Mobile thermal boundary simulation method and system based on gap contact heat transfer equivalent loading

Abstract

The application provides a mobile thermal boundary simulation method and system based on gap contact heat transfer equivalent loading, and belongs to the field of heat transfer and thermal coupling numerical simulation. The method constructs a workpiece simulation model, and constructs a cooling area based on a cooling medium coverage area. A gap is left between the cooling area and the outer surface of the workpiece, so that the cooling area and the outer surface of the workpiece realize the heat exchange boundary condition without generating structural contact stress. A real forced convection heat transfer coefficient is obtained, and equivalent conversion is performed to obtain a gap contact heat transfer coefficient. A contact pair is established between the cooling area and the outer surface of the workpiece. A relative motion speed field is applied. When a contact pair is searched, the gap contact heat transfer coefficient is activated, and the heat transfer process of the thermal boundary is automatically calculated. When no contact pair is searched, the temperature field is calculated according to the heat exchange condition of the natural air cooling area. Finally, global thermal coupling transient solution is carried out. The application realizes accurate simulation of the thermal coupling behavior under the mobile thermal boundary condition.

Description

Technical Field

[0001] This invention belongs to the field of numerical simulation of heat transfer and thermo-mechanical coupling, and specifically relates to a method and system for simulating a moving thermal boundary based on equivalent loading of gap contact heat transfer. Background Technology

[0002] In industrial production processes such as steel rolling, welding, additive manufacturing, and continuous casting, forced convection heat transfer is commonly observed on the surfaces of moving workpieces. Examples include high-pressure water descaling in steel rolling, localized water spray cooling in section steel, follow-up spray cooling in welding, airflow heat dissipation in additive manufacturing, and moving water spray cooling of continuously cast billets. Accurately simulating the thermo-mechanical coupling behavior under these moving thermal boundary conditions is the core foundation for predicting the distribution and evolution of the workpiece's temperature field, stress, and strain field.

[0003] Existing numerical simulation methods based on thermal boundaries can be mainly divided into the following two categories: The first category is fluid-structure conjugate heat transfer simulation, which involves simultaneously constructing fluid and solid domain models and solving the convective heat transfer field through fluid simulation. This type of method has high accuracy, but it suffers from problems such as large mesh size, huge computational load of dual-domain iteration, easy distortion of fluid mesh under high-speed moving conditions, and easy divergence in long-process simulations, resulting in poor engineering applicability.

[0004] The second category is the traditional moving boundary loading method, which dynamically applies convective heat transfer boundaries by retrieving workpiece surface elements step-by-step based on a user subroutine. This type of method does not require a fluid domain, but in scenarios such as moving workpieces passing through fixed cooling zones (e.g., steel sections passing through fixed water spray cooling zones), the convective heat transfer coefficient needs to be converted into a time function in combination with the moving speed and spatial position. Due to the diverse shapes of workpieces, establishing a set of surface element nodes is difficult, resulting in complex programming and extremely poor versatility.

[0005] In addition, existing equivalent modeling methods mostly simplify convective heat transfer to a uniformly distributed heat transfer coefficient. If simplified to a fixed uniform thermal boundary, there is a significant technical shortcoming that it cannot reflect the real-time evolution and distribution of local thermal stress during the moving cooling process. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a method and system for simulating moving thermal boundaries based on equivalent loading of gap contact heat transfer. By utilizing the equivalent mechanism across heat transfer modes, it balances efficient modeling, simulation accuracy, computational efficiency, solution stability, and versatility across multiple scenarios to simulate moving thermal boundaries. This method is applicable to efficient simulation modeling of forced convection heat transfer on workpiece surfaces in fields such as metallurgical rolling, welding, additive manufacturing, continuous casting, and heat treatment. It enables efficient, accurate, and stable simulation of moving thermal boundaries in multiple industrial scenarios, thereby solving the technical problems of traditional technologies, such as difficulty in directly applying moving boundary conditions, high computational costs, poor adaptability, and insufficient industry versatility.

