CN117189553A - Piezoelectric micropump for increasing flow by utilizing synthetic jet principle - Google Patents

Abstract

The invention discloses a piezoelectric micropump for increasing flow by utilizing a synthetic jet principle; the piezoelectric micropump comprises a current inlet layer, a barrier layer, a vibration substrate layer, a first upper power supply layer, a shell layer, a first vibration layer and a closed cavity layer, wherein the current inlet layer, the barrier layer, the vibration substrate layer, the first upper power supply layer and the shell layer are sequentially laminated, and the first vibration layer and the closed cavity layer are fixed on one side of the vibration substrate layer, which is away from the barrier layer. The center of the shell layer is provided with a flow outlet hole; jet holes aligned with the jet holes are formed in the closed cavity layer. An inner-layer converging cavity is formed between the closed cavity layer and the vibration substrate layer; the jet hole is the only channel for fluid exchange between the inner-layer converging cavity and the outside. The invention introduces a closed cavity layer between the vibrating substrate layer and the shell layer, and forms an inner-layer converging cavity with the vibrating substrate layer; the inner-layer confluence cavity only has jet holes aligned with the micro pump jet holes as an inlet and outlet flow passage, and the flow of the piezoelectric micro pump is obviously increased by utilizing the synthetic jet principle.

Description

Piezoelectric micropump for increasing flow by utilizing synthetic jet principle

Technical Field

The invention belongs to the technical field of piezoelectric gas micropumps, and particularly relates to a piezoelectric micropump for increasing flow by utilizing a synthetic jet flow principle.

Background

In the micropump field, the principle of synthetic jet has attracted extensive attention and exploration as an important research technique. The micropump is used as a key device for micro fluid transmission and control, and has important application value in the fields of medical treatment, biological analysis, chemical reaction and the like. However, conventional pump designs and operating principles face challenges on the micro scale due to the small size of the micropump, complex flow channel characteristics, and fluid viscosity. While miniaturization is pursued, it is also a challenging goal to ensure high performance output of micropumps. The introduction of synthetic jets provides a new approach to solving these challenges.

Conventional micropump designs often require balancing the pressure drop, flow stability, and flow characteristics at small scales of the fluid in the micro channels, while maintaining miniaturization. The synthetic jet principle effectively increases the kinetic energy and velocity of the fluid by mixing the high velocity fluid with the low velocity fluid, thereby hopefully overcoming these problems. While miniaturization is pursued, the synthetic jet principle can achieve higher output flow, and the potential of the micropump in large-flow application is further expanded. The technology can not only improve the output flow and the fluid conveying capacity of the micropump, but also realize more accurate flow control and fluid mixing, thereby meeting the requirements of the microfluidic application on the flow performance.

In the field of micropumps, researchers are actively exploring the application of synthetic jet principles, especially in research directions pursuing miniaturization and large flow output. Through reasonable design of the geometric structure, the runner shape and the synthetic jet flow parameters of the micropump, the working efficiency and the performance of the micropump can be optimized, and simultaneously, the miniaturization and the large-flow output of the micropump are realized. In addition, the synthetic jet principle can also be used for designing an innovative micropump, for example, the synthetic jet mixing is performed on the multi-channel fluid, so that the conveying efficiency of the fluid is further improved.

The synthetic jet principle is a key technology based on fluid kinetic energy transfer and mixing, and is widely used in various engineering and scientific fields. By reasonably mixing the high velocity fluid with the low velocity fluid, the synthetic jet can achieve a variety of goals, such as improving fluid delivery efficiency, enhancing combustion reactions, optimizing liquid atomization and injection, and the like. In the fields of aerospace, energy, biomedicine, environmental protection and the like, the synthetic jet principle is applied to jet engines, combustors, microfluidic systems, sprayers and other devices, and important support is provided for improving and innovating system performance. By careful design of the structure and parameters of the synthetic jet system, high energy transfer, precise fluid control, and more efficient material conversion can be achieved, promoting technological progress and engineering development.

