Liquid drop efficient generation method and device based on space orthogonal mechanical waves

Abstract

The invention discloses a liquid drop efficient generation method and device based on space-time orthogonal mechanical waves. A liquid supply device is connected with an orthogonal mechanical wave disturbance liquid drop generator and used for providing high-pressure liquid; the disturbance signal driving device is used for driving the orthogonal mechanical wave disturbance liquid drop generator so as to generate continuous single-particle orderly-distributed liquid drops; the orthogonal mechanical wave disturbance liquid drop generator is provided with a longitudinal wave generating unit and a transverse wave generating unit which are driven by the disturbance signal driving device, the orthogonal mechanical wave disturbance liquid drop generator orthogonally and synergistically acts on the liquid jet process, liquid interface wave development is gradually promoted in a stepped mode, and in combination with the air disturbance effect caused by high-speed jet, ordered distribution of continuous particle liquid drops is efficiently and rapidly achieved; the generation of disordered satellite liquid drops among different theme liquid drops is effectively reduced, the flow of a jet flow fracture liquid drop transition area is remarkably shortened, the liquid drop oscillation effect is weakened, the efficient, accurate and controllable required main body liquid drops are formed, and the accuracy and efficiency of the required liquid drops are improved.

Description

Technical Field

[0001] The present invention relates to a droplet generation method and device, and particularly to a high-efficiency droplet generation method and device based on spatial orthogonal mechanical waves, which are applicable to fields such as spray cooling, fuel injection, and surface coating. Background Art

[0002] The technology of using jet breakup to prepare droplets is commonly used in various fields of industry and research, such as inkjet printing, spray cooling, spray drying, fuel injection, and surface coating, and is also used for spray generation for medical or agricultural purposes. As the source for generating droplets, it should have high requirements.

[0003] The breakup of a jet usually involves complex fluid mechanics knowledge, including the interaction between the liquid phase and the gas phase in a multiphase flow. When an external perturbation is applied to the surface of a liquid jet, the jet breaks into droplets under the drive of Rayleigh Plateau instability and surface tension.

[0004] In the prior art, interference sources based on various physical principles are applied to the jet to prepare droplets. This transformation from a jet to monodisperse droplets generally needs to go through a perturbation wave growth stage and an oscillation stage. In the perturbation wave growth stage, the initial perturbation signal grows from the upstream to the downstream on the surface of the jet, and a jet transition morphology with obvious wave peaks and wave valleys is formed. As the perturbation grows to a certain extent, the jet finally breaks at the downstream and continuously separates droplets. The droplets just separated from the jet tend to form spherical droplets under the action of surface tension. Therefore, after the jet breaks, the droplets immediately enter the oscillation stage, and the separated droplets are no longer affected by the perturbation. As the oscillation progresses, the droplets finally approach a spherical shape, forming a sequence of monodisperse droplets.

[0005] Regarding droplet generation devices, there are already many at present. Most of them only use a single perturbation signal to quickly prepare monodisperse droplets on the existing droplet generation devices, but there are few mentions of methods for shortening the growth time of surface waves at the liquid interface by step-by-step advancement and synergistic action, thereby efficiently and quickly obtaining or forming monodisperse ordered droplets. However, during the process of the action of a single excitation signal on the liquid interface, usually due to the rigidity of the liquid flow process itself, it often leads to a decrease in the development stability of the surface waves excited by the liquid, making it difficult to quickly and efficiently form a continuous droplet chain and its ordered distribution in a relatively small space-time region. Even, it will form chaotic and disordered satellite droplets, which cross-infect and interact with the main droplets, affecting the quality and scale of the main droplet particles, and further affecting the morphology and accuracy of the required main droplet particles, reducing the accuracy and efficiency of the droplet generation device. Summary of the Invention

[0006] In view of the limitations of the above droplet generator, the present invention provides a method and device for efficiently generating droplets based on spatio-temporal orthogonal mechanical waves. Through the orthogonal cooperative action of mechanical waves in different spatial regions and different time domains on the liquid jet process, the development of liquid interface waves is gradually promoted step by step. Combining with the air disturbance effect caused by high-speed jet, the continuous jet droplets and their orderly distribution are realized efficiently and quickly, the generation of disordered satellite droplets between droplets of different subjects is effectively reduced, the process of the jet breakage droplet transition region is significantly shortened, the droplet oscillation effect is weakened, and thus the required main droplets with high efficiency, precision and controllability are formed.

