liquid film pressure load and wall shear stress to the solid domain, and the solid domain feeds back the interface displacement, velocity and deformed boundary geometry information to the fluid domain. Set up bidirectional fluid-structure interaction boundary conditions and dynamic mesh update strategy to perform multi-condition performance calculations, impact load condition analysis, result output and performance evaluation; The establishment of the layered joint calculation model for the fluid domain includes the following steps: dividing the fluid domain into a non-groove main load-bearing region and a groove local fine solution region. In the non-groove main load-bearing region, the modified Reynolds equation based on the two-dimensional thin film assumption is used to solve the overall liquid film pressure distribution. The groove local fine solution region includes the groove body, the groove leading edge, the groove trailing edge, and the high gradient transition region adjacent to the groove. In the overall region, the Reynolds equation is used to solve the overall liquid film pressure distribution, film thickness distribution, and load-bearing capacity of the double-liner grooved water-lubricated bearing. In the local region of the groove, the three-dimensional Navier-Stokes equation is used to solve the local flow field. Interface coupling is achieved through pressure continuity and flow continuity conditions. The mass conservation equation and momentum conservation equation are combined to form a layered coupled joint calculation mode, satisfying the pressure continuity condition and the mass flow continuity condition at the coupling interface. The solid domain computational model is established, including the following steps: Different material parameters are assigned to the inner liner, outer liner, and journal, including elastic modulus, Poisson's ratio, density, and damping parameters. A displacement response model of the double-liner structure and journal is established to solve for the stress, strain, and deformation distribution under liquid film pressure and external loads. The solid domain is solved using dynamic equilibrium equations, geometric equations, and material constitutive equations. The material model selected is either a linear elastic model, a viscoelastic model, or a nonlinear constitutive model. The fluid domain and solid domain satisfy displacement compatibility and stress equilibrium conditions at the coupling interface. Solid deformation feedback is used to update the liquid film thickness, achieving a two-way fluid-structure interaction iterative solution. Establishing a journal dynamic model includes the following steps: incorporating liquid film support force, friction force, gravity, and external load into the journal motion equations; calculating the motion equations of the shaft center displacement trajectory and transient dynamic response in the X and Y directions; and calculating the bearing capacity, shear stress, and friction force. The setting of bidirectional fluid-structure interaction boundary conditions and dynamic mesh update strategy includes the following steps: The liquid film domain and the inner surface of the bearing are set as the main solid-mainstream coupling interface, the liquid film domain and the journal surface are set as the relative motion boundary, the journal surface is set as the rotating wall surface, and its tangential velocity is determined by the rotational speed. The liquid film inlet and outlet are set as the pressure inlet and pressure outlet boundaries, respectively, and the outer surface of the outer liner is set as the fixed constraint boundary or the elastic support boundary. In each time step or each coupling iteration step, the position of the boundary node of the fluid domain is updated according to the interface displacement obtained from the solid domain. The deformation correction of the liquid film domain is performed using a dynamic mesh method. The dynamic mesh update adopts the spring smoothing method, the diffusion smoothing method, the local reconstruction method, or a combination thereof. A partitioned coupled iterative strategy is adopted to jointly solve the fluid domain, solid domain, and journal dynamic equations: In each time step, the fluid domain solves the liquid film pressure field and wall shear stress distribution, mapping the pressure load and shear load to the inner liner surface; the solid domain solves the displacement field, stress field, and strain field of the double-liner structure, and the journal dynamic equations update the axis trajectory, eccentricity, and offset angle; the deformation of the inner liner and the journal displacement are fed back to the fluid domain to correct the liquid film thickness distribution and boundary geometry, and the next iteration is performed until all field variables meet the convergence criteria.

2. The method of performance evaluation of a double-liner grooved water lubricated stern bearing according to claim 1, characterized in that: The process of performing multi-condition performance calculations, impact load condition analysis, result output, and performance evaluation includes the following steps: Multi-condition performance calculations: Set different rotational speeds, eccentricities, groove parameters, and external load conditions to calculate and compare the maximum liquid film pressure, minimum liquid film pressure, minimum film thickness, bearing capacity, friction force, friction coefficient, axial displacement, maximum stress of inner and outer linings, and maximum deformation. Impact load analysis: The acceleration impact load spectrum is equivalently converted into the force impact load spectrum and applied to the journal dynamic model in the time domain. Positive triangular wave, negative triangular wave or combined impact load are constructed to analyze the transient support behavior, shaft displacement response and liner deformation characteristics of the bearing under X-axis impact and Y-axis impact conditions. The system outputs results and evaluates performance. Output parameters include: local velocity field, eddy field, pressure recovery zone, overall pressure distribution, minimum film thickness, bearing capacity, friction coefficient, liner stress, liner displacement, axial trajectory, and peak impact response. The system comprehensively evaluates the role of the trench in film formation, bearing capacity, friction reduction, and impact resistance.

