A Venturi compound atomization device

Abstract

The present invention discloses a Venturi composite gas atomization device, which belongs to the field of metal additive manufacturing technology, and includes a smelting chamber and an atomization chamber; the atomization chamber includes a guide nozzle, a Venturi tube and an atomizing spray disc, and the guide nozzle is connected to the smelting chamber and the Venturi tube; the Venturi tube is used to form a stable air pressure in the throat section by connecting to the air source, and pre-crush the molten metal in the throat section, and spray the molten metal in the throat section after pre-crushing to form a gas-liquid mixed jet; the atomizing spray disc is located above the gas-liquid mixed jet and is used to spray a supersonic airflow toward the gas-liquid mixed jet to atomize the molten metal in the gas-liquid mixed jet. The Venturi composite gas atomization device of the present invention solves the problem that the existing equipment cannot effectively control the air pressure at the outlet of the guide nozzle and cannot further reduce the initial characteristic size of the molten metal, so as to improve the stability and efficiency of the atomization operation, and is conducive to obtaining atomized powder with higher quality and smaller particle size.

Description

Technical Field

[0001] The invention belongs to the technical field of metal additive manufacturing, and in particular relates to a Venturi composite gas atomization device. Background Art

[0002] In recent years, the application scale of metal additive manufacturing technology in aerospace, automobile manufacturing, biomedicine, industrial molds and other fields has continued to grow, and the consumption of metal powder raw materials used in additive manufacturing has also increased accordingly. At present, iron-based, aluminum-based, copper-based, nickel-based and other powders are generally produced by vacuum induction melting inert gas atomization process (VIGA). In the VIGA process, the molten metal forms a cylindrical molten metal flow through the guide nozzle installed under the tundish. The mass flow rate of the molten metal significantly affects the yield and particle size distribution of the powder prepared by the VIGA process. The power of the molten metal passing through the guide nozzle depends on the hydraulic pressure difference and the air pressure difference. The air pressure difference is the difference between the air pressure of the melt surface in the tundish and the air pressure at the outlet of the guide nozzle. Although the air pressure of the melt surface in the tundish can be maintained relatively stable, the air pressure at the outlet of the guide nozzle fluctuates violently with the atomization operation. Therefore, the air pressure difference fluctuates violently with the atomization operation, causing the mass flow rate of the molten metal to fluctuate violently with the atomization operation. Conventional VIGA process equipment cannot interfere with the air pressure at the outlet of the guide nozzle. Therefore, the mass flow rate of the molten metal fluctuates dramatically over time during production using conventional VIGA process equipment, making it difficult to always maintain the high efficiency of the atomization operation.

[0003] On the other hand, since the initial characteristic size of the metal molten in conventional VIGA process equipment is consistent with the aperture of the outlet at the end of the guide nozzle, the aperture of the outlet at the end of the guide nozzle is limited by the initial characteristic size of the metal melt. In order to prevent the guide nozzle from being blocked, the aperture of the outlet at the end of the guide nozzle of conventional VIGA process equipment can often only be designed within the range of 3-6mm. At the same time, the particle size of the atomized powder is also related to the initial characteristic size of the metal melt, which makes it impossible to further reduce the particle size of the atomized powder.

[0004] Therefore, the existing technology needs to be improved and developed. Summary of the invention

[0005] The purpose of the present invention is to provide a Venturi composite gas atomization device to solve the problem that the existing equipment cannot effectively control the gas pressure at the outlet of the guide nozzle and cannot further reduce the initial characteristic size of the metal melt, so as to improve the stability and efficiency of the atomization operation and facilitate the acquisition of atomized powder with higher quality and smaller particle size.

[0006] In a first aspect, the present invention provides a Venturi composite aerosolization device, comprising:

[0007] A smelting chamber, wherein the smelting chamber is used to smelt the alloy mother material into a liquid metal melt;

[0008] An atomization chamber, the atomization chamber comprising a guide nozzle, a venturi tube and an atomizing spray disc, the guide nozzle connecting the smelting chamber and the venturi tube, the terminal outlet of the guide nozzle being located at the throat section of the venturi tube and the throat section being arranged parallel to a horizontal plane, the guide nozzle being used to guide the molten metal to the inside of the throat section; the venturi tube being used to form a stable air pressure in the throat section by connecting to an air source, and to pre-crush the molten metal in the throat section, and to spray the molten metal in the throat section after pre-crushing to form a gas-liquid mixed jet; the atomizing spray disc being located above the gas-liquid mixed jet and being used to spray a supersonic airflow toward the gas-liquid mixed jet to atomize the molten metal in the gas-liquid mixed jet.

[0009] The Venturi composite gas atomization equipment provided by the present invention utilizes the characteristic that the air pressure in the throat section of the Venturi tube has higher controllability to control the air pressure at the end of the guide nozzle, thereby avoiding drastic fluctuations in the atomization operation, ensuring the stability and efficiency of the atomization operation, and being conducive to obtaining high-quality atomized powder; at the same time, the gas in the Venturi tube effectively reduces the initial characteristic size of the metal melt by pre-crushing the metal melt, thereby being conducive to obtaining atomized powder with a smaller particle size, and at the same time avoiding the limitation of the initial characteristic size of the atomized melt by the outlet aperture at the end of the guide nozzle, and the aperture of the outlet at the end of the guide nozzle is allowed to be designed to be larger, and the risk of clogging of the guide nozzle is reduced.

[0010] Furthermore, the venturi tube includes an outer shell that encloses a flow channel, and the outer shell as a multi-layer structure includes an inner layer, an insulation layer and a protective layer from the inside to the outside; the inner layer is made of a high temperature resistant and corrosion resistant material; the insulation layer is made of a insulation material; and the protective layer is made of a protective material.

[0011] This multi-layer structure design not only increases the service life of the Venturi tube, but also ensures the stability of the atomization process. The stable internal temperature and structural integrity help maintain the smooth movement of the metal melt and the stability of the airflow, thereby improving the atomization efficiency and product quality.

[0012] Furthermore, the flow channel includes an air chamber, an air inlet section, the throat section, a diffuser section and an air outlet section which are connected in sequence, the cross-sectional area of ​​the air chamber is constant and larger than the cross-sectional area of ​​the throat section, and the air chamber is used to connect to an air source; the cross-sectional area of ​​the air inlet section gradually decreases toward the throat section; the cross-sectional area of ​​the throat section is constant; the cross-sectional area of ​​the diffuser section gradually increases toward the throat section; the cross-sectional area of ​​the air outlet section is constant and smaller than the cross-sectional area of ​​the air chamber, and the air outlet section is used to spray out the gas-liquid mixed jet.

