CN-122021128-A - Silicon rubber insulator laser cleaning parameter optimization method based on multi-physical field simulation

CN122021128ACN 122021128 ACN122021128 ACN 122021128ACN-122021128-A

Abstract

The invention relates to a silicon rubber insulator laser cleaning parameter optimization method based on multi-physical field simulation, which comprises the following steps of 1, establishing a multi-physical field coupling finite element model for cleaning an aging layer on the surface of silicon rubber by pulse laser, 2, calculating a temperature field evolution curve and a thermal stress field evolution curve of a key region of the aging layer under different laser power parameters based on the multi-physical field coupling finite element model established in the step 1, and 3, analyzing a synergistic relationship between vibration and an ablation mechanism based on the temperature field and the thermal stress field evolution curve of the key region of the aging layer under different laser power obtained in the step 2, so as to obtain the temperature and thermal stress time-space distribution characteristics of the aging layer under the action of the pulse laser, and screening out a power interval which can realize preliminary stripping of the aging layer through thermal stress, can realize thorough removal through thermal decomposition and can not cause matrix damage due to overhigh energy. The invention can accurately simulate the evolution of the transient temperature field and the thermal stress field, quantitatively analyze the space-time synergistic effect of vibration and an ablation mechanism, thereby predefining a safe and efficient process parameter window and providing scientific guidance for actual cleaning production.

Inventors

GAO YANFENG
ZHANG XU
LIU MIN
CHEN YUAN
ZHAO YUAN
GAO JING
HUA XUEJIAO
LIU YICHEN
LU YI
HUANG XIAOLONG
WANG KANG
ZHAO YAN
SU BIN
YU JINGZHE
YANG XIAOXUAN

Assignees

国网冀北电力有限公司电力科学研究院

Dates

Publication Date: 20260512
Application Date: 20251231

Claims (7)