[0007] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows: In a first aspect, embodiments of the present invention provide a method for simulating a moving thermal boundary based on equivalent loading of gap contact heat transfer, the method comprising the following steps: Step S1: Construct a three-dimensional solid geometric simulation model of the workpiece to be simulated, and construct a cooling area on the outside of the workpiece model based on the cooling medium coverage area; a set gap is left between the cooling area and the outer surface of the workpiece, so that the cooling area and the outer surface of the workpiece achieve heat exchange boundary conditions without generating structural contact stress. Step S2: For the target heat exchange condition, obtain the actual forced convection heat transfer coefficient; based on the equivalent principle of heat flow conservation, by setting the temperature of the cooling zone, the heat flux density is equivalently converted to obtain the gap contact heat transfer coefficient. Step S3: Establish a contact pair between the cooling zone and the outer surface of the workpiece; Step S4: Apply a relative motion velocity field to the workpiece and the cooling area according to the motion conditions to achieve equivalent loading of the moving boundary and automatically search for contact pairs; when a contact pair is found, automatically identify that the workpiece is currently in the cooling area and proceed to step S5; when no contact pair is found, automatically identify that the workpiece is currently in the natural air cooling area and proceed to step S6. Step S5: Activate the gap contact heat transfer coefficient, automatically calculate the heat transfer process of the cooling area and the outer surface of the workpiece in the virtual gap based on the gap contact heat transfer coefficient, realize the automatic loading of the moving thermal boundary, and proceed to step S7. Step S6: Calculate the temperature field based on the heat exchange conditions with the naturally air-cooled area, then proceed to step S7; Step S7: Determine whether all relative motion steps have been loaded; if yes, proceed to step S8; if no, the relative motion proceeds to the next step and proceeds to step S4. Step S8: Perform a global thermo-mechanical coupling transient solution for the three-dimensional temperature field, stress field, and strain field of the workpiece.

[0008] In a preferred embodiment of the present invention, in step S1, the cooling area is modeled according to the surface contour shape of a flat, curved, or irregularly shaped workpiece.

[0009] In a preferred embodiment of the present invention, in step S2, the actual forced convection heat transfer coefficient is obtained by means of empirical model derivation, fluid dynamics simulation or experimental calibration, to obtain the actual convection heat transfer coefficient under different fluid pressures, cooling medium temperatures and relative motion velocities.

[0010] In a preferred embodiment of the present invention, in step S2, the equivalent principle of heat flow conservation refers to the conservation of total interface heat flow, which is described as follows: the actual forced convection heat flux density and the gap contact heat conduction heat flux density are equivalently converted, and the instantaneous heat exchange is kept consistent before and after the equivalence by setting the temperature of the cooling area and the gap contact heat transfer coefficient.

[0011] As a preferred embodiment of the present invention, the formula for the actual forced convection heat flux density is as follows: (1) In equation (1), This represents the actual forced convection heat flux density. Indicates the convective heat transfer coefficient. This indicates the temperature difference between the wall surface and the cooling medium; The formula for the heat flux density of the gap contact heat transfer is as follows: (2) In equation (2), This indicates the heat flux density during gap contact heat transfer. Indicates the heat transfer coefficient of the gap contact. This indicates the temperature difference between the wall surface and the cooling area; Based on the conservation of heat flux, the heat flux density is equivalently transformed as follows: (3) Equivalent to: (4) By setting the temperature of the cooling zone, This achieves an equivalent conversion of the heat transfer coefficient, i.e. = .

[0012] In a preferred embodiment of the present invention, the gap contact heat transfer coefficient is a working condition parameter related to the type of cooling medium, the moving speed of the workpiece or tool, the fluid pressure, and the fluid temperature.

[0013] In a preferred embodiment of the present invention, the contact pair exists in a virtual gap.

[0014] In a preferred embodiment of the present invention, in step S4, the applied relative motion velocity field does not distinguish the source of motion.

[0015] In a preferred embodiment of the present invention, the relative motion velocity field includes workpiece motion, cooling zone motion, or both motion simultaneously.

