Ultrasonic resonance supersonic gas atomization spray disc

Abstract

The invention relates to an ultrasonic resonance supersonic gas atomization spray disc. The spray disc comprises an outer sleeve; the upper lip seat and the upper lip are sequentially arranged on the upper end face of the outer sleeve from inside to outside; the lower lip seat and the lower lip are sequentially arranged on the lower end face of the outer sleeve from inside to outside; the butt joint faces of the upper lip seat and the lower lip seat form a first Laval channel, and first acceleration of airflow is achieved. The upper lip base, the upper lip, the lower lip base and the lower lip define a supersonic resonant cavity, and high-frequency resonance of supersonic airflow from the first Laval channel is achieved. A second Laval channel is formed by the butt joint faces of the upper lip and the lower lip, and high-frequency vibration airflow is accelerated to the supersonic speed. Supersonic gas accelerated through the first Laval channel firstly enters the supersonic resonant cavity, after ultrasonic resonance is generated in the resonant cavity, the supersonic gas is accelerated through the second Laval channel to reach the supersonic speed and then is sprayed out, and the ultrasonic resonance supersonic atomization function is achieved; the atomization effects that the particle size is more uniform, the particle size distribution is narrower, and the yield of fine powder in a specific particle size section is higher can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of powder metallurgy, and particularly relates to an ultrasonic resonance supersonic gas atomization nozzle disc. Background Art

[0002] The particle size of metal powders prepared by gas atomization follows a normal distribution, with a standard deviation of approximately between 1.7 and 2.3. Therefore, the yield of powders in a specific particle size range is relatively low. For example, for metal powders prepared by gas atomization, the yield of 15 - 53μm powders suitable for selective laser melting additive manufacturing technology is approximately 30 - 45%. Therefore, for gas atomization powder preparation technology, developing the design and research of the atomization nozzle disc, the core component of gas atomization, to narrow the particle size distribution range of the produced powders, improve the yield of powders in a specific particle size range, and reduce the powder production cost has become one of the common technical difficulties that urgently need to be solved in the current stage of gas atomization powder preparation technology.

[0003] The mainstream idea of traditional nozzle disc design is to adopt a Laval structure or to heat the gas to increase the gas flow velocity at the nozzle disc outlet to supersonic speed, thereby enhancing the impact force of the atomizing gas on the metal melt and making the overall powder finer. For example, patents such as CN110052620A and CN202845789U have achieved an increase in the yield of fine powders through the design of the outlet Laval structure. Patent CN113681017A realizes the heating of the outlet gas flow by designing induction heating at the nozzle outlet, obtaining an increase in gas flow velocity and thus enhancing the yield of fine powders.

[0004] In - depth analysis of the above patents shows that the current mainstream nozzle disc design idea mainly improves the yield of fine powders by increasing the gas velocity at the nozzle disc outlet through structural design, and fails to coordinate the vibration frequency of the outlet gas, resulting in a random gas flow vibration frequency. Therefore, the significant defect of such a design is that it can only achieve the overall left - shift of the powder normal distribution curve, but cannot narrow the powder particle size distribution. For example, patent CN202845789U has increased the yield of powders with <45μm and <23μm, but the yield of powders in the 23 - 45μm particle size range has shown a downward trend instead. Summary of the Invention

[0005] In view of at least one of the technical problems existing in the current gas atomization nozzle disc, such as uneven particle size distribution of atomized powders, wide particle size distribution range, and low yield of fine powders in a specific particle size range, the present invention provides an ultrasonic resonance supersonic gas atomization nozzle disc.

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] An ultrasonic resonance supersonic gas atomization nozzle disc, comprising:

[0008] An outer jacket;

[0009] An upper lip seat and an upper lip which are arranged on the upper end face of the outer sleeve in sequence from inside to outside;

[0010] A lower lip seat and a lower lip which are arranged on the lower end face of the outer sleeve in sequence from inside to outside;

[0011] Wherein:

[0012] The butting surfaces of the upper lip seat and the lower lip seat form a first Laval channel to realize the first acceleration of the air flow;

[0013] The upper lip seat, the upper lip, the lower lip seat and the lower lip enclose a supersonic resonance cavity to realize the high-frequency resonance of the supersonic air flow from the first Laval channel and improve the air flow vibration frequency;

[0014] The butting surfaces of the upper lip and the lower lip form a second Laval channel to accelerate the high-frequency vibrating air flow to supersonic speed.

