Tuyere design method, system, device and medium for laser selective melting device

Abstract

The present invention discloses a method, system, device and medium for designing an air vent of a laser selective melting device, wherein the method comprises: obtaining the design volume of the air vent of the laser selective melting device; designing the height of the air flow channel according to the size of the air inlet duct, and designing the guide area and the static pressure area according to the design volume and the height of the air flow channel; obtaining the friction resistance coefficient of the gap air outlet grille, and designing the shape of the main flow channel according to the friction resistance coefficient, so that the air pressure on each section of the guide area is equal; designing a simulation model according to the shape of the main flow channel, verifying the air vent, and printing the air vent after passing the verification. The present invention can solve the problem of uneven air outlet of large-scale laser selective melting air vents, and more efficiently design air vents with basically consistent air outlet flow rates at various positions of the porous mesh plate while minimizing the wind speed kinetic energy loss, so as to meet the removal of smoke and splashes during large-scale laser selective melting, and can be widely used in the field of laser additive manufacturing.

Description

Technical Field

[0001] The present invention relates to the field of laser additive manufacturing, and in particular to a tuyere design method, system, device and medium for a laser selective melting device. Background Art

[0002] Additive manufacturing technology is a processing technology that prints materials layer by layer through three-dimensional digital modeling. Among them, powder bed 3D printing technology is one of the more mature and main 3D printing forming technologies. During processing, a layer of material powder is evenly spread on the processing plane, and the control system controls the laser to output laser, and the laser is concentrated on the powder layer through the galvanometer to scan the processing pattern. The scanned powder is melted and solidified into a solid together with the parts under the powder layer. Through the continuous melting, solidification and superposition of layers of powder, it is finally formed into the desired product.

[0003] The inert gas circulation during the printing process prevents the molten metal from oxidizing. At the same time, the airflow above the powder bed can remove the by-products produced during the printing process from the powder bed to avoid pollution that affects the printing quality. With the demand for manufacturing large aerospace parts such as rockets and aircraft, large-scale laser selective melting equipment (SLM equipment) directly forming large components is the current development direction of the SLM field. The increase in format and the increase in the number of lasers will pose challenges to the design of the air outlet. The traditional manifold design is difficult to control the uniformity of the air outlet of large-scale SLM equipment. Uneven air outlets need to be redesigned, resulting in material waste and increased trial and error costs. Summary of the invention

[0004] In order to solve at least one of the technical problems existing in the prior art to a certain extent, the purpose of the present invention is to provide a tuyere design method, system, device and medium for a laser selective melting device based on the principle of static pressure air supply, so as to improve the uniformity of large-area wind field distribution.

[0005] The technical solution adopted by the present invention is:

[0006] A method for designing a tuyere for a laser selective melting device comprises the following steps:

[0007] Obtain the design volume of the tuyere of the laser selective melting device;

[0008] The height of the air flow channel is designed according to the size of the air inlet duct, and the guide area and the static pressure area are designed according to the design volume and the height of the air flow channel; wherein the guide area is arranged between the main channel and the gap air outlet grille, and the static pressure area is arranged between the gap air outlet grille and the porous mesh plate; one end of the guide area is connected to the air inlet duct, and after the gas enters the guide area from the air inlet duct, it flows from one end of the guide area to the other end of the guide area; the gas in the guide area enters the static pressure area through the gap air outlet grille, and the gas in the static pressure area is output through the porous mesh plate;

[0009] Obtain the friction resistance coefficient of the slot air outlet grille, and design the shape of the main flow channel according to the friction resistance coefficient so that the air pressure on each section of the guide area is equal;

[0010] A simulation model is designed according to the shape of the main channel, the air outlet is verified, and after the verification, the air outlet is printed using 3D printing technology.

