Piezoelectric fluid driving pump performance test analysis method based on solid-liquid coupling

Abstract

The invention discloses a piezoelectric fluid driving pump performance test analysis method based on solid-liquid coupling, and relates to the field of piezoelectric fluid driving pumps. Main factors influencing vibration characteristics and flow output characteristics of the piezoelectric fluid drive pump are analyzed, the influence rule of the main factors of an electromechanical hydraulic system on the performance of the piezoelectric fluid drive pump and a reasonable system parameter matching relation are obtained, key structure parameters restricting the output performance of the piezoelectric fluid drive pump are extracted, and a three-dimensional model of the piezoelectric fluid drive pump is constructed; the specific flowing condition and the pressure loss condition of a liquid medium in a pump cavity are obtained, key structure parameters and a nonlinear coupling rule between fluids are analyzed, the optimal matching relation between the structure and the parameters of the piezoelectric fluid driving pump system is sought, and a test platform of the output performance is constructed. And performing an experimental test on the test platform by utilizing a control variable method, and acquiring an influence relationship between each key structure parameter and the output performance under the driving voltage and the driving frequency according to experimental test data.

Description

Technical Field

[0001] The invention relates to the field of piezoelectric fluid driven pumps, and in particular to a piezoelectric fluid driven pump performance testing and analysis method based on solid-liquid coupling. Background Art

[0002] In recent years, due to the widespread application of micro-electromechanical systems (MEMS) and the rapid development of nanotechnology, micro-flow systems, as an important branch of micro-electromechanical systems, have also been better developed and applied. As the core driving source of micro-flow systems, micro pumps play a key role in energy conversion and are widely used in the fields of drug delivery, fuel cells, and trace chemical analysis. The working principle of piezoelectric fluid-driven pumps can be divided into suction stroke and discharge stroke, such as Figure 2 As shown, (a) is the suction stroke: the single-chip piezoelectric vibrator is stimulated by the positive AC signal, and the volume inside the pump chamber increases, the pressure decreases, and the liquid is sucked into the pump chamber from the inlet and outlet at the same time; (b) is the discharge stroke: the single-chip piezoelectric vibrator is stimulated by the reverse AC signal, and the volume inside the pump chamber gradually decreases to the lowest point, and the pressure gradually rises to the highest point. At this time, the liquid in the chamber is discharged from the pump body through the inlet and outlet at the same time. After the continuous operation of the above working process, a directional flow of the liquid is formed.

[0003] At present, piezoelectric pumps in the existing technology generally have common technical problems such as small flow rate and weak pumping capacity. The improvement of the existing structure piezoelectric pump is mostly based on the finite element method to build a three-dimensional model of the piezoelectric pump, so as to optimize the design and improvement of its structural parameters. However, the existing method lacks a certain theoretical analysis basis and cannot systematically design and test the output performance of the existing piezoelectric pump, so that it cannot effectively solve the common technical problems of the existing piezoelectric pump mentioned above. To this end, we propose a performance test and analysis method for piezoelectric fluid-driven pumps based on solid-liquid coupling. Summary of the invention

[0004] The main purpose of the present invention is to provide a piezoelectric fluid driven pump performance test and analysis method based on solid-liquid coupling, which can effectively solve the problems in the background technology.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A piezoelectric fluid driven pump performance test and analysis method based on solid-liquid coupling, comprising:

[0007] Analyze the vibration characteristics and output characteristics of the piezoelectric vibrator, build a mathematical model of the mutual coupling of the flow field, stress field and electric field in the system, and analyze the main factors affecting its vibration characteristics and flow output characteristics;

[0008] Obtain the influence of the main factors of the electromechanical-hydraulic system on the performance of the piezoelectric fluid-driven pump and the reasonable matching relationship of system parameters, establish a mathematical model using multi-objective optimization and particle swarm algorithm, and use hierarchical analysis method to perform global multi-layer parallel optimization selection according to the different importance of each factor to the evaluation factor, and extract the key structural parameters that restrict the output performance of the piezoelectric fluid-driven pump; wherein the output performance includes output flow and output pressure;

[0009] The components of the piezoelectric fluid driven pump include a liquid inlet, a liquid outlet and a pump body, wherein the internal pump cavity of the pump body is provided with a dome composite structure having the key structural parameters, and the dome composite structure includes:

[0010] A dome structure is provided at the pump chamber directly opposite to the liquid inlet;

[0011] The dome structure is used to reduce the pressure loss caused by the forward impact of the liquid medium. When the liquid enters the pump chamber from the liquid inlet and hits the front surface of the dome structure, the liquid medium will form a diversion state and then flow closely along the surface of the dome structure.