[0016] Secondly, embodiments of the present invention also provide a moving thermal boundary simulation system based on equivalent loading of gap contact heat transfer. The system includes a model building module, a heat transfer coefficient equivalent conversion module, a contact pair construction module, a relative motion step loading module, a contact pair search module, a moving thermal boundary calculation module, an air-cooled temperature field calculation module, and a workpiece global thermo-mechanical coupling module; wherein... The model building module is used to build a three-dimensional solid geometric simulation model of the workpiece to be simulated, and to build a cooling area on the outside of the workpiece model based on the cooling medium coverage area; a set gap is left between the cooling area and the outer surface of the workpiece, so that the cooling area and the outer surface of the workpiece achieve heat exchange boundary conditions without generating structural contact stress. The heat transfer coefficient equivalent conversion module is used to obtain the true forced convection heat transfer coefficient for the target heat exchange condition; based on the equivalent principle of heat flow conservation, the heat flux density is equivalently converted by setting the temperature of the cooling area to obtain the gap contact heat transfer system. The contact pair building module is used to establish contact pairs between the cooling area and the outer surface of the workpiece; The relative motion step loading module is used to apply a relative motion velocity field to the workpiece and the cooling area according to the motion conditions to achieve equivalent loading of the moving boundary; it is also used to determine whether all relative motion steps have been loaded; if yes, the workpiece global thermo-coupling module is activated; if no, the relative motion velocity field corresponding to the next motion step is loaded. The contact pair search module is used to automatically search for contact pairs after each relative motion step is loaded; when a contact pair is found, it automatically identifies that the current area is in the cooling zone and starts the moving thermal boundary calculation module; when no contact pair is found, it automatically identifies that the current area is in the natural air-cooled zone and starts the air-cooled temperature field calculation module. The moving thermal boundary calculation module is used to activate the gap contact heat transfer coefficient and automatically calculate the heat transfer process of the cooling area and the outer surface of the workpiece in the virtual gap based on the gap contact heat transfer coefficient, so as to realize the automatic loading of the moving thermal boundary. The air-cooled temperature field calculation module is used to calculate the temperature field based on the heat exchange conditions with the natural air-cooled area; The workpiece global thermo-mechanical coupling module is used to perform global thermo-mechanical coupling transient solution of the workpiece's three-dimensional temperature field, stress field, and strain field.

[0017] The moving thermal boundary simulation method and system based on gap contact heat transfer equivalent loading provided in the embodiments of the present invention have at least the following beneficial effects: (1) High computational efficiency: No need for fluid domain modeling and dynamic mesh reconstruction, nor for actively traversing and searching surface elements to apply boundary conditions, significantly reducing computational overhead and making it suitable for long-process, multi-pass continuous transient simulation; (2) Good solution stability: The moving boundary loading is realized by relying on the automatic search characteristics of the contact interface, without mesh distortion and boundary loading oscillation problems, avoiding the technical defects of easy divergence in multi-step iteration in traditional methods; (3) Wide structural adaptability: The cooling area can be modeled according to different contour shapes such as flat plates, irregular steel sections, and curved components, effectively solving the problem of accurate loading of local heat exchange in irregular structures; (4) Strong versatility: A single modeling method can be adapted to mobile convection heat transfer scenarios in multiple fields such as metallurgy, welding, additive manufacturing, continuous casting and heat treatment, and has good reusability; (5) Controllable accuracy: Based on the heat flow conservation conversion of equivalent parameters, the simulation accuracy meets engineering requirements; (6) No additional structural stress: There is only a set gap between the cooling zone and the workpiece surface, which only realizes the heat exchange boundary conditions, does not generate any structural contact stress, and does not affect the mechanical state of the workpiece.

[0018] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of the moving thermal boundary simulation method and system based on the equivalent loading of gap contact heat transfer according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the clearance fit between the cooling area and the workpiece surface and the temperature field in an embodiment of the present invention; Figure 3 In this embodiment of the invention, the moving thermal boundary automatically updates the temperature field and stress field cloud maps at different times; Figure 4 This is a schematic diagram comparing a moving local thermal boundary and a fixed uniform thermal boundary in an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can also be combined with each other.

[0022] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of the embodiments of the present invention, the terms "first," "second," "third," "fourth," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, sometimes a subscript such as W1 may be written in a non-subscript form such as W1, and their meanings are consistent unless the distinction is emphasized.