[0011] Furthermore, the step of designing the shape of the main flow channel according to the friction resistance coefficient includes:

[0012] The cross section of the main flow channel is obtained according to the gap of the gap air outlet grille, and two adjacent cross sections are obtained in sequence according to the direction of gas flow;

[0013] The equivalent diameter is obtained according to the average diameter of the two sections, and the resistance loss along the way between the two sections is obtained according to the equivalent diameter, the average velocity of the gas flow in the main channel, and the gas density;

[0014] The dynamic pressure difference of the section is obtained according to the resistance loss along the way, the wind speed of the main channel at the next section position is obtained, and the height of the current main channel is obtained according to the wind speed and the gas flow rate; wherein the height of the current main channel is the vertical distance between the current main channel and the gap air outlet grille;

[0015] After traversing all the sections, the shape of the main flow channel is obtained.

[0016] Furthermore, the energy conservation equation is followed from section xi to section xi+1, and the calculation formula is as follows:

[0017] P(x i ) j +P(x i ) d =P(x i+1 ) j +P(x i+1 ) d +ΔP y +ΔP j

[0018] In the formula, P(x i ) j 、P(x i+1 ) j Main air duct upper section x i , cross section x i+1 Static pressure on i ) d 、P(x i+1 ) d Main air duct section x i , cross section x i+1 Dynamic pressure on the cross section; ΔP y From the cross section x iTo section x i+1 Resistance loss along the upper main air duct; ΔP j From the cross section x i Section to Section x i+1 Local resistance loss in the upper main air duct.

[0019] Furthermore, ΔP y The calculation formula is as follows:

[0020]

[0021] Where, λ(x) is the friction coefficient of the main air duct; D(x) is the equivalent diameter of the main air duct at (x1+x2) / 2; V(x) is the average flow velocity of the main air duct section at (x1+x2) / 2; ρ is the gas density in the air duct;

[0022] If long slits are used for air supply, local resistance can be ignored, ΔP j =0;

[0023]

[0024] Make the static pressure in the main air duct equal everywhere, P(x i ) j =P(x i+1 ) j , then the dynamic pressure drop between the two sections is equal to the resistance between the two sections:

[0025]

[0026] Furthermore, the slot air outlet grille is provided with a plurality of orifices arranged side by side along the flow direction of the gas, and the flow rate on the orifices is calculated by the following method:

[0027]

[0028] Among them, P s v is the static pressure of the protective gas in the tuyere; j is the flow rate caused by the static pressure difference; μ is the flow coefficient; ρ is the gas density; f0 is the orifice area;

[0029] To ensure that the outflow rate of each orifice is equal, the f0, ρ are equal.

[0030] Furthermore, each orifice corresponds to a section, and the calculation formula for the height of the main channel is as follows:

[0031]

[0032]

[0033]

[0034] In the formula, S i+1 is the area of ​​the i+1th section, h is the width of the main channel; Q is the total flow rate of the air inlet; i represents the i-th section, B is the coefficient; V d is the flow velocity in the inner flow channel caused by the dynamic pressure, Pd is the dynamic pressure of the protective gas in the tuyere, and ρ is the gas density.

[0035] Furthermore, the simulation model is designed according to the shape of the main channel to verify the tuyere, including:

[0036] The k-ε turbulence model is used to perform computational fluid simulation of the air flow, where the turbulent kinetic energy equation is as follows:

[0037]

[0038] Where ρ is the density of the gas, k is the kinetic energy of the turbulent flow, and u i is the molecular viscosity of the fluid, t is the time step, x i 、x j are position vectors, μ t represents the turbulent viscosity, σ k is the turbulent Prandtl constant for k, G k is the turbulent kinetic energy generated by the average velocity gradient, G b is the turbulent dynamics generated by buoyancy, ε is the dissipation rate of turbulent pulsation kinetic energy, γ M is the effect of turbulent expansion in compressible turbulence on the total dissipation rate, S k It is a custom source item;

[0039] The energy dissipation equation is as follows:

[0040]

[0041] In the formula, C 1ε , C2, C 3ε is a constant; ε is the turbulent Prandtl constant; v is the fluid velocity, S ε Is a custom source item.