[0013] Through this structural design, the present application can form a relatively stable air pressure environment in the Venturi tube, thereby reducing the fluctuation of the mass flow rate of the metal melt and improving the stability and efficiency of the atomization process.

[0014] Furthermore, the flow channel includes an air chamber, an air inlet section, the throat section, a diffuser section and an air outlet section which are connected in sequence, the cross-sectional area of ​​the air chamber is constant and larger than the cross-sectional area of ​​the throat section, and the air chamber is used to connect to an air source; the cross-sectional area of ​​the air inlet section gradually decreases toward the throat section; the cross-sectional area of ​​the throat section is constant; the cross-sectional area of ​​the diffuser section gradually increases toward the direction away from the throat section; the air outlet section includes a straight pipe section and an arc-shaped transition section with constant cross-sectional area, the arc-shaped transition section connects the straight pipe section and the diffuser section, and the cross-sectional area of ​​the arc-shaped transition section gradually decreases toward the direction away from the diffuser section, and the air outlet section is used to spray out the gas-liquid mixed jet.

[0015] The arc-shaped transition section reduces the turbulence and energy loss of the air flow and improves the stability of the air flow. This helps to maintain a stable air pressure in the throat section, thereby ensuring the stability of the mass flow rate of the metal melt.

[0016] Furthermore, the size of the air intake section satisfies:

[0017] ;

[0018] in, is the inlet inner diameter of the air inlet section, is the inner diameter of the throat section, is the length of the air intake section;

[0019] The dimensions of the diffuser section satisfy:

[0020] ;

[0021] in, is the outlet inner diameter of the diffuser section, is the length of the diffuser section.

[0022] Furthermore, the gas velocity in the throat section satisfies:

[0023] ;

[0024] in, is the gas velocity in the throat section, is the gas adiabatic index, is the gas constant, is the gas temperature.

[0025] Furthermore, the relationship between the inlet air pressure of the air intake section and the air pressure of the throat section satisfies:

[0026] ;

[0027] in, is the air pressure in the throat section, is the inlet pressure of the air inlet section, is the second pressure loss coefficient, is the gas density, is the acceleration due to gravity, is the vertical distance between the geometric center of the throat section cross section and the reference plane, wherein the reference plane is a plane parallel to the axis of the Venturi tube, is the vertical distance between the geometric center of the inlet cross section and the reference plane, is the first pressure loss coefficient.

[0028] Furthermore, the atomization chamber is provided with a baffle, which is arranged opposite to the Venturi tube and is used to prevent the gas-liquid mixed jet from impacting the inner wall of the atomization chamber; the atomization spray disc is located between the baffle and the Venturi tube.

[0029] Furthermore, it also includes a cyclone separator, a dust collector, a return fan and a heater connected in sequence, the cyclone separator is connected to the atomization chamber and is used to separate particles in the gas output by the atomization chamber; the dust collector is used to separate particles in the gas output by the cyclone separator; the return fan is used to suck the gas processed by the dust collector; the heater is used to heat the gas output by the return fan, and the heater is connected to the venturi tube so that the heated gas can be connected to the venturi tube as a gas source.

[0030] Furthermore, the atomizing spray disc includes an air inlet pipe, an air inlet chamber and a LAVAL type flow channel which are connected in sequence, and the angle between the center line of the LAVAL type flow channel and the center line of the Venturi tube is in the range of 70°-100°.

[0031] As can be seen from the above, the guide nozzle in the Venturi composite gas atomization equipment of the present invention is connected to the throat section of the Venturi tube. Since the air pressure in the throat section of the Venturi tube is more controllable, the air pressure at the outlet of the guide nozzle end can be more easily controlled through the Venturi tube, thereby avoiding drastic fluctuations in the atomization operation and ensuring the stability and efficiency of the atomization operation; at the same time, the molten metal flowing out of the end of the guide nozzle and the inert gas in the Venturi tube collide and shear in the subsequent flow process, thereby pre-crushing the molten metal, greatly reducing the characteristic size of the molten metal, helping to reduce the particle size of the atomized powder, and improving the fine powder recovery rate. At the same time, the limitation of the aperture of the outlet at the end of the guide nozzle on the initial characteristic size of the atomized melt is avoided, and the aperture of the outlet at the end of the guide nozzle is allowed to be designed to be larger, and the risk of clogging of the guide nozzle is reduced.

[0032] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or be understood by implementing the embodiments of the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic structural diagram of a Venturi composite gas atomization device provided in an embodiment of the present invention.

[0034] Figure 2 It is a cross-sectional view of the first venturi tube in the embodiment of the present invention.

[0035] Figure 3 4 is a cross-sectional view of a second venturi tube in an embodiment of the present invention.

[0036] Figure 4 Parameter design diagram of the venturi tube in the embodiment of the present invention.

[0037] Figure 5 Schematic diagram of the structure of the atomizing spray disc in an embodiment of the present invention.

[0038] Figure 6 This is a design diagram of the angle parameters between the center line of a LAVAL-type flow channel and the center line of the Venturi tube in an embodiment of the present invention.

[0039] Figure 7 This is a design diagram of angle parameters between the center lines of multiple LAVAL-type flow channels and the center line of the Venturi tube in an embodiment of the present invention.

[0040] Description of labels:

[0041] 100, smelting chamber; 200, atomizing chamber; 210, guide nozzle; 220, venturi tube; 221, throat section; 222, shell; 223, air chamber; 224, air inlet section; 225, expansion section; 226, air outlet section; 230, atomizing spray disc; 231, air inlet pipe; 232, air inlet chamber; 233, LAVAL type flow channel; 240, baffle; 300, cyclone separator; 400, dust collector; 500, return air fan; 600, heater. DETAILED DESCRIPTION

[0042] The embodiments of the present invention are described in detail below, examples of which 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 cannot be understood as limiting the present invention.

