Surface self-cleaning method based on leidenfrost effect

Abstract

The present application relates to the technical field of precision instrument surface cleaning, and discloses a surface self-cleaning method based on Leidenfrost effect, comprising the following steps: S100, cleaning agent conveying, using the driving potential generated by capillary force, and through the capillary transport structure connected between the liquid storage device and the surface of the component to be cleaned, the cleaning agent is autonomously, quantitatively and continuously and stably transported to the surface of the component to be cleaned; S200, cleaning agent self-adaptively and actively moving forward and cleaning, the cleaning agent transported to the surface of the component to be cleaned, under the condition that the surface temperature of the component to be cleaned at the transport target position is higher than the Leidenfrost temperature point of the cleaning agent, the Leidenfrost effect occurs, the self-propelling force is generated by the asymmetric vapor film formed at the bottom of the cleaning agent, so that the cleaning agent autonomously moves on the surface of the component to be cleaned and carries away the pollutants, and the autonomous cleaning of the surface of the component to be cleaned is realized.

Description

Technical Field

[0001] This invention relates to the field of precision instrument surface cleaning technology, and in particular, to a surface self-cleaning method based on the Leidenfrost effect. Background Technology

[0002] With the rapid development of microelectronics technology, computers, servers, and other devices integrate a large number of highly precise microelectronic components (such as CPUs, GPUs, and memory). These components generate heat during operation, and the cleanliness of their surfaces is crucial to their heat dissipation performance and long-term operational stability. Accumulated dust and other contaminants can form a heat insulation layer, leading to a sharp decrease in heat dissipation efficiency, which can then cause overheating, performance degradation, or even permanent damage to the components. However, due to the typically precise structure, small size, and sensitivity to physical contact of these components, efficient and non-destructive cleaning has always been a technical challenge.

[0003] Currently, the industry offers various cleaning solutions for the surfaces of precision instruments. For example, some solutions use adhesive rollers made of antistatic materials, removing surface dust through physical rolling contact. While this method avoids the hazards of static electricity, its cleaning efficiency is limited, and it is ineffective for firmly attached contaminants or those in confined spaces. It also carries the risk of mechanical contact with precision surfaces. Another solution is based on machine vision positioning technology, identifying dust locations through image comparison and controlling a robotic arm to precisely remove dust using a dust removal rod. This method is highly automated, but the system is complex and costly, and it also relies on physical contact with the device surface, potentially leading to scratches or electrostatic discharge (ESD) damage. Furthermore, some solutions utilize microfluidic pumps or pressure valves to generate oscillating fluid to create self-propelled cleaners that move across surfaces for cleaning. While these methods achieve a degree of "self-drive," they still fundamentally rely on complex built-in micro-power sources, resulting in high energy consumption, complex structures, and limited reliability and lifespan.

[0004] In summary, existing cleaning methods have the following limitations: First, most methods rely on external mechanical contact or force, which poses a risk of physical damage to precision surfaces or the introduction of static electricity; second, solutions such as power systems based on micro-pumps and valves or vision-positioning robots have complex system structures, high manufacturing costs, and require continuous power consumption during operation, resulting in low energy efficiency; finally, traditional methods may face the problem of cleaning agent residue after cleaning, and the stains or films formed after the residual droplets evaporate may affect the electrical performance or appearance of components. Summary of the Invention

[0005] This invention provides a surface self-cleaning method based on the Leidenfrost effect. It does not require complex external mechanical structures, has low energy consumption, and can achieve autonomous and efficient transport and contactless cleaning of cleaning agents. It can achieve self-driven cleaning and is suitable for cleaning the surfaces of precision instruments. This solves the technical problems of existing cleaning methods that rely on physical contact or complex external power sources, which are difficult to avoid damaging precision surfaces, have high energy consumption, and are prone to cleaning agent residue.

[0006] This invention provides a surface self-cleaning method based on the Leidenfrost effect, comprising the following steps: S100, detergent delivery: utilizing the driving force generated by capillary action, the detergent is autonomously, quantitatively, and continuously and stably delivered to the surface of the component to be cleaned through a capillary transport structure connected between the liquid storage device and the surface of the component to be cleaned; S200, the detergent adaptively and actively moves to propel and clean: when the surface temperature of the component to be cleaned at the delivery target location is higher than the Leidenfrost temperature point of the detergent, the detergent delivers to the surface of the component to be cleaned. The Leidenfrost effect occurs, and the asymmetric vapor film formed at the bottom of the detergent generates a self-propulsive force, thereby enabling the detergent to move autonomously on the surface of the component to be cleaned and carry away contaminants, achieving autonomous cleaning of the surface of the component to be cleaned.

[0007] Furthermore, the structural design of the capillary transport structure in step S100 is specifically as follows: the liquid forms a tortuous liquid surface in the hydrophilic capillary and generates additional pressure. Relationship between p and the radius of curvature of the liquid surface:

[0008] ;

[0009] in, For liquid surface tension, r 1 and r 2 represents the radius of curvature of the liquid surface in two directions. Assuming the liquid surface is spherical, then... r 1= r 2, Order r 1 =r 2= r If 0, then the above expression can be transformed into:

[0010] ;

[0011] When equilibrium is reached, the pressure at two points at the same liquid level should be equal, from which the following capillary rise formula can be derived:

[0012] ;

[0013] in, Contact angle, R It is the radius of the circular capillary.Δρ It is the density difference between the liquid and the gas. g It is gravitational acceleration.