[0007] In a first aspect, a droplet generating device based on spatio-temporal orthogonal mechanical waves of the present invention includes an orthogonal mechanical wave excited droplet generator, a liquid supply device and an excitation signal driving device;

[0008] The liquid supply device is connected to the orthogonal mechanical wave excited droplet generator for providing driving liquid;

[0009] The excitation signal driving device is used to drive the orthogonal mechanical wave excited droplet generator to generate continuous single droplets;

[0010] The orthogonal mechanical wave excited droplet generator is configured with a longitudinal wave generating unit and a transverse wave generating unit driven by the excitation signal driving device. The excitation waves formed by each unit act on the liquid fluid, and a periodic axial mechanical wave is rapidly formed on the liquid fluid itself and fully develops as the liquid flows. Utilizing the entrained air disturbance effect caused by the jet at the nozzle outlet, and simultaneously under the action of the liquid's own surface tension and the development of surface waves, the rapid and efficient periodic breakage of the liquid jet direction is realized, forming a series of continuous single-particle orderly distributed droplets.

[0011] In a second aspect, a method for generating droplets based on spatio-temporal orthogonal mechanical waves of the present invention is specifically as follows:

[0012] After the liquid enters the liquid chamber from the liquid chamber inlet through the liquid supply device and then flows out of the liquid chamber outlet into the nozzle body, under the cooperative excitation or individual excitation of the longitudinal wave generating unit and the transverse wave generating unit respectively, the liquid jet formed at the nozzle outlet forms continuous single-particle droplets under the action of its own wave and surface tension, and the direction of the jet droplets is along the central axis direction of the nozzle outlet;

[0013] Among them:

[0014] The axial longitudinal wave generated by the longitudinal wave generating unit at the top is conducted to the liquid through the wall surface. Under the action of mechanical wave excitation, the fluid particles move in the flow direction and develop rapidly, causing the fluid itself to form a periodic axial pressure mechanical wave. On the fluid surface, the wave peaks and valleys appear alternately along the fluid direction, that is, the high / low pressure regions of the fluid appear alternately, and the period of the fluid itself is consistent with the period of the driving signal of the longitudinal wave generator;

[0015] In the trough region of the axial mechanical wave in the fluid region, the trough region of the mechanical wave is vertically excited axially through the shear wave generating unit to form a transverse excitation drive perpendicular to the jet direction, and then cooperate with the axial mechanical wave to generate an orthogonal mechanical wave under the spatio-temporal orthogonal cooperation, further exciting the driven trough region. During the liquid fluid flow process, the wave crest and trough regions that alternately appear in the fluid itself continue to develop. Through the air entrainment and perturbation effect of the jet at the nozzle outlet, under the action of the liquid's own surface tension and surface wave development, it breaks efficiently and rapidly to form a dispersed single-particle continuous and orderly distributed droplet flow.

[0016] The technical solution adopted in the present invention is as follows: Compared with other droplet generation technologies, the spatio-temporal orthogonal mechanical waves in the present invention can cooperate with each other and gradually promote the development of the liquid interface wave. Combining with the air perturbation effect caused by the high-speed jet effect, it efficiently realizes the jet breaking into a droplet chain. At the same time, during the process of the liquid surface wave gradually advancing step by step, it is more conducive to the formation between the controlled droplet chains, effectively reducing the formation of satellite droplets between different droplets, avoiding the cross-influence of satellite droplets, and is particularly suitable for the requirements of high-precision droplet production; In addition, the spatio-temporal cooperation of the orthogonal mechanical waves in the present invention can be applied to more types of liquids during the process of gradually promoting the surface development, not limited to liquids with specific viscosities or compositions, increasing the universality of its application. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of a droplet generating device based on spatial orthogonal mechanical waves according to an embodiment of the present application.