Although the research of the principle of synthetic jet is still in the exploration phase in the micropump field, the potential advantages and application prospect of the principle are widely interesting in the research community. With the continuous development and innovation of the micro-fluidic technology, the synthetic jet principle is expected to provide a new solution for the performance improvement, miniaturization and large-flow output of the micro-pump, and the further development and application of the micro-pump technology in the fields of medicine, biology, chemistry and the like are promoted.

Disclosure of Invention

The invention aims to provide a piezoelectric micropump which utilizes the synthetic jet flow principle to increase the flow, so as to obtain a pump body structure with higher quality and higher precision, and simultaneously improve the stability and the tightness of the micropump.

The piezoelectric micropump comprises a flow inlet layer, a blocking layer, a vibration substrate layer, a first upper power supply layer, a shell layer, a first vibration layer and a closed cavity layer, wherein the flow inlet layer, the blocking layer, the vibration substrate layer, the first upper power supply layer and the shell layer are sequentially stacked, and the first vibration layer and the closed cavity layer are fixed on one side of the vibration substrate layer, which is away from the blocking layer. The center of the shell layer is provided with a flow outlet hole; jet holes aligned with the jet holes are formed in the closed cavity layer. An inner-layer converging cavity is formed between the closed cavity layer and the vibration substrate layer; the jet hole is the only channel for fluid exchange between the inner-layer converging cavity and the outside.

In the working process, the first upper power supply layer and the barrier layer are formed into two poles for supplying power to the first vibration layer; the closed cavity layer deforms along with the vibration of the vibration substrate layer, the volume of the inner-layer converging cavity changes periodically, and a synthetic jet flow phenomenon is formed at the outflow hole.

Preferably, the diameter d of the inner-layer converging cavity is 8-11 mm; diameter d of jet hole ₀ Is 1 mm-2 mm.

Preferably, the first vibration layer is located inside the inner-layer converging cavity; the inner side edge of the first upper power supply layer is connected with a first wiring terminal; the first wiring terminal penetrates through the side wall of the closed cavity layer, stretches into the inner-layer converging cavity and is electrically connected with the side face, deviating from the vibrating substrate layer, of the first vibrating layer.

Preferably, the piezoelectric micropump for increasing the flow rate by using the principle of synthetic jet flow further comprises a second vibration layer and a second upper power supply layer. The second vibration layer is fixed on the closed cavity layer and is positioned on one side of the closed cavity layer, which is away from the vibration substrate layer. The second upper power supply layer is arranged between the first upper power supply layer and the shell layer; the first upper power supply layer and the barrier layer are formed as two poles for supplying power to the second vibration layer.

Preferably, a second connecting terminal is connected to the inner side edge of the second upper power supply layer; the second wiring terminal extends to the second vibration layer and is electrically connected with the side surface of the second vibration layer, which is away from the closed cavity layer.

Preferably, the first vibration layer and the second vibration layer are both made of piezoelectric ceramics.

Preferably, the side of the vibration substrate layer facing the barrier layer is provided with a reinforcing layer; the barrier layer is provided with a central through hole aligned with the reinforcing layer; the center through hole on the barrier layer is in a two-stage stepped hole shape and comprises a first hole section close to the inflow layer and a second hole section close to the vibration substrate layer. The diameter of the first hole section is larger than the diameter of the second hole section and smaller than the diameter of the reinforcing layer. The joint of the first hole section and the second hole section forms a step surface; a flaky elastic deformation structure is formed between the step surface and the side surface of the barrier layer facing the vibration substrate layer; the thickness of the sheet-like elastically deformable structure is 40 μm to 60 μm.

Preferably, the reinforcing layer is integrally formed with the central vibration portion of the vibration substrate layer.

Preferably, the vibration substrate layer includes an edge fixing portion, an elastic connection member, and a central vibration portion. The edge of the central hole of the edge fixing part is connected with the outer edge of the central vibrating part through a plurality of elastic connecting pieces. The reinforcing layer and the closed cavity layer are respectively disposed on opposite sides of the central vibrating portion of the vibrating substrate layer.

Preferably, the elastic connecting piece adopts an elastic metal strip and comprises a first connecting part, a second connecting part and an elastic section. One end of the first connecting part is connected with the central vibrating part, and the other end of the first connecting part is connected with one end of the elastic section. One end of the second connecting part is connected with the other end of the elastic section; the other end of the second connecting part is connected with the edge fixing part. The elastic section is arc-shaped.