[0014] Furthermore, record , ,in, r It is the inner radius of the capillary tube. It is the density of the liquid. This refers to the viscosity of the liquid; It is the surface tension of the liquid; L This represents the maximum height the liquid column rises. T Let the total capillary rise time be denoted by the Washburn equation:

[0015] ;

[0016] Where t( h The height to which the liquid column rises in the capillary is the height at which it rises. h The time required This is the solid-liquid contact angle.

[0017] Furthermore, given the distance between the component to be cleaned and the water storage device... h 0. Taking the time derivative of the Washburn equation, we obtain the instantaneous rate of ascent v:

[0018] ;

[0019] Based on the goal of maximizing transport capacity, i.e., transporting the maximum amount of cleaning agent per unit time, the basic formula for liquid flow rate in a pipeline is as follows:

[0020] ;

[0021] The radius of the circular capillary tube in the capillary transport structure at the maximum flow rate was obtained using MATLAB calculations. R .

[0022] Further, step S200 specifically involves: designing and installing a self-propelled structure around the component to be cleaned, and ensuring that the surface temperature of the self-propelled structure is higher than the Leidenfrost temperature of the cleaning agent. The cleaning agent droplets transported to the surface of the component to be cleaned via the capillary transport structure interact with the surface of the self-propelled structure through the Leidenfrost effect, forming a stable asymmetric vapor film at the bottom of the cleaning agent and generating self-propelling force. This provides the cleaning agent with a certain initial velocity, enabling it to move autonomously on the surface of the component to be cleaned and carry away contaminants, thereby achieving autonomous cleaning of the surface of the component to be cleaned.

[0023] Furthermore, the self-propelled structure adopts a sawtooth structure.

[0024] Furthermore, a force analysis was performed on the cleaning agent droplets. Due to the combined effects of surface tension and viscous forces on the serrated surface, and the pressure difference between the serrated tip and the channel due to the asymmetry of the serrated surface, a traction force was generated. Under the action of the traction force, the droplets achieved self-propelled motion. The force analysis formula is shown below:

[0025] ;

[0026] in, The total traction force or net propulsion force experienced by the droplet due to the Leidenfrost effect. This represents the maximum static frictional resistance or maximum adhesion force. For dynamic viscous resistance, It is the critical force or characteristic force. The heat flux density ratio, For density, For isobaric specific heat capacity, Thermal conductivity, L 0 represents the physical property of a constant-pressure droplet. W These are the physical properties of a solid wall surface.

[0027] Furthermore, the configuration of the serrated structure is: a straight tooth-shaped surface, a convex tooth surface, or a concave tooth surface.

[0028] Furthermore, the cleaning agent is a water-based cleaner or a propanol cleaner; and / or the material of the capillary transport structure is quartz or metal; and / or the material of the serrated structure is iron, aluminum, magnesium or copper.

[0029] Furthermore, the capillary transport structure adopts a tubular capillary or a grooved capillary.

[0030] The present invention has the following beneficial effects:

[0031] 1. Achieved extremely low energy consumption and even passive cleaning agent transport: Utilizing capillary force as the transport driving force, capillary action is a spontaneous physical process that does not require external power components such as pumps and valves or the electrical energy they require, thereby significantly reducing the overall energy consumption of the system, simplifying the system structure, and improving reliability.

[0032] 2. Provides continuous, stable and adaptive detergent supply: The capillary transport structure can achieve quantitative and stable liquid transport based on its own physical characteristics (such as pore size and hydrophilicity) and the physicochemical properties of the detergent (such as surface tension), avoiding the instability that may be caused by pulsed liquid supply. It can autonomously adjust the supply rate according to the actual consumption of the cleaned surface, ensuring the continuity and stability of the cleaning process.

[0033] 3. Achieves efficient, contactless self-driven cleaning: The self-propelled force generated by the Leidenfrost effect drives the movement of droplets. This power comes from the phase change (vaporization) of the cleaning agent on the superheated surface. There is no need to install internal drive mechanisms such as micro motors and actuators. The droplets are suspended on the vapor film, avoiding direct physical contact with the surface of precision devices, thus fundamentally eliminating the risk of scratches, wear or stress damage caused by contact.

[0034] 4. Improved cleaning efficiency and reduced residue: Droplets exhibiting the Leidenfrost effect move at high speed on the surface. The kinetic energy and fluid shear force they carry can effectively peel off and remove contaminants. At the same time, because the droplets are in a state of violent boiling and are separated from the surface by a vapor layer, their evaporation efficiency is extremely high. After completing the cleaning task, they can quickly evaporate and leave, greatly reducing the residue of cleaning agents on the surface and avoiding the problems of watermarks or decreased electrical performance caused by liquid residue.

