Monodisperse uniform fogdrop device and atomizing nozzle orifice array arrangement method

Abstract

The invention relates to the technical field of micron-sized jet flow and uniform atomization, in particular to a monodisperse uniform fog drop device and an atomization spray head spray hole array arrangement method, and the monodisperse uniform fog drop device comprises a driving source, a liquid supply device and a spray head; the spray head is a monodisperse atomizing spray head, the driving source is an ultrasonic signal generating system, the liquid supply device supplies constant-pressure fluid to the spray head, and the spray head forms monodisperse spray under the driving of high-frequency sound waves of the ultrasonic signal generating system; the spraying hole array arrangement method of the atomizing nozzle comprises the following steps of: setting smaller spraying hole spacing in small deformation areas close to the center of the spraying hole plate and constraint ends on two sides of the spraying hole plate; a large safety distance is arranged in a large deformation area between the restraining end of the spray orifice plate and the center of the spray orifice plate, so that intersection caused by jet flow intersection is prevented. According to the device and the arrangement method, the problems of mutual interference and the like between large-scale array jet flows are solved; the controllability of the size and the speed of the monodisperse atomized liquid drops can be effectively improved, so that macro micro liquid drops with uniform size and concentrated speed are generated.

Description

Technical Field

[0001] The invention relates to the technical field of micron-level jet and uniform atomization, and in particular to a monodisperse uniform droplet device and an atomizing nozzle spray hole array arrangement method. Background Art

[0002] In the field of micron-scale jets and uniform atomization, single-split scattering and fine atomization technologies have broad application prospects, especially in advanced manufacturing processes such as physical cleaning of integrated circuits, photoresist coating, film spraying, pharmaceutical equipment and particle drying. These processes place extremely high demands on the scale, distribution and speed of atomized droplets. For example, in the physical cleaning process of integrated circuits, it is necessary to achieve a high particle removal rate while avoiding any mechanical damage to the micro-nano device structure. In addition, high-quality photoresist coating and film spraying also require smaller and more uniform droplets to ensure the thickness and uniformity of the film.

[0003] In recent years, the advanced process of integrated circuits has entered a new process node (10nm), which has put forward higher requirements for the physical cleaning process: high particle removal rate must be achieved while avoiding any mechanical damage to the micro-nano device structure. In addition, high-quality photoresist coating and film spraying also put forward new requirements for atomization technology. In order to produce thinner (<5μm) and more uniform (<10%) films, smaller droplets and higher uniformity are required. These requirements have put forward higher requirements on the controllability and concentration of atomized droplets. Therefore, it is urgent to develop a new atomization technology with high droplet controllability to produce macro-scale micro-droplets with uniform size and concentrated speed.

[0004] However, current typical liquid atomization technologies, such as two-fluid atomization and ultrasonic atomization, have limitations that are difficult to overcome. Two-fluid atomization technology is based on the instability between the gas-liquid phases. Although it can produce a large number of micro droplets, its atomization effect is significantly affected by the airflow, and it is difficult to achieve independent regulation of droplet velocity and particle size. Ultrasonic atomization uses high-frequency vibration to stimulate liquid interface oscillation to form fine droplets, but the atomization effect also depends on the vibration frequency and amplitude, and the droplet diameter and velocity distribution show normal distribution characteristics, which are difficult to accurately control.

[0005] Although inkjet technology can produce micro-droplets of uniform size, its jet velocity is low, flow rate is small, and it is expensive and has poor pressure resistance, which limits its application in industrial-grade spraying with large flow rate and high speed. In addition, the compact nozzle layout easily causes adhesion and clogging of the orifice plate due to wetting, affecting the uniformity and stability of the spray. When the working pressure of the spray chamber is too high, the orifice plate will also deform, causing the jet direction to deviate or even merge between the jets, further reducing the stability and concentration of the spray.

