A Multi-Field Coupled Simulation Method for Electrolytic Machining of Integral Bladed Disk Bushings

Abstract

This invention discloses a multi-field coupled simulation method for electrolytic machining of integral bladed disks (IBDs), relating to the field of electrolytic machining technology. First, based on design requirements, the cathode geometry for the IBD electrolytic machining simulation is designed. The flow channels in the IBD cathode geometry are simplified to obtain the geometric model required for the simulation study, and the material type is selected. Then, a multi-field coupled simulation model is established based on the physical fields and machining process involved in the IBD electrolytic machining. Finally, simulation is performed based on the multi-field coupled simulation model, and the simulation results are obtained. By introducing the rotation and feeding process of the IBD cathode, the changes in the electric and flow field states during electrolytic machining can be reflected more accurately, improving the consistency between the simulation results and the actual machining results. This allows for the early detection of potential problems during machining, mitigation of machining risks, reduction of experimental costs, and improvement of production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of electrolytic machining technology, and in particular relates to a multi-field coupling simulation method for electrolytic machining of integral bladed disk sleeves. Background Technology

[0002] Integral bladed disks (IBDs) are a typical integral structural component in advanced aero-engine design, significantly improving engine efficiency, thrust-to-weight ratio, and reliability. Two common machining methods for IBDs are electrolytic machining and CNC milling. Compared to CNC milling, electrolytic machining offers advantages such as higher efficiency (reducing machining time by over 50%), no electrode (tool) wear, and no residual stress or deformation in thin-walled structures. Therefore, electrolytic machining of IBDs is widely used in actual production.

[0003] The electrochemical machining process for integral bladed disks (IBDs) is highly complex, involving multiple physical fields such as electric field, flow field, and temperature field, as well as rotational and feeding motions. These physical fields and motions all influence the conductivity and flow distribution of the electrolyte, making it difficult to predict the machining profile. Currently, optimization of IBD electrochemical machining relies primarily on experience, adjusting the cathode structure and machining parameters based on experimental results. However, the machining results are highly dependent on the electric field distribution and flow field conditions during the machining process. Relying solely on experience and experimental results cannot provide a comprehensive understanding of the specific machining conditions, thus significantly limiting the optimization of IBD machining. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a multi-field coupled simulation method for electrolytic machining of integral bladed disks. By analyzing the simulation results, the changes in the electric and flow fields of the integral bladed disk during electrolytic machining can be understood, enabling more precise optimization and adjustment of machining parameters and cathode profiles. This effectively shortens the experimental iteration cycle of electrolytic machining of integral bladed disks and reduces the cost of experimental optimization and improvement.

[0005] A multi-field coupled simulation method for electrolytic machining of integral bladed disk sleeves includes the following steps:

[0006] Step 1: According to the design requirements, design the cathode geometry for the simulation of the integral bladed disk electrolytic machining, simplify the flow channels in the integral bladed disk cathode geometry to obtain the geometric model required for the simulation study and select the material type; the simplification specifically means: removing the electrolyte collection cavity and retaining only the flow channel structure of the guide area and the main machining area;

[0007] Step 2: Establish a multi-field coupled simulation model based on the physical fields and processing procedures involved in the electrolytic machining of the integral bladed disk; the multi-field coupled simulation model includes an electric field model, a flow field model, a temperature field model, and a motion model;

[0008] Step 2.1: Establish an electric field model and set the relevant parameters of the electric field model in the software; the parameters include electrolyte conductivity, equilibrium potential of the cathode surface, exchange current density of the cathode surface, equilibrium potential of the anode surface, and exchange current density of the anode.

[0009] The electric field model is as follows:

[0010]

[0011]

[0012] In the formula, σ is the electrolyte conductivity. The electrolyte potential gradient; is the Laplace operator; i is the current density.

[0013] The conductivity of the electrolyte is:

[0014]

[0015] Where σ0 is the initial conductivity; β is the bubble rate; α is the conductivity temperature coefficient; m is the influence index of the bubble rate on conductivity; T0 is the initial temperature; and T is the electrolyte temperature.