The invention has the beneficial effects that:

1. the invention introduces a closed cavity layer between the vibrating substrate layer and the shell layer, and forms an inner-layer converging cavity with the vibrating substrate layer; the inner-layer confluence cavity only has jet holes aligned with the micro pump jet holes as an inlet and outlet flow passage, and the flow of the piezoelectric micro pump is obviously increased by utilizing the synthetic jet principle.

2. According to the invention, the vibrating layers are arranged on the vibrating substrate layer and the closed cavity layer, so that the micro-pump can adapt to different use scenes, and accurate flow control is realized by adjusting parameters of the synthetic jet flow.

3. The invention can realize the pulse injection of the fluid through the high-frequency vibration of the piezoelectric layer, thereby realizing the unidirectional high-mass flow transmission of the fluid.

Drawings

FIG. 1 is a schematic cross-sectional view of embodiment 1 of the present invention;

FIG. 2 is a first exploded view of embodiment 1 of the present invention;

FIG. 3 is a second exploded view of example 1 of the present invention;

fig. 4a is a schematic view showing a downward movement of the piezoelectric vibrator according to embodiment 1 of the present invention;

fig. 4b is a schematic diagram illustrating deformation of the vibrating substrate layer and the closed cavity layer when the piezoelectric vibrator moves downward in embodiment 1 of the present invention;

fig. 5a is a schematic view showing an upward movement of the piezoelectric vibrator according to embodiment 1 of the present invention;

fig. 5b is a schematic diagram illustrating deformation of the vibrating substrate layer and the closed cavity layer when the piezoelectric vibrator moves upward in embodiment 1 of the present invention;

FIG. 6 is a schematic view showing the internal structure of embodiment 2 of the present invention;

Detailed Description

The first embodiment of the present invention will be further described with reference to the accompanying drawings.

Example 1

As shown in fig. 1, 2 and 3, a piezoelectric micropump for increasing a flow rate using a synthetic jet principle includes a flow inlet layer 100, a barrier layer 200, a vibration substrate layer 300, a first vibration layer 400, a closed cavity layer 500, a second vibration layer 600, a first upper power supply layer 700, a second upper power supply layer 800, and a housing layer 900. The intake layer 100, the barrier layer 200, the vibration substrate layer 300, the first upper power supply layer 700, the second upper power supply layer 800, and the case layer 900 are sequentially stacked. The side of the vibration substrate layer 300 facing the barrier layer 200 is provided with a reinforcing layer 301.

An input cavity A is formed between the inflow layer 100 and the barrier layer 200; a transition cavity B is formed between the barrier layer 200 and the vibration substrate layer 300; the output cavity C is formed between the vibration substrate layer 300 and the case layer 900. The inflow layer 100 is provided with an inflow hole 101; the shell layer 900 is provided with an outflow hole 901; the reinforcing layer 301 is in the transition cavity B and is fixed with the vibration substrate layer 300; the closed cavity layer 500, the first vibration layer 400, and the second vibration layer 600 are all disposed in the output cavity C.

The closed cavity layer 500 includes an annular lifting section and a jet flow closing section formed in sequence. The annular lifting section is annular, and the edge is fixed with the side surface of the vibration substrate layer 300 facing the output cavity C. The annular raised section serves to space the jet seal section from the vibration substrate layer 300. A jet hole 501 is arranged at the center of the jet sealing section. An inner-layer converging cavity 502 is formed between the jet flow sealing section of the sealing cavity layer 500 and the vibration substrate layer 300; jet hole 501 is the only inlet and outlet of inner-layer converging cavity 502 and is aligned with outflow hole 901. The first vibration layer 400 is fixed to the side of the vibration substrate layer 300 facing the output cavity C and is located in the inner-layer converging cavity 502; the second vibration layer 600 is fixed to the jet seal section of the seal cavity layer 500 and does not block the jet hole 501.