[0018] Figure 2 It is a schematic structural diagram of a shear wave perturbation droplet generator.

[0019] Figure 3 It is a schematic diagram of the action mechanism of the perturbation signal.

[0020] In the figure: 1 - gas storage tank, 2 - pressure gauge, 3 - gas-liquid pipeline, 4 - liquid storage tank, 5 - signal generator, 6 - electric wire, 7 - disc-shaped piezoelectric crystal, 8 - conical liquid cavity, 9 - nozzle body, 10 - hollow cylindrical piezoelectric crystal, 11 - nozzle orifice plate, 12 - pipeline connection end. Detailed Embodiments

[0021] The principles, structures, methods, and technical effects of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the examples of the present invention patent, so as to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention patent, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention patent without creative efforts or technical solutions that can be obtained through logical analysis, reasoning, or limited experiments on the basis of the existing technology of the present invention belong to the scope of protection of the present invention patent.

[0022] The present application provides a droplet generation system based on spatial orthogonal mechanical waves, including an orthogonal mechanical wave perturbation droplet generator, a liquid supply device, and a perturbation signal driving device;

[0023] The liquid supply device is connected to the orthogonal mechanical wave excitation droplet generator for providing driving liquid;

[0024] The excitation signal driving device is used to drive the orthogonal mechanical wave excitation droplet generator to generate continuous single droplets;

[0025] The orthogonal mechanical wave excitation droplet generator is configured with a longitudinal wave generating unit and a transverse wave generating unit driven by the excitation signal driving device. The excitation waves formed by each unit act on the liquid fluid, rapidly forming periodic axial mechanical waves on the liquid fluid itself, and fully developing as the liquid flows. Utilizing the entrainment air perturbation effect caused by the jet at the nozzle outlet, and simultaneously under the action of the liquid's own surface tension and the development of surface waves, the rapid and efficient periodic fracture of the liquid jet is realized, forming a series of continuously single-particle orderly distributed droplets.

[0026] The orthogonal mechanical wave excitation droplet generator includes a longitudinal wave generating unit, a transverse wave generating unit, a liquid chamber, and a nozzle body. The longitudinal wave generating unit and the transverse wave generating unit can be piezoelectric crystals or other devices that can generate high-frequency excitation signals; a nozzle outlet is provided at the outlet of the nozzle body for forming a liquid jet.

[0027] The excitation signal driving device can simultaneously or separately generate periodic excitation electrical signals of various waveforms such as square waves, trigonometric function waves, and pulse waves, respectively for the longitudinal wave generating unit and the transverse wave generating unit.

[0028] The liquid chamber is provided with a liquid fluid inlet, and the fluid outlet is preferably arranged at the lower part or the bottom of the chamber, and the outlet is directly connected to the nozzle body to form a liquid fluid channel.

[0029] The cavity structure of the liquid chamber includes but is not limited to structures such as spheres, cones, frustums of cones, cylinders, cubes, and cuboids.

[0030] Above the liquid cavity, a longitudinal wave generating unit is provided. Under the drive of an excitation signal acting device, the longitudinal wave generating unit generates an excitation signal parallel to the liquid flow trend.

[0031] The transverse wave generating unit is arranged on the nozzle body directly connected to the liquid cavity outlet. Under the drive of an excitation signal acting device, it generates an excitation signal perpendicular to the liquid flow direction.

[0032] The longitudinal wave generating unit and the periodic excitation signal generated by the longitudinal wave generating unit can be separately excited or act synergistically to form an orthogonal excitation effect.

[0033] When the longitudinal wave generating unit and the transverse wave generating unit act synergistically, the periodic excitation signal during the synergistic action can use a unified excitation signal driving device to form the same waveform and amplitude, or can select the required waveform and amplitude of their respective excitation signal driving devices according to the liquid characteristics, but they need to be of the same frequency.

[0034] After the liquid enters the liquid cavity from the liquid cavity inlet through the liquid supply device and flows into the nozzle body from the liquid cavity outlet, under the synergistic excitation or separate excitation of the longitudinal wave generating unit and the transverse wave generating unit in sequence, the liquid jet formed at the nozzle outlet forms continuous single-particle liquid droplets under the action of its own wave and surface tension, and the direction of the jet liquid droplets is along the central axis direction of the nozzle outlet.