[0043] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0044] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0046] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0047] Reference Figure 1 The present invention provides a Venturi composite aerosolization device, comprising:

[0048] A smelting chamber 100, wherein the smelting chamber 100 is used to smelt the alloy mother material into a liquid metal melt;

[0049] The atomizing chamber 200 includes a guide nozzle 210, a venturi tube 220 and an atomizing spray disc 230. The guide nozzle 210 connects the smelting chamber 100 and the venturi tube 220. The end outlet of the guide nozzle 210 is located at the throat section 221 of the venturi tube 220, and the throat section 221 is arranged parallel to the horizontal plane. The guide nozzle 210 is used to guide the metal melt to the inside of the throat section 221; the venturi tube 220 is used to form a stable air pressure in the throat section 221 by connecting to the air source, and pre-crush the metal melt in the throat section 221, and spray the metal melt in the throat section 221 after pre-crushing to form a gas-liquid mixed jet; the atomizing spray disc 230 is located above the gas-liquid mixed jet and is used to spray a supersonic airflow toward the gas-liquid mixed jet to atomize the metal melt in the gas-liquid mixed jet.

[0050] The core innovation of this application is to introduce the Venturi tube as a key component for metal melt atomization. The throat section of the Venturi tube forms a stable air pressure, which solves the problem of air pressure fluctuation at the outlet of the guide nozzle in traditional technology. At the same time, the Venturi tube pre-crushes the metal melt, effectively reducing the initial characteristic size of the metal melt. This design not only stabilizes the mass flow rate of the metal melt, but also creates conditions for the production of finer metal powders.

[0051] In the present application, the melting chamber adopts a vacuum induction melting furnace structure, and an induction coil and a crucible are arranged inside. The melting chamber maintains a low oxygen environment through a vacuum system, and the induction coil generates an electromagnetic field to heat the alloy masterbatch in the crucible to melt it into a liquid metal melt.

[0052] The atomization chamber is a sealed metal box structure, which is equipped with a guide nozzle, a venturi tube and an atomizing spray disc. The guide nozzle is made of high-temperature resistant ceramic material and has a conical structure. The large end is connected to the smelting chamber, and the small end extends into the throat section of the venturi tube. The venturi tube is made of high-temperature resistant composite materials, including an air intake section, a throat section and a diffuser section connected in sequence. The throat section of the venturi tube is arranged parallel to the horizontal plane. This design helps to stabilize the flow of the molten metal. The atomizing spray disc is located above the outlet of the venturi tube and adopts a ring nozzle array structure.

[0053] During operation, the liquid metal melt first enters the throat section of the Venturi tube through the guide nozzle. The Venturi tube is connected to low-pressure gas through an external gas source, forming a stable negative pressure or slightly positive pressure environment in the throat section. This stable air pressure condition effectively solves the problem of air pressure fluctuation at the outlet of the guide nozzle in traditional technology, thereby stabilizing the mass flow rate of the metal melt.

[0054] At the same time, the high-speed airflow in the venturi tube pre-crushes the molten metal entering the throat section. The pre-crushing process significantly reduces the initial characteristic size of the molten metal, breaking through the limitation of traditional technology on the initial characteristic size of the molten metal flow. The pre-crushed molten metal is ejected from the venturi tube in the form of a gas-liquid mixed jet.

[0055] The atomizing spray disc sprays high-speed supersonic airflow above the gas-liquid mixed jet to perform secondary atomization on the pre-crushed metal melt. This secondary atomization further refines the metal particles, which is conducive to the production of finer and more evenly distributed metal powder.

[0056] The Venturi tube was chosen as a key component based on its unique fluid mechanics properties. The contraction-expansion structure of the Venturi tube can form a stable air pressure in the throat section, which just meets the need for stable air pressure. At the same time, the high-speed airflow generated by the Venturi effect can effectively pre-crush the molten metal, a process that is crucial to reducing the initial characteristic size of the molten metal.

[0057] In certain embodiments, referring to Figure 2 The venturi tube 220 includes an outer shell 222 that encloses a flow channel. The outer shell 222 is a multi-layer structure that includes an inner layer, a thermal insulation layer and a protective layer from the inside to the outside (the multi-layer structure is not shown); the inner layer is made of a high temperature resistant and corrosion resistant material; the thermal insulation layer is made of a thermal insulation material; and the protective layer is made of a protective material.

[0058] The outer shell of the Venturi tube adopts a multi-layer structure design, including an inner layer, an insulation layer and a protective layer. The inner layer is made of high temperature and corrosion resistant materials, which can directly contact the high temperature metal melt and airflow, protecting the Venturi tube from corrosion and damage. The insulation layer is made of insulation material, which can reduce heat loss and keep the internal temperature of the Venturi tube stable. The protective layer is made of protective material to protect the internal structure.

[0059] Specifically, the inner layer can be made of materials such as graphite or high-temperature ceramics, such as silicon nitride, silicon carbide, aluminum oxide, etc. These materials have excellent high-temperature resistance and corrosion resistance, and can maintain stable performance for a long time in a high-temperature environment.

[0060] The insulation layer can use high-efficiency insulation materials such as ceramic fiber, alumina fiber or aluminum silicate fiber. These materials have low thermal conductivity and high temperature stability, which can effectively reduce heat loss. For example, a ceramic fiber felt with a density of 128kg / m³ and a thermal conductivity of 0.035W / (m·K) can be used as the insulation layer material. Its thickness can be designed according to actual needs, usually between 10-50mm.

[0061] The protective layer can be made of wear-resistant and impact-resistant materials, such as stainless steel or titanium alloy. These materials can protect the internal structure from the influence of the external environment and extend the service life of the equipment. For example, 316L stainless steel can be used as the protective layer material, and its thickness can be between 2-5mm.

[0062] This multi-layer structure design solves the problems of high temperature resistance, corrosion resistance and thermal insulation performance of the Venturi tube. The inner layer is resistant to high temperature and corrosion, and can withstand the impact of high temperature molten metal and airflow for a long time without damage. The thermal insulation layer reduces heat loss, helps to maintain the temperature of the molten metal and improves the atomization efficiency. The protective layer further protects the integrity of the entire structure. This design not only ensures the service life of the Venturi tube, but also improves the stability and efficiency of the atomization process.