[0023] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0024] This invention provides a method for simulating moving thermal boundaries based on equivalent loading of gap contact heat transfer. In numerical simulations of moving forced convection heat transfer, the heat transfer region moves across the workpiece surface, and the area where the convection heat transfer boundary conditions are applied changes in real time. Traditional fixed boundary methods struggle to handle this, and setting convection boundary conditions that vary with time and spatial location is complex. Furthermore, methods using a fixed surface domain with uniform thermal boundary conditions cannot reflect the real-time evolution and distribution of local thermal stress during the cooling process of the workpiece surface under moving thermal boundary conditions. To overcome the shortcomings of existing numerical simulation techniques for moving convection heat transfer, such as the difficulty in directly applying moving boundary conditions, high computational cost, poor solution stability, weak adaptability to irregular structures, low scenario versatility, and insufficient accuracy, this invention transforms the difficult-to-directly-apply moving convection heat transfer boundary into a mature gap contact heat transfer problem within the finite element method. This invention constructs a cooling zone located outside the workpiece, with a predetermined gap between this zone and the workpiece surface. A velocity field is applied to the workpiece or the cooling zone, and the spatial relationship between the workpiece and the cooling zone is automatically identified through contact search, eliminating the need to apply time-varying thermal boundary condition curves to numerous nodes on the workpiece surface individually. By offline calibration of the gap contact heat transfer coefficient and the equivalent convective heat transfer coefficient of the workpiece surface, heat flow conservation is ensured. This invention is applicable to scenarios such as descaling in rolling, controlled cooling, spray cooling in the secondary cooling zone of continuous casting, welding quenching during welding, and follow-up gas cooling in additive manufacturing. It significantly simplifies the modeling process and improves solution stability and versatility while maintaining accuracy.

[0025] like Figure 1 As shown, the moving thermal boundary simulation method based on gap contact heat transfer equivalent loading is applicable to moving forced convection heat transfer scenarios and includes the following steps: Step S1: Construct a three-dimensional solid geometric simulation model of the workpiece to be simulated, and construct a cooling area on the outside of the workpiece model based on the cooling medium coverage area; leave a set virtual gap between the cooling area and the outer surface of the workpiece, so that the cooling area and the outer surface of the workpiece achieve heat exchange boundary conditions without generating structural contact stress.

[0026] In this step, the cooling area is the area covered by the cooling medium. As the heat exchange area of ​​the equivalent fluid medium, it can be modeled according to the surface contour shape of various workpieces such as flat plates, curved surfaces and irregular cross sections, and a contact gap of a set width is reserved so as to achieve the heat exchange boundary conditions without generating structural contact stress.

[0027] Traditional methods require pre-determining the movement path of the heat transfer zone on the workpiece surface and applying time-varying thermal boundary conditions to the surface nodes step-by-step, resulting in complex programming and poor versatility. This step constructs a cooling zone on the outside of the workpiece and utilizes the gap heat transfer function of the contact algorithm to automatically update the heat transfer boundary with the relative movement of the workpiece and the cooling zone.

[0028] like Figure 2 As shown, the virtual gap, cooling zone, and temperature distribution are illustrated through a 3D schematic diagram, side view, and enlarged partial view of the cooling zone. Only a predetermined gap is left between the cooling zone and the workpiece surface; the heat transfer coefficient through this gap is equivalent to convective heat transfer, without generating any structural contact stress.

[0029] Step S2: For the target heat exchange condition, obtain the actual forced convection heat transfer coefficient; based on the equivalent principle of heat flow conservation, by setting the temperature of the cooling zone, the heat flux density is equivalently converted to obtain the gap contact heat transfer coefficient.

[0030] In this step, the actual forced convection heat transfer coefficient is obtained by means of empirical model derivation, fluid dynamics simulation or experimental calibration, to obtain the actual convection heat transfer coefficient under different fluid pressures, cooling medium temperatures and relative motion velocities.

[0031] The equivalent principle of heat flow conservation refers to the conservation of total interface heat flow, as described below: the actual forced convection heat flux density and the gap contact heat conduction heat flux density are equivalently converted, and the instantaneous heat exchange is kept consistent before and after equivalence by setting the temperature of the cooling zone and the gap contact heat transfer coefficient.

[0032] The formula for the actual forced convection heat flux density is as follows: (1) In equation (1), This represents the actual forced convection heat flux density. Indicates the convective heat transfer coefficient. This indicates the temperature difference between the wall surface and the cooling medium.

[0033] The formula for the heat flux density of the gap contact heat transfer is as follows: (2) In equation (2), This indicates the heat flux density during gap contact heat transfer. Indicates the heat transfer coefficient of the gap contact. This indicates the temperature difference between the wall surface and the cooling area.