The inner side edge of the first upper power supply layer 700 is connected with a first wiring terminal 701; the first connection terminal 701 penetrates through the side wall of the closed cavity layer 500, stretches into the inner layer converging cavity 502, and is welded with a node (vibration minimum position) of the side surface of the first vibration layer 400, which is far away from the vibration substrate layer 300, so that the stability of the device can be greatly improved, and electric connection is formed. The connection of the first connection terminal 701 and the closed cavity layer 500 is subjected to insulation and sealing treatment.

The inner edge of the second upper power supply layer 800 is connected with a second wiring terminal 801; the second connection terminal 801 extends to the second vibration layer 600 and is soldered to a node of the second vibration layer 600 to form an electrical connection.

The first upper power supply layer 700 is separated from the second upper power supply layer 800 by a spacer layer. In some embodiments, the lift-off layer is an insulating material to facilitate independent control of the two vibration layers.

The sides of the first and second vibration layers 400 and 600 facing away from the outflow hole 901 are electrically connected together through the conductive closed cavity layer 500 and the vibration substrate layer 300 and are led out of the barrier layer 200 to form a first control interface; the sides of the first and second vibration layers 400 and 600 near the outflow hole 901 are respectively led out through the first and second upper power supply layers 700 and 800 to form a second control interface and a second control interface. Independent vibration control of the first and second vibration layers 400 and 600 is achieved through three control interfaces.

The input cavity A is communicated with the transition cavity B through a central through hole 201 on the barrier layer 200; the stiffening layer 301 is aligned with the central through hole 201 in the barrier layer 200. The central through hole 201 in the barrier layer 200 is in the shape of a two-stage stepped hole comprising a first hole section near the input chamber a and a second hole section near the transition chamber B. The diameter of the first hole section is larger than the diameter of the second hole section and smaller than the diameter of the reinforcing layer 301. The diameter of the second hole section is 5 mm-7 mm. The joint of the first hole section and the second hole section forms a step surface; a flaky elastic deformation structure is formed between the step surface and the side surface of the barrier layer 200 facing the transition cavity B; the thickness of the sheet-shaped elastic deformation structure is 40-60 mu m (the existence of the sheet-shaped elastic deformation structure is highlighted in the figure, the thickness is drawn to be larger, the actual thickness is far smaller than that of the inflow layer 100), the sheet-shaped elastic deformation structure has good elasticity, and the sheet-shaped elastic deformation structure can replace the buffer layer in a conventional piezoelectric micropump.

The vibration substrate layer 300 includes an edge fixing portion, an elastic connection member, and a central vibration portion. The edge of the central hole of the edge fixing part is connected with the outer edge of the central vibrating part through an elastic connecting piece. The elastic connecting piece comprises a first connecting part, a second connecting part and an elastic section. One end of the first connecting part is connected with the central vibrating part, and the other end of the first connecting part is connected with one end of the elastic section. One end of the second connecting part is connected with the other end of the elastic section; the other end of the second connecting part is connected with the edge fixing part. The elastic connecting pieces are elastic and nonlinear metal strips, and the central vibration part of the vibration substrate layer 300 is elastically supported at four connection points of the edge fixing part through four elastic connecting pieces (the elastic connecting pieces are distributed at 90 degrees); thus allowing the center vibration part to vibrate up and down with respect to the edge fixing part. The reinforcing layer 301 and the closed cavity layer 500 are respectively disposed on opposite sides of the central vibration portion of the vibration substrate layer 300.

The outer contour diameters, thicknesses and materials of the first and second vibration layers 400 and 600 are the same; the diameter of the outer contour is 3mm-6mm; the thickness is 50-300 mu m; the material is one or more of aluminum nitride, scandium-doped aluminum nitride, zinc oxide, lithium nickelate or lead zirconate titanate, preferably PZT4.

The first vibration layer 400 and the vibration substrate layer 300, and the second vibration layer 600 and the closed cavity layer 500 are bonded by single-component or two-component epoxy glue.

The diameter of the closed cavity layer 500 is 8 mm-11 mm, the thickness is 30 μm-50 μm, and the material is one or more of copper, silver, aluminum and aluminum alloy. The aperture of the jet hole 501 is 1mm to 2mm and smaller than the aperture of the outflow hole 901.