3. A performance evaluation system for a double-liner grooved water-lubricated stern bearing, characterized in that, include: The three-dimensional geometric model building unit is used to: build a three-dimensional geometric model of a double-linerd grooved water-lubricated stern bearing; Mesh generation cells are used to mesh the fluid domain and the solid domain separately. The fluid domain hierarchical joint computation model establishment unit is used to: establish a fluid domain hierarchical joint computation model; Solid domain computational model establishment unit, used for: establishing solid domain computational models; Journal dynamics model establishment unit, used for: establishing journal dynamics model; The fluid-structure interaction interface transfer model establishment unit is used to: establish a fluid-structure interaction interface transfer model. The boundary and update settings unit is used to: set bidirectional fluid-structure interaction boundary conditions and dynamic mesh update strategies; Multi-condition performance calculation unit, used for: performing multi-condition performance calculations; The impact load condition analysis unit is used for: performing impact load condition analysis; The evaluation unit is used to: output results and perform performance evaluation; The three-dimensional geometric model establishment unit, mesh generation unit, fluid domain hierarchical joint calculation model establishment unit, solid domain calculation model establishment unit, journal dynamics model establishment unit, fluid-structure interaction interface transfer model establishment unit, boundary and update setting unit, multi-condition performance calculation unit, impact load condition analysis unit, and evaluation unit sequentially establish the data flow connection; The three-dimensional geometric model building unit is used to: build a three-dimensional geometric model of a double-lined grooved water-lubricated stern bearing, wherein the three-dimensional geometric model of the double-lined grooved water-lubricated stern bearing includes at least: a journal, a liquid film region, an inner liner, and an outer liner, and the inner surface of the bearing is provided with a groove structure; the groove parameters include: groove shape, groove width, groove depth, number of grooves, and distribution position; the groove shape is a groove type with guiding and throttling functions, including: rectangular straight groove, rectangular spiral groove, U-shaped straight groove, trapezoidal groove, herringbone groove, and composite groove; The meshing unit is used to: mesh the fluid domain and the solid domain respectively. The fluid domain adopts a structured hexahedral mesh and combines a block method to handle the narrow gap liquid film region. The solid domain is meshed according to the material properties of the inner and outer liner layers, and the radial, circumferential and axial mesh densities are determined by mesh independence analysis. The fluid domain hierarchical joint calculation model establishment unit is used to establish a fluid domain hierarchical joint calculation model: the fluid domain is divided into a non-groove main load-bearing region and a groove local fine solution region. In the non-groove main load-bearing region, the modified Reynolds equation based on the two-dimensional thin film assumption is used to solve the overall liquid film pressure distribution. The groove local fine solution region includes the groove body, the groove leading edge, the groove trailing edge, and the high gradient transition region adjacent to the groove. The Reynolds equation is used in the overall region to solve the overall liquid film pressure distribution, film thickness distribution, and load-bearing capacity of the double-liner grooved water-lubricated bearing. In the local region of the groove, the three-dimensional Navier-Stokes equation is used to solve the local flow field. The interface coupling is achieved through pressure continuity and flow continuity conditions. The mass conservation equation and momentum conservation equation are combined to form a hierarchical coupled joint calculation mode. The pressure continuity condition and the mass flow continuity condition are satisfied at the coupling interface. The solid domain computational model building unit is used to establish a solid domain computational model: different material parameters are assigned to the inner liner, outer liner, and journal, including elastic modulus, Poisson's ratio, density, and damping parameters, to establish a displacement response model of the double-liner structure and journal, in order to solve for the stress, strain, and deformation distribution under liquid film pressure and external load; the solid domain is solved using dynamic equilibrium equations, geometric equations, and material constitutive equations, and the material model is selected as: linear elastic model, viscoelastic model, or nonlinear constitutive model; the fluid domain and solid domain satisfy displacement compatibility and stress balance conditions at the coupling interface, and solid deformation feedback is used to update the liquid film thickness, realizing bidirectional fluid-structure interaction iterative solution; The journal dynamic model establishment unit is used to establish the journal dynamic model: the liquid film support force, friction force, gravity and external load are introduced into the journal motion equation, the motion equation of the axis displacement trajectory and transient dynamic response in the X and Y directions is calculated, and the bearing capacity, shear stress and friction force are calculated. The fluid-structure interaction interface transfer model establishment unit is used to establish a fluid-structure interaction interface transfer model: a two-way fluid-structure interaction interface is established between the liquid film domain and the inner surface of the inner liner. The fluid domain transfers the liquid film pressure load and wall shear stress to the solid domain, and the solid domain feeds back the interface displacement, velocity and deformed boundary geometry information to the fluid domain. The boundary and update setting unit is used to set the bidirectional fluid-structure interaction boundary conditions and dynamic mesh update strategy: the liquid film domain and the inner surface of the bearing are set as the main fluid-structure interaction interface; the liquid film domain and the journal surface are set as the relative motion boundary; the journal surface is set as a rotating wall surface, and its tangential velocity is determined by the rotational speed; the liquid film inlet and outlet are set as pressure inlet and pressure outlet boundaries, respectively; and the outer surface of the outer liner is set as a fixed constraint boundary or an elastic support boundary. In each time step or each coupling iteration step, the boundary node positions of the fluid domain are updated according to the interface displacement obtained from the solid domain, and the deformation correction of the liquid film domain is performed using a dynamic mesh method. The dynamic mesh update adopts... The spring smoothing method, diffusion smoothing method, local reconstruction method, or a combination thereof are used. A partitioned coupling iteration strategy is adopted to jointly solve the fluid domain, solid domain, and journal dynamic equations: In each time step, the liquid film pressure field and wall shear stress distribution are solved by the fluid domain, and the pressure load and shear load are mapped to the surface of the inner liner; the displacement field, stress field, and strain field of the double-liner structure are solved by the solid domain, and the journal dynamic equations are used to update the axis trajectory, eccentricity, and offset angle; the deformation of the inner liner and the journal displacement are fed back to the fluid domain to correct the liquid film thickness distribution and boundary geometry, and the next iteration is performed until all field variables meet the convergence criteria.