[0042] Another technical solution adopted by the present invention is:

[0043] A tuyere design system for a laser selective melting device, comprising:

[0044] A volume range confirmation module is used to obtain the design volume of the tuyere of the laser selective melting device;

[0045] The area division module is used to design the height of the air flow channel according to the size of the air inlet duct, and to design the guide area and the static pressure area according to the design volume and the height of the air flow channel; wherein the guide area is arranged between the main channel and the slot air outlet grille, and the static pressure area is arranged between the slot air outlet grille and the porous mesh plate; one end of the guide area is connected to the air inlet duct, and after the gas enters the guide area from the air inlet duct, it flows from one end of the guide area to the other end of the guide area; the gas in the guide area enters the static pressure area through the slot air outlet grille, and the gas in the static pressure area is output through the porous mesh plate;

[0046] The main channel shape design module is used to obtain the friction resistance coefficient of the slot air outlet grille and design the shape of the main channel according to the friction resistance coefficient so that the air pressure on each section of the guide area is equal;

[0047] The verification printing module is used to design a simulation model according to the shape of the main channel, verify the air outlet, and print the air outlet through 3D printing technology after the verification is passed.

[0048] Another technical solution adopted by the present invention is:

[0049] A tuyere design device for a laser selective melting device, comprising:

[0050] at least one processor;

[0051] at least one memory for storing at least one program;

[0052] When the at least one program is executed by the at least one processor, the at least one processor implements the above method.

[0053] Another technical solution adopted by the present invention is:

[0054] A computer-readable storage medium stores a program executable by a processor, wherein the program executable by the processor is used to execute the method described above when executed by the processor.

[0055] The beneficial effects of the present invention are as follows: the present invention can solve the problem of uneven air outlet in large-scale laser selective melting, and can more efficiently design air outlets with basically consistent air flow rates at various positions of the porous mesh plate while minimizing wind speed kinetic energy loss, thereby meeting the requirements for removing smoke and splashes during large-scale laser selective melting. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the embodiments of the present invention or the drawings of related technical solutions in the prior art are introduced below. It should be understood that the drawings introduced below are only for the convenience of clearly describing some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0057] Figure 1 It is a flow chart of the steps of a method for designing an air outlet of a laser selective melting device based on the static pressure air supply principle in an embodiment of the present invention;

[0058] Figure 2 is an outflow diagram of an air outlet in an embodiment of the present invention;

[0059] Figure 3 is a schematic diagram of flow conservation in an inner flow channel in an embodiment of the present invention;

[0060] Figure 4 Schematic diagram of the structure of the air outlet in the embodiment of the present invention. DETAILED DESCRIPTION

[0061] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limitations of the present invention. For the step numbers in the following embodiments, they are only provided for the convenience of explanation, and the order between the steps is not limited in any way, and the execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0062] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0063] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0064] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0065] like Figure 1 As shown, this embodiment provides a method for designing an air outlet of a laser selective melting device based on the principle of static pressure air supply, comprising the following steps:

[0066] S1. Dimension planning: Design reasonable length, width and height of the tuyere according to the molding format that the laser selective melting device needs to meet. Design the tuyere size provided by the laser selective melting device with different molding formats, and leave processing allowance.

[0067] S2. Internal structural division of the air outlet: Design the initial air flow channel width according to the size of the air inlet duct, and then design the guide area and static pressure area; as well as the thickness of the straightened porous mesh plate.

[0068] Specifically, the width of the porous mesh plate is not less than 10 mm, and the initial width of the air flow channel is the same as the diameter of the air inlet duct.

[0069] S3. Calculate friction resistance, local resistance, and flow conservation equation. Calculate friction resistance: Obtain the friction resistance coefficient by consulting, and obtain the equivalent diameter from the average diameter of the two sections of the main channel. The resistance loss along the two sections can be obtained from the equivalent diameter, the average velocity of the gas in the main channel, and the gas density; According to the flow conservation equation: To make the static pressure of two adjacent sections constant, the dynamic pressure reduction between the two adjacent sections is equal to the calculated resistance loss along the way; Calculate the wind speed of the main channel at the next section position from the section dynamic pressure difference, calculate the height of the current main channel from the flow rate and the height of the wind channel, and then obtain the main channel shape of the wind channel.