As shown in fig. 4 and 5, the piezoelectric vibrator of the micro pump moves downward and upward, and it is not difficult to see that when the piezoelectric vibrator moves downward, the volume of the inner-layer converging chamber 502 can be changed more due to the structure of the double-layer piezoelectric layer. Similarly, when the piezoelectric vibrator moves upwards, compressed gas can achieve a larger effect.

The piezoelectric micropump utilizing the synthetic jet flow principle to increase the flow has the following working principle:

when the micropump operates, the first electric signal, the second electric signal and the third electric signal are respectively fed to the barrier layer 200, the first upper power supply layer 700 and the second upper power supply layer 800; the first electric signal, the second electric signal and the third electric signal are rectangular waves, the peak value is 10-40Vpp, and the driving frequency is set to be a first-order resonant frequency (about 23 KHz); the phase difference between the first electric signal and the second electric signal is 180 degrees; the second electric signal and the third electric signal have the same phase; the first vibration layer 400 and the second vibration layer 600 vibrate synchronously and in the same direction, and the central vibration part of the vibration substrate layer 300 reciprocates up and down under the driving of the first vibration layer 400, so that the transition cavity B and the output cavity C periodically change, and periodic pumping is performed.

The operation of the micropump can be divided into four phases during one working cycle.

The first stage: as shown in fig. 4a and 4b, the piezoelectric vibrator moves downward from the equilibrium state (i.e., in a direction approaching the barrier layer 200), and the reinforcing layer 301 on the back of the vibrator blocks the flow hole 104, so that the gas is very small or is not easily flown out from the flow hole 104; but at this time the volume of the inner-layer converging chamber 502 increases (as shown in fig. 4), gas is sucked into the inner-layer converging chamber 502 from the jet hole 501;

and a second stage: the piezoelectric vibrator moves upwards from the lowest part to an equilibrium state, at this time, the volume of the inner-layer converging cavity 502 is reduced, the gas in the inner-layer converging cavity 502 is discharged outwards through the jet hole 501, and the gas flows out cleanly;

and a third stage: as shown in fig. 5a and 5b, the piezoelectric vibrator moves upward from the equilibrium state to the topmost end, at which time the volume of the inner-layer converging chamber 502 is further reduced, and the gas continuously flows out cleanly, but since the vibration substrate layer 300 moves upward more severely than the first vibration layer 400 (as shown in fig. 5), the upward vibration compressed gas can be larger, and a large amount of gas flows out from the jet holes 501 and the outflow holes 901.

Fourth stage: the piezoelectric vibrator moves downwards from the topmost end to an equilibrium state, and gas is sucked into the cavity, but a large amount of air discharged in the exhaust process moves towards the air outlet at a high speed, so that a large amount of gas is sucked back to two sides and cannot be sucked back to the pump cavity again. During this alternate suction and exhaust, the gas in the vicinity of the jet aperture 501 is subjected to a strong shearing action, thereby forming a counter-rotating swirling pair.

Upon entering the next duty cycle, the vortex pair generated in the third stage has been moved away from the jet aperture 501 and is therefore not re-sucked back into the cavity. Fluid in the pressure-variable chamber is input to the output flow channel. This periodic reciprocation creates a series of vortex pairs that increase the flow near the output orifice.

Therefore, the periodic alternating voltage is applied to the piezoelectric vibrator, so that the fluid can be unidirectionally transmitted in the cavity, and high-quality and large-flow unidirectionally circulation can be continuously generated at the outflow hole 901.

According to the experimental result of the invention, the piezoelectric micropump structure which increases the flow by utilizing the synthetic jet flow principle can achieve the flow of 500ml/min, and compared with the common structure with a single piezoelectric layer, the flow is improved obviously.

Structural constraints are provided in conjunction with the following formulas, such as the relationship between dimensions:

the formation of the synthetic jet phenomenon in the present invention is affected by two dimensionless parameters: dimensionless stroke length L and reynolds number Re. The specific expression of the dimensionless stroke length L and the reynolds number Re is as follows:

where d is the jet hole diameter, d ₀ For the diameter of the closed cavity layer, l is the stroke length, T is the period,k is a constant including the material property and the structural size of the piezoelectric material, U is input voltage, v is kinematic viscosity, f ₀ Is the operating frequency.