[0015] Further, a plurality of grooves are uniformly distributed on the circumference of the upper lip facing the outlet of the first Laval channel, and the distance between two adjacent grooves is 1-2 mm.

[0016] Further, the groove is a circular groove with a diameter of 0.2-1 mm and a depth of 0.1-0.8 mm.

[0017] Further, the distance between two adjacent grooves is 1-2 mm.

[0018] Further, the number of the grooves is 20-80, preferably 60.

[0019] The first Laval channel :

[0020] In the present invention, the throat diameter of the first Laval channel is denoted as D1, and D1 is 0.4-0.8 mm;

[0021] In the present invention, the outlet cross-sectional diameter of the first Laval channel is denoted as D2, and D2 is 0.9-1.5 mm;

[0022] In the present invention, the expansion section cone apex angle of the first Laval channel is denoted as α, and α is 9-12°;

[0023] Supersonic resonance cavity :

[0024] In the present invention, the minimum width of the supersonic resonance cavity is denoted as D3, and D3 is 3 mm;

[0025] In the present invention, the resonance effective length of the supersonic resonance cavity is denoted as D4, and D4 is 10-15 mm.

[0026] The second Laval channel :

[0027] In the present invention, the throat diameter of the second Laval channel is denoted as D5, and D5 is 0.6 - 0.8 mm;

[0028] In the present invention, the outlet cross-sectional diameter of the second Laval channel is denoted as D6, and D6 is 1.2 - 1.6 mm;

[0029] In the present invention, the cone angle of the expansion section of the second Laval channel is denoted as β, and β is 9 - 12°.

[0030] Further, the upper lip seat and the lower lip seat are respectively threadedly connected to the outer sleeve.

[0031] Further, the upper lip is threadedly connected to the upper lip seat; the lower lip is threadedly connected to the lower lip seat.

[0032] The atomizing spray disc provided by the present invention draws on the Hartmann resonance effect, and a supersonic resonance cavity is coupled on the basis of a traditional annular slit supersonic gas atomizing spray disc, overcoming the drawback that the traditional Hartmann resonance tube integrated into the atomizing spray disc alone is limited by the atomizing size and affects the design of the aspect ratio. By using a double Laval channel, it is realized that the air flow reaches supersonic speed before entering the resonance cavity, and a periodic shock wave flow field structure is obtained, further strengthening the air flow resonance effect, realizing ultrasonic resonance supersonic air atomization, improving the periodic consistency of the supersonic air resonance frequency, making the "liquid film" formed during the primary wave-forming process smaller, more uniform and stable in size. Therefore, after secondary atomization and spheroidization solidification, the obtained particle size is more uniform, the particle size distribution is narrower, and the fine powder yield in a specific particle size range is higher.

[0033] Compared with the prior art, the present invention provides an ultrasonic resonance supersonic gas atomizing spray disc. The supersonic gas accelerated by the first Laval channel first enters the supersonic resonance cavity, generates ultrasonic resonance in the resonance cavity, and then is accelerated to supersonic speed and ejected through the second Laval channel, realizing the ultrasonic resonance supersonic atomization function, and can obtain an atomization effect with more uniform particle size, narrower particle size distribution and higher fine powder yield in a specific particle size range. Description of the Drawings

[0034] Figure 1 It is a schematic diagram of the ultrasonic resonance supersonic gas atomizing spray disc in Example 1;

[0035] Figure 2 It is Figure 1 a partial view in

[0036] Figure 3 It is an electron microscope image of the powder particles obtained by using the ultrasonic resonance supersonic gas atomizing spray disc in Application Example 1;

[0037] Figure 4 The electron microscope image of the powder particles obtained using a traditional spray disk;

[0038] As shown by the reference numerals in the figure: 1 - upper lip; 2 - upper lip seat; 3 - lower lip; 4 - lower lip seat; 5 - outer jacket; 6 - first Laval channel; 7 - supersonic resonance cavity; 8 - second Laval channel; 9 - groove; D3 - minimum width of the supersonic resonance cavity; D4 - effective resonance length of the supersonic resonance cavity. Specific embodiments

[0039] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. These embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation procedures are given, but the protection scope of the present invention is not limited to the following embodiments.