[0016] Step 2.2: Establish the flow field model. Set the relevant parameters of the flow field model in the software. The relevant parameters include bubble diameter, cathode surface gas flux, inlet boundary condition parameters, and outlet boundary condition parameters. The inlet boundary condition parameter is the electrolyte flow rate. The outlet boundary condition parameter is the outlet electrolyte pressure.

[0017] The flow field model is as follows:

[0018]

[0019]

[0020]

[0021]

[0022] Where ρ is the electrolyte density; u l ε is the electrolyte flow rate; k is the turbulent dissipation rate; μ is the turbulent kinetic energy. l The dynamic viscosity of the electrolyte; μ T ρ is the turbulent viscosity. K For the generation of turbulent kinetic energy; σ k , σ ε C is the Prandtl number; μ C ε1 Cε2 These are empirical constants;

[0023] Step 2.3: Establish a temperature field model and set the relevant parameters of the temperature field model in the software; the relevant parameters include electrolyte density, inflow boundary condition parameters, outflow boundary condition parameters, and heat flux boundary condition parameters; the inflow boundary condition parameters are the inflow locations of the electrolyte; the outflow boundary condition parameters are the outflow locations of the electrolyte;

[0024] The temperature field model is as follows:

[0025]

[0026]

[0027] in, The electrolyte potential gradient; C p For constant-pressure heat capacity of electrolyte; u l Electrolyte flow rate; γ is the rate of change of temperature over time; Q is the thermal conductivity of the electrolyte; and Q is the Joule heat. For temperature gradient.

[0028] Step 2.4: Establish the motion model and set the anode material removal process function and the cathode rotation feed process function in the software, and set the boundary conditions of the coefficient form boundary partial differential equation;

[0029] The motion model is as follows:

[0030] V = Cit (11)

[0031] Where V is the volume of anode metal dissolved; i is the current density; t is the processing time; and C is the volumetric electrochemical equivalent.

[0032] x=tcos(θ)-f(t)sin(θ) (12)

[0033] y=tsin(θ)+f(t)cos(θ) (13)

[0034] z = vt (14)

[0035] Where x is the displacement of the cathode along the x-axis; y is the displacement of the cathode along the y-axis; z is the displacement of the cathode along the z-axis; t is the processing time; and θ is the rotation angle of the cathode.

[0036] The anode material removal process function is:

[0037] v a =ηCi n (15)

[0038] Among them, va η is the anodic dissolution rate; η is the current efficiency; i n This represents the normal current density.

[0039] The function for the rotary feed process of the cathode is:

[0040] dx=(-1+cosωt)*Xg-sin(ωt)*Yg (16)

[0041] dy=sinωt*Xg+(-1+cosωt)*Yg (17)

[0042] dz=v*t (18)

[0043] In the formula, dx is the X-axis component of the rotary feed motion; dy is the Y-axis component of the rotary feed motion; dz is the Z-axis component of the rotary feed motion; ω is the angular velocity of the cathode; t is the motion time, which should be the same variable as the previous processing time in the multi-field coupling model; v is the Z-axis feed speed; Xg and Yg are the X-axis and Y-axis coordinates, respectively.

[0044] Step 3: Perform simulation based on the multi-field coupling simulation model and obtain simulation results;

[0045] Step 3.1: Mesh the geometric model established in Step 1 to obtain the meshed geometric model;

[0046] Step 3.2: Select the solver type and use the multi-field coupled simulation model to simulate the meshed geometric model to obtain simulation results;

[0047] Step 3.3: Determine whether the ratio of the current density in the simulation result to the actual current density in the field is less than the set threshold. If it is less, return to step 2; otherwise, output the simulation result.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] The present invention discloses a multi-field coupled simulation method for electrolytic machining of integral bladed disks. Its features and advantages lie in the introduction of the rotation and feeding process of the integral bladed disk cathode, which can more accurately reflect the changes in the electric field and flow field state during electrolytic machining, improve the consistency between simulation results and actual machining results, detect potential problems in advance, avoid machining risks, reduce test costs, and improve production efficiency. Attached Figure Description