[0035] Among them: The axial longitudinal wave generated by the longitudinal wave generating unit at the top is conducted to the liquid through the wall surface. Under the excitation of the mechanical wave, the fluid particles move in the flow direction and develop rapidly, causing the fluid itself to form a periodic axial pressure mechanical wave. On the fluid surface, wave crests and wave troughs appear alternately along the fluid direction, that is, high / low pressure regions of the fluid appear alternately, and the period of the fluid itself is consistent with the period of the driving signal of the longitudinal wave generator.

[0036] In the wave trough region of the axial mechanical wave in the fluid region, through the transverse wave generating unit to vertically excite the wave trough region of the mechanical wave, a transverse excitation drive perpendicular to the jet direction is formed, and then it acts synergistically with the axial mechanical wave to generate an orthogonal mechanical wave under the spatio-temporal orthogonal synergistic action, further exciting the wave trough region of the drive. During the liquid fluid flow process, the alternately appearing wave crest and wave trough regions of the fluid itself continue to develop. Through the air entrainment and perturbation effect of the jet at the nozzle outlet, under the action of the liquid's own surface tension and the development of surface waves, it breaks efficiently and rapidly to form a dispersed single-particle continuous and orderly distributed liquid droplet flow.

[0037] The single-particle continuous-distribution droplets formed under the synergistic action of spatio-temporal orthogonal mechanical waves can not only efficiently achieve precise control of the net droplet size and shape, but also have the continuity of generating a single controllable droplet chain, which is more efficient and stable and beneficial to the production process; under the action of the orthogonal mechanical wave system, based on the adjustment of the frequency and amplitude of the mechanical wave excitation, the generation rate of the particulate droplets and the spacing between the droplet chains can be effectively controlled.

[0038] This application uses disturbance sources at different positions in space to generate mechanically perpendicular waves in space. The two waves act synergistically to accelerate droplet formation rapidly, which is used to reduce the jet length and droplet oscillation time and improve droplet quality.

[0039] Preferably, the orthogonal mechanical wave-excited droplet generator includes two piezoelectric crystals, which are respectively located at the top of the conical liquid cavity and on the nozzle body above the orthogonal mechanical wave-disturbed droplet generator.

[0040] Preferably, a connection port is opened on the outer edge side of the conical liquid cavity to connect a pipeline leading to the liquid supply device, and a connection port is opened at the cone top to connect the nozzle body. The internal space is also conical and the corners of the space are rounded, which effectively enhances the fluid streamline trajectory, reduces the flow resistance, and avoids the disturbance of the development of the liquid surface wave caused by the turbulent effect.

[0041] Preferably, the aperture of the nozzle orifice plate is 0.005 mm to 5 mm, and the thickness is 0.1 mm to 3 mm.

[0042] Preferably, the excitation signal driving device generates a sine wave signal with a voltage amplitude of 10 - 300 V and a frequency of 1 - 300 kHz, which are respectively used to drive the disturbance shear wave and longitudinal wave generating units, and the two disturbance signals are set to be out of phase.

[0043] Preferably, the piezoelectric crystals are respectively a longitudinal wave generating crystal and a shear wave generating crystal; among them, the longitudinal wave generating crystal is arranged at the top of the conical liquid cavity above the orthogonal mechanical wave-disturbed droplet generator, and the shear wave generating crystal is arranged at the upper middle position of the upper nozzle body. The spatial region spacing between the two is adjusted accordingly according to parameters such as the required liquid physical properties, liquid cavity structure, and liquid flow rate.

[0044] Preferably, the liquid first passes through the conical liquid cavity where the longitudinal wave generating crystal is located and then passes through the nozzle body where the shear wave generating crystal is located.

[0045] Preferably, the longitudinal wave generating crystal and the shear wave generating crystal allow the use of electrical signals with different peak voltages, duty cycles, phase differences, and signal frequencies to control mechanical vibrations respectively.