[0034] Based on the conservation of heat flux, the heat flux density is equivalently transformed as follows: (3) Equivalent to: (4) By setting the temperature of the cooling zone, This achieves an equivalent conversion of the heat transfer coefficient, i.e. = The gap contact heat transfer coefficient is the equivalent interface contact heat transfer coefficient, which is a working condition parameter related to the type of cooling medium, the moving speed of the workpiece or tool, the fluid pressure, and the fluid temperature. Based on different forced convection heat transfer coefficients, different working conditions correspond to different values ​​of the gap contact heat transfer coefficient.

[0035] This step transforms the moving convection heat transfer boundary, which is difficult to load directly, into a mature gap contact heat transfer problem in the finite element method by numerical equivalent substitution across heat transfer modes. It does not rely on physical assumptions such as whether the fluid jet forms a stable thin medium. It only needs to ensure the conservation of the total heat flow at the equivalent interface before and after the heat transfer to achieve an equivalent simulation of the heat transfer effect.

[0036] Step S3: Establish a contact cooling area between the cooling area and the outer surface of the workpiece.

[0037] In this step, contact pairs are established between the working outer surface and the cooling area relative to the working outer surface to determine the virtual gap during the boundary movement process. A virtual gap exists only when a contact pair is calculated to exist during the movement, indicating the existence of a corresponding cooling area. This allows for the equivalent heat transfer coefficient and the corresponding heat transfer calculations. Through the cooperation of contact pairs and virtual gaps, a spatial search of the movable boundary is performed without the need for traditional convection-time curve loading or the conversion of space to time.

[0038] Step S4: Apply a relative motion velocity field to the workpiece and the cooling area according to the motion conditions to achieve equivalent loading of the moving boundary and automatically search for contact pairs; when a contact pair is found, automatically identify that the workpiece is currently in the cooling area and proceed to step S5; when no contact pair is found, automatically identify that the workpiece is currently in the natural air cooling area and proceed to step S6.

[0039] The relative velocity field applied in this step does not distinguish the source of motion—whether it is workpiece motion, cooling zone motion, or both motion simultaneously, as long as there is relative motion, the equivalent loading of the moving thermal boundary can be achieved by applying a relative velocity field.

[0040] like Figure 3 As shown, during the workpiece's movement, it passes through cooling zones arranged at different positions and natural air-cooling zones between these zones. When a contact pair is detected between the workpiece's outer surface and a cooling zone, this contact pair represents the corresponding cooling zone. The heat transfer process between the cooling zone and the workpiece's outer surface in the virtual gap can then be automatically calculated based on the gap contact heat transfer coefficient. The workpiece surface gradually cools within the contact zone. As the workpiece continues to move and exits the cooling zone, no contact pair will be detected, and it will then enter the natural air-cooling zone. Simultaneously, the workpiece's movement and the cooling zone's movement are relative, allowing for real-time calculation of the thermo-mechanical coupling of the moving temperature field and the structural field.

[0041] Step S5: Activate the gap contact heat transfer coefficient, automatically calculate the heat transfer process of the cooling area and the outer surface of the workpiece in the virtual gap based on the gap contact heat transfer coefficient, realize the automatic loading of the moving thermal boundary, and proceed to step S7.

[0042] Step S6: Calculate the temperature field based on the heat exchange conditions with the naturally air-cooled region, and proceed to step S7.

[0043] Step S7: Determine whether all relative motion steps have been loaded; if yes, proceed to step S8; if no, the relative motion proceeds to the next step and proceeds to step S4.

[0044] Step S8: Perform a global thermo-mechanical coupling transient solution for the three-dimensional temperature field, stress field, and strain field of the workpiece.

[0045] like Figure 4 As shown, when multiple sets of cooling water in different cooling zones intermittently impact and cool the surface of the workpiece during its movement, the temperature and stress evolution of the workpiece throughout the entire process, whether or not it is impacted by cooling water, can be calculated using the moving thermal boundary simulation based on the equivalent loading of gap contact heat transfer described in this embodiment. This simulation is more detailed and accurate than the temperature and structural response obtained under fixed uniform thermal boundary conditions.