4. The performance evaluation system for a double-liner grooved water-lubricated stern bearing as described in claim 3, characterized in that: The multi-condition performance calculation unit is used to perform multi-condition performance calculations: setting different rotational speeds, eccentricities, groove parameters and external load conditions, and calculating and comparing the maximum liquid film pressure, minimum liquid film pressure, minimum film thickness, bearing capacity, friction force, friction coefficient, axial displacement, maximum stress and maximum deformation of inner and outer linings; The impact load condition analysis unit is used to perform impact load condition analysis: the acceleration impact load spectrum is equivalently converted into the force impact load spectrum, and applied to the journal dynamic model in a time domain manner to construct positive triangular wave, negative triangular wave or combined impact load, and analyze the transient support behavior, shaft displacement response and liner deformation characteristics of the bearing under X-axis impact and Y-axis impact conditions. The evaluation unit is used to output results and evaluate performance. The output parameters include: local velocity field of the trench, eddy field, pressure recovery zone, overall pressure distribution, minimum film thickness, bearing capacity, friction coefficient, liner stress, liner displacement, axial trajectory and peak impact response. The evaluation comprehensively assesses the role of the trench in film formation, bearing capacity, friction reduction and impact resistance.

5. An electronic device, characterized in that, include: The system includes at least one processor, at least one memory, and a communication interface, wherein the processor, memory, and communication interface communicate with each other. The memory stores program instructions that can be executed by a processor; the processor invokes the program instructions to execute the performance evaluation method for the double-liner grooved water-lubricated stern bearing as described in claim 1 or 2.

6. A non-transitory computer-readable storage medium, characterized in that: The non-transitory computer-readable storage medium stores computer instructions; the computer instructions cause the computer to execute the performance evaluation method for the double-lined grooved water-lubricated stern bearing as described in claim 1 or 2.

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