[0046] This application jointly uses excitation signals whose excitation directions are the same as and perpendicular to the jet direction respectively. By coordinating in space and time and acting on the jet, the transition time for generating uniform droplets is reduced, and at the same time, the quality of the droplets is improved. The monodisperse droplets generated by this application are closer to the nozzle, can generate more stable droplets, and reduce the oscillation effect of the droplets. The droplet generation method used in this application is more energy-efficient. Compared with the signal excitation in a single direction, using signal excitations in multiple different space-time can improve the power factor of the droplet generator. The droplet generation method used in this application has higher reliability. When the excitation in any space-time fails, the excitations in other space-times can still act and normally generate uniform droplets.

[0047] Embodiment:

[0048] Figure 1 It is a schematic diagram of a high-efficiency droplet generation device based on spatial orthogonal mechanical waves. This embodiment includes an orthogonal mechanical wave excitation droplet generator, a liquid supply device, and an excitation signal driving device. The liquid is stored in the liquid storage tank 4 and pressurized by a gas in the gas storage tank 1 that is insoluble in the used liquid and higher than atmospheric pressure. The output air pressure can be displayed by the pressure gauge 2. The pressurized liquid is input into the nozzle body 9 through the pipeline 3 at the other end to provide liquid for droplet generation; the excitation signal forms a certain high-frequency excitation electrical signal through the external signal generator 5 and is connected to the piezoelectric crystal through the electrical wire 6 to drive the piezoelectric crystal to generate an excitation disturbance wave acting on the flowing liquid.

[0049] Figure 2 It is a structural schematic diagram of the orthogonal mechanical wave disturbance droplet generation device. The orthogonal mechanical wave excitation droplet generation device mainly consists of a conical liquid cavity 8, a nozzle body 9, a nozzle 11, a longitudinal wave generating piezoelectric crystal 7, and a transverse wave generating piezoelectric crystal 10; a piezoelectric crystal 7 is provided at the top of the conical liquid cavity 8 to generate a driving excitation signal, which is fully applied to the wall surface and conducted to the flowing liquid in the cavity 8. The conical liquid cavity 8 is provided with a pipeline connected to the liquid inlet 12 and connected to the pipeline 3 to the liquid supply device. The lower section of the cone is connected to the nozzle body 9 to form a liquid channel. The conical liquid cavity buffers the liquid, and the rounded corner streamline design at its internal corner reduces the resistance, enhances the fluid streamline flow trajectory, avoids the existence of flow dead zones and the enhancement of its own turbulence effect, and the disturbance to the development of the liquid's own surface wave. The longitudinal wave generating piezoelectric crystal 7 and the transverse wave generating piezoelectric crystal 10 are connected to the disturbance signal driving device. The longitudinal wave generating piezoelectric crystal 7 is placed at the top of the orthogonal mechanical wave disturbance droplet generator and can generate an axial vibration in the same direction as the flow direction, and the transverse wave generating piezoelectric crystal 10 is arranged on the nozzle body and can generate a radial vibration perpendicular to the flow direction.

[0050] Figure 3 It is a schematic diagram of the excitation signal action mechanism. According to Figure 2 and Figure 3To illustrate the droplet generation method of this device: After the liquid enters the conical liquid chamber 8 through the liquid supply device 4, it is excited by the mechanical wave generated by the longitudinal wave generating piezoelectric crystal 7, flows into the nozzle body 9 from the outlet of the liquid chamber 8, and then undergoes further cooperative excitation by the mechanical wave generated by the transverse wave generating piezoelectric crystal 10. Periodic mechanical waves are formed on the liquid flow surface, and a liquid jet is ejected through the nozzle outlet 11. With the further growth and development of the surface wave on its own surface and the further action of surface tension, under the action of the environmental air entrainment disturbance caused by the jet effect, continuous single-particle orderly distributed droplets are formed, and the direction of the jet droplets is along the central axis direction of the nozzle outlet.