[0006] Therefore, the existing atomization technology still has many difficulties in meeting the high requirements of advanced manufacturing processes for droplet size, speed and controllability. In response to these problems, the present invention proposes a monodisperse uniform droplet device and an atomizing nozzle nozzle orifice array arrangement method, which aims to improve the controllability of monodisperse atomized droplet size and speed by optimizing the arrangement design of the nozzle array, thereby generating a large amount of micro droplets with uniform size and concentrated speed to meet the urgent needs of advanced manufacturing processes. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a monodisperse uniform droplet device and an atomizing nozzle nozzle array arrangement method, which can solve the mutual interference between large-scale array jets and other problems; and can effectively improve the controllability of the scale and speed of monodisperse atomized droplets, thereby producing a large amount of micro droplets with uniform scale and concentrated speed.

[0008] The technical solution of the present invention is as follows: A monodisperse uniform droplet device comprises a driving source, a liquid supply device and a nozzle; the nozzle is a monodisperse atomizing nozzle, the driving source is an ultrasonic signal generating system, the liquid supply device supplies constant pressure fluid to the nozzle, and the nozzle forms a monodisperse spray under the high-frequency sound wave drive of the ultrasonic generating system.

[0009] The ultrasonic signal generating system comprises a signal generator, a power amplifier and a piezoelectric transducer. The signal generator is connected to the power amplifier. The ultrasonic signal is amplified by the power amplifier and then connected to the piezoelectric transducer as a driving source.

[0010] The nozzle includes a nozzle plate and a pressure-resistant cavity. The nozzle plate is sealingly arranged at the bottom of the pressure-resistant cavity. The piezoelectric transducer is arranged on the opposite side of the nozzle plate and is adhered to the outer surface of the pressure-resistant cavity.

[0011] The piezoelectric transducer has three shapes to choose from, namely a square piezoelectric piece, a disc-shaped piezoelectric piece or a cylindrical piezoelectric piece, and the nozzle can be a square nozzle, a cylindrical nozzle or a tubular nozzle corresponding to the shape of the piezoelectric transducer.

[0012] The nozzle array of the square nozzle is generally arranged in a rectangular shape, and the nozzles in the same row or column have equal spacing; The nozzle array of the cylindrical nozzle is generally arranged in a circular pattern, the nozzles are arranged along concentric circles, the nozzles are evenly distributed on the same circle, and the circle is concentric with the disc-shaped piezoelectric piece; The nozzles of the tubular nozzle are arranged on the opposite side of the cylindrical piezoelectric sheet, and the nozzle array is arranged equidistantly along the length direction of the tubular nozzle.

[0013] The distance between the nozzle holes near the center of the nozzle plate and the restraining ends on both sides is smaller than the distance between the nozzle holes in the area between the restraining ends and the center of the nozzle plate.

[0014] A fixed end constraint is set in the center of the orifice plate.

[0015] The minimum safe spacing of the nozzles on the nozzle plate is:

[0016] Where: d is the nozzle hole diameter; t0 is the distance between the nozzle holes; σ is the surface tension of the fluid; P is the liquid supply pressure; P0 is the reference pressure; C is an empirical parameter.

[0017] A method for arranging the nozzle orifice array of an atomizing nozzle of a monodisperse uniform droplet device is disclosed. A smaller nozzle spacing is set in the area with slight deformation near the center of the nozzle plate and the constraint ends on both sides; a larger safety spacing is set in the large deformation area between the constraint end of the nozzle plate and the center of the nozzle plate to prevent intersection caused by jet intersection.

[0018] The minimum safety spacing of the nozzles on the nozzle plate is calculated according to the following formula:

[0019] Where: d is the nozzle hole diameter; t0 is the distance between the nozzle holes; σ is the surface tension of the fluid; P is the liquid supply pressure; P0 is the reference pressure; C is an empirical parameter.