[0012] a trapezoidal structure connected to the rear of the dome structure;

[0013] Two gradually contracting flow channels are formed on both sides of the trapezoidal structure. When the liquid flows through the contracting flow channels, the flow velocity gradually increases, which causes more liquid medium to flow through the flow channels. When the liquid medium flows into the pump chamber from the liquid outlet in the opposite direction and hits the rear end vertical surface of the trapezoid, more pressure loss will be generated, resulting in a significant reduction in the reflux volume.

[0014] A rounded flow guide structure is provided at the rear end of the pump chamber;

[0015] The rounded flow guide structure can provide a better flow route for the liquid medium to flow out of the pump body;

[0016] When the liquid medium enters the pump chamber from the liquid inlet and hits the top corner of the dome structure, double rows of vortices are formed on both sides of the dome structure, thereby changing the flow direction of the liquid, causing it to gradually flow along the flow channels on both sides of the trapezoidal structure to the rounded guide structure at the tail end, and then be guided to the liquid outlet to flow out of the pump body.

[0017] The key structural parameters include:

[0018] The radius of the dome structure;

[0019] One-side angle of the trapezoidal structure;

[0020] The fillet radius of the fillet guide structure.

[0021] The trapezoidal structure is provided with two steps of different heights at the tail end, wherein:

[0022] The steps are used to alleviate backflow. When the backflowing liquid medium hits the steps, a large amount of pressure can be lost, and the backflow amount can be reduced;

[0023] The steps are also used to increase the output flow rate. When the liquid medium flowing into the pump body from the liquid inlet flows through the flow channels on both sides of the ladder, it flows out of the pump body through the gap between the two steps;

[0024] Using fluid mechanics simulation tools, a three-dimensional model of a piezoelectric fluid-driven pump is constructed to obtain the specific flow conditions and pressure loss of the liquid medium inside the pump chamber, analyze the key structural parameters and the nonlinear coupling law between fluids, seek the optimal matching relationship between the structure and parameters of the piezoelectric fluid-driven pump system, and establish a systematic theoretical model of the piezoelectric fluid-driven pump;

[0025] Constructing an output performance test platform, using a control variable method to conduct experimental tests on the test platform, and obtaining the influence relationship between each of the key structural parameters and the output performance under the driving voltage and driving frequency according to the experimental test data;

[0026] The test platform includes: an AC power supply module, an output flow acquisition module, an output pressure acquisition module, a sinusoidal signal generation module, a fixing module, and a piezoelectric fluid drive pump to be tested;

[0027] The piezoelectric fluid driven pump to be measured is fixed by the fixing module;

[0028] The sinusoidal signal generating module outputs a sinusoidal driving signal to act on the piezoelectric fluid driving pump to be tested;

[0029] The output flow acquisition module and the output pressure acquisition module are used to respectively acquire the output flow parameter and the output pressure parameter of the liquid medium of the piezoelectric fluid driven pump to be tested during the test process;

[0030] The AC power supply module is used to provide the required electrical energy for the testing process.

[0031] Among them, the theory of piezoelectric fluid driven pump mainly includes volume change modeling, flow condition analysis theory inside the pump cavity and pump output flow analysis theory. The single-chip piezoelectric vibrator produces periodic up and down reciprocating vibration under the excitation of a sinusoidal AC signal. The volume change produced by its half-cycle motion is similar to the volume at the top of a sphere. It can be established as follows Figure 3 The sphere model shown;

[0032] The volume formula of a sphere can be expressed by the following equation:

[0033] x 2 +y 2 +z 2 =R 2 (1-1)

[0034] By integrating, we can get the volume generated when the piezoelectric vibrator is deformed to its maximum:

[0035]

[0036] Depend on Figure 2 From the vibration volume model of the piezoelectric vibrator, we know that in the Z-axis direction:

[0037] c+d=R (1-3)

[0038] Inside △ACR we have:

[0039] a 2 +c 2 =R 2 (1-4)

[0040] The simultaneous equations (1-1 to 1-4) yield:

[0041]

[0042] Where: ΔV is the maximum volume change of the piezoelectric vibrator under the excitation of an electrical signal; a is the radius of the piezoelectric ceramic; d is the highest center height of the piezoelectric ceramic at the highest volume deformation.