[0046] Based on the same idea, this invention also provides a moving thermal boundary simulation system based on equivalent loading of gap contact heat transfer. The system includes a model building module, a heat transfer coefficient equivalent conversion module, a contact pair construction module, a relative motion step loading module, a contact pair search module, a moving thermal boundary calculation module, an air-cooled temperature field calculation module, and a workpiece global thermo-mechanical coupling module. The model building module is used to build a three-dimensional solid geometric simulation model of the workpiece to be simulated, and to build a cooling area on the outside of the workpiece model based on the cooling medium coverage area; a set gap is left between the cooling area and the outer surface of the workpiece, so that the cooling area and the outer surface of the workpiece achieve heat exchange boundary conditions without generating structural contact stress. The heat transfer coefficient equivalent conversion module is used to obtain the true forced convection heat transfer coefficient for the target heat exchange condition; based on the equivalent principle of heat flow conservation, the heat flux density is equivalently converted by setting the temperature of the cooling area to obtain the gap contact heat transfer system. The contact pair building module is used to establish contact pairs between the cooling area and the outer surface of the workpiece; The relative motion step loading module is used to apply a relative motion velocity field to the workpiece and the cooling area according to the motion conditions to achieve equivalent loading of the moving boundary; it is also used to determine whether all relative motion steps have been loaded; if yes, the workpiece global thermo-coupling module is activated; if no, the relative motion velocity field corresponding to the next motion step is loaded. The contact pair search module is used to automatically search for contact pairs after each relative motion step is loaded; when a contact pair is found, it automatically identifies that the current area is in the cooling zone and starts the moving thermal boundary calculation module; when no contact pair is found, it automatically identifies that the current area is in the natural air-cooled zone and starts the air-cooled temperature field calculation module. The moving thermal boundary calculation module is used to activate the gap contact heat transfer coefficient and automatically calculate the heat transfer process of the cooling area and the outer surface of the workpiece in the virtual gap based on the gap contact heat transfer coefficient, so as to realize the automatic loading of the moving thermal boundary. The air-cooled temperature field calculation module is used to calculate the temperature field based on the heat exchange conditions with the natural air-cooled area; The workpiece global thermo-mechanical coupling module is used to perform global thermo-mechanical coupling transient solution of the workpiece's three-dimensional temperature field, stress field, and strain field.

[0047] The system or device for executing the method in this embodiment of the invention can be a terminal or a server. The system includes a processor, a memory, and / or a transceiver, etc., and is connected via a communication bus. Each module can be implemented by a processor, a memory, and / or a transceiver, etc. The processor can be, but is not limited to, one or more microprocessors (MPUs), central processing units (CPUs), network processors (NPs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and other programmable logic devices, discrete gates, transistor logic devices, discrete hardware components, etc., or can be configured to implement one or more integrated circuits of this invention. The processor can perform various functions by running or executing software programs in the memory and calling data in the memory. The memory includes Random Access Memory (RAM), Read-Only Memory (ROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Compact Disc Read-Only Memory (CD-ROM), and / or Non-Volatile Memory (NVM), etc. The transceiver is used to communicate with network devices or terminal devices, and includes a receiver and a transmitter. The memory and transceiver can be integrated with the processor or exist independently.

[0048] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0049] It should also be noted that the moving thermal boundary simulation system based on gap contact heat transfer equivalent loading described in this embodiment corresponds to the moving thermal boundary simulation method based on gap contact heat transfer equivalent loading. The description and limitations of the method also apply to the system, and will not be repeated here.

[0050] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the following embodiments are only used to explain the present invention and do not constitute any limitation on the scope of protection of the present invention.

[0051] Example 1: This embodiment provides a method and system for simulating the moving thermal boundary under the high-speed moving cooling condition of high-pressure water jet descaling in hot rolling production lines.

[0052] First, a three-dimensional solid geometric simulation model of hot-rolled strip steel is constructed, and a cooling zone located on the outer side of the strip steel is created, with a predetermined gap between this zone and the upper surface of the strip steel. Second, the forced convection heat transfer coefficient is calibrated using an empirical heat flux density model and equivalently converted to the interfacial contact heat transfer coefficient. Then, a contact pair is established between the strip steel and the cooling zone, activating the equivalent heat transfer coefficient only within the narrow zone of the high-pressure water jet; the remaining areas are set to be under convection and radiation conditions with the surrounding air-cooled environment. Next, the rolling speed of the strip steel is applied (with the cooling zone fixed), and the automatic update of the water jet's moving heat transfer boundary is achieved based on the automatic search characteristics of the contact interface. Finally, a three-dimensional thermo-mechanical coupling simulation of the descaling process during strip steel rolling is completed.