[0020] The beneficial effects of the present invention are: 1. The monodisperse uniform droplet device and the atomizing nozzle nozzle orifice array arrangement method disclosed in the present invention are designed with nozzle arrays of different geometric configurations, ensuring the uniformity of the jets in nozzles of different structures being regulated by the sound field; piezoelectric sheets of different shapes have different vibration distribution laws, and the atomization effect during high-speed jets is extremely sensitive to the sound field difference; the nozzle array proposed in the present invention takes into account the sound field distribution of typical piezoelectric elements to ensure that the ultrasonic excitations received by different jets remain consistent, on the one hand ensuring the consistency of the sound field distribution laws at the nozzles at different positions in the array, on the other hand avoiding the internal vortex caused by the jet causing the sound field to be disordered, thereby reducing the deviation of the particle size between different nozzles.

[0021] 2. The monodisperse uniform droplet device and atomizing nozzle nozzle array arrangement method disclosed in the present invention propose a nozzle layout for compensating for jet direction deviation, which can greatly reduce the abnormality of jet direction; by adjusting the nozzle spacing to adapt to the deformation law of the nozzle plate, the direction deviation of different nozzles on the same axis is compensated; by setting fixed constraints on the nozzle plate, its deformation displacement is limited, thereby reducing the degree of jet direction deviation; on the one hand, this layout ensures the controllability of the jet direction, which plays an important role in optimizing process parameters; on the other hand, the correction of the jet direction deviation can also reduce the probability of intersection between jets due to factors such as eddy currents; this layout method improves the stability and durability of large-scale, large-flux monodisperse sprays.

[0022] 3. The design criteria for the minimum safe spacing between adjacent nozzles proposed in the monodisperse uniform droplet device and the atomizing nozzle nozzle nozzle array arrangement method disclosed in the present invention can effectively reduce the mutual interference between adjacent jets; through numerical simulation and experimental verification, considering factors such as fluid physical properties, jet velocity, intracavity pressure, nozzle diameter and driving frequency, and combining test data, an empirical criterion for the minimum safe spacing is proposed; the nozzle array designed according to this criterion effectively weakens the influence of vortices generated in the spatial flow field when a jet occurs on adjacent jets, realizes the stability and uniformity of monodisperse spray under specific process parameters, and ensures the compactness of the nozzle array, thereby improving the spray efficiency.

[0023] 4. The monodisperse uniform droplet device and the atomizing nozzle nozzle hole array arrangement method disclosed in the present invention have the unique advantages of uniform droplet size, concentrated velocity distribution, controllable jet direction, and independent and precise regulation of particle size and velocity. At the same time, by optimizing the nozzle hole arrangement, the spray flow rate is increased and the atomization stability of the nozzle is enhanced when working for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] By reading the detailed description of the preferred embodiment below, the scheme and advantages of the present application will become clear to those skilled in the art. The accompanying drawings are only for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention.

[0025] Figure 1 A schematic diagram of the composition of a monodisperse uniform droplet device according to an embodiment of the present invention; Figure 2 A schematic structural diagram of a nozzle of a monodisperse uniform droplet device according to an embodiment of the present invention; Figure 3 A schematic diagram of three piezoelectric transducers and a nozzle structure of a monodisperse uniform droplet device according to an embodiment of the present invention; Figure 4 For Figure 3 Schematic diagram of the corresponding geometric configuration of the nozzle nozzle hole arrangement; Figure 5Schematic diagram of the deformation of the nozzle plate caused by pressure; Figure 6 Schematic diagram of the jet direction deviation on the same axis caused by nozzle deformation; Figure 7 Schematic diagram of nozzle layout for compensating jet deviation; Fig. 8A Schematic diagram of jet deviation for fixed constraint compensation; Figure 8B Schematic diagram of the deformation offset of the orifice plate before and after the fixed constraint; Fig.9A Schematic diagram of abnormal interference and instability of adjacent jets; Fig. 9B Schematic diagram of velocity vortex distribution on both sides of adjacent jets; Fig. 10A Schematic diagram of the arrangement of triangular nozzle holes in compliance with the safety spacing rule; Fig. 10B Schematic diagram of the square nozzle arrangement method that complies with the safety spacing rule; Fig.11 is the particle size distribution of monodisperse spray; Fig.12 is the velocity concentration of monodisperse spray; Fig.13 It is the microscopic local morphology of monodisperse spray; The components represented by the reference numerals in the figure are: The present invention: 140, nozzle, 141, square nozzle, 142, cylindrical nozzle, 143, tubular nozzle, 150, safety valve, 200, signal generator, 210, power amplifier, 230, monitor and control box, 240, LED light source, 250, waste liquid recovery, 260, high-speed industrial camera, 270, droplet, 280, piezoelectric transducer, 281, square piezoelectric sheet, 282, disc-shaped piezoelectric sheet, 283, cylindrical piezoelectric sheet, 290, liquid supply device, 310, pressure-resistant cavity, 320, sealing ring, 330, nozzle plate, 340, nozzle. DETAILED DESCRIPTION