The following formula is used for finding: the dimensionless stroke length is proportional to the amplitude of the piezoelectric vibrator; the Reynolds number is proportional to the amplitude and operating frequency of the piezoelectric vibrator. And by calculation, the Reynolds number of the existing structure is 2600-3800, which is far greater than the boundary condition (Re > 2000) of the turbulent flow. Therefore, the working state of the piezoelectric vibrator can be obtained to determine the output performance of the synthetic jet device.

Further given is a specific expression of the synthetic jet formation discriminant:

wherein S is Stokes number.

Under the condition that the amplitude of the piezoelectric vibrator, the size of the closed cavity and the size of the jet hole are all determined, whether the synthetic jet phenomenon can be formed normally can be judged preliminarily through the formula, theoretical guidance is provided for the processing of an actual prototype, and the parameter requirement of the device is far greater than the discriminant of the synthetic jet.

The use of the synthetic jet principle of the invention is briefly described below:

the given dimensionless stroke length L is defined as follows:

where d is the jet orifice diameter and l is the length of the column of fluid discharged during one cycle of the synthetic jet, i.e., the stroke length, defined as follows:

wherein T is a period of time and wherein,for the average velocity at the jet aperture over a cycle period, it is defined:

wherein s is the sectional area of the jet hole, v (r, t) is the velocity distribution of the vibrator, and r is the radius of the closed cavity.

The Reynolds number Re is defined as follows:

where v is the kinematic viscosity.

Stokes number S, defined as:

where ω=2pi f is the angular frequency of the vibrator.

The dimensionless stroke length L is proportional to the inverse of the strouhal number St, from which the formula can be derived:

in summary, to form the synthetic jet phenomenon, the following equation needs to be satisfied, which is also a prerequisite for designing the piezoelectric micropump by applying the synthetic jet principle:

generally, when the value of the constant C is greater than 2, we consider that it reaches the conditions for forming a synthetic jet.

The diameter d of the inner layer confluence cavity is 8 mm-11 mm, and the diameter d of the jet hole is arranged on the inner layer confluence cavity ₀ Is 1 mm-2 mm, and has a peak-to-peak voltage U of 40Vpp and a frequency f of 23KHz ₀ Under driving, the obtained constant C can reach about 15-20, and meets the conditions of forming synthetic jet flow.

Example 2

The difference between this embodiment and embodiment 1 is that the piezoelectric micropump that increases the flow rate using the synthetic jet principle is: the second vibration layer and the second upper power supply layer are eliminated.

As shown in fig. 6, in the present embodiment, the first vibration layer 400 is fixed on the side of the vibration substrate layer 300 away from the barrier layer 200. The first vibration layer 400 is also bonded with one-or two-component epoxy glue as with the vibration substrate layer 300.

When a rectangular wave signal having a peak value of 20Vpp, a first-order resonance frequency (about 23 kHz), and a phase difference of 180 ° is applied to the first vibration layer 400, the intra-cavity pressure and volume change are the same as those of embodiment 1, and the same flow effect as in embodiment 1 can be achieved. In addition, the number of layers of the micropump can be reduced by eliminating the second vibration layer and the second upper power supply layer, so that the whole micropump is more compact in structure.

Claims (10)

1. A piezoelectric micropump for increasing flow by utilizing a synthetic jet principle comprises a flow inlet layer (100), a barrier layer (200), a vibration substrate layer (300), a first upper power supply layer (700) and a shell layer (900) which are sequentially stacked, and a piezoelectric micropump fixed on one side of the vibration substrate layer (300) away from the barrier layer (200); the method is characterized in that: the vibration isolation layer also comprises a closed cavity layer (500) fixed on one side of the vibration substrate layer (300) away from the barrier layer (200); a discharge hole (901) is formed in the center of the shell layer (900); jet holes (501) aligned with the outflow holes (901) are formed in the closed cavity layer (500); an inner-layer converging cavity (502) is formed between the closed cavity layer (500) and the vibration substrate layer (300); the jet hole (501) is the only channel for fluid exchange between the inner-layer converging cavity (502) and the outside;

in the working process, the first upper power supply layer (700) and the barrier layer (200) form two poles for supplying power to the first vibration layer (400); the closed cavity layer (500) deforms along with the vibration of the vibration substrate layer (300) and enables the volume of the inner-layer converging cavity (502) to change periodically, and a synthetic jet flow phenomenon is formed at the outflow hole (901).