[0050] Figure 1 This is a flowchart of a multi-field coupling simulation method for electrolytic machining of integral bladed disk sleeves according to an embodiment of the present invention;

[0051] Figure 2This is a geometric model diagram of the cathode processed by electrolytic machining of integral bladed disk sleeve in an embodiment of the present invention;

[0052] Figure 3 This is a schematic diagram of the boundary condition loading in the multi-field coupling simulation of the integral bladed disk sleeve electrolysis in an embodiment of the present invention. Detailed Implementation

[0053] The following detailed description is provided in conjunction with the accompanying drawings and embodiments.

[0054] A multi-field coupled simulation method for electrolytic machining of integral bladed disk sleeves, such as Figure 1 As shown, it includes the following steps:

[0055] Step 1: According to the design requirements, design the cathode geometry for the simulation of the integral bladed disk electrolytic machining, simplify the flow channels in the integral bladed disk cathode geometry to obtain the geometric model required for the simulation study and select the material type; the simplification specifically means: removing the electrolyte collection cavity and retaining only the flow channel structure of the guide area and the main machining area;

[0056] In this embodiment, based on design requirements, the commonly used cathode design method (cosθ method) in electrolytic machining is adopted. The cathode geometry for the overall bladed disk electrolytic machining simulation is constructed using UG software. To reduce the computational load of the simulation model, the flow channel of the overall bladed disk cathode is simplified by removing the electrolyte collection chamber and retaining only the flow channel structures of the guiding area and the main machining area. It is assumed that the actual electrolyte flow rate at the inlet is consistent with the simplified inlet flow rate, thus obtaining the geometric model required for the simulation study. Figure 2 As shown.

[0057] Step 2: Establish a multi-field coupled simulation model based on the physical fields and processing procedures involved in the electrolytic machining of the integral bladed disk; the multi-field coupled simulation model includes an electric field model, a flow field model, a temperature field model, and a motion model;

[0058] A multi-field coupled simulation model was established using COMSOL Multiphysics software. The model involves various physical and chemical processes such as electrolyte flow, anode dissolution, and cathode movement. The model mainly combines the actual situation to establish a coupled model of multiple physical fields, including electric field, flow field, temperature field, and deformation geometry. At the same time, the boundary conditions and related parameters that need to be applied to each physical field are clarified in combination with the actual processing process of the integral bladed disk sleeve electrolysis. Figure 3 This reflects the boundary condition loading and cathode movement during the electrolytic machining of the integral bladed disk sleeve.

[0059] Step 2.1: Establish an electric field model and set the relevant parameters of the electric field model in the software; the parameters include electrolyte conductivity, equilibrium potential of the cathode surface, exchange current density of the cathode surface, equilibrium potential of the anode surface, and exchange current density of the anode.

[0060] When establishing the electric field model, select the "Secondary Current Distribution" module in the software. Considering the effects of temperature field and bubble flow, the conductivity formula of the electrolyte in the model should be adjusted to formula (3). At the same time, the equilibrium potential and exchange current density of the anode and cathode surfaces should be set according to the electrochemical dissolution characteristics of the material. In this model, the anode equilibrium potential is set to -0.4V, the cathode equilibrium potential is set to -0.3V, and the exchange current density of both the anode and cathode is 1000A / m. 2 .

[0061] In electrolytic machining, assuming that the ion concentration in the electrolyte is uniformly distributed and does not change with time, and that both the cathode and anode surfaces are potential surfaces, the potential distribution within the machining gap, i.e., the electric field model, satisfies the following:

[0062]

[0063]

[0064] In the formula, σ is the electrolyte conductivity. The electrolyte potential gradient; is the Laplace operator; i is the current density.

[0065] The conductivity of the electrolyte is affected by temperature and air bubbles, and the relationship can be expressed as:

[0066] σ=σ0(1-β) m [1+α(T-T0)] (3)

[0067] Where σ0 is the initial conductivity; β is the bubble rate; α is the conductivity temperature coefficient; m is the influence index of the bubble rate on conductivity; T0 is the initial temperature; and T is the electrolyte temperature.