[0035] 5. An intelligent energy utilization closed loop has been formed: The waste heat generated by the components to be cleaned (such as high-performance CPUs) during operation is used as energy (reaching the Leidenfrost temperature point), and the waste heat is converted into the driving force for cleaning. This realizes an intelligent mode of cleaning on demand. The more heat the device generates during operation and the more heat dissipation is needed (i.e., the more cleaning is needed), the stronger the cleaning kinetic energy becomes. This constitutes an efficient and adaptive energy utilization system, further highlighting its energy-saving characteristics.

[0036] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0037] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0038] Figure 1 This is a numerical simulation result diagram of a single-tube COMSOL tube according to a preferred embodiment of the present invention;

[0039] Figure 2 This is a numerical simulation result diagram of the dual-tube COMSOL of a preferred embodiment of the present invention;

[0040] Figure 3 This is a preferred embodiment of the present invention. Φ =0.3mm partial experimental diagram;

[0041] Figure 4 This is a preferred embodiment of the present invention. Φ =0.2mm partial experimental diagram;

[0042] Figure 5 This is a preferred embodiment of the present invention. H Diagram showing the self-propulsion motion of droplets on the surface of a 0.1mm serrated component.

[0043] Figure 6 This is a preferred embodiment of the present invention. H Diagram showing the self-propulsion motion of droplets on the surface of a 0.2mm serrated component.

[0044] Figure 7 This is a preferred embodiment of the present invention. H =0.3mm Graph of self-propulsion motion of droplets on the surface of a serrated component. Detailed Implementation

[0045] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0046] The surface self-cleaning method based on the Leidenfrost effect in this embodiment includes the following steps: S100, detergent delivery: using the driving force generated by capillary action, the detergent is autonomously, quantitatively, and continuously and stably delivered to the surface of the component to be cleaned through a capillary transport structure connected between the liquid storage device and the surface of the component to be cleaned; S200, detergent adaptively and actively moves to propel and clean: when the surface temperature of the component to be cleaned at the delivery target location is higher than the Leidenfrost temperature point of the detergent, the detergent delivered to the surface of the component to be cleaned exhibits the Leidenfrost effect, and the asymmetric vapor film formed at the bottom of the detergent generates a self-propulsive force, thereby enabling the detergent to move autonomously on the surface of the component to be cleaned and carry away contaminants, thus achieving autonomous cleaning of the surface of the component to be cleaned. This invention relates to a surface self-cleaning method based on the Leidenfrost effect. Step S100 utilizes capillary force as the transport driving force. Capillary action is a spontaneous physical process that requires no external power components such as pumps or valves, thus significantly reducing overall system energy consumption, simplifying system structure, and improving reliability. The capillary transport structure can achieve quantitative and stable liquid transport based on its own physical characteristics (such as pore size and hydrophilicity) and the physicochemical properties of the cleaning agent (such as surface tension), avoiding the instability that may be caused by pulsed liquid supply. It can autonomously adjust the supply rate according to the actual consumption of the cleaned surface, ensuring the continuity and stability of the cleaning process. Step S200 utilizes the self-propelled force generated by the Leidenfrost effect to drive the droplet movement. This power originates from the phase change (vaporization) of the cleaning agent on the superheated surface, eliminating the need for internal drive mechanisms such as micromotors and actuators. The droplets suspend and move on the vapor film, avoiding contact with precision surfaces. Direct physical contact with the device surface fundamentally eliminates the risks of scratches, wear, or stress damage caused by contact. The Leidenfrost effect causes droplets to move at high speed on the surface; their kinetic energy and fluid shear force effectively strip away and remove contaminants. Simultaneously, because the droplets are in a state of vigorous boiling and separated from the surface by a vapor layer, their evaporation efficiency is extremely high, allowing them to quickly evaporate after cleaning, greatly reducing cleaning agent residue on the surface and avoiding watermarks or degradation of electrical performance due to liquid residue. The waste heat generated by the component to be cleaned (such as a high-performance CPU) during operation is used as the energy source for step S200 (reaching the Leidenfrost temperature point), converting waste heat into a driving force for cleaning. This achieves an intelligent on-demand cleaning mode; the more heat the device generates and the more heat dissipation is needed (i.e., the more cleaning is required), the stronger the cleaning kinetic energy becomes, forming a highly efficient and adaptive energy utilization system, further highlighting its energy-saving characteristics.This invention presents a surface self-cleaning method based on the Leidenfrost effect. By organically combining capillary transport with Leidenfrost self-propulsion, it successfully achieves excellent technical results with low energy consumption or passive drive, non-contact operation, self-adaptation, and minimal residue after cleaning. It is particularly suitable for cleaning the surfaces of precision instruments where cleaning safety, energy consumption, and reliability requirements are extremely high, providing a novel, efficient, and reliable solution to the self-cleaning challenges in fields such as microelectronic devices.