1. A method for optimizing laser cleaning parameters of a silicon rubber insulator based on multi-physical field simulation is characterized by comprising the following steps: step 1, establishing a multi-physical field coupling finite element model for cleaning an aging layer on the surface of silicon rubber by pulse laser; step 2, calculating a temperature field evolution curve and a thermal stress field evolution curve of a key region of the aging layer under different laser power parameters based on the multi-physical field coupling finite element model constructed in the step 1; And step 3, analyzing the synergistic effect relation between vibration and an ablation mechanism based on the temperature field and thermal stress field evolution curves of the key areas of the ageing layer under different laser powers obtained in the step 2, obtaining the temperature and thermal stress space-time distribution characteristics of the ageing layer of the silicon rubber under the action of pulse laser, and screening out a power interval which can realize preliminary stripping of the ageing layer through thermal stress and can realize complete removal through thermal decomposition without damaging a matrix due to overhigh energy.
2. The method for optimizing the laser cleaning parameters of the silicon rubber insulator based on the multi-physical-field simulation of claim 1, wherein the specific steps of the step 1 comprise the following steps: Step 1.1, determining a core module and a simulation target of multi-physical field coupling simulation, selecting a solid heat transfer module and a solid mechanical module, starting a thermal expansion multi-physical field coupling node, and determining a transient temperature field and a thermal stress field of an aging layer and a matrix under the condition that the model needs to be accurately simulated by laser irradiation; Step 1.2, defining a core control equation of multi-physical field coupling simulation, and sequentially constructing a transient heat conduction equation (a laser heat source item containing space Gaussian distribution and time square wave pulse), a Gaussian distribution surface heat source model of pulse laser energy deposition, a momentum conservation equation for describing mechanical response of materials, a thermal-force coupling constitutive equation for calculating thermal stress induced by temperature gradients, and a Van der Waals force adhesion calculation equation for representing bonding force between an aging layer and a substrate; Step 1.3, inputting basic parameters of a multi-physical field coupling finite element model, and substituting the material parameters of density, specific heat capacity, heat conductivity, absorptivity and Young modulus of a silicon rubber matrix and an aging layer, and initial process parameters such as laser wavelength, pulse width and light spot radius into the multi-physical field coupling simulation model; Step 1.4, optimizing grid division of the multi-physical field coupling finite element model, carrying out grid refinement treatment on a key area directly acted by laser, ensuring calculation accuracy, and further completing establishment of the multi-physical field coupling finite element model for cleaning an aging layer on the surface of the silicon rubber by pulse laser.
3. The method for optimizing the laser cleaning parameters of the silicon rubber insulator based on the multi-physical-field simulation of claim 2 is characterized in that the specific method in the step 1.2 is as follows: defining a core control equation of multi-physical field coupling simulation, and sequentially constructing a transient heat conduction equation, wherein a heat source term is a laser heat source which is in Gaussian distribution in space and is in square wave pulse in time: (1) Wherein ρ is the material density (kg/m 3 );C p is the specific heat capacity (J/(kg. K)), K is the thermal conductivity (W/(m. K)), T is the temperature (K), Q laser is the laser heat source term (W/m 3 ), and it is the gradient operator; The deposition of the pulse laser energy on the surface of the material adopts a Gaussian distribution surface heat source model: (2) wherein A is the absorptivity of the material to laser, P is the laser power, r 0 is the radius of a laser spot, r is the radial distance from the center of the spot, and pulse (t) is a function describing the pulse time characteristic; the time function pulse (t) is defined in terms of the laser pulse shape and can be expressed for square wave pulses as: (3) wherein t is time, τ is pulse width; The conservation of momentum equation describes the mechanical response of a material: (4) Wherein ρ is density, u is displacement vector, t is time, σ is Cauchy stress tensor, F is volumetric force vector, and v is gradient operator; the constitutive equation of the thermal-force coupling is used for calculating the thermal stress induced by the temperature gradient, and the internally generated thermal stress is as follows: (5) wherein E is elastic modulus, alpha is thermal expansion coefficient, T is material temperature, and T ext is external temperature; neglecting the influence of other forces, considering that the adhesion force of the aged surface layer of the silicone rubber insulator is Van der Waals force, the adhesion force per unit area is as follows: (6) Wherein H is Hamaker constant, D is distance between planes, negative sign indicates attractive force, A is adhesion area; (7) Wherein H 11 is a silicone rubber having a Hamaker constant of about 3.5X10 -19 J;H 22 and SiO 2 is a Hamaker constant of about 6.5X10 -19 J.
4. The method for optimizing the laser cleaning parameters of the silicon rubber insulator based on the multi-physical-field simulation of claim 1, wherein the specific steps of the step 2 comprise the following steps: step 2.1, setting a laser power variable range, and selecting typical values covering low, medium and high power to form a laser power parameter set to be calculated; step 2.2, starting transient solution calculation, substituting each laser power parameter into the multi-physical field coupling finite element model constructed in the step 1 in sequence, focusing key positions such as a laser spot acting core area and the like after simulation calculation is completed, and extracting original data of temperature and thermal stress changing along with time; and 2.3, performing finishing analysis on the extracted original data, and drawing a temperature field evolution curve and a thermal stress field evolution curve of the key region of the ageing layer under different laser powers.
5. The method for optimizing the laser cleaning parameters of the silicon rubber insulator based on the multi-physical-field simulation of claim 1 is characterized in that the specific method in the step 3 is as follows: based on the temperature field evolution curve and the thermal stress field evolution curve of the key region of the aging layer under different laser powers obtained in the step 2, analyzing the synergistic relationship between vibration and ablation mechanism: When the laser power is in the range of 50W-60W, two criteria that the stress peak exceeds the adhesion and the temperature peak reaches the decomposition threshold are well met, and the optimal laser power optimization interval is determined to be 50W-60W; Based on the method, for the case of shallower ageing layers, 30-40W laser power is selected, thinner ageing layers are removed by means of a vibration mechanism, for the case of deeper ageing layers, 50-60W laser power is selected, ageing layers are removed by means of a vibration and ablation mechanism cooperation mechanism, and for the case of severe ageing, more than 70W laser power is adopted, most ageing layers are removed by means of an ablation mechanism firstly, then laser power is reduced, and the ageing layers are removed accurately under the condition of ensuring that unaged substrates are not damaged by means of the vibration and ablation mechanism cooperation.
6. The method for optimizing the laser cleaning parameters of the silicon rubber insulator based on the multi-physical-field simulation of claim 1, further comprising the following steps after the step 3: and 4, guiding the pulse laser to clean the actual technological parameters of the silicon rubber insulator based on the laser power optimization interval determined in the step 3.
7. The method for optimizing the laser cleaning parameters of the silicon rubber insulator based on the multi-physical-field simulation of claim 6, wherein the specific steps of the step 4 include: step 4.1, optimizing the detailed parameters of the interval, defining the specific range 50W to 60W of the laser power optimizing interval, and synchronously marking the key matched data of the thermal stress peak value 1.8-2.0MPa and the temperature peak value 750-816K in the interval; and 4.2, forming a process guidance file, and combining the optimized interval with the fixed parameters of the pulse laser to form a pulse laser peeling silicon rubber ageing layer guidance scheme.