[0068] Step 2.2: Establish the flow field model. Set the relevant parameters of the flow field model in the software. The relevant parameters include bubble diameter, cathode surface gas flux, inlet boundary condition parameters, and outlet boundary condition parameters. The inlet boundary condition parameter is the electrolyte flow rate. The outlet boundary condition parameter is the outlet electrolyte pressure.

[0069] In the electrolytic machining of integral bladed disk (IB) bushings, the electrolyte flow velocity is 15 m / s. Based on the Reynolds number calculation formula, Re > 2000, indicating a turbulent flow state. When establishing the flow field model, the "bubble flow, k-ω" module is selected in the software. The bubble diameter is set according to the geometry of the IIB bushing cathode; in this model, the bubble diameter is set to 1 × 10⁻⁶. -8 m. Simultaneously set the gas flux on the cathode surface and the boundary conditions at the inlet / outlet.

[0070] For ease of calculation, the three-phase flow of gas, liquid, and solid in actual electrolytic processing is simplified to a two-phase flow of gas and liquid. The fluid state satisfies the laws of conservation of mass and momentum, i.e., the flow field model is:

[0071]

[0072]

[0073]

[0074]

[0075] Where ρ is the electrolyte density; u l ε is the electrolyte flow rate; k is the turbulent dissipation rate; μ is the turbulent kinetic energy. l The dynamic viscosity of the electrolyte; μ T ρ is the turbulent viscosity. K For the generation of turbulent kinetic energy; σ k , σ ε C is the Prandtl number; μ C ε1 C ε2 These are empirical constants;

[0076] In this embodiment, C μ C ε1 C ε2 σ k σ ε The values ​​are 0.09, 1.44, 1.93, 1.0, and 1.3, respectively.

[0077] Hydrogen gas is generated on the cathode surface during electrolytic machining. The amount of hydrogen gas generated per unit time and per unit area is:

[0078]

[0079] in, The amount of hydrogen produced per unit time and per unit area is F, which is the Faraday constant with a value of 96485.3365 [C / mol].

[0080] Step 2.3: Establish a temperature field model and set the relevant parameters of the temperature field model in the software; the relevant parameters include electrolyte density, inflow boundary condition parameters, outflow boundary condition parameters, and heat flux boundary condition parameters; the inflow boundary condition parameters are the inflow locations of the electrolyte; the outflow boundary condition parameters are the outflow locations of the electrolyte;

[0081] To establish a temperature field model, the "Fluid Heat Transfer" module should be selected in the software. The function of electrolyte density needs to take into account the effects of bubbles and temperature.

[0082] In the temperature field, considering the influence of Joule heating generated by the current on the processing, according to the law of conservation of energy and Joule's law of heat, the governing equations of the temperature field model are:

[0083]

[0084]

[0085] in, The electrolyte potential gradient; C p For constant-pressure heat capacity of electrolyte; u l Electrolyte flow rate; γ is the rate of change of temperature over time; Q is the thermal conductivity of the electrolyte; and Q is the Joule heat. For temperature gradient.

[0086] Step 2.4: Establish the motion model and set the anode material removal process function and the cathode rotation feed process function in the software, and set the boundary conditions of the coefficient form boundary partial differential equation;

[0087] There are two types of motion in the electrolytic machining process of integral bladed disk sleeve: one is the motion caused by the dissolution of anode metal, and the other is the rotational feeding motion of the sleeve cathode.

[0088] The anodic metal dissolution process obeys Faraday's first law. In actual modeling, by introducing the volumetric electrochemical equivalent, Faraday's first law can be transformed into:

[0089] V = Cit (11)

[0090] Where V is the volume of anode metal dissolved; i is the current density; t is the processing time; and C is the volumetric electrochemical equivalent.