[0043] When the piezoelectric vibrator vibrates, the volume inside the pump chamber changes periodically, and the pressure inside the pump chamber changes. The pressure change caused by the vibration can be regarded as the change of standard atmospheric pressure. According to the standard atmospheric pressure equation, we can get:

[0044] PV=nRT (1-6)

[0045]

[0046] The simultaneous equations (1-6 to 1-8) can be used to obtain the maximum pressure change inside the pump chamber:

[0047]

[0048] Where: P 1 represents the standard atmospheric pressure; V 1 P is the volume inside the pump cavity when the piezoelectric vibrator is in equilibrium; 2 It is the pressure change inside the pump chamber when the piezoelectric vibrator deforms upward to the maximum displacement under the stimulation of the electrical signal.

[0049] The pressure change inside the pump cavity caused by the deformation of the piezoelectric vibrator can theoretically be converted into the pressure of the liquid itself. According to the theory of V. Singhal et al., we can get:

[0050]

[0051] The pressure loss of the liquid inside the pump chamber can be divided into forward pressure loss and reverse pressure loss. The forward pressure loss of the liquid inside the pump chamber can be expressed as:

[0052] ΔP i =P i1 +P i2 +P i3 (1-11)

[0053] The reverse pressure loss of the liquid inside the pump chamber is:

[0054] ΔP o =P o1 +P o2 (1-12)

[0055]

[0056] Where: k i is the pressure loss coefficient; v 2 P is the flow rate generated when the liquid enters the pump chamber; i1 is the pressure loss caused by the liquid entering the pump chamber from the liquid inlet and hitting the dome structure; P i2 is the pressure loss generated when the liquid flows through the contraction channel on both sides of the trapezoid; P i3 It is the pressure loss caused by the liquid flowing through the rounded corner structure at the tail end. o1 It is the pressure loss caused by the liquid flowing from the outlet into the pump chamber and hitting the vertical surface of the step; P o2 It is the pressure loss caused by the reverse flow of liquid through the contraction tube. The pressure loss caused by the liquid entering the pump chamber can be obtained by formula (1-13).

[0057] The relationship between the pressure loss generated when the liquid hits the dome structure and the half angle of the top of the dome structure is similar to a parabola with an opening downward, which can be expressed by the equation:

[0058] k 1 =-K 1 α 2 (0 ° <α<90 ° ) (1-14)

[0059] From the triangular relationship we can get:

[0060]

[0061] Where: l is the vertical length from the top of the dome to the front end of the trapezoid; r is the radius of the bottom of the dome; ρ is the density of the working fluid.

[0062] The pressure loss coefficient of the liquid inside the pump chamber through the contraction flow channel is approximately in the shape of a parabola with the opening downward, and the established equation is:

[0063] k 2 =-K 2 α 1 2 (0 ° <α 1 <90 ° ) (1-17)

[0064] When the liquid passes through the rounded guide structure, the relationship between the pressure loss coefficient and the radius of the rounded guide structure is approximately linear, which can be expressed as:

[0065] k 3 =K 3 C (1-18)

[0066] Where: K 1 , K 2 , K 3 is a constant, α 1 is the single-side angle of the trapezoid; C is the radius size of the rounded corner guide structure.

[0067] By deducing the above formula, we can get the pressure loss of each element of the dome composite structure, and the formula for the efficiency of the piezoelectric pump can be obtained, which can be expressed as:

[0068]

[0069] According to the efficiency formula, the output flow of the piezoelectric pump can be obtained:

[0070] Q=fΔVη (1-20)

[0071] Where: η is the efficiency of the piezoelectric pump; f is the driving frequency of the piezoelectric pump.

[0072] The combined formula can get the output flow rate of the piezoelectric pump:

[0073]

[0074] The present invention has the following beneficial effects:

[0075] Compared with the prior art, the technical solution of the present invention constructs a mathematical model of the mutual coupling of the flow field, stress field and electric field in the system by analyzing the vibration characteristics and output characteristics of the piezoelectric vibrator, and analyzes the main factors affecting its vibration characteristics and flow output characteristics. Theoretically, the influence of the electromechanical and hydraulic system elements on the performance of the new piezoelectric fluid-driven pump and the reasonable system parameter matching relationship are obtained; the mathematical model is established using multi-objective optimization and particle swarm algorithm, and the hierarchical analysis method is used to perform global multi-layer parallel optimization selection according to the different importance of each factor to the evaluation factor, and the key factors that restrict the pumping capacity are extracted;