[0047] In this embodiment, the structural design of the capillary transport structure in step S100 is specifically as follows: the liquid forms a tortuous liquid surface in the hydrophilic capillary and generates additional pressure. Relationship between p and the radius of curvature of the liquid surface:

[0048] ;

[0049] in, For liquid surface tension, r 1 and r 2 represents the radius of curvature of the liquid surface in two directions. Assuming the liquid surface is spherical, then... r 1= r 2, Order r 1 =r 2= r If 0, then the above expression can be transformed into:

[0050] ;

[0051] When equilibrium is reached, the pressure at two points at the same liquid level should be equal, from which the following capillary rise formula can be derived:

[0052] ;

[0053] in, Contact angle, R It is the radius of the circular capillary. Δρ It is the density difference between the liquid and the gas. g It is gravitational acceleration. Step S100 involves precisely designing the physical parameters of the capillary transport structure (such as the capillary radius). R Material hydrophilicity to control contact angle θ ), utilizing the additional pressure generated by the surface tension (σ) of the liquid in the capillary phenomenon ( Δρ As the driving force, the capillary rise height ( hThe flow rate and flow rate can be accurately predicted and designed using the above theoretical formulas, enabling the cleaning agent to achieve quantitative, continuous, stable, and controllable autonomous transport without relying on external power components such as pumps and valves. This fundamentally reduces system energy consumption, simplifies the structure, and improves reliability. Step S200 cleverly transforms the cleaning agent delivered in step S100 into a self-propelled cleaning unit on a high-temperature surface that reaches the Leidenfrost point using the waste heat of the component itself. The Leidenfrost effect causes the droplets to suspend above the vapor film, avoiding direct physical contact with the surface of precision components and completely eliminating the risk of scratch damage. The self-propelled force generated by the asymmetric vapor film drives the droplets to move autonomously and at high speed on the surface, efficiently stripping and removing contaminants using their fluid kinetic energy, achieving highly efficient cleaning. Both stages of the method of this invention demonstrate good adaptability. Capillary transport energy autonomously adjusts its supply based on cleaning consumption; while the Leidenfrost self-propulsion stage directly utilizes the waste heat of the component to be cleaned (such as the CPU) as the driving energy. The greater the device's workload, the more heat it generates, and the more it needs enhanced heat dissipation (i.e., the more it needs cleaning), the stronger the driving force for cleaning becomes, forming an intelligent, efficient, and energy-saving closed-loop system for energy utilization and cleaning. Based on the Leidenfrost effect, the droplets are in a state of vigorous boiling, and they can evaporate rapidly and completely during and after their movement, thereby greatly reducing the residue of cleaning agent on precision surfaces. This effectively avoids secondary problems such as watermarks, films, or resulting electrical performance degradation and corrosion caused by liquid residue, ensuring the long-term operational reliability of the cleaned components. Through the creative combination of a capillary transport structure with a clear theoretical model and sufficient design basis and the Leidenfrost self-propulsion effect, a superior technical effect has been successfully achieved, characterized by strong theoretical predictability, precise and stable transport, built-in driving energy, non-contact throughout the process, and no residue after cleaning.

[0054] In this embodiment, (Note:) , ,in, r It is the inner radius of the capillary tube. It is the density of the liquid. This refers to the viscosity of the liquid; It is the surface tension of the liquid; L This represents the maximum height the liquid column rises. T Let the total capillary rise time be denoted by the Washburn equation:

[0055] ;

[0056] Where t( h The height to which the liquid column rises in the capillary is the height at which it rises. h The time required The solid-liquid contact angle is given. By introducing the Washburn equation, the rise of the detergent column through the capillary structure to any capillary rise height can be accurately calculated. h The required time t( h It can determine key parameters of the capillary transport structure (such as the inner radius of the capillary tube) based on the location of the target cleaning surface and the required cleaning agent supply rate. r Material solid-liquid contact angle By employing reverse engineering and precise matching, accurate and stable control of the detergent delivery rate and flow rate is achieved, providing a reliable and predictable supply guarantee for the entire self-cleaning system; the maximum liquid column rise height defined in the scheme... L Total Time T The transport performance was clearly established. L , T ) and the physical properties of the cleaning agent (density of the liquid) ρ Viscosity of liquids η Liquid surface tension σ ) and capillary structure geometric parameters (capillary inner tube radius) r The quantitative relationship between these parameters provides a solid theoretical framework and computational tools for the scientific design and optimization of the size and material selection of capillary transport structures for cleaning agents with different properties and different installation space constraints. This avoids traditional trial-and-error design and improves design efficiency and reliability. The mathematical model elevates the capillary transport process from a qualitative or empirical description to a quantitative scientific design level, ensuring that the capillary transport in the first step (step S100) is precisely matched and seamlessly connected with the Leidenfrost self-propelled cleaning requirements in the second step (step S200) in terms of time and flow rate. For example, the time it takes for the cleaning agent to reach the high-temperature surface can be calculated, thereby coordinating with the device's heating start-up process, avoiding supply interruptions or overflows, and ensuring the continuous, stable, and efficient operation of the entire self-cleaning process.