[0063] Therefore, the multi-layer structure design of the venturi tube of the present application can effectively solve the problems of high temperature resistance, corrosion resistance and thermal insulation performance. The high temperature and corrosion resistant material of the inner layer can directly contact the high temperature metal melt and airflow to prevent the venturi tube from being corroded and damaged. The thermal insulation material of the thermal insulation layer can reduce heat loss and maintain the stability of the internal temperature of the venturi tube, which is crucial to maintaining the superheat and atomization effect of the metal melt. The protective layer further enhances the durability and safety of the entire structure.

[0064] This multi-layer design not only increases the service life of the Venturi tube, but also ensures the stability of the atomization process. The stable internal temperature and structural integrity help maintain the smooth movement of the molten metal and the stability of the airflow, thereby improving the atomization efficiency and product quality. For example, when atomizing high-temperature alloy powders, the stable internal temperature of the Venturi tube can prevent the molten metal from solidifying in the pipe, ensuring the continuity and uniformity of the atomization process.

[0065] Compared with the prior art, the traditional single-layer Venturi tube often cannot meet the requirements of high temperature resistance, corrosion resistance and heat preservation at the same time, and is prone to problems of large heat loss and short service life. The multi-layer structure design of the present application optimizes various performances by rationally selecting and combining materials with different functions. For example, compared with the traditional single-layer heat-resistant steel Venturi tube, the multi-layer structure of the present application can extend the service life and reduce heat loss, which is of great significance for improving the production efficiency and product quality of atomization equipment.

[0066] In some embodiments, an induction or resistance heating device may be provided between the inner layer and the insulation layer to maintain the temperature of the molten metal in the venturi tube.

[0067] In certain embodiments, referring to Figure 2 The flow channel includes an air chamber 223, an air inlet section 224, a throat section 221, a diffuser section 225 and an air outlet section 226 which are connected in sequence. The cross-sectional area of ​​the air chamber 223 is constant and larger than the cross-sectional area of ​​the throat section 221, and the air chamber 223 is used to connect to the air source; the cross-sectional area of ​​the air inlet section 224 gradually decreases toward the throat section 221; the cross-sectional area of ​​the throat section 221 is constant; the cross-sectional area of ​​the diffuser section 225 gradually increases toward the throat section 221; the cross-sectional area of ​​the air outlet section 226 is constant and smaller than the cross-sectional area of ​​the air chamber 223, and the air outlet section 226 is used to spray out a gas-liquid mixed jet.

[0068] The design of the flow channel is one of the core features of this application. The cross-sectional area of ​​the air chamber is constant and larger than the cross-sectional area of ​​the throat section. This design can provide a stable air source inlet and a stable air pressure environment for the entire flow channel. The cross-sectional area of ​​the air inlet section gradually decreases towards the throat section. This design can gradually increase the air flow velocity and prepare for the subsequent throat section pre-crushing process.

[0069] The cross-sectional area of ​​the throat section is constant, which is the part with the fastest air velocity and the lowest pressure. The constant cross-sectional area design can form a stable air pressure at this location, which is conducive to the pre-crushing and stable movement of the metal melt. The cross-sectional area of ​​the diffuser section gradually increases in the direction away from the throat section. This design gradually reduces the air velocity and gradually restores the pressure, which helps to control the speed and pressure changes of the air flow.

[0070] The cross-sectional area of ​​the gas outlet section is constant and smaller than the cross-sectional area of ​​the gas chamber, and is used to spray out a gas-liquid mixed jet. This design can ensure the stability of the gas-liquid mixed jet and reduce the fluctuation of the mass flow rate of the metal melt. Through this structural design, a relatively stable air pressure environment can be formed in the Venturi tube, thereby improving the stability and efficiency of the atomization process.

[0071] The technical solution of the present application solves the problem of fluctuations in the mass flow rate of molten metal due to unstable air pressure by designing a venturi tube with a specific structure. The various parts of the venturi tube have different cross-sectional area change characteristics, and this design can effectively control the speed and pressure changes of the airflow. In particular, the constant cross-sectional area design of the throat section can form a stable air pressure there, which is conducive to the pre-crushing and stable movement of the molten metal. At the same time, the constant cross-sectional area design of the air outlet section helps to maintain the stability of the gas-liquid mixed jet.

[0072] Through this structural design, the present application can form a relatively stable air pressure environment in the venturi tube, thereby reducing the fluctuation of the mass flow rate of the metal melt and improving the stability and efficiency of the atomization process. Specifically, the air chamber provides a stable air source, the air inlet section accelerates the air flow, the throat section forms a stable air pressure to pre-crush the metal melt, and the expansion section and the air outlet section control the air flow speed and pressure, and finally form a stable gas-liquid mixed jet.

[0073] Compared with the prior art, the Venturi composite gas atomization equipment of the present application can effectively control the velocity and pressure changes of the airflow through a specific flow channel design to form a stable air pressure environment. This design not only solves the problem of drastic fluctuations in air pressure at the outlet of the guide nozzle in the traditional VIGA process, but also can further reduce the initial characteristic size of the metal melt through the pre-crushing effect of the throat section, thereby facilitating the production of finer metal powders. This innovative design significantly improves the stability and efficiency of the atomization process and provides a new technical path for the production of high-quality metal powders.

[0074] In certain embodiments, referring to Figure 3 The flow channel includes an air chamber 223, an air inlet section 224, a throat section 221, a diffuser section 225 and an air outlet section 226 which are connected in sequence. The cross-sectional area of ​​the air chamber 223 is constant and larger than the cross-sectional area of ​​the throat section 221, and the air chamber 223 is used to connect to the air source; the cross-sectional area of ​​the air inlet section 224 gradually decreases toward the direction approaching the throat section 221; the cross-sectional area of ​​the throat section 221 is constant; the cross-sectional area of ​​the diffuser section 225 gradually increases toward the direction away from the throat section 221; the air outlet section 226 includes a straight pipe section and an arc-shaped transition section with constant cross-sectional area, the arc-shaped transition section connects the straight pipe section and the diffuser section 225, and the cross-sectional area of ​​the arc-shaped transition section gradually decreases toward the direction away from the diffuser section 225, and the air outlet section 226 is used to spray out a gas-liquid mixed jet.