[0076] Compared with the prior art, the technical solution of the present invention uses fluid mechanics simulation tools to understand the specific flow conditions and pressure loss of the liquid inside the pump cavity of the piezoelectric fluid-driven pump, analyze the key structural parameters of the piezoelectric fluid-driven pump and the nonlinear coupling law between fluids, and seek the optimal matching relationship between the system structure and parameters of the piezoelectric fluid-driven pump, thereby establishing a systematic theoretical model of the piezoelectric fluid-driven pump;

[0077] Compared with the prior art, the technical solution of the present invention verifies the reliability of the structure and simulation analysis by utilizing the control variable method, designs an experimental test platform for the output performance of a dome composite structure valveless piezoelectric pump, and realizes the construction of the platform, manufactures prototypes with different structural parameters and conducts experimental tests, tests the output flow and output pressure of the pump under different dome structures, different trapezoidal single-side angles and different fillet diversion structure parameters, and analyzes the influence of each parameter on the output performance;

[0078] Compared with the prior art, the technical solution of the present invention proposes a piezoelectric fluid-driven pump with a dome composite structure arranged inside the pump chamber. The dome structure is arranged at the pump chamber opposite to the liquid inlet to reduce the pressure loss caused by the positive impact of the liquid. When the liquid enters the pump chamber from the liquid inlet and hits the front surface of the dome structure, the liquid will form a diversion state and then flow close to the surface of the dome structure; a trapezoidal structure is connected to the rear of the dome structure, and two gradually shrinking flow channels are formed on both sides of the trapezoidal structure. The flow velocity generated when the liquid flows through the shrinking flow channel gradually increases, prompting more liquid to flow through the flow channel. When the liquid flows into the pump chamber from the liquid outlet in the opposite direction and hits the rear end vertical surface of the trapezoid, more pressure loss will be generated, resulting in a significant reduction in the reflux volume; a rounded guide structure is arranged at the tail end of the pump chamber to provide a better flow route for the liquid to flow out of the pump body, which can effectively solve the common technical problems of piezoelectric pumps in the prior art, such as small flow rate and weak pumping capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 This is a flow chart of a method for testing and analyzing the performance of a piezoelectric fluid-driven pump based on solid-liquid coupling according to the present invention;

[0080] Figure 2 A schematic diagram of the working principle of the piezoelectric fluid driven pump pressure proposed in the solution of the present invention;

[0081] Figure 3 The theoretical spherical model of a piezoelectric fluid driven pump;

[0082] Figure 4 The pump frequency-flow curve under the influence of different dome structural parameters;

[0083] Figure 5 The pump voltage-flow diagram under different dome structure parameters;

[0084] Figure 6 The frequency-flow relationship diagram of the piezoelectric pump under different trapezoidal single-side angles;

[0085] Figure 7 The voltage-frequency diagram of the piezoelectric pump at different trapezoidal single-side angles;

[0086] Figure 8 The relationship between the driving frequency and flow rate of the piezoelectric pump under different fillet diversion structure sizes;

[0087] Fig. 9 The pump outflow diagram of the piezoelectric pump with different fillet diversion structure sizes;

[0088] Fig.10 This is a schematic diagram of the structure of the piezoelectric fluid driven pump pressure proposed in the solution of the present invention;

[0089] Fig.11 This is a structural block diagram of the test platform proposed in the solution of the present invention. DETAILED DESCRIPTION

[0090] The present invention will be further described below in conjunction with specific implementation methods, wherein the accompanying drawings are only used for exemplary descriptions and represent only schematic diagrams rather than actual drawings, and should not be understood as limiting the present invention. In order to better illustrate the specific implementation methods of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product.

[0091] Example 1

[0092] like Figure 1-Figure 11 As shown, in this embodiment, the CFX module in the ANSYS simulation software is used to perform fluid simulation analysis. The piezoelectric fluid driven pump model is established using the three-dimensional drawing software Solidworks, and the model is imported into CFX, and then the grid is divided, and finally the flow field distribution diagram of the piezoelectric fluid driven pump is output.