[0070] See also Figure 2 and Figure 3 Specifically, the fan delivers air through the circulation duct at a certain frequency, passes through the inside of the vent, and is discharged from the holes of the slit air outlet grille. The flow rate Q generated by the fan in the duct is set by the set wind speed outflow angle α (α ≥ 60°), and the theoretical outflow velocity v k Calculate the outlet area f0 and select the appropriate orifice area and quantity according to the air outlet size. The calculation formula is as follows:

[0071]

[0072]

[0073] The local resistance loss of the air duct can be simplified as:

[0074]

[0075] Therefore, the calculation formula for the flow velocity in the inner channel of section i+1 is:

[0076]

[0077] Calculate the main channel width, specifically: Calculate based on the calculated gas flow velocity at the flow channel in the fracture:

[0078] Cross-sectional area:

[0079]

[0080] Duct width:

[0081]

[0082] S i+1 is the area of ​​the i+1th section, w i+1 is the height of the i+1th node.

[0083] By analogy, the width of each orifice section is calculated one by one, and then the structure of the specific main channel is generated, such as Figure 4 shown.

[0084] S4. Simulation verification: Use computational fluid simulation software to set the inlet flow rate and outlet pressure, and use the k-ε turbulence model for simulation. Place fine-tuning guide plate correction: According to the simulation results, locally design the guide plate for correction and then simulate again. FDM prints the air outlet.

[0085] Computational fluid simulation (CFD) large-format wind field. Specifically, the designed tuyere is assembled into the molding chamber of the equipment. Solidworks flow simulation software is used to define the inlet flow value and the outlet static pressure as 1 atmosphere. The grid is automatically divided to a density less than the orifice. The k-ε turbulence model is used for fluid simulation. The contour wind speed distribution map of the horizontal surface of the substrate is intercepted to view the wind field distribution. For uneven air outlets, a fine-tuning drainage plate is added inside the tuyere. The simulation steps are repeated until the results show uniform air outlet. Finally, FDM is used to print the tuyere and the assembly is put into the laser selective melting equipment for production.

[0086] In some optional embodiments, the uniformity of the air outlet is determined based on the plane contour wind speed diagram obtained by computational fluid simulation, and a guide plate is provided in the inner flow channel at a local uneven location so that the protective gas tends to be sprayed out evenly.

[0087] Using the k-ε turbulence model, the turbulent kinetic energy equation is:

[0088]

[0089] Energy dissipation equation:

[0090]

[0091] G k is the turbulent kinetic energy generated by the average velocity gradient; G b Turbulence dynamics caused by buoyancy; C 1ε , C2, C 3ε is a constant; k is the turbulent Prandtl constant of k; γ M is the effect of turbulent expansion in compressible turbulence on the total dissipation rate; ρ is the density of argon; u i is the gas velocity, x i is the position vector; t is the time step; μ is the molecular viscosity of the fluid; μ t is the turbulent viscosity; S k and S ε is a user-defined source term.

[0092] In summary, compared with the existing laser selective melting tuyere design method, the method of this embodiment can meet the design of uniform tuyere for large-size laser selective melting equipment while saving costs, ensure the uniformity of airflow ejection, and improve the removal rate of splashing smoke and dust.

[0093] This embodiment also provides a tuyere design system for a laser selective melting device, comprising:

[0094] A volume range confirmation module is used to obtain the design volume of the tuyere of the laser selective melting device;

[0095] The area division module is used to design the height of the air flow channel according to the size of the air inlet duct, and to design the guide area and the static pressure area according to the design volume and the height of the air flow channel; wherein the guide area is arranged between the main channel and the slot air outlet grille, and the static pressure area is arranged between the slot air outlet grille and the porous mesh plate; one end of the guide area is connected to the air inlet duct, and after the gas enters the guide area from the air inlet duct, it flows from one end of the guide area to the other end of the guide area; the gas in the guide area enters the static pressure area through the slot air outlet grille, and the gas in the static pressure area is output through the porous mesh plate;

[0096] The main channel shape design module is used to obtain the friction resistance coefficient of the slot air outlet grille and design the shape of the main channel according to the friction resistance coefficient so that the air pressure on each section of the guide area is equal;

[0097] The verification printing module is used to design a simulation model according to the shape of the main channel, verify the air outlet, and print the air outlet through 3D printing technology after the verification is passed.