[0040] Embodiment 1

[0041] This embodiment provides an ultrasonic resonance supersonic gas atomization spray disk, and the specific structure is shown in Figure 1-2 , including: an outer jacket 5, an upper lip seat 2 and an upper lip 1 sequentially arranged from the inside to the outside on the upper end surface of the outer jacket 5, and a lower lip seat 4 and a lower lip 3 sequentially arranged from the inside to the outside on the lower end surface of the outer jacket 5;

[0042] In this embodiment, the docking surface of the upper lip seat 2 and the lower lip seat 4 forms a first Laval channel 6, which is connected to an intake pipe to achieve the first acceleration of the air flow; the upper lip seat 2, the upper lip 1, the lower lip seat 4 and the lower lip 3 enclose a supersonic resonance cavity 7 to achieve high-frequency resonance of the supersonic air flow from the first Laval channel 6 and improve the air flow vibration frequency; the docking surface of the upper lip 1 and the lower lip 3 forms a second Laval channel 8 to accelerate the high-frequency vibrating air flow to supersonic speed.

[0043] In this embodiment, a plurality of grooves 9 are evenly distributed on the circumference of the upper lip 1 facing the outlet of the first Laval channel 6, and the distance between two adjacent grooves 9 is 1 - 2 mm. The main function of the grooves is to achieve air flow rectification and further make the air flow vibration frequencies consistent.

[0044] In this embodiment, the grooves 9 are circular grooves with a diameter of 0.2 - 1 mm and a depth of 0.1 - 0.8 mm; the distance between two adjacent grooves 9 is 1 - 2 mm; the number of the grooves is 20 - 80, preferably 60.

[0045] In this embodiment of the present invention, the throat diameter of the first Laval channel 6 is denoted as D1, D1 is 0.4 - 0.8 mm; the outlet cross-sectional diameter of the first Laval channel 6 is denoted as D2, D2 is 0.9 - 1.5 mm; the expansion section cone angle of the first Laval channel 6 is denoted as α, α is 9 - 12°.

[0046] In this embodiment, the minimum width of the supersonic resonance cavity 7 is denoted as D3, and D3 is 3 mm; the effective resonance length of the supersonic resonance cavity 7 is denoted as D4, and D4 is 10 - 15 mm.

[0047] In this embodiment, the throat diameter of the second Laval nozzle 8 is denoted as D5, and D5 is 0.6 - 0.8 mm; the outlet cross-sectional diameter of the second Laval nozzle 8 is denoted as D6, and D6 is 1.2 - 1.6 mm; the expansion section cone angle of the second Laval nozzle 8 is denoted as β, and β is 9 - 12°.

[0048] In this embodiment, the upper lip seat 2 and the lower lip seat 4 are respectively threadedly connected to the outer sleeve 5; the upper lip 1 is threadedly connected to the upper lip seat 2; the lower lip 3 is threadedly connected to the lower lip seat 4.

[0049] Application Example 1

[0050] This application example is based on Embodiment 1 and defines the following parameters: 60 circular grooves with a diameter of 1 mm and a depth of 0.8 mm are evenly distributed on the circumference of the outlet of the first Laval nozzle 6, the groove pitch is 1 mm, the throat diameter D1 of the first Laval nozzle 6 is 0.5 mm, and the outlet cross-sectional diameter D2 is 1.2 mm. The dimensions of the second Laval nozzle are closely related to the design of the first Laval nozzle. If the dimensions of the second nozzle are too large relative to the first Laval nozzle dimensions, there will be a situation of insufficient gas flow, affecting the atomization effect; if the dimensions of the second nozzle are too small relative to the first Laval nozzle dimensions, congestion will occur in the second nozzle, thus reducing the outlet velocity and affecting the atomization effect. The throat diameter D3 of the second Laval nozzle 8 is 0.52 mm, and the outlet cross-sectional diameter D4 is 1.14 mm.

[0051] Copper-based alloy powder production is carried out based on a 100 kg free-form gas atomization powder production equipment. The specific process is that the superheat degree is 150 °C, the atomization pressure is 2.0 MPa, the material of the deflector nozzle is alumina, and the diameter is 4.5 mm. The particle size distribution of the obtained powder is narrowed by 1.84% after screening through -100 mesh, as shown in Figure 3 . At the same time, powder production is carried out under the same conditions using a traditional spray disc, as shown in Figure 4 . From Figure 3 and Figure 4 's scanning diagrams, it can be clearly seen that the particle size distribution of the powder obtained by the ultrasonic resonance supersonic gas atomization spray disc provided by the present invention is more concentrated, that is, the particle sizes are relatively consistent.