2. A piezoelectric micropump for increasing flow using the principle of synthetic jet according to claim 1, wherein: the diameter d of the inner-layer converging cavity (502) is 8-11 mm; diameter d of jet hole (501) ₀ Is 1 mm-2 mm.

3. A piezoelectric micropump for increasing flow using the principle of synthetic jet according to claim 1, wherein: the first vibration layer (400) is positioned in the inner-layer converging cavity (502); the inner side edge of the first upper power supply layer (700) is connected with a first wiring terminal (701); the first wiring terminal (701) penetrates through the side wall of the closed cavity layer (500), stretches into the inner-layer converging cavity (502), and is electrically connected with the side surface of the first vibration layer (400) away from the vibration substrate layer (300).

4. A piezoelectric micropump for increasing flow using the principle of synthetic jet according to claim 1, wherein: also comprises a second vibration layer (600) and a second upper power supply layer (800); the second vibration layer (600) is fixed on the closed cavity layer (500) and is positioned on one side of the closed cavity layer (500) away from the vibration substrate layer (300); the second upper power supply layer (800) is arranged between the first upper power supply layer (700) and the shell layer (900); the first upper power supply layer (700) and the barrier layer (200) are formed as two poles for supplying power to the second vibration layer (600).

5. A piezoelectric micropump for increasing flow utilizing the principle of synthetic jet according to claim 4 wherein: the inner side edge of the second upper power supply layer (800) is connected with a second wiring terminal (801); the second connection terminal (801) extends onto the second vibration layer (600) and is electrically connected to a side of the second vibration layer (600) facing away from the closed cavity layer (500).

6. A piezoelectric micropump for increasing flow utilizing the principle of synthetic jet according to claim 4 wherein: the first vibration layer (400) and the second vibration layer (600) are made of piezoelectric ceramics.

7. A piezoelectric micropump for increasing flow using the principle of synthetic jet according to claim 1, wherein: the side surface of the vibration substrate layer (300) facing the barrier layer (200) is provided with a reinforcing layer (301); the barrier layer (200) is provided with a central through hole (201) aligned with the reinforcing layer (301); the central through hole (201) on the barrier layer (200) is in a two-stage stepped hole shape and comprises a first hole section close to the inflow layer (100) and a second hole section close to the vibration substrate layer (300); the diameter of the first hole section is larger than the diameter of the second hole section and smaller than the diameter of the reinforcing layer (301); the joint of the first hole section and the second hole section forms a step surface; a flaky elastic deformation structure is formed between the step surface and the side surface of the barrier layer (200) facing the vibration substrate layer (300); the thickness of the sheet-like elastically deformable structure is 40 μm to 60 μm.

8. A piezoelectric micropump for increasing flow utilizing the principle of synthetic jet according to claim 7, wherein: the reinforcing layer (301) is integrally formed with the central vibration portion of the vibration substrate layer (300).

9. A piezoelectric micropump for increasing flow using the principle of synthetic jet according to claim 1, wherein: the vibration substrate layer (300) comprises an edge fixing part, an elastic connecting piece and a central vibration part; the edge of the central hole of the edge fixing part is connected with the outer edge of the central vibrating part through a plurality of elastic connecting pieces; the reinforcing layer (301) and the closed cavity layer (500) are respectively disposed on opposite sides of the central vibration portion of the vibration substrate layer (300).

10. A piezoelectric micropump for increasing flow utilizing the principle of synthetic jet according to claim 9, wherein: the elastic connecting piece adopts an elastic metal strip and comprises a first connecting part, a second connecting part and an elastic section; one end of the first connecting part is connected with the central vibrating part, and the other end of the first connecting part is connected with one end of the elastic section; one end of the second connecting part is connected with the other end of the elastic section; the other end of the second connecting part is connected with the edge fixing part; the elastic section is arc-shaped.