[0026] The method and device for arranging the nozzle array of a monodisperse atomizing nozzle are intended to improve the uniformity and stability of the monodisperse atomizing array jet. Specifically, nozzle arrays of different geometric configurations are designed according to the sound field distribution in a specific structural chamber to ensure uniform transmission of ultrasound at different nozzles; considering the case where the orifice plate is deformed due to pressure, a special nozzle layout scheme is designed to compensate for the jet deviation caused by the orifice plate deformation, and a method for setting a fixed constraint is provided to limit the orifice plate deformation, effectively ensuring the controllability of the jet direction; further, a design criterion for the minimum safe spacing between nozzles is proposed to avoid instability caused by mutual interference between jets while ensuring the maximum atomization efficiency. The innovative nozzle array arrangement method proposed in the present invention solves the common problems of poor stability and uneven jets in conventional atomization technology, and realizes large-flux monodisperse atomization with uniform scale and concentrated velocity.

[0027] like Figure 1 As shown, a monodisperse uniform droplet device includes a driving source, a liquid supply device 290 and a nozzle 140; the nozzle 140 is a monodisperse atomizing nozzle, the driving source is an ultrasonic signal generating system, the liquid supply device 290 supplies constant pressure fluid to the nozzle 140, and the nozzle 140 forms a monodisperse spray under the high-frequency sound wave drive of the ultrasonic generating system.

[0028] The ultrasonic generating device includes a function signal generator 200, a high voltage power amplifier 210 and a piezoelectric transducer (PZT piezoelectric ceramic sheet) 280; the signal generator 200 is directly connected to the power amplifier 210, and the ultrasonic signal is directly connected to the piezoelectric ceramic sheet 280 as a driving source after being amplified by the power amplifier 210. The observation device includes a high-speed industrial camera (industrial CCD camera) 260 and an LED light source (stroboscopic light source) 240, etc. The high-speed industrial camera (industrial CCD camera) 260 is connected to the monitor and control box 230 for communication.

[0029] The function-type signal generator 200 can generate high-frequency AC signals of different waveforms; the signal generator 200 is directly connected to the power amplifier 210, and the ultrasonic signal is directly used as a driving source after being amplified by the power amplifier 210.

[0030] The liquid supply device 290 includes a large flow rate and high pressure micro pump, a buffer / energy storage cartridge, a PTFE filter, a back pressure valve, a high precision pressure sensor, a micro controller and a liquid source. The large flow rate and high pressure micro pump directly supplies liquid to the buffer cartridge and delivers it to the monodisperse atomizing nozzle through the PTFE filter. The high precision pressure sensor and controller provide real-time feedback and adjust the ink circuit pressure.