Description

Silicon rubber insulator laser cleaning parameter optimization method based on multi-physical field simulation Technical Field The invention belongs to the technical field of laser cleaning, relates to a method for optimizing laser cleaning parameters of a silicon rubber insulator, and particularly relates to a method for optimizing laser cleaning parameters of a silicon rubber insulator based on multi-physical field simulation. Background The silicon rubber composite insulator is widely applied to a power grid system by virtue of excellent hydrophobicity and weather resistance. However, the insulator runs in an outdoor complex environment for a long time, and an aging layer with chemical property degradation is gradually formed on the surface, and the aging layer can cause the insulation performance of the insulator to be remarkably reduced, so that the safe and stable running of a power grid is directly threatened. At present, the traditional cleaning method for the ageing layer on the surface of the silicon rubber insulator mainly comprises high-pressure water flushing, chemical cleaning, mechanical polishing and the like, but the methods have obvious defects that the high-pressure water flushing and cleaning efficiency is low, water resources are wasted, the chemical cleaning is easy to produce environmental pollution, potential corrosion is possibly caused to an insulator substrate, and the mechanical polishing is contact cleaning, so that the surface structure of the insulator is extremely easy to damage, and the subsequent use performance is influenced. The pulse laser cleaning technology is used as a high-efficiency and environment-friendly non-contact cleaning method, has great application potential in the field of insulator cleaning, and has the main mechanisms of ablation effect (thermal decomposition and gasification removal of an ageing layer by laser energy) and vibration effect (stripping of the ageing layer from a substrate by laser induced thermal stress). However, the technology still faces a key technical bottleneck in practical application, and the defects and shortcomings of the technology are embodied in the following three aspects: 1. The process parameters are determined to lack theoretical support, and an experience trial-and-error method is relied on, so that the process parameters of the current pulsed laser cleaning silicon rubber insulator are selected mainly by repeated experiment trial-and-error, a great amount of labor and material resource cost is required to be input, the process development period is long, blindness of parameter selection exists, and accurate regulation and control are difficult to realize. 2. The two cleaning mechanisms cannot be regulated and controlled cooperatively, so that the cleaning efficiency and the substrate safety are difficult to balance, and due to the lack of deep understanding of the interaction relation between the vibration mechanism and the ablation mechanism in the cleaning process, effective cooperation of the two mechanisms cannot be realized, so that in practical application, the ablation effect is excessively depended on, the thermal damage of the silicone rubber substrate is caused, or the ageing layer is difficult to completely remove only by means of the vibration effect, and the cleaning efficiency and the substrate safety cannot be considered all the time. 3. Numerical simulation is an effective means for revealing the intrinsic mechanism of a complex physical process, but the existing laser ablation numerical simulation model mainly aims at metal materials, has intrinsic differences between the ablation mechanism (taking melting and gasification as cores) and thermodynamic properties of the metal materials and polymer materials (taking pyrolysis and gasification as cores), and cannot be directly applied to laser cleaning simulation of a silicone rubber insulator, so that the intrinsic mechanism of cleaning cannot be revealed through the numerical simulation means, and further scientific guidance cannot be provided for process parameter optimization. Therefore, there is a need to develop a method for optimizing the laser cleaning parameters of a silicone rubber insulator based on multi-physical-field simulation, which is adaptive to the characteristics of the silicone rubber material and can precisely reveal the cleaning mechanism, so as to solve the above-mentioned defects and shortcomings in the process of cleaning the silicone rubber insulator by using the existing pulse laser. No prior art publication is found, either the same or similar to the present invention, upon retrieval. Disclosure of Invention Aiming at the defects of the prior art, the invention provides the optimization method for the laser cleaning parameters of the silicon rubber insulator based on the multi-physical-field simulation, which can accurately simulate the evolution of a transient temperature field and a thermal stress field and quantitatively analy