[0075] Compared with the above-mentioned embodiment, the cross-sectional shape of the air outlet section in this embodiment is designed to transition from an arc-shaped transition section to a groove-shaped straight pipe section. First, the arc-shaped transition section reduces the turbulence and energy loss of the airflow and improves the stability of the airflow. This helps to maintain a stable air pressure in the throat section, thereby ensuring the stability of the mass flow rate of the molten metal. Secondly, the groove-shaped design makes the gas-liquid mixed jet more concentrated and directional, which is beneficial to the subsequent atomization process. This directional gas-liquid mixed jet can more effectively interact with the supersonic airflow ejected by the atomizing spray disc to improve the atomization efficiency, while keeping the cross-sectional area of ​​the groove-shaped part unchanged, so that the supersonic airflow ejected by the atomizing spray disc can fully impact the low-speed gas-liquid mixture ejected by the venturi tube as soon as possible, thereby completing the atomization operation of the molten metal.

[0076] Compared with the existing technology, it is difficult to control the air pressure at the outlet of the guide nozzle in the traditional VIGA process equipment. However, the present application realizes effective control of the air pressure through the special design of the Venturi tube, especially the innovative structure of the air outlet section. This not only improves the stability of the mass flow rate of the metal melt, but also reduces the initial characteristic size of the metal melt through the formation of pre-crushing and directional gas-liquid mixed jets. Therefore, the present application can produce metal powders with more uniform particle size distribution and smaller average particle size to meet the needs of high-end additive manufacturing.

[0077] In certain embodiments, referring to Figure 4 , the size of the air intake section meets:

[0078] ;

[0079] in, is the inlet inner diameter of the air intake section, is the inner diameter of the throat section (usually between 6-20mm), is the length of the air intake section;

[0080] The dimensions of the diffuser section meet the following requirements:

[0081] ;

[0082] in, is the outlet inner diameter of the diffuser section, is the length of the diffuser section.

[0083] This embodiment solves the problem of airflow control in the Venturi composite gas atomization device by precisely controlling the size of the air inlet section and the diffuser section. By reasonably setting the contraction angle of the air inlet section and the expansion angle of the diffuser section, effective control of the airflow velocity and pressure can be achieved. This design helps to form a stable air pressure in the throat section, improve the pre-crushing effect of the metal melt, and achieve better pressure recovery in the diffuser section.

[0084] In the size design of the air inlet section, the contraction angle ranges from 6° to 60°. This range is selected after consideration. If the angle is less than 6°, the air inlet section will be too long, resulting in increased energy loss; if the angle is greater than 60°, it may cause air flow separation and affect the stability of the air flow. Within this range, the appropriate angle can be selected according to specific needs. For example, for applications that require higher air flow speeds, a larger angle can be selected; for applications that require more stable air flow, a smaller angle can be selected.

[0085] In the dimension design of the diffuser section, the expansion angle ranges from 6° to 15°. The selection of this range is also a trade-off. If the angle is less than 6°, the diffuser section will be too long, increasing the overall size of the equipment; if the angle is greater than 15°, it may cause airflow separation and vortex formation, reducing the pressure recovery efficiency. Within this range, the appropriate angle can be selected according to specific needs. For example, for applications that require higher pressure recovery, a smaller angle can be selected; for applications that require a shorter diffuser section, a larger angle can be selected.

[0086] The size design of the air intake section and the diffuser section cooperate with each other to control the airflow. The design of the air intake section mainly affects the acceleration process of the airflow, while the design of the diffuser section mainly affects the pressure recovery process. By optimizing the size of these two sections, the airflow velocity and pressure can be precisely controlled, thereby improving the airflow characteristics in the Venturi tube.

[0087] An important advantage of this design is its flexibility. By adjusting the size of the air inlet section and the diffuser section, it can adapt to different atomization requirements. For example, for applications that require higher atomization efficiency, a larger air inlet section contraction angle and a smaller diffuser section expansion angle can be selected to obtain higher air flow velocity and better pressure recovery effect.

[0088] Compared with the prior art, the traditional venturi tube design often adopts empirical values ​​or simple geometric relationships, which makes it difficult to achieve precise airflow control. This application provides a quantifiable and optimizable design method by clearly defining the size relationship between the air intake section and the diffuser section. This method can not only improve the atomization efficiency, but also can be flexibly adjusted according to different application requirements, and has a wider applicability.

[0089] In some embodiments, in order to make the gas in the venturi tube have the characteristics of incompressible gas, it is necessary to add limiting conditions to the gas velocity in the throat section. of gas, we can calculate:

[0090] ;

[0091] in, is the speed of sound, is the gas adiabatic index, is the gas constant, is the gas temperature (degrees Celsius).

[0092] Then the gas velocity in the throat section satisfies:

[0093] ; ;

[0094] in, is the gas velocity in the throat section.

[0095] In this embodiment, the gas temperature is increased Can increase the gas velocity in the throat section The level of can not only more effectively break up the molten metal flowing out of the guide nozzle, but also reduce the temperature drop of the molten metal. 10 Taking Mg alloy as an example, the atomization temperature is controlled at 800°C. In order to prevent the aluminum alloy melt from cooling down in the Venturi tube, the nitrogen in the Venturi tube is heated to 800°C, and the nitrogen flow rate in the throat section of the Venturi tube does not exceed 200.4m / s.

[0096] Based on the Venturi tube structure provided by the present invention, the relationship between the inlet air pressure of the air intake section and the air pressure of the throat section is deduced as follows:

[0097] The Bernoulli equation is established for the cross section of the inlet section and the cross section of the guide nozzle outlet at the throat section:

[0098] ;

[0099] in, is the vertical distance between the geometric center of the inlet cross section and the reference plane, where the reference plane is a plane parallel to the axis of the Venturi tube. is the inlet air pressure of the air intake section (the same as the air pressure of the air chamber. Compared with the air intake section, it is more convenient to set the air pressure detection point in the air chamber and it is conducive to reducing the interference of the air pressure detection device on the air flow). is the gas density, is the acceleration due to gravity, is the gas velocity at the inlet of the air inlet section, is the first pressure loss coefficient, is the vertical distance between the geometric center of the throat section and the reference plane, is the air pressure in the throat, is the second pressure loss coefficient.

[0100] From the Bernoulli equation we can get:

[0101] ;

[0102] When the air flow velocity is less than 0.3 times the local sound speed, the gas can be considered incompressible, that is, the gas density does not change with pressure. The following relationship exists for the inlet section and throat section:

[0103] ;

[0104] in, is the inlet cross-sectional area of ​​the air intake section, is the cross-sectional area of ​​the throat section.