[0091] In the electrolytic machining of integral bladed disk sleeves, the sleeve cathode needs to undergo simultaneous rotation and feed motions, and the functional relationship satisfies:

[0092] x=tcos(θ)-f(t)sin(θ) (12)

[0093] y=tsin(θ)+f(t)cos(θ) (13)

[0094] z = vt (14)

[0095] Where x is the displacement of the cathode along the x-axis; y is the displacement of the cathode along the y-axis; z is the displacement of the cathode along the z-axis; t is the processing time; and θ is the rotation angle of the cathode.

[0096] In the software, select the "Deformation Geometry" module. For the removal deformation of anode materials, the removal rate is generally expressed by the current efficiency, as shown in formula (15). In the actual processing, the anode is also accompanied by side reactions such as metal peeling and oxygen evolution. Therefore, the actual amount of anode metal dissolved deviates from the theoretical calculation value. Therefore, the anode material removal process function is set as follows:

[0097] v a =ηCi n (15)

[0098] Among them, v a η is the anodic dissolution rate; η is the current efficiency; i n This represents the normal current density.

[0099] During the rotary feed of the cathode, according to the formulas (16)-(18) for the rotary motion function and the feed motion function, the rotary feed function is set as follows:

[0100] dx=(-1+cosωt)*Xg-sin(ωt)*Yg (16)

[0101] dy=sinωt*Xg+(-1+cosωt)*Yg (17)

[0102] dz=v*t (18)

[0103] In the formula, dx is the X-axis component of the rotary feed motion; dy is the Y-axis component of the rotary feed motion; dz is the Z-axis component of the rotary feed motion; ω is the angular velocity of the cathode; t is the motion time (in the multi-field coupling model, it should be the same variable as the previous processing time); v is the Z-axis feed speed; Xg and Yg are the X-axis and Y-axis coordinates, respectively.

[0104] In the actual machining process, the Z-axis feed linear velocity is known to be v = 1 mm / min, the radial feed distance after machining is dz = 4 mm, and the cathode rotation angle is θ = 0.6°. From this, the machining time for the blanking electrolytic process can be derived, and thus the cathode rotation angular velocity can be obtained.

[0105] Step 3: Based on the multi-field coupling simulation model, perform simulation and obtain simulation results;

[0106] Step 3.1: Mesh the geometric model established in Step 1 to obtain the meshed geometric model;

[0107] After setting the physical boundary conditions, the geometric model should be meshed. Due to the complexity of the geometric model, to reduce the number of mesh cells and improve mesh accuracy, "User Control Mesh" should be selected, the calibration should be set to "Fluid Dynamics," and the boundary layer should be meshed separately.

[0108] Step 3.2: Select the solver type and use the multi-field coupled simulation model to simulate the meshed geometric model to obtain simulation results;

[0109] The solver type is generally set to the default setting, and the tolerance and time step can be appropriately reduced to improve the convergence of the model.

[0110] Step 3.3: Determine whether the ratio of the current density in the simulation result to the actual current density in the field is less than the set threshold. If it is less, return to step 2; otherwise, output the simulation result.

[0111] Based on the above process, a model is established and calculations are performed. The model confidence level can be determined by referring to the current density. The calculation results are compared and analyzed with the on-site processing results. If the ratio is less than 0.7, the modeling process needs to be returned to above, and the boundary condition settings need to be modified appropriately. If it is greater than 0.7, the calculation results can be output. In this scheme, the current density value obtained after model calculation is approximately 124 A / m. 2 The average current density in actual processing is 148 A / m. 2 The ratio of the calculated value to the actual value is approximately 0.84, which indicates that the model has a certain degree of accuracy.

[0112] This modeling method fully considers the physical fields and chemical phenomena involved in the electrolytic machining of integral bladed disks, providing an accurate modeling method for subsequent multi-field coupling simulation studies.