[0052] Application Example 2

[0053] This application example is based on Example 1 and defines the following parameters: 60 circular grooves with a diameter of 1 mm and a depth of 0.8 mm are evenly distributed on the circumference of the outlet of the first Laval channel 6, the groove spacing is 1 mm, the throat diameter D1 of the first Laval channel 6 is 0.64 mm, and the outlet cross-section diameter D2 is 1.32 mm. The size of the second Laval channel is closely related to the first Laval design; the throat diameter D3 of the second Laval channel 8 is 0.6 mm, and the outlet cross-section diameter D4 is 1.34 mm.

[0054] Cobalt-based alloy powder production is carried out based on a 250 kg vacuum tight-coupling gas atomization powder production equipment. The specific process is as follows: the superheat degree is 280 °C, the atomization pressure is 4.5 MPa, the tundish temperature is 1200 °C, the diameter of the tundish nozzle is 5 mm, and the extension length is 4.5 mm. After screening through -100 mesh, the particle size distribution of the obtained powder is narrowed by 1.34%.

[0055] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. An ultrasonic resonance supersonic atomization spray disc, characterized in that: include: Coat (5); An upper lip seat (2) and an upper lip (1) are arranged on the upper end surface of the outer sleeve (5) in sequence from the inside to the outside; A lower lip seat (4) and a lower lip (3) are arranged on the lower end surface of the outer sleeve (5) in sequence from the inside to the outside; in: The butt joint surface of the upper lip seat (2) and the lower lip seat (4) forms a first Laval channel (6) to achieve the first acceleration of the airflow; The upper lip seat (2), the upper lip (1), the lower lip seat (4) and the lower lip (3) together form a supersonic resonance cavity (7), which realizes high-frequency resonance of the supersonic airflow from the first Laval channel (6) and increases the vibration frequency of the airflow; The butt joint surface of the upper lip (1) and the lower lip (3) forms a second Laval channel (8), which accelerates the high-frequency vibrating airflow to supersonic speed.

2. The ultrasonic resonance supersonic atomization spray disc according to claim 1, characterized in that: A plurality of grooves are evenly distributed on the circumference of the upper lip (1) facing the outlet of the first Laval channel (6), and the distance between two adjacent grooves is 1-2 mm.

3. The ultrasonic resonance supersonic atomization spray disc according to claim 2, characterized in that: The groove is a circular groove with a diameter of 0.2-1 mm and a depth of 0.1-0.8 mm.

4. The ultrasonic resonance supersonic atomization spray disc according to claim 2, characterized in that: The distance between two adjacent grooves is 1-2 mm.

5. The ultrasonic resonance supersonic atomization spray disc according to claim 2, characterized in that: The number of the grooves is 20-80.

6. The ultrasonic resonance supersonic atomization spray disc according to claim 1, characterized in that: The first Laval channel (6) satisfies at least one of the following conditions: ① The throat diameter of the first Laval channel (6) is denoted as D1, and D1 is 0.4-0.8 mm; ② The outlet cross-sectional diameter of the first Laval channel (6) is denoted as D2, and D2 is 0.9-1.5 mm; ③ The cone vertex angle of the expansion section of the first Laval channel (6) is denoted as α, and α is 9-12°.

7. The ultrasonic resonance supersonic atomization spray disc according to claim 1, characterized in that: The supersonic resonance cavity (7) satisfies at least one of the following conditions: ① The minimum width of the supersonic resonance cavity (7) is denoted as D3, and D3 is 3 mm; ② The effective resonance length of the supersonic resonance cavity (7) is denoted as D4, and D4 is 10-15 mm.

8. The ultrasonic resonance supersonic atomization spray disc according to claim 1, characterized in that: The second Laval channel (8) satisfies at least one of the following conditions: ① The throat diameter of the second Laval channel (8) is denoted as D5, and D5 is 0.6-0.8 mm; ② The outlet cross-sectional diameter of the second Laval channel (8) is denoted as D6, and D6 is 1.2-1.6 mm; ③ The cone vertex angle of the expansion section of the second Laval channel (8) is denoted as β, and β is 9-12°.

9. The ultrasonic resonance supersonic aerosol spray disc according to claim 1, characterized in that: The upper lip seat (2) and the lower lip seat (4) are respectively threadedly connected to the outer sleeve (5).

10. The ultrasonic resonance supersonic atomization spray disc according to claim 1, characterized in that: The upper lip (1) is threadedly connected to the upper lip seat (2); the lower lip (3) is threadedly connected to the lower lip seat (4).

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