[0105] Furthermore, due to , ;

[0106] Therefore, the relationship between the inlet pressure of the intake section and the pressure of the throat section satisfies:

[0107] ;

[0108] In this embodiment, the length of the Venturi tube is short, the flow channel changes smoothly, and the pressure loss coefficient and If it is less than 7%, it can be set to 5%, or it can be measured by pre-experimental method. and In addition, you can design a suitable Increase the surface pressure of the molten metal in the tundish and The stability of the air pressure difference between the guide nozzle and the guide nozzle helps to improve the stability of the metal melt flow rate flowing out of the guide nozzle.

[0109] In certain embodiments, referring to Figure 1 The atomizing chamber 200 is provided with a baffle 240 , which is arranged opposite to the venturi tube 220 and is used to prevent the gas-liquid mixed jet from impacting the inner wall of the atomizing chamber 200 ; the atomizing spray disc 230 is located between the baffle 240 and the venturi tube 220 .

[0110] In order to solve the problem that the gas-liquid mixed jet may damage the inner wall of the atomizing chamber, the present application sets a baffle in the atomizing chamber. The baffle is arranged opposite to the venturi tube to prevent the gas-liquid mixed jet from directly impacting and damaging the inner wall of the atomizing chamber. The atomizing spray disc is cleverly arranged between the baffle and the venturi tube. This layout ensures that the atomization process can be carried out in an appropriate position without being disturbed by the baffle and can fully utilize the kinetic energy of the gas-liquid mixed jet.

[0111] The baffle can be arranged in a variety of ways. For example, the baffle can be a flat plate structure directly fixed to the inner wall of the atomizing chamber. It can also be designed as a structure with adjustable angle to adapt to different directions and intensities of the gas-liquid mixed jet. The material of the baffle can be selected from a high temperature resistant and corrosion resistant alloy to withstand the impact of the high temperature gas-liquid mixed jet.

[0112] The relative position of the baffle and the venturi tube is also critical. The baffle can be set slightly tilted so that the gas-liquid mixed jet can be deflected downward after hitting the baffle, which is conducive to the collection of powder. The distance between the baffle and the venturi tube outlet can be determined according to the expected length of the gas-liquid mixed jet, and can usually be set to 5-10 times the diameter of the venturi tube outlet.

[0113] The position of the atomizing spray disc is equally important. It can surround the gas-liquid mixed jet to form a ring structure to ensure uniform atomization. The nozzle angle of the atomizing spray disc can be designed to be adjustable to meet different atomization requirements.

[0114] This design not only solves the problem of the gas-liquid mixed jet damaging the inner wall of the atomization chamber, but also brings additional advantages. First, the presence of the baffle can help control the airflow distribution during the atomization process and improve the uniformity of atomization. Second, by adjusting the position and angle of the baffle, the cooling path of the powder can be optimized, thereby affecting the morphology and performance of the final powder.

[0115] In certain embodiments, referring to Figure 1 The Venturi composite gas atomization equipment also includes a cyclone separator 300, a dust collector 400, a return fan 500 and a heater 600 which are connected in sequence. The cyclone separator 300 is connected to the atomization chamber 200 and is used to separate particles in the gas output by the atomization chamber 200; the dust collector 400 is used to separate particles in the gas output by the cyclone separator 300; the return fan 500 is used to suck the gas processed by the dust collector 400; the heater 600 is used to heat the gas output by the return fan 500, and the heater 600 is connected to the Venturi tube 220 so that the heated gas is connected to the Venturi tube 220 as a gas source.

[0116] The present application constructs a closed-loop system for gas and particle recycling by providing a cyclone separator, a dust collector, a return air fan and a heater (which may be a serpentine elbow heat exchanger or a plate-fin heat exchanger). The cyclone separator and the dust collector effectively separate the metal particles generated during the atomization process and recover valuable metal powder. The return air fan inputs the gas purified by the dust collector into the heater for heating treatment, making it suitable for reuse in the atomization process. This recycling not only improves the efficiency of resource utilization, but also may reduce production costs and reduce environmental pollution. By reconnecting the treated gas to the Venturi tube as a gas source, the system realizes the continuous recycling of gas and effectively solves the technical problem of gas and particle recycling in the metal powder production process.

[0117] Specifically, in the Venturi composite gas atomization device of the present application, the cyclone separator is connected to the atomization chamber and is used to preliminarily separate larger particles in the output gas of the atomization chamber. The cyclone separator can adopt a variety of designs, such as a tangential inlet type or an axial inlet type, to meet different separation requirements. The size and shape of the cyclone separator can be optimized according to the gas flow rate and particle characteristics to improve the separation efficiency.

[0118] The dust collector is used to further separate the fine particles in the cyclone separator output gas. The dust collector can be of different types such as bag filters or electrostatic precipitators. The most suitable dust removal method is selected according to the particle size and gas characteristics. For example, for submicron metal dust, a high-efficiency filter or electrostatic precipitator can be considered.

[0119] The return fan is used to draw the dust-removed gas into the heater to provide power for gas recirculation. The selection of the return fan needs to consider factors such as gas flow, pressure requirements and energy consumption. Centrifugal or axial flow fans can be used, and equipped with a variable frequency control system to adjust the air volume and pressure according to actual needs.

[0120] The heater is used to heat the gas to ensure that the temperature of the recovered gas is suitable for reuse in the atomization process. The heater can be electrically heated or gas heated, and the specific choice depends on energy availability and economic considerations. The temperature control system of the heater should be accurate and reliable to ensure that the temperature of the recovered gas is stable within the required range.

[0121] These components are connected through pipes and control systems to form a closed-loop circulation system. Multiple monitoring points can be set in the system, such as temperature sensors, pressure sensors, and flow meters, to monitor the system operation status in real time. The control system can automatically adjust the return fan speed, heater power, etc. according to these parameters to optimize system performance.

[0122] Therefore, the technical solution of the present application not only realizes the recycling of gas and particles, but also improves the efficiency and stability of the entire atomization system through the coordinated work of various components. The combined use of cyclone separator and dust collector can effectively capture metal particles of different sizes and improve the recovery rate of metal powder. The setting of the return air fan and heater ensures that the pressure and temperature of the recovered gas meet the atomization requirements, so that the gas can be continuously recycled.