[0053] Example 2: This embodiment provides a method and system for simulating the moving thermal boundary under the welding torch follow-up water cooling (i.e., welding rapid cooling) condition during arc welding.

[0054] First, a three-dimensional solid geometric simulation model of the welding plate is constructed, and a cooling zone located on the outer side of the plate is built. The forced convection heat transfer coefficient is calibrated based on the welding spray flow rate and moving speed, and then converted into the interfacial contact heat transfer coefficient. A spray zone that moves with the welding torch trajectory is established. Through contact search, the workpiece surface currently in the heat transfer zone is automatically identified and the equivalent interfacial contact heat transfer coefficient is activated, realizing that the spray cooling boundary moves synchronously with the welding torch, and completing the coupled simulation of the welding temperature field and thermal stress.

[0055] Example 3: This embodiment provides a method and system for simulating the moving thermal boundary under the condition of inert gas follow-up cooling in metal additive manufacturing.

[0056] This embodiment is basically the same as Embodiment 1, except that the convective heat transfer of the gas cooling medium is equivalent to gap contact heat conduction, and the equivalent interface contact heat transfer coefficient between the cooling area and the printed metal is set to achieve efficient simulation of the moving cooling boundary of the printed substrate and accurately predict the temperature gradient and deformation defects during the printing process.

[0057] This invention is applicable to all scenarios involving forced convection heat transfer with relative motion, including but not limited to: high-pressure water descaling in steel rolling, controlled cooling after rolling of section steel, secondary water spray cooling of continuously cast billets, welding quenching during welding, follow-up gas cooling in additive manufacturing, and moving air-cooled quenching of workpieces.

[0058] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0059] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed, and is not intended to limit the scope of the claimed invention, but merely to illustrate preferred embodiments of the invention. Those skilled in the art should understand that the scope of the invention is not limited to the specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for simulating a moving thermal boundary based on equivalent loading for gap contact heat transfer, characterized in that, The method includes the following steps: Step S1: Construct a three-dimensional solid geometric simulation model of the workpiece to be simulated, and construct a cooling area on the outside of the workpiece model based on the cooling medium coverage area; a set gap is left between the cooling area and the outer surface of the workpiece, so that the cooling area and the outer surface of the workpiece achieve heat exchange boundary conditions without generating structural contact stress. Step S2: For the target heat exchange condition, obtain the actual forced convection heat transfer coefficient; based on the equivalent principle of heat flow conservation, by setting the temperature of the cooling zone, the heat flux density is equivalently converted to obtain the gap contact heat transfer coefficient. Step S3: Establish a contact pair between the cooling zone and the outer surface of the workpiece; Step S4: Apply a relative motion velocity field to the workpiece and the cooling area according to the motion conditions to achieve equivalent loading of the moving boundary and automatically search for contact pairs; when a contact pair is found, automatically identify that the workpiece is currently in the cooling area and proceed to step S5; when no contact pair is found, automatically identify that the workpiece is currently in the natural air cooling area and proceed to step S6. Step S5: Activate the gap contact heat transfer coefficient, automatically calculate the heat transfer process of the cooling area and the outer surface of the workpiece in the virtual gap based on the gap contact heat transfer coefficient, realize the automatic loading of the moving thermal boundary, and proceed to step S7. Step S6: Calculate the temperature field based on the heat exchange conditions with the naturally air-cooled area, then proceed to step S7; Step S7: Determine whether all relative motion steps have been loaded. If so, proceed to step S8; If not, the relative motion proceeds to the next step and then to step S4; Step S8: Perform a global thermo-mechanical coupling transient solution for the three-dimensional temperature field, stress field, and strain field of the workpiece.

2. The method according to claim 1, characterized in that, In step S1, the cooling area is modeled according to the surface contour shape of the workpiece, which is a flat plate, curved surface, or irregular cross-section.