[0051] Among them: The axial longitudinal wave generated by the longitudinal wave generator piezoelectric crystal 7 at the top is conducted to the liquid through the wall surface. Under the action of mechanical wave excitation, the up and down vibration of the mechanical wave string will cause the fluid particles to be compressed and diluted in the local area in the flow direction, generating a periodic pressure wave in the axial direction, forming local high-density areas and low-density areas, that is, the high / low pressure areas of the fluid appear alternately. The self-period of the fluid pressure wave is consistent with the period of the driving signal of the longitudinal wave generator; for example: If it is defined that when the vibration direction of the mechanical wave string is the same as the movement direction of the fluid particles, it is forward propagation, and when it is opposite, it is backward propagation and negative. When the vibration direction of the excited mechanical wave string is the same as the movement direction of the fluid particles, it will push the fluid particles to accelerate forward, and the flowing liquid will form a so-called high-density wave crest area, such as Figure 3 the wave crest area in ; When it is opposite to the flow direction of the physical particles, the flowing liquid will form a so-called low-density wave trough area, such as Figure 3 the wave trough area in. Due to the high-frequency periodicity of the excitation signal, a dense area is formed every other period T, and T is also the cycle time for generating droplets.

[0052] Similarly, in the low-density wave trough area of the axial mechanical wave in the fluid area, the transverse wave generator piezoelectric crystal 10 continues to vertically excite the axial pressure wave of the flowing liquid formed by the action of the piezoelectric crystal 7, and cooperatively controls the wave trough of the transverse wave signal to exactly act on the low-density wave trough area of the axial pressure wave, and the wave crest of the transverse wave acts on the high-density wave crest area of the axial pressure wave. The two periods can have the same period T, but the phase difference needs to be Furthermore, a transverse excitation driving wave perpendicular to the jet direction is formed in a coordinated manner, and finally an orthogonal mechanical wave excitation effect under the spatio-temporal orthogonal cooperation is formed. During the liquid flow process, the alternately appearing wave crest and wave trough areas on the liquid surface itself form a liquid surface wave and continue to develop. Through the jet effect of the nozzle outlet 11, the entrained air further enhances the disturbance effect, and under the action of the liquid's own surface tension and the propagation, development and growth of the surface wave, the jet at the nozzle outlet can quickly break, significantly shortening the time required for the propagation, development and growth stage of the liquid surface wave, and bringing forward the oscillation stage of the droplets, which has an obvious promoting effect on obtaining a continuous single-particle orderly distributed droplet chain.

[0053] The continuously ordered single-particle distributed droplets formed under the synergistic action of spatiotemporal orthogonal mechanical waves can not only efficiently achieve precise control of the net droplet size and shape, but also have the continuity of generating a single controllable droplet chain, which is more efficient and stable and beneficial to the production process; under the action of the orthogonal mechanical wave system described above, the generation rate of particle droplets and the spacing between droplet chains can be effectively controlled based on the adjustment of the frequency and amplitude of mechanical wave excitation.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A highly efficient droplet generating device based on spatiotemporal orthogonal mechanical waves, characterized in that: It includes an orthogonal mechanical wave excitation droplet generator, a liquid supply device and an excitation signal driving device; The liquid supply device is connected to the orthogonal mechanical wave excitation droplet generator and is used to provide driving liquid; The excitation signal driving device is used to drive the orthogonal mechanical wave to excite the droplet generator, thereby generating continuous single droplets; The orthogonal mechanical wave excited droplet generator is equipped with a longitudinal wave generating unit and a transverse wave generating unit driven by the excitation signal driving device. The excitation waves formed by each unit act on the liquid fluid, and quickly form periodic axial mechanical waves on the liquid fluid itself. As the liquid flow fully develops, the entrainment air disturbance effect caused by the nozzle outlet jet is utilized. At the same time, under the action of the liquid's own surface tension and surface wave development, the liquid jet direction is quickly and efficiently periodically fractured to form a series of continuous single-particle orderly distributed droplets.

2. The highly efficient droplet generating device based on spatiotemporal orthogonal mechanical waves according to claim 1, characterized in that: The orthogonal mechanical wave excited droplet generator also includes a liquid cavity and a nozzle body, the liquid cavity is provided with a liquid fluid inlet, the liquid fluid outlet is arranged at the lower part or bottom of the liquid cavity, the liquid fluid outlet is directly connected to the nozzle body to form a liquid fluid channel, and a nozzle outlet is provided at the outlet of the nozzle body for forming a liquid jet.