[0123] This closed-loop system design forms a good match with the Venturi tube atomization device. The Venturi tube requires a stable gas source to maintain the atomization process, and this system provides a stable gas source through recycling and processing, which helps to improve the stability and efficiency of the atomization process. At the same time, the gas and particles generated by atomization can be recycled and processed by the system, forming an efficient cycle process.

[0124] It should be noted that if the gas filtered by the dust collector meets the oxygen content requirements, part of the gas will enter the return fan and finally act on the Venturi tube, and the other part of the gas will be discharged through the induced draft fan.

[0125] Furthermore, the technical solution of the present application can be flexibly adjusted according to actual needs. For example, a secondary separation device can be added between the cyclone separator and the dust collector to further improve the particle separation efficiency. The heater can adopt a multi-stage heating design to achieve more precise temperature control. A gas composition analysis device can also be added to the system to monitor the composition of the recovered gas in real time to ensure that the gas quality meets the atomization requirements.

[0126] Furthermore, in order to adjust the pressure of the gas entering the venturi tube, a pressure regulating valve may be provided between the venturi tube and the heater.

[0127] Through this configuration, the technical solution of the present application can improve the gas recovery rate and significantly reduce production costs and environmental pollution. At the same time, since a stable gas source is provided, the stability of the atomization process is improved, and the quality and consistency of the metal powder are also improved.

[0128] Compared with the existing technology, the traditional metal powder production process usually adopts an open system, and the gas is directly discharged or simply treated before discharge, resulting in resource waste and environmental pollution. However, by constructing a closed-loop system, this application not only greatly improves the efficiency of resource utilization, but also reduces environmental impact. In addition, it is difficult for traditional systems to ensure the stability of the gas source, while this application provides more stable atomization conditions by recycling the treated gas as the gas source, which is conducive to improving product quality and production efficiency.

[0129] In certain embodiments, referring to Figure 5 , Attachment Figure 6 and attached Figure 7 The atomizing spray disc 230 includes an air inlet pipe 231, an air inlet chamber 232 and a LAVAL type flow channel 233 which are connected in sequence. The angle between the center line of the LAVAL type flow channel 233 and the center line of the Venturi tube 220 is in the range of 70°-100°.

[0130] The atomizing spray disc of the present application is an important component of the Venturi compound gas atomizing device, and is used to spray supersonic airflow toward the gas-liquid mixed jet to atomize the metal melt in the gas-liquid mixed jet. The structural design of the atomizing spray disc has a direct impact on the atomization effect.

[0131] This technical solution improves the performance of the atomizing spray disc through a specific structural design. The atomizing spray disc includes an air inlet pipe, an air inlet chamber and a LAVAL type flow channel (the number is generally not more than 4 groups) that are connected in sequence. This structural design can accelerate the airflow when passing through the LAVAL type flow channel, increase the kinetic energy of the airflow, and thus enhance the atomization effect on the metal melt. The angle range (denoted as θ) between the center line of the LAVAL type flow channel and the center line of the Venturi tube is 70°-100°. The design of this angle range can ensure that the supersonic airflow can meet the gas-liquid mixed jet ejected from the Venturi tube at a suitable angle.

[0132] Through this structural design, the atomizing spray disc can generate high-speed, high-kinetic energy supersonic airflow, and meet the metal melt gas-liquid mixed jet at a suitable angle, thereby improving the atomization effect and producing finer and more uniform metal powder particles. Compared with the traditional atomizing spray disc structure, this design may have higher atomization efficiency and better powder quality control capabilities.

[0133] The innovation of this technical solution lies in the use of LAVAL flow channel and its specific angle design with the center line of the venturi tube. This design can not only improve the atomization efficiency, but also bring better powder particle size distribution and morphology control, which is of great significance to improving the quality and performance of metal powder.

[0134] Furthermore, the LAVAL type flow channel can be designed as a contraction-expansion structure, in which the cross-sectional area of ​​the contraction section gradually decreases, and the cross-sectional area of ​​the expansion section gradually increases. This design can accelerate the airflow to subsonic speed in the contraction section and further accelerate to supersonic speed in the expansion section, thereby improving the atomization effect. For example, the contraction section of the LAVAL type flow channel can be designed to have a contraction angle of 15°-30°, and the expansion section can be designed to have an expansion angle of 5°-15°.

[0135] The air inlet pipe of the atomizing spray disc can be of circular cross section, and the air inlet chamber can be designed as cylindrical or spherical to facilitate uniform distribution of the airflow. The connection between the air inlet pipe and the air inlet chamber can be designed as a gradual structure to reduce the pressure loss of the airflow.

[0136] The angle between the LAVAL flow channel and the centerline of the Venturi tube is 70°-100°. The selection of this angle range is based on the principle of fluid mechanics and the actual atomization effect. When θ is less than 70° or θ is greater than 100°, the supersonic airflow may be too parallel to the gas-liquid mixed jet of the metal melt, resulting in insufficient atomization.

[0137] The atomizing spray disc design of the present application forms a synergistic effect with the structure of the venturi tube. The venturi tube pre-crushes the metal melt through its special structure, while the atomizing spray disc further atomizes the pre-crushed metal melt using supersonic airflow. This synergistic effect can significantly improve the atomization efficiency and produce finer and more uniform metal powder.

[0138] The atomizing spray disc design of the present application can effectively solve the atomizing effect problem of the atomizing spray disc spraying supersonic airflow through the LAVAL type flow channel and the specific angle setting. The LAVAL type flow channel can accelerate the airflow and increase the kinetic energy of the airflow, thereby enhancing the atomizing effect of the gas-liquid mixed jet ejected from the venturi tube. When the airflow passes through the LAVAL type flow channel, it is first accelerated to subsonic speed in the contraction section, and then further accelerated to supersonic speed in the expansion section. This flow characteristic can significantly improve the atomizing ability of the airflow.

[0139] Setting θ ensures that the supersonic airflow can meet the gas-liquid mixed jet ejected from the venturi tube at the best angle. The selection of this angle range is the result of careful consideration and can ensure sufficient atomization.

[0140] When the supersonic airflow meets the pre-crushed molten metal, the molten metal can be more effectively dispersed into fine droplets. These droplets quickly cool and solidify during flight to form spherical or nearly spherical metal powder particles. Due to the improved atomization effect, the design of the present application can produce metal powders with narrower particle size distribution and more regular morphology.