[0057] In this embodiment, the distance between the component to be cleaned and the water storage device is given. h 0. Taking the time derivative of the Washburn equation, we obtain the instantaneous rate of ascent v:

[0058] ;

[0059] Based on the goal of maximizing transport capacity, i.e., transporting the maximum amount of cleaning agent per unit time, the basic formula for liquid flow rate in a pipeline is as follows:

[0060] ;

[0061] The radius of the circular capillary tube in the capillary transport structure at the maximum flow rate was obtained using MATLAB calculations. RBy differentiating the Washburn equation, which describes capillary rise, with respect to time, the instantaneous rise velocity of the detergent column in a capillary structure was derived for the first time with precise accuracy. v ) and interval height ( h The mathematical relationship between 0 and 0 can transcend traditional static empirical design, dynamically and accurately predicting and simulating the transport state of the detergent at any given time, providing a solid theoretical basis for system design; it clearly defines maximizing transport capacity, i.e., transporting the maximum amount of detergent per unit time, as the optimization objective, and considers the instantaneous rate of increase ( v ) and the radius of the circular capillary ( R ) through the basic formula of liquid flow rate ( Related to this, the design approach has evolved from ensuring transport capacity to pursuing optimal transport, elevating transport efficiency to a theoretically calculable and achievable extreme level. Based on the aforementioned theoretical model, further numerical calculations are performed using computational tools (such as MATLAB) to uniquely determine the flow rate (under given conditions) that can be maximized. The core geometric parameter of the capillary transport structure that corresponds to the maximum value is the radius of the circular capillary. R The output is no longer a vague design range, but a precise dimensional value that has been rigorously mathematically optimized and can be directly used to guide production and manufacturing, thereby ensuring that the manufactured capillary structure has the optimal transport performance in theory.

[0062] In this embodiment, step S200 specifically involves: designing and installing a self-propelled structure around the component to be cleaned, and ensuring that the surface temperature of the self-propelled structure is higher than the Leidenfrost temperature of the cleaning agent. The cleaning agent droplets, transported to the surface of the component via a capillary transport structure, interact with the surface of the self-propelled structure using the Leidenfrost effect. This forms a stable asymmetric vapor film at the bottom of the cleaning agent and generates a self-propelling force, giving the cleaning agent an initial velocity. This allows the cleaning agent to move autonomously on the surface of the component and carry away contaminants, achieving autonomous cleaning of the component's surface. By ensuring that the surface temperature of the self-propelled structure is higher than the Leidenfrost temperature of the cleaning agent, the bottom of the droplets instantly vaporizes to form a vapor film, suspending the droplets above the surface. The asymmetry of this vapor film generates a net thrust, giving the cleaning agent droplets an initial velocity for autonomous movement. This avoids the complex transmission mechanisms required for mechanical contact propulsion and eliminates physical contact and potential damage to the surface of precision components. As an independent heat source module, the self-propelled structure's surface temperature can be precisely controlled and maintained at a level higher than the Leidenfrost temperature of the cleaning agent. This ensures that every drop of cleaning agent delivered to the surface of the component to be cleaned via the capillary transport structure can continuously and reliably generate the Leidenfrost effect and produce self-propelling force, providing initial velocity for the autonomous movement of the cleaning agent, thereby ensuring the continuity and stability of the entire autonomous cleaning process. The cleaning agent droplets, having acquired initial velocity, move autonomously on the surface of the component to be cleaned. The kinetic energy of the droplets and the fluid shear force between them and surface contaminants effectively peel off, entrain, and carry away contaminant particles. Due to the Leidenfrost effect, the droplets are in a state of violent phase transition, and they evaporate quickly and completely after completing the cleaning task, thus greatly reducing the residue of cleaning agent on the precision surface and avoiding the degradation of electrical performance or secondary pollution caused by liquid residue. The self-propelled structure is designed to be installed around the component to be cleaned, rather than on the component itself. This layout scheme does not require any modification or addition to the precision component itself, thus protecting its integrity and reliability to the greatest extent. This design allows for flexible design and arrangement of the direction and position of the self-propelled structure according to the specific shape and contamination distribution of the surface to be cleaned, so as to guide the droplets to move along the optimal path, thereby achieving efficient full-coverage cleaning.

[0063] In this embodiment, the self-propelled structure employs a serrated structure. The serrated structure, through its periodically arranged inclined teeth, creates a geometrically asymmetrical substrate environment at the bottom of the droplet. When the droplet undergoes the Leidenfrost effect, the escape channel of the vapor at its bottom exhibits a significant difference between the steep and gentle sides of the serrations. This difference leads to a directional gradient in the pressure distribution within the vapor film, generating a net thrust pointing in a specific direction, providing the core driving force for the droplet's directional self-propelled motion. The periodicity of the serrated structure provides continuous, directional guidance for the droplet's initial velocity. As the droplet moves from one serrated unit to the downstream component to be cleaned, its motion direction is maintained and reinforced, avoiding random and disordered motion that might occur on smooth surfaces. This ensures that the cleaning agent can efficiently and orderly cover specific areas of the surface to be cleaned, significantly improving the predictability and efficiency of the cleaning path. The serrated macroscopic surface structure provides a larger surface area and more uniform heat conduction conditions for the temperature distribution on its surface, which helps to maintain a stable and uniform high-temperature field, ensures the continuous and stable occurrence of the Leidenfrost effect, provides a clear physical guidance for the droplet, reduces deflection and swaying during the droplet's motion, and makes the self-propulsion process more stable and reliable.