Claims

1. A multi-field coupled simulation method for electrolytic machining of integral bladed disk sleeves, characterized in that, Includes the following steps: Step 1: According to the design requirements, design the cathode geometry for the simulation of the integral bladed disk electrolytic machining, simplify the flow channels in the integral bladed disk cathode geometry to obtain the geometric model required for the simulation study and select the material type; the simplification specifically means: removing the electrolyte collection cavity and retaining only the flow channel structure of the guide area and the main machining area; Step 2: Establish a multi-field coupled simulation model based on the physical fields and processing procedures involved in the electrolytic machining of the integral bladed disk; the multi-field coupled simulation model includes an electric field model, a flow field model, a temperature field model, and a motion model; Step 3: Perform simulation based on the multi-field coupling simulation model and obtain simulation results; Step 2 specifically includes: Step 2.1: Establish an electric field model and set the relevant parameters of the electric field model in the software; the parameters include electrolyte conductivity, equilibrium potential of the cathode surface, exchange current density of the cathode surface, equilibrium potential of the anode surface, and exchange current density of the anode. The electric field model is as follows: （1） （2） In the formula, The electrolyte conductivity, The electrolyte potential gradient; Here, i is the Laplace operator; i is the current density. The conductivity of the electrolyte is: （3） in, The initial conductivity; Bubble rate; The temperature coefficient of electrical conductivity; m This is an index representing the influence of bubble rate on conductivity. The initial temperature; T The electrolyte temperature; Step 2.2: Establish the flow field model. Set the relevant parameters of the flow field model in the software. The relevant parameters include bubble diameter, cathode surface gas flux, inlet boundary condition parameters, and outlet boundary condition parameters. The inlet boundary condition parameter is the electrolyte flow rate. The outlet boundary condition parameter is the outlet electrolyte pressure. The flow field model is as follows: （4） （5） （6） （7） in, The electrolyte density; Electrolyte flow rate; ε The turbulent dissipation rate; It is turbulent kinetic energy; This refers to the dynamic viscosity of the electrolyte. For turbulent viscosity; This is the term for the generation of turbulent kinetic energy; , It is the Prandtl number; , , These are empirical constants; Step 2.3: Establish a temperature field model and set the relevant parameters of the temperature field model in the software; the relevant parameters include electrolyte density, inflow boundary condition parameters, outflow boundary condition parameters, and heat flux boundary condition parameters; the inflow boundary condition parameters are the inflow locations of the electrolyte; the outflow boundary condition parameters are the outflow locations of the electrolyte; The temperature field model is as follows: （9） （10） in, The electrolyte potential gradient; The constant pressure heat capacity of the electrolyte; Electrolyte flow rate; The rate of change of temperature over time; The thermal conductivity of the electrolyte; It is Joule fever; For temperature gradient; Step 2.4: Establish the motion model and set the anode material removal process function and the cathode rotation feed process function in the software, and set the boundary conditions of the coefficient form boundary partial differential equation; The motion model is as follows: （11） in, This represents the volume of anolyte metal dissolved. Current density; Processing time; It is the volumetric electrochemical equivalent; （12） （13） （14） Where x is the displacement of the cathode along the x-axis; y is the displacement of the cathode along the y-axis; and z is the displacement of the cathode along the z-axis. t Processing time; This refers to the rotation angle of the cathode sleeve. The anode material removal process function is: （15） in, This refers to the anodic dissolution rate. For current efficiency; The normal current density; The function for the rotary feed process of the cathode is: （16） （17） （18） In the formula, dx The X-axis component of the rotary feed motion; dy The Y-axis component of the rotary feed motion; dz The Z-axis component of the rotary feed motion; ω The angular velocity of the cathode is the material being packaged. t For motion time, in a multi-field coupled model, it should be the same variable as the previous processing time; v Z-axis feed rate; These are the X-axis and Y-axis coordinates, respectively.

2. The multi-field coupled simulation method for electrolytic machining of integral bladed disk sleeves according to claim 1, characterized in that, Step 3 specifically includes: Step 3.1: Mesh the geometric model established in Step 1 to obtain the meshed geometric model; Step 3.2: Select the solver type and use the multi-field coupled simulation model to simulate the meshed geometric model to obtain simulation results; Step 3.3: Determine whether the ratio of the current density in the simulation result to the actual current density in the field is less than the set threshold. If it is less than the threshold, return to step 2; otherwise, output the simulation result.

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