[0031] like Figure 2As shown, the monodisperse spray nozzle 140 includes a piezoelectric transducer (PZT piezoelectric ceramic sheet) 280, a spray hole plate 330, a pressure-resistant cavity 310 and a sealing element (seal ring) 320; the components are physically installed (mechanically connected or ultrasonically welded) without using any adhesive, which can avoid the introduction of pollution sources. The liquid supply device 290 supplies constant pressure fluid to the monodisperse spray nozzle 140, and under the high-frequency ultrasonic drive generated by the ultrasonic generating system, the jet is forced to break regularly, and finally forms monodisperse spray droplets 270. The spray hole plate can be selected from quartz glass, silicon, stainless steel, PEEK and other materials according to the application scenario. The spray hole can be manufactured by laser processing, etching processing and mechanical processing according to the accuracy and orifice plate material requirements. The orifice plate 330 is arranged in the lower half of the pressure-resistant cavity 310, and a plurality of orifices 340 are provided on the orifice plate 330, and is sealed and installed in the cavity; the piezoelectric transducer (PZT piezoelectric ceramic sheet) 280 is arranged on the opposite side of the orifice plate 330, and is adhered to the outer surface of the cavity using a two-component epoxy resin adhesive; a safety valve (back pressure valve) 150 is arranged on the other side of the nozzle 140, and a waste liquid recovery (box) 250 is arranged below the outlet of the safety valve 150.

[0032] The piezoelectric transducer (PZT piezoelectric ceramic piece) 280 has different implementations according to the actual application scenario, such as Figure 3 As shown, it includes: a square piezoelectric piece 281, a disc-shaped piezoelectric piece 282 and a 1 / n cylindrical piezoelectric piece 283. The piezoelectric ceramic pieces are all polarized in the thickness direction, that is, the vibration mode is a stretching oscillation along the thickness direction. The vibration modes of the three piezoelectric pieces are analyzed using ANASY WORKBENCH, and it can be seen that piezoelectric pieces of different shapes can produce different sound field distribution laws. The square piezoelectric piece 281 and the disc-shaped piezoelectric piece 282 both transmit vibrations to the fluid medium in the cavity in a plane form. On the surface of the circular piezoelectric piece 282, the vibration form is transmitted from the center in the radial direction in the form of concentric ring harmonics. Under ideal conditions, the vibration state of any point on its surface is the same as that of all points on the same circle. The vibration transmission law of the cylindrical piezoelectric piece 283 is different from that of the other two piezoelectric pieces. The direction of the sound wave it generates is the same as the normal direction of the inner surface of the piezoelectric piece, and it is focused along the length direction in the internal space.

[0033] The monodisperse spray nozzle 140 has different embodiments for piezoelectric ceramic sheets 280 of different shapes, such as Figure 3 The monodisperse spray nozzle 140 may have different embodiments according to actual application conditions, and in particular, the structure needs to be adjusted to cope with sound fields with different distribution patterns. Figure 3Three typical embodiments of square nozzle 141, cylindrical nozzle 142 and tubular nozzle 143 are respectively given, corresponding to piezoelectric elements 281, 282 and 283. The cavity structure of the nozzle is adapted to the law of sound field transmission, avoiding the disorder of sound propagation direction caused by mismatch of the cavity structure, and ensuring that ultrasound can be evenly transmitted in the cavity and radiated to the bottom nozzle 340. The nozzle embodiment is not limited to the three typical structures proposed. For other special-shaped piezoelectric ceramic sheets, the nozzle embodiment can be made of metal, engineering plastics, organic glass, quartz and other materials according to the application scenario.

[0034] The optimized arrangement and layout method of the large-scale array nozzles 340 of the monodisperse uniform droplet device includes: The geometric configurations of the nozzle holes 340 for different nozzle implementations are as follows: Figure 4 For the implementation of the monodisperse atomizing nozzle 280 matching piezoelectric ceramic pieces 140 of different specifications, different geometric configurations of nozzle arrangement modes are provided: equidistant arrangement, circumferential arrangement and centerline arrangement, which correspond to the typical square nozzle 141, cylindrical nozzle 142 and tubular nozzle 143 respectively.