[0064] In this embodiment, a force analysis is performed on the cleaning agent droplet. Due to the combined effects of surface tension and viscous force on the serrated surface, and the pressure difference between the serrated tip and the channel due to the asymmetry of the serrated surface, a traction force is generated. Under the action of the traction force, the droplet achieves self-propelled motion. The force analysis formula is shown below:

[0065] ;

[0066] in, The total traction force or net propulsion force experienced by the droplet due to the Leidenfrost effect. This represents the maximum static frictional resistance or maximum adhesion force. For dynamic viscous resistance, It is the critical force or characteristic force. The heat flux density ratio, For density, For isobaric specific heat capacity, Thermal conductivity, L 0 represents the physical property of a constant-pressure droplet. W This refers to the physical properties of the solid wall. The serrated structure, through its inherent geometric asymmetry, creates an asymmetric vapor escape environment at the bottom of the droplet. According to the force analysis model, this results in a significant pressure difference between the vapor film at the serrated tip and the channel region, thereby converting the energy inherent in the Leidenfrost effect into a net traction force with controllable direction. This provides a core, quantifiable, and predictable driving force for the directional self-propulsion of droplets. The above formula shows that the magnitude of the propulsion force is related to the ratio of the heat flux density of the droplet and the wall material (…). Directly related to this, the serrated structure increases the solid-liquid heat transfer area, and its specific geometry helps to utilize the wall surface more efficiently. W The thermal energy of the droplet is used to heat the liquid droplet. L The bottom maintains a stable vapor film, thereby improving the efficiency of converting thermal energy (high surface temperature) into mechanical energy and enhancing self-propulsion. The periodically arranged serrated structure provides continuous and consistent physical guidance for the droplet's motion, increasing net traction. Under continuous action, the droplet can overcome dynamic viscous resistance ( It moves steadily and continuously along a specific direction defined by the sawtooth structure, avoiding randomness in movement, thus ensuring that the cleaning agent can efficiently and orderly cover the predetermined cleaning path.

[0067] In this embodiment, the serrated structure is configured as a straight toothed surface, a convex toothed surface, or a concave toothed surface. Different serrated configurations, by changing the specific form of their geometric asymmetry (such as tilt angle and curvature), directly affect the morphology and resistance distribution of the vapor escape channel at the bottom of the droplet. According to the above formula, this difference in geometric shape ultimately manifests as an effect on the net traction force ( The designability of the size and orientation of the droplet; for example, a convex toothed surface may enhance local constraint to increase thrust, while a concave toothed surface may expand the vapor cavity to change the direction of action, thus providing diverse design freedom for precisely controlling the propulsion intensity and motion path of the droplet. Different configurations, due to their different contact areas and heat transfer paths with the droplet, directly affect the interaction between the droplet and the wall surface (…). W The heat exchange efficiency between the two is determined by the heat flux density ratio ( ). Quantification; convex tooth structures can provide higher local heat flux density, while concave tooth structures may be beneficial for the stable maintenance of vapor film; therefore, droplet ( ) can be actively matched by selecting the configuration. L ) and wall ( W By analyzing the thermophysical properties of the material, the efficiency of converting thermal energy into mechanical energy can be optimized, ensuring the effectiveness and reliability of the self-propelled process under different operating conditions. Different serrated configurations will produce droplet motions with different intensities and characteristics; for contaminants with strong adhesion, a configuration that can generate greater propulsion force (such as straight teeth at a specific angle) may be selected; for cleaning scenarios requiring large-area coverage, a configuration that can generate more uniform and stable propulsion (such as concave teeth) may be selected; this allows the self-propelled structure to be specifically optimized according to the characteristics of contaminants on the surface to be cleaned, improving the overall cleaning capability and application flexibility of the entire method.

[0068] In this embodiment, the cleaning agent is a water-based cleaning agent or a propanol-based cleaning agent; and / or the material of the capillary transport structure is quartz or metal; and / or the material of the serrated structure is iron, aluminum, magnesium or copper.

[0069] In this embodiment, the capillary transport structure adopts a tubular capillary or a grooved capillary.

[0070] In practice, a surface self-cleaning method based on the Leidenfrost effect is provided, which mainly consists of two coupled systems: a cleaning agent transport system based on capillary phenomena and a droplet self-propulsion transport system based on the Leidenfrost effect.

[0071] (1) Capillary transport structure design:

[0072] The given distance between the surface of the component to be cleaned and the water storage device is now specified. h 0 = 5cm, differentiating the above equation with respect to time, we get:

[0073] ;

[0074] The design goal of capillary transport structures is to maximize transport capacity, that is, to transport the maximum amount of cleaning agent per unit time. The basic formula for liquid flow rate in the pipeline is as follows:

[0075] ;

[0076] Substituting the above calculations, and performing calculations based on MATLAB, the radius of the circular capillary tube of the capillary transport structure when the flow rate is maximum is found to be 0.3 mm.