3. The method according to claim 1, characterized in that, In step S2, the actual forced convection heat transfer coefficient is obtained by means of empirical model derivation, fluid dynamics simulation or experimental calibration, to obtain the actual convection heat transfer coefficient under different fluid pressures, cooling medium temperatures and relative motion velocities.

4. The method according to claim 1, characterized in that, In step S2, the equivalent principle of heat flow conservation refers to the conservation of total interface heat flow, which is described as follows: the actual forced convection heat flux density and the gap contact heat conduction heat flux density are equivalently converted, and the instantaneous heat exchange is kept consistent before and after equivalence by setting the temperature of the cooling area and the gap contact heat transfer coefficient.

5. The method according to claim 4, characterized in that, The formula for the actual forced convection heat flux density is as follows: ，(1) In equation (1), This represents the actual forced convection heat flux density. Indicates the convective heat transfer coefficient. This indicates the temperature difference between the wall surface and the cooling medium; The formula for the heat flux density of the gap contact heat transfer is as follows: ，(2) In equation (2), This indicates the heat flux density during gap contact heat transfer. Indicates the heat transfer coefficient of the gap contact. This indicates the temperature difference between the wall surface and the cooling area; Based on the conservation of heat flux, the heat flux density is equivalently transformed as follows: ，(3) Equivalent to: ，(4) By setting the temperature of the cooling zone, This achieves an equivalent conversion of the heat transfer coefficient, i.e. = .

6. The method according to any one of claims 1 to 5, characterized in that, The gap contact heat transfer coefficient is a working condition parameter related to the type of cooling medium, the speed of the workpiece or tool, the fluid pressure, and the fluid temperature.

7. The method according to claim 1, characterized in that, The contact pairs exist within the virtual gaps.

8. The method according to claim 1, characterized in that, In step S4, the relative motion velocity field is loaded without distinguishing the source of motion.

9. The method according to claim 8, characterized in that, The relative motion velocity field includes workpiece motion, cooling zone motion, or both motion simultaneously.

10. A moving thermal boundary simulation system based on gap contact heat transfer equivalent loading, characterized in that, The system includes a model building module, a heat transfer coefficient equivalent conversion module, a contact pair construction module, a relative motion step loading module, a contact pair search module, a moving thermal boundary calculation module, an air-cooled temperature field calculation module, and a workpiece global thermo-mechanical coupling module; among which... The model building module is used to build a three-dimensional solid geometric simulation model of the workpiece to be simulated, and to build a cooling area on the outside of the workpiece model based on the cooling medium coverage area; a set gap is left between the cooling area and the outer surface of the workpiece, so that the cooling area and the outer surface of the workpiece achieve heat exchange boundary conditions without generating structural contact stress. The heat transfer coefficient equivalent conversion module is used to obtain the true forced convection heat transfer coefficient for the target heat exchange condition; based on the equivalent principle of heat flow conservation, the heat flux density is equivalently converted by setting the temperature of the cooling area to obtain the gap contact heat transfer system. The contact pair building module is used to establish contact pairs between the cooling area and the outer surface of the workpiece; The relative motion step loading module is used to apply a relative motion velocity field to the workpiece and the cooling area according to the motion conditions to achieve equivalent loading of the moving boundary; it is also used to determine whether all relative motion steps have been loaded; if yes, the workpiece global thermo-coupling module is activated; if no, the relative motion velocity field corresponding to the next motion step is loaded. The contact pair search module is used to automatically search for contact pairs after each relative motion step is loaded; when a contact pair is found, it automatically identifies that the current area is in the cooling zone and starts the moving thermal boundary calculation module; when no contact pair is found, it automatically identifies that the current area is in the natural air-cooled zone and starts the air-cooled temperature field calculation module. The moving thermal boundary calculation module is used to activate the gap contact heat transfer coefficient and automatically calculate the heat transfer process of the cooling area and the outer surface of the workpiece in the virtual gap based on the gap contact heat transfer coefficient, so as to realize the automatic loading of the moving thermal boundary. The air-cooled temperature field calculation module is used to calculate the temperature field based on the heat exchange conditions with the natural air-cooled area; The workpiece global thermo-mechanical coupling module is used to perform global thermo-mechanical coupling transient solution of the workpiece's three-dimensional temperature field, stress field, and strain field.

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