[0035] The nozzle layouts of different geometric configurations are all realized on the nozzle plate 330 by laser, etching or mechanical processing. In the equidistant arrangement of the square nozzle 141, the nozzles 340 on the same row or column are equally spaced, and the nozzle array is generally arranged in a rectangular shape. In the circumferential arrangement of the cylindrical nozzle 142, the nozzles 340 are arranged along concentric circles, the nozzles 340 on the same circumference are evenly distributed, and the circumference is concentric with the circular piezoelectric film. The shape of the nozzle array 340 of the above-mentioned equidistant arrangement and circumferential arrangement corresponds to the piezoelectric transducer, and the array area is not larger than the corresponding piezoelectric film area. In the centerline arrangement of the tubular nozzle 143, the nozzle array 340 is equidistantly arranged along the only centerline. The centerline is along the length direction of the tubular nozzle and is on the opposite side of the cylindrical piezoelectric film 283. This design ensures, on the one hand, that the acoustic field distribution patterns at the nozzle holes 340 at different positions in the array are consistent, and on the other hand, avoids the internal vortex caused by the jet that causes the acoustic field to become turbulent, thereby ensuring the regular transmission of the acoustic waves in the cavity to the jet and improving the uniformity of the array jet.

[0036] When the orifice plate 330 is working, it will deform due to the chamber pressure. Figure 5 As shown in FIG. 1 , the distance from any point on the orifice plate diameter to the center is defined as Ln. The jet direction deviation rule caused by the deformation of the orifice plate 330 is as follows: Figure 6As shown. The jet direction deviation is the smallest at the center of the orifice plate 330 and near the constraint end, while the deviation between the two gradually increases, and the jet deviation reaches the maximum at the center of the two. In order to meet the high-speed and large-flow spray requirements in engineering applications, high-pressure liquid supply and compact orifice arrangement are required. As the pressure increases, the orifice plate deformation increases, and the jet direction deviation will also increase. At the same time, the compact nozzle arrangement increases the probability of jet intersection.

[0037] Nozzle layout method to compensate for jet direction deviation, such as Figure 7 As shown, according to the deformation of the nozzle plate 330 and the jet deviation law, an array of nozzle holes 340 with unequal spacing is set. Figure 7 An example of the center line of a nozzle array of 340 is given. A smaller nozzle spacing is set in the area with small deformation near the center of the orifice plate and the constraint ends on both sides; a larger safety spacing is set in the large deformation area between the constraint end and the center of the orifice plate to prevent intersection caused by jet intersection. Figure 7 The nozzle layout method for compensating for jet direction deviation is shown using the circular array arrangement as an example for illustration purposes and does not represent the array spacing ratio and size in actual application. Similar arrangement arrays can also be designed based on this concept for the equidistant arrangement and centerline arrangement.

[0038] In the nozzle layout method for compensating for the deviation of the jet direction, the spacing of the nozzles 340 can be adjusted according to the atomization parameters. Specifically, for high-pressure spray, the spacing should be increased to adapt to the aggravated deformation of the orifice plate; for the setting of the spacing of the nozzles 340 on the same circumference, it is necessary to ensure that the jets do not interfere with each other or the orifice plate is wetted to cause the adjacent nozzles 340 to stick together and block the nozzles. This method is suitable for applications with high requirements for the controllability of the atomization direction, especially for large flow and high-speed spray applications.

[0039] In addition, a method for setting a fixed constraint to compensate for the jet deviation and a method for arranging the nozzle holes 340 are proposed, such as Fig. 8A and Figure 8B As shown, the jet direction deviation is caused by the pressure deformation of the orifice plate 330. When the spray device is working, the center of the orifice plate 330 is deformed the most and the constraint end is deformed the least. An additional arrangement is provided at the center of the orifice plate with the largest deformation to reduce the deformation of the orifice plate 330 to alleviate the jet direction deviation. By adding the fixed end constraint, the degree of deformation is alleviated and the jet direction deviation is corrected.