[0077] (2) Design of self-propelled structure around the component

[0078] Three sawtooth surface structures with sawtooth heights of H=0.1mm, H=0.2mm, and H=0.3mm and an inclination angle of 45° were designed to investigate the transport velocity of cleaning agent droplets. Aluminum alloys were fabricated and surface structures were designed for the components. The transport performance was investigated at a temperature of T=200℃. The experiment verified the superior transport performance of the H=0.3mm surface structure.

[0079] (3) Overall design of the invention

[0080] The capillary transport system of this invention is designed with a pipe diameter of 0.3 mm, a water transport height of 5 cm, and a horizontal distance of 1 cm between the transport outlet and the surface of the component. The self-propelled structure is made of aluminum alloy material with a thickness depending on the situation. It is installed around the component with a width of 1 cm on each side. Its upper surface is a serrated surface with a serration angle of 45° and a serration height of 0.3 mm.

[0081] The beneficial effects of the surface self-cleaning method based on the Leidenfrost effect of this invention are as follows:

[0082] (1) Pump-free detergent delivery system: Based on capillary action, the detergent is delivered without pumps;

[0083] (2) Cleaning agent self-propelled system: Based on the Leidenfrost effect, the cleaning agent is self-propelled to "inflow" and "outflow" to clean the target components by biomimetic design of the component surface.

[0084] (3) Capillary transport system configuration: There are two types of capillary transport systems for cleaning agents: pipeline type and groove type. The pipeline type transports the cleaning agent through a pre-designed pipeline, which is usually cylindrical and the diameter can be flexibly changed according to actual needs. The groove type processes existing components, and the shape, diameter, and other dimensions of the groove can be flexibly changed according to actual needs. In addition, the number of pipelines used for cleaning transport can be flexibly designed according to the size and shape of the microelectronic instrument being cleaned and the location to be cleaned.

[0085] (4) Biomimetic self-propelled surface configurations: There are various configurations of the surface of the component used for biomimetic self-propelled propulsion; for straight tooth surface, the tooth height and tilt angle can be flexibly changed according to actual needs; for convex tooth surface, the tooth height and curvature can be flexibly changed according to actual needs; for concave tooth surface, the tooth height and curvature can be flexibly changed according to actual needs.

[0086] (5) System coupling scheme: There are multiple schemes for the capillary transport system and the bionic self-propulsion system to be coupled. For pipeline transport, the cleaning agent can be transported to the bionic self-propulsion system by using an inclined pipe, first vertical and then turning 90°. For groove transport, the shape of the transport pipe can be flexibly designed according to actual needs, and the pipe bending angle and pipe size can be flexibly changed.

[0087] (6) Material selection: The cleaning agent can be selected according to actual needs. Water, propanol and other cleaning agents are all suitable for this invention. The capillary tube material can be selected according to actual needs. Quartz, metal and other materials are all suitable for this invention. The biomimetic sawtooth surface material can be selected according to actual needs. Iron, aluminum, magnesium, copper and other materials are all suitable for this invention.

[0088] The advantages of this invention are: (1) "Pump-free" capillary transport of cleaning agents with low energy consumption: applying capillary phenomena to cleaning agent transport achieves truly pump-free transport; (2) Highly efficient biomimetic self-propulsion capability, improving cleaning efficiency and effect: cleverly utilizing the Leidenfrost effect, through microscale biomimetic design of the component surface, achieving efficient directional propulsion and autonomous cleaning of cleaning agent droplets; (3) Intelligent and reconfigurable parameterized modular system: based on cooling target requirements, intelligent customization can be achieved. Among them, the diameter of the capillary tube used for transport and the shape of the sawtooth on the component surface can be flexibly changed according to actual needs, so that the product can be changed to the corresponding configuration according to the actual application scenario.

[0089] Simulation results of capillary transport systems, such as Figure 1 and Figure 2 As shown in the figure. Numerical simulations were performed on single-tube and double-tube models using COMSOL software. Both single-tube and double-tube simulations employed the optimal Φ=0.3mm capillary tube with a height of 2mm. The single-tube model contained 23,049 elements, and the double-tube model contained 559,877 elements. Both configurations achieved the upward movement of the detergent, demonstrating the feasibility of capillary transport.

[0090] Experimental results of capillary transport systems, such as Figure 3 and Figure 4 As shown, the rise in liquid level was clearly observed under the observation of a high-speed camera, proving the feasibility of capillary transport.

[0091] Experimental results of biomimetic self-propelled systems, such as Figure 5 , Figure 6 and Figure 7 As shown, obvious droplet-directed self-propulsion was observed on surfaces of different sizes, proving the feasibility of the biomimetic self-propulsion system.

[0092] Matters not covered in this invention are common knowledge.