[0098] A tuyere design system for a laser selective melting device in this embodiment can execute a tuyere design method for a laser selective melting device provided in a method embodiment of the present invention, can execute any combination of implementation steps of the method embodiment, and has the corresponding functions and beneficial effects of the method.

[0099] This embodiment also provides a tuyere design device for a laser selective melting device, comprising:

[0100] at least one processor;

[0101] at least one memory for storing at least one program;

[0102] When the at least one program is executed by the at least one processor, the at least one processor implements Figure 1 The method shown.

[0103] A tuyere design device for a laser selective melting device in this embodiment can execute a tuyere design method for a laser selective melting device provided in a method embodiment of the present invention, can execute any combination of implementation steps of the method embodiment, and has the corresponding functions and beneficial effects of the method.

[0104] The present application also discloses a computer program product or a computer program, which includes a computer instruction stored in a computer-readable storage medium. A processor of a computer device can read the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the computer device executes Figure 1 The method shown.

[0105] This embodiment also provides a storage medium, which stores instructions or programs that can execute a tuyere design method for a laser selective melting device provided by an embodiment of the method of the present invention. When the instructions or programs are run, any combination of implementation steps of the method embodiment can be executed, and the corresponding functions and beneficial effects of the method can be obtained.

[0106] In some selectable embodiments, the function / operation mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the function / operation involved, the two boxes shown in succession can actually be executed substantially simultaneously or the boxes can sometimes be executed in reverse order. In addition, the embodiment presented and described in the flow chart of the present invention is provided by way of example, for the purpose of providing a more comprehensive understanding of technology. The disclosed method is not limited to the operation and logic flow presented herein. Selectable embodiments are expected, wherein the order of various operations is changed and the sub-operation of a part for which is described as a larger operation is performed independently.

[0107] In addition, although the present invention is described in the context of functional modules, it should be understood that, unless otherwise specified, one or more of the functions and / or features described may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in separate physical devices or software modules. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the present invention. More specifically, in view of the properties, functions, and internal relationships of the various functional modules in the device disclosed herein, the actual implementation of the module will be understood within the conventional skills of the engineer. Therefore, those skilled in the art can implement the present invention set forth in the claims without excessive experimentation using ordinary techniques. It is also understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0108] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0109] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0110] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0111] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0112] In the above description of this specification, the description with reference to the terms "one embodiment / example", "another embodiment / example" or "certain embodiments / examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0113] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