[0040] The installation and layout method of the fixed constraint compensation jet direction deviation uses the circular array arrangement as an example for illustration purposes and does not represent the setting position, quantity and method of the constraints in actual application. Similar arrangement arrays can also be designed based on this idea for the equidistant arrangement and centerline arrangement.

[0041] Furthermore, a design criterion for the minimum safe spacing of the array nozzle holes 340 is proposed to ensure that the nozzle hole array 340 arranged on the nozzle hole plate 330 has an optimal spacing. A velocity vortex will be generated around the high-speed jet. If the hole spacing is too small, the direction of the jet will deviate, and even the jets will intersect. Fig.9A As shown in Figure 2, the velocity vortex distribution on both sides of the jet is obtained using the computational fluid dynamics method when the multi-nozzle jet is atomized, as shown in Figure 2. Fig. 9B As shown. According to the target flow rate, flow velocity and particle size, determine the safe distance between the jets of different specifications of spray nozzles. That is, under the premise of ensuring that the jets do not interfere with each other and cause intersection, ensure a sufficiently compact layout to improve the atomization efficiency.

[0042] The design criteria for the minimum safe spacing of the array nozzles 340 are specifically stated as follows: by adjusting the nozzle layout and spacing, the vortex and bubbles caused are reduced to improve the stability and uniformity of the injection. Define the aperture d, the aperture spacing t0, the fluid surface tension σ, the liquid supply pressure P, the reference pressure P0, and the empirical parameter C; define the minimum pressure at which a stable jet can occur under the conditions of the fluid type and aperture as P0; obtain the initial value of the empirical parameter C through computational fluid dynamics simulation, and measure the adjacent jets under different experimental conditions without mutual interference (such as Fig.9A ) is used to correct C. Based on the computational fluid dynamics simulation of the flow field distribution and combined with experimental experience, the minimum safe spacing of the nozzle 340 array is proposed as: The actual design hole spacing Through the above measures, the interaction between the nozzles is effectively controlled, reducing the influence of vortices and bubbles that may occur during the injection process. The minimum safe spacing arrangement design criteria of the array nozzles 340 are applicable to the circumferential arrangement, equidistant arrangement and centerline arrangement.

[0043] Based on the design criteria of the minimum safe spacing of the array nozzle holes 340, a typical arrangement method that complies with the safe spacing rule is proposed, as shown in FIG10, including: A triangular distribution and B square arrangement. The adjacent rows of nozzle holes 340 in the triangular arrangement are arranged in a staggered manner, and the adjacent rows and columns of the square arrangement are distributed along a straight line. The above hole spacings all meet the minimum safe spacing design criteria.

[0044] The monodisperse atomization device with optimized spray hole arrangement can produce monodisperse spray with uniform size, concentrated speed and controllable direction. Fig.11 The monodisperse spray particle size distribution produced by the present invention has a particle size concentration of 95%@98±5μm; the monodisperse spray velocity distribution produced is as follows Fig.12 As shown, the droplet velocity is concentrated at 20.1-20.3 m / s; Fig.13This is the microscopic local morphology of the monodisperse spray obtained by the in-situ high-speed observation device. It can be seen that the monodisperse atomized jet obtained by the present invention has the advantages of high straightness and controllable direction.

[0045] The monodisperse uniform droplet device and the atomizing nozzle nozzle array arrangement method of the present invention can avoid mutual interference between large-scale array jets; compensate for the jet direction deviation caused by the deformation of the nozzle plate; and optimize the sound field distribution to enhance the uniformity and stability of ultrasonically regulated jet breakup. The present invention can effectively improve the controllability of the size and speed of monodisperse spray droplets, and produce a large amount of micro droplets with uniform size and concentrated speed.