[0093] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A surface self-cleaning method based on the Leidenfrost effect, for surface cleaning of precision instruments, characterized in that, Includes the following steps: S100, Cleaning agent delivery: Utilizing the driving force generated by capillary action, the cleaning agent is autonomously, quantitatively, and continuously and stably delivered to the surface of the component to be cleaned through a capillary transport structure connected between the liquid storage device and the surface of the component to be cleaned. S200: The cleaning agent adaptively and actively moves to propel and clean. When the surface temperature of the cleaning agent at the target location is higher than the Leidenfrost temperature of the cleaning agent, the Leidenfrost effect occurs. The asymmetric vapor film formed at the bottom of the cleaning agent generates self-propulsion force, thereby enabling the cleaning agent to move autonomously on the surface of the cleaning agent and carry away contaminants, thus achieving autonomous cleaning of the surface of the cleaning agent. Step S200 specifically involves: designing and installing a self-propelled structure around the component to be cleaned, and ensuring that the surface temperature of the self-propelled structure is higher than the Leidenfrost temperature of the cleaning agent. The cleaning agent droplets transported to the surface of the component to be cleaned via the capillary transport structure interact with the surface of the self-propelled structure through the Leidenfrost effect, forming a stable asymmetric vapor film at the bottom of the cleaning agent and generating self-propelling force. This gives the cleaning agent a certain initial velocity, allowing it to move autonomously on the surface of the component to be cleaned and carry away contaminants, thereby achieving autonomous cleaning of the surface of the component to be cleaned. The self-propelled structure employs a serrated design. Through its periodically arranged, inclined teeth, the serrated structure creates a geometrically asymmetrical substrate environment at the bottom of the droplet. When the droplet undergoes the Leidenfrost effect, the escape channels for vapor at its bottom exhibit a significant difference between the steep and gentle sides of the serrations. This difference leads to a directional gradient in the pressure distribution within the vapor film, generating a net thrust pointing in a specific direction, providing the core driving force for the droplet's directional self-propelled propulsion. The serrated macroscopic surface structure provides a larger surface area and more uniform heat conduction conditions for its surface temperature distribution, helping to maintain a stable and uniform high-temperature field. This ensures the continuous and stable occurrence of the Leidenfrost effect, providing the droplet with a clear physical orientation, reducing deflection and swaying during droplet movement, and making the self-propelled process more stable and reliable.

2. The surface self-cleaning method based on the Leidenfrost effect according to claim 1, characterized in that, The structural design of the capillary transport structure in step S100 is as follows: The liquid forms a tortuous liquid surface in the hydrophilic capillary and generates additional pressure. Relationship between p and the radius of curvature of the liquid surface: in, For liquid surface tension, r 1 and r 2 represents the radius of curvature of the liquid surface in two directions. Assuming the liquid surface is spherical, then... r 1 =r 2, Order r 1 =r 2= r If 0, then the above expression can be transformed into: When equilibrium is reached, the pressure at two points at the same liquid level should be equal, from which the following capillary rise formula can be derived: in, Contact angle, R It is the radius of the circular capillary. Δρ It is the density difference between the liquid and the gas. g It is gravitational acceleration.

3. The surface self-cleaning method based on the Leidenfrost effect according to claim 2, characterized in that, remember , , in, r It is the inner radius of the capillary tube. It is the density of the liquid. This refers to the viscosity of the liquid; It is the surface tension of the liquid; L This represents the maximum height the liquid column rises. T Let the total capillary rise time be denoted by the Washburn equation: Where t( h The height to which the liquid column rises in the capillary is the height at which it rises. h The time required This is the solid-liquid contact angle.

4. The surface self-cleaning method based on the Leidenfrost effect according to claim 3, characterized in that, Given the distance between the component to be cleaned and the water storage device. h 0. Taking the time derivative of the Washburn equation, we obtain the instantaneous rate of ascent v: Based on the goal of maximizing transport capacity, i.e., transporting the maximum amount of cleaning agent per unit time, the basic formula for liquid flow rate in a pipeline is as follows: The radius of the circular capillary tube in the capillary transport structure at the maximum flow rate was obtained using MATLAB calculations. R .

5. The surface self-cleaning method based on the Leidenfrost effect according to any one of claims 1 to 4, characterized in that, Force analysis of the cleaning agent droplet reveals that the serrated surface is subjected to a combination of surface tension and viscous forces. Due to the asymmetry of the serrated surface, the pressure difference between the serrated tip and the channel generates a traction force. Under the action of this traction force, the droplet achieves self-propelled motion. The force analysis formula is shown below: in, The total traction force or net propulsion force experienced by the droplet due to the Leidenfrost effect. This represents the maximum static frictional resistance or maximum adhesion force. For dynamic viscous resistance, It is the critical force or characteristic force. The heat flux density ratio, For density, For isobaric specific heat capacity, Thermal conductivity, L 0 represents the physical property of a constant-pressure droplet. W These are the physical properties of a solid wall surface.

6. The surface self-cleaning method based on the Leidenfrost effect according to claim 5, characterized in that, The configuration of a serrated structure is: a straight tooth-shaped surface, a convex tooth surface, or a concave tooth surface.

7. The surface self-cleaning method based on the Leidenfrost effect according to claim 5, characterized in that, The cleaning agent is a water-based cleaner or a propanol cleaner; and / or The capillary transport structure is made of quartz or metal; and / or The serrated structure is made of materials such as iron, aluminum, magnesium, or copper.

8. The surface self-cleaning method based on the Leidenfrost effect according to any one of claims 1 to 4, characterized in that, The capillary transport structure uses either a tubular capillary or a grooved capillary.

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