3. A highly efficient droplet generating device based on spatiotemporal orthogonal mechanical waves according to claim 1 or 2, characterized in that: A longitudinal wave generating unit is provided above the liquid cavity, and the longitudinal wave generating unit is driven by the excitation signal action device to generate an excitation signal parallel to the liquid flow trend; The transverse wave generating unit is arranged on the nozzle body directly connected to the liquid fluid outlet, and generates an excitation signal perpendicular to the liquid flow direction under the drive of the excitation signal action device.

4. The device for efficiently generating droplets based on spatiotemporal orthogonal mechanical waves according to claim 3, characterized in that: The periodic excitation signals generated by the longitudinal wave generating unit and the transverse wave generating unit respectively have an excitation effect alone or in coordination to form an orthogonal excitation effect.

5. The device for efficiently generating droplets based on spatiotemporal orthogonal mechanical waves according to claim 4, characterized in that: When the longitudinal wave generating unit and the transverse wave generating unit work together, the periodic excitation signal uses a unified excitation signal driving device to form the same waveform and amplitude, or selects the required waveform and amplitude of the respective excitation signal driving device according to the liquid characteristics, but needs to be in opposite frequencies.

6. The device for efficiently generating droplets based on spatiotemporal orthogonal mechanical waves according to claim 1, characterized in that: The longitudinal wave generating unit and the transverse wave generating unit are piezoelectric crystals.

7. A highly efficient droplet generating device based on spatiotemporal orthogonal mechanical waves according to claim 1 or 6, characterized in that: The excitation signal driving device can simultaneously or separately generate periodic excitation electrical signals of square waves, triangular function waves, and pulse waves, which are respectively used for the longitudinal wave generating unit and the transverse wave generating unit.

8. The device for efficiently generating droplets based on spatiotemporal orthogonal mechanical waves according to claim 1 or 2, characterized in that: The cavity structure of the liquid cavity is a sphere, a cone, a frustum, a cylinder, a cube or a cuboid.

9. A highly efficient droplet generating device based on spatiotemporal orthogonal mechanical waves according to claim 1 or 2, characterized in that: The nozzle outlet aperture is 0.005 mm to 5 mm.

10. A droplet generation method based on spatiotemporal orthogonal mechanical waves, using the droplet efficient generation device according to any one of claims 1 to 9, characterized in that: After the liquid enters the liquid cavity from the liquid cavity inlet through the liquid supply device, it flows into the nozzle body from the liquid cavity outlet, and is successively excited by the longitudinal wave generating unit and the transverse wave generating unit under the synergistic excitation or individual excitation, and the liquid jet formed by the nozzle outlet forms a continuous single particle droplet under the action of its own wave and surface tension, and the direction of the jet droplet is along the central axis direction of the nozzle outlet; in: The axial longitudinal wave generated by the longitudinal wave generating unit at the top is transmitted into the liquid through the wall surface. Under the stimulation of the mechanical wave, the fluid particles move in the flow direction and develop rapidly, so that the fluid itself forms a periodic axial pressure mechanical wave. On the surface of the fluid, the peaks and troughs appear alternately along the direction of the fluid, that is, the high / low pressure areas of the fluid appear alternately, and the period of the fluid itself is consistent with the period of the driving signal of the longitudinal wave generator; In the trough area of ​​the axial mechanical wave in the fluid area, the trough area of ​​the mechanical wave is vertically axially excited by the transverse wave generating unit, forming a lateral excitation drive perpendicular to the jet direction, and then synergizing with the axial mechanical wave to generate an orthogonal mechanical wave under the orthogonal synergy of time and space, and further exciting the driven trough area. In the process of liquid fluid flow, the alternating peaks and troughs of the fluid itself continue to develop, and through the disturbance effect of the nozzle outlet jet on the air suction, under the surface tension of the liquid itself and the development of surface waves, it breaks efficiently and quickly to form a dispersed single particle continuous and orderly distributed droplet flow.

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