Claims

1. A monodisperse uniform droplet device, characterized in that: The invention comprises a driving source, a liquid supply device (290) and a nozzle (140); the nozzle (140) is a monodisperse atomizing nozzle, the driving source is an ultrasonic signal generating system, the liquid supply device (290) supplies a constant pressure fluid to the nozzle (140), and the nozzle (140) forms a monodisperse spray under the driving of high-frequency sound waves of the ultrasonic generating system.

2. A monodisperse uniform droplet device according to claim 1, characterized in that: The ultrasonic signal generating system comprises a signal generator (200), a power amplifier (210) and a piezoelectric transducer (280); the signal generator (200) is connected to the power amplifier (210); and the ultrasonic signal is amplified by the power amplifier (210) and then connected to the piezoelectric transducer (280) as a driving source.

3. A monodisperse uniform droplet device according to claim 2, characterized in that: The nozzle (140) comprises a nozzle plate (330) and a pressure-resistant cavity (310); the nozzle plate (330) is sealingly arranged at the bottom of the pressure-resistant cavity (310); the piezoelectric transducer (280) is arranged on the opposite side of the nozzle plate (330); and the piezoelectric transducer (280) is adhered to the outer surface of the pressure-resistant cavity (310).

4. A monodisperse uniform droplet device according to claim 3, characterized in that: The piezoelectric transducer (280) has three optional shapes, namely a square piezoelectric sheet (281), a disc-shaped piezoelectric sheet (282), or a cylindrical piezoelectric sheet (283); the nozzle (140) can be a square nozzle (141), a cylindrical nozzle (142), or a tubular nozzle (143) corresponding to the shape of the piezoelectric transducer (280).

5. A monodisperse uniform droplet device according to claim 4, characterized in that: The array of spray holes (340) of the square spray head (141) is generally arranged in a rectangular shape, and the spray holes (340) in the same row or column are spaced at equal intervals; The nozzle holes (340) array of the cylindrical nozzle (142) are generally arranged in a circular pattern, the nozzle holes (340) are arranged along concentric circles, the nozzle holes (340) are evenly distributed on the same circle, and the circle is concentric with the disc-shaped piezoelectric piece (282); The spray holes (340) of the tubular spray head (143) are arranged on the opposite side of the cylindrical piezoelectric sheet (283), and the spray hole (340) array is arranged at equal distances along the length direction of the tubular spray head (143).

6. A monodisperse uniform droplet device according to claim 5, characterized in that: The distance between the spray holes near the center and the two side restraining ends of the spray hole plate (330) is smaller than the distance between the spray holes in the area between the restraining ends and the center of the orifice plate.

7. The monodisperse uniform droplet device according to claim 5, characterized in that: A fixed end constraint is provided in the center of the spray hole plate (330).

8. The monodisperse uniform droplet device according to claim 5, characterized in that: The minimum safety spacing of the spray holes (340) on the spray hole plate (330) is: Where: d is the nozzle hole diameter; t0 is the distance between the nozzle holes; σ is the surface tension of the fluid; P is the liquid supply pressure; P0 is the reference pressure; C is an empirical parameter.

9. A method for arranging a nozzle array of a monodisperse uniform droplet device, based on the monodisperse uniform droplet device according to any one of claims 1 to 8, characterized in that: A smaller nozzle spacing is set in the area with slight deformation near the center and the two side constraint ends of the nozzle plate (330); and a larger safety spacing is set in the area with large deformation between the constraint end of the nozzle plate (330) and the center of the nozzle plate (330) to prevent intersection caused by the intersection of jets.

10. The method for arranging the spray hole array of the atomizing nozzle of the monodisperse uniform droplet device according to claim 9, characterized in that: The minimum safety spacing of the spray holes (340) on the spray hole plate (330) is calculated according to the following formula: Where: d is the nozzle hole diameter; t0 is the distance between the nozzle holes; σ is the surface tension of the fluid; P is the liquid supply pressure; P0 is the reference pressure; C is an empirical parameter.

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