[0114] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the above embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for designing a tuyere for a laser selective melting device, characterized in that: The following steps are involved: Obtain the design volume of the tuyere of the laser selective melting device; The height of the air flow channel is designed according to the size of the air inlet duct, and the guide area and the static pressure area are designed according to the design volume and the height of the air flow channel; wherein the guide area is arranged between the main channel and the gap air outlet grille, and the static pressure area is arranged between the gap air outlet grille and the porous mesh plate; one end of the guide area is connected to the air inlet duct, and after the gas enters the guide area from the air inlet duct, it flows from one end of the guide area to the other end of the guide area; the gas in the guide area enters the static pressure area through the gap air outlet grille, and the gas in the static pressure area is output through the porous mesh plate; Obtain the friction resistance coefficient of the slot air outlet grille, and design the shape of the main flow channel according to the friction resistance coefficient so that the air pressure on each section of the guide area is equal; Design a simulation model based on the shape of the main channel, verify the tuyere, and after passing the verification, print the tuyere using 3D printing technology; The designing of the shape of the main flow channel according to the friction resistance coefficient includes: The cross section of the main flow channel is obtained according to the gap of the gap air outlet grille, and two adjacent cross sections are obtained in sequence according to the direction of gas flow; The equivalent diameter is obtained according to the average diameter of the two sections, and the resistance loss along the way between the two sections is obtained according to the equivalent diameter, the average velocity of the gas flow in the main channel, and the gas density; The dynamic pressure difference of the section is obtained according to the resistance loss along the way, the wind speed of the main channel at the next section position is obtained, and the height of the current main channel is obtained according to the wind speed and the gas flow rate; wherein the height of the current main channel is the vertical distance between the current main channel and the gap air outlet grille; After traversing all the sections, the shape of the main flow channel is obtained; From the cross section x i To section x i+1 Following the energy conservation equation, the calculation formula is as follows: P(x i ) j +P(x i ) d =P(x i+1 ) j +P(x i+1 ) d +ΔP y +ΔP j In the formula, P(x i ) j 、P(x i+1 ) j Main air duct upper section x i , cross section x i+1 Static pressure on the i ) d 、P(x i+1 ) d Main air duct section x i , cross section x i+1 Dynamic pressure on y From the cross section x i To section x i+1 Resistance loss along the upper main air duct; ΔP j From the cross section x i To section x i+1 Local resistance loss in the upper main air duct; ΔP y The calculation formula is as follows: Where, λ(x) is the friction coefficient of the main air duct; D(x) is the equivalent diameter of the main air duct at (x1+x2) / 2; V(x) is the average flow velocity of the main air duct section at (x1+x2) / 2; ρ is the gas density in the air duct; If long slits are used for air supply, local resistance can be ignored, ΔP j =0; Make the static pressure in the main air duct equal everywhere, P(x i ) j =P(x i+1 ) j , then the dynamic pressure drop between the two sections is equal to the resistance between the two sections: The slot air outlet grille is provided with a plurality of orifices arranged side by side along the flow direction of the gas, and the flow rate at the orifices is calculated by the following method: Among them, P s v is the static pressure of the protective gas in the tuyere; j is the flow rate caused by the static pressure difference; μ is the flow coefficient; ρ is the gas density; f0 is the orifice area; To ensure that the outflow rate of each orifice is equal, the f0, ρ is equal; Each orifice corresponds to a section, and the calculation formula for the height of the main channel is as follows: In the formula, S i+1 is the area of ​​the i+1th section, h is the width of the main channel; Q is the total flow rate of the air inlet; i represents the i-th section, B is the coefficient; V d is the flow velocity in the inner channel caused by dynamic pressure, P d is the dynamic pressure of the protective gas in the tuyere, and ρ is the gas density.

2. The method for designing a tuyere for a laser selective melting device according to claim 1, characterized in that: The simulation model is designed according to the shape of the main channel to verify the air outlet, including: The k-ε turbulence model is used to perform computational fluid simulation of the air flow, where the turbulent kinetic energy equation is as follows: Where ρ is the density of the gas, k is the kinetic energy of the turbulent flow, and u i is the molecular viscosity of the fluid, t is the time step, x i 、x j are position vectors, μ t represents the turbulent viscosity, σ k is the turbulent Prandtl constant for k, G k is the turbulent kinetic energy generated by the average velocity gradient, G b is the turbulent kinetic energy generated by buoyancy, ε is the dissipation rate of turbulent pulsation kinetic energy, γ M is the effect of turbulent expansion in compressible turbulence on the total dissipation rate, T k Is a custom source item.

3. A tuyere design system for a laser selective melting device, applied to a tuyere design method for a laser selective melting device according to claim 1 or 2, characterized in that: include: A volume range confirmation module is used to obtain the design volume of the tuyere of the laser selective melting device; The area division module is used to design the height of the air flow channel according to the size of the air inlet duct, and to design the guide area and the static pressure area according to the design volume and the height of the air flow channel; wherein the guide area is arranged between the main channel and the slot air outlet grille, and the static pressure area is arranged between the slot air outlet grille and the porous mesh plate; one end of the guide area is connected to the air inlet duct, and after the gas enters the guide area from the air inlet duct, it flows from one end of the guide area to the other end of the guide area; the gas in the guide area enters the static pressure area through the slot air outlet grille, and the gas in the static pressure area is output through the porous mesh plate; The main channel shape design module is used to obtain the friction resistance coefficient of the slot air outlet grille and design the shape of the main channel according to the friction resistance coefficient so that the air pressure on each section of the guide area is equal; The verification printing module is used to design a simulation model according to the shape of the main channel, verify the air outlet, and print the air outlet through 3D printing technology after passing the verification.

4. A tuyere design device for a laser selective melting device, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method according to any one of claims 1 to 2.

5. A computer-readable storage medium storing a program executable by a processor, characterized in that: The processor-executable program is used to perform the method according to any one of claims 1 to 2 when executed by the processor.

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