[0141] This application provides greater flexibility for different atomization conditions by setting an angle range of 70°-100°. The operator can select the best spray angle within this range according to the specific metal material and target powder particle size.

[0142] In general, the atomizing spray disc design of the present application effectively solves the atomization effect problem of the atomizing spray disc spraying supersonic airflow through the LAVAL-type flow channel and specific angle setting, which can significantly improve the atomization efficiency and produce higher quality metal powder.

[0143] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" 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.

[0144] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A Venturi composite gas atomization device, characterized in that: include: A smelting chamber (100), wherein the smelting chamber (100) is used to smelt the alloy mother material into a liquid metal melt; An atomizing chamber (200), the atomizing chamber (200) comprising a guide nozzle (210), a venturi tube (220) and an atomizing spray disc (230), the guide nozzle (210) being connected to the smelting chamber (100) and the venturi tube (220), the end outlet of the guide nozzle (210) being located at a throat section (221) of the venturi tube (220) and the throat section (221) being arranged parallel to a horizontal plane, the guide nozzle (210) being used to guide the molten metal to the throat section (221) The venturi tube (220) is used to form a stable air pressure in the throat section (221) by connecting to an air source, and to pre-crush the molten metal in the throat section (221), and to spray the molten metal in the throat section (221) after the pre-crushing to form a gas-liquid mixed jet; the atomizing spray disc (230) is located above the gas-liquid mixed jet and is used to spray a supersonic airflow toward the gas-liquid mixed jet to atomize the molten metal in the gas-liquid mixed jet.

2. The Venturi composite gas atomization device according to claim 1, characterized in that: The venturi tube (220) comprises an outer shell (222) that encloses a flow channel. The outer shell (222) is a multi-layer structure that includes, from inside to outside, an inner layer, a thermal insulation layer, and a protective layer; the inner layer is made of a high-temperature resistant and corrosion-resistant material; the thermal insulation layer is made of a thermal insulation material; and the protective layer is made of a protective material.

3. The Venturi composite gas atomization device according to claim 2, characterized in that: The flow channel comprises an air chamber (223), an air inlet section (224), the throat section (221), a diffuser section (225), and an air outlet section (226) which are connected in sequence; the cross-sectional area of ​​the air chamber (223) is constant and is larger than the cross-sectional area of ​​the throat section (221); the air chamber (223) is used to connect to an air source; the cross-sectional area of ​​the air inlet section (224) gradually decreases in a direction approaching the throat section (221); the cross-sectional area of ​​the throat section (221) is constant; the cross-sectional area of ​​the diffuser section (225) gradually increases in a direction away from the throat section (221); the cross-sectional area of ​​the air outlet section (226) is constant and is smaller than the cross-sectional area of ​​the air chamber (223); the air outlet section (226) is used to spray out the gas-liquid mixed jet.

4. The Venturi composite gas atomization device according to claim 2, characterized in that: The flow channel comprises an air chamber (223), an air inlet section (224), the throat section (221), a diffuser section (225), and an air outlet section (226) which are connected in sequence; the cross-sectional area of ​​the air chamber (223) is constant and greater than the cross-sectional area of ​​the throat section (221); the air chamber (223) is used to connect to an air source; the cross-sectional area of ​​the air inlet section (224) gradually decreases in a direction approaching the throat section (221); the cross-sectional area of ​​the throat section (221) is constant; the cross-sectional area of ​​the diffuser section (225) gradually increases in a direction away from the throat section (221); the air outlet section (226) comprises a straight pipe section and an arc-shaped transition section with a constant cross-sectional area; the arc-shaped transition section connects the straight pipe section and the diffuser section (225), and the cross-sectional area of ​​the arc-shaped transition section gradually decreases in a direction away from the diffuser section (225); the air outlet section (226) is used to spray the gas-liquid mixed jet.

5. The Venturi composite gas atomization device according to claim 3 or 4, characterized in that: The dimensions of the air intake section satisfy: ； in, is the inlet inner diameter of the air inlet section, is the inner diameter of the throat section, is the length of the air intake section; The dimensions of the diffuser section satisfy: ； in, is the outlet inner diameter of the diffuser section, is the length of the diffuser section.

6. The Venturi composite gas atomization device according to claim 5, characterized in that: The gas velocity in the throat section satisfies: ； in, is the gas velocity in the throat section, is the gas adiabatic index, is the gas constant, is the gas temperature.

7. The Venturi composite gas atomization device according to claim 6, characterized in that: The relationship between the inlet air pressure of the air inlet section and the air pressure of the throat section satisfies: ； in, is the air pressure in the throat section, is the inlet pressure of the air inlet section, is the second pressure loss coefficient, is the gas density, is the acceleration due to gravity, is the vertical distance between the geometric center of the throat section cross section and the reference plane, wherein the reference plane is a plane parallel to the axis of the Venturi tube, is the vertical distance between the geometric center of the inlet cross section and the reference plane, is the first pressure loss coefficient.

8. The Venturi composite gas atomization device according to claim 1, characterized in that: The atomizing chamber (200) is provided with a baffle (240), the baffle being arranged opposite to the venturi tube (220) and used to prevent the gas-liquid mixed jet from impacting the inner wall of the atomizing chamber (200); the atomizing spray disc (230) is located between the baffle (240) and the venturi tube (220).

9. The Venturi composite gas atomization device according to claim 1, characterized in that: The invention also comprises a cyclone separator (300), a dust collector (400), a return air fan (500) and a heater (600) which are connected in sequence, wherein the cyclone separator (300) is communicated with the atomization chamber (200) and is used to separate particles in the gas output by the atomization chamber (200); the dust collector (400) is used to separate particles in the gas output by the cyclone separator (300); the return air fan (500) is used to suck the gas processed by the dust collector (400); the heater (600) is used to heat the gas output by the return air fan (500), and the heater (600) is communicated with the venturi tube (220) so that the heated gas is connected to the venturi tube (220) as a gas source.

10. The Venturi composite gas atomization device according to claim 1, characterized in that: The atomizing spray disc (230) comprises an air inlet pipe (231), an air inlet chamber (232), and a LAVAL-type flow channel (233) which are connected in sequence, and the included angle between the center line of the LAVAL-type flow channel (233) and the center line of the Venturi tube (220) is in the range of 70°-100°.

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