[0093] Among them, in this embodiment, the diameter of the inlet and outlet of the piezoelectric fluid-driven pump is set to 5mm, the diameter of the single-chip piezoelectric vibrator is 35mm, the diameter of the piezoelectric ceramic is 25mm, the depth of the pump cavity is 6mm, and the width of the rectangular flow channel is 12mm. In order to facilitate calculation, the pressure change generated inside the pump cavity when the single-chip piezoelectric vibrator vibrates is set to a constant value in the simulation. Since the piezoelectric fluid-driven pump has reflux, the simulation process is divided into two steps: forward simulation and reverse simulation. In the forward simulation, the inlet is set to the in state and the outlet is set to the opening state; in the reverse simulation, the outlet is set to the in state and the inlet is set to the opening state, indicating that the piezoelectric fluid-driven pump can reflux, thereby establishing a three-dimensional model of a piezoelectric fluid-driven pump with a dome composite structure.

[0094] In order to verify the reliability of the structure, the backflow of the piezoelectric pump is alleviated by reducing the pressure loss of the liquid, and the output performance of the piezoelectric pump is improved. In this embodiment, a model of the piezoelectric pump test system is established and the output performance of the piezoelectric pump is tested to explore the influence of dome structures with different parameters, trapezoidal single-side angles and rounded guide structures on the output performance. The specific value of the piezoelectric pump output performance can be obtained by adjusting the driving voltage and driving frequency.

[0095] The piezoelectric pump output performance test system includes the piezoelectric fluid driven pump to be tested, and:

[0096] AC power module for providing the required power for the test process;

[0097] An output flow acquisition module for acquiring output flow parameters of a liquid medium of a piezoelectric fluid driven pump to be tested during a test;

[0098] An output pressure acquisition module for acquiring output pressure parameters of the liquid medium of the piezoelectric fluid driven pump to be tested during the test;

[0099] A sinusoidal signal generating module for outputting a sinusoidal driving signal acting on the piezoelectric fluid driven pump to be tested;

[0100] A fixing module for fixing a piezoelectric fluid driven pump to be tested;

[0101] In this embodiment, the output range of the sinusoidal drive signal drive voltage is set to 0-220V, the drive frequency is set to 40Hz-400Hz; the liquid medium is pure water;

[0102] The specific experimental test content and the obtained data results are as follows:

[0103] Effect of dome structure size on output flow

[0104] The dome structure can change the flow direction of the liquid entering the pump chamber, which directly affects the output performance of the piezoelectric pump. The parameter values ​​of the dome structure are divided into 4 groups for testing, namely 2mm, 4mm, 6mm and 8mm. The parameter values ​​of the trapezoidal single-side angle are divided into 5 groups for testing, namely 1°, 3°, 5°, 7° and 9°. The parameter values ​​of the rounded guide structure are divided into 7 groups, and the parameter value range is 0 to 6mm.

[0105] During the test, the voltage is first fixed to adjust the frequency, and the effect of the frequency change on the output flow of the piezoelectric pump is observed. The frequency test range increases from 40Hz to the end of the test when the flow of the piezoelectric pump decreases to 0.

[0106] The test method for the influence of driving voltage on flow is: select the best driving frequency point in the frequency test, ensure that the frequency remains unchanged, and gradually change the voltage until the output flow is 0, then end the test. Since long-term work has a great impact on the life of the piezoelectric vibrator and the number of measurement tests is too large, each group of piezoelectric pumps selects a flow test at a time interval of 30s.

[0107] After testing, we can get Figure 4 The pump frequency-flow curve under the influence of different dome structure parameters is shown. When the size of the dome structure increases, the overall trend of the piezoelectric pump output flow is first to decrease and then to increase, and in the flow curve under each size, as the frequency increases, the output flow shows a change pattern of first increasing and then decreasing; when the size of the dome structure is 4mm, the pump output flow reaches the lowest value of 145.4ml / min, and the adjustable range of the output flow is relatively low, only 25Hz control range, when the frequency reaches 65Hz, the output flow is interrupted due to insufficient self-priming ability; with the increase of the size of the dome structure, the self-priming ability of the piezoelectric pump is continuously enhanced, so that the adjustable range of the piezoelectric pump is gradually increased. When the size of the dome structure is 8mm, the driving frequency of the piezoelectric pump ranges from 40Hz to 95Hz.

[0108] Depend on Figure 5 From the pump voltage-flow diagram under different dome structure parameters, it can be seen that in each dome structure of a specific size, as the driving voltage increases, the output flow first shows a linear growth trend and reaches a maximum value and then rapidly decreases; when the size of the dome structure increases, the output flow of the piezoelectric pump also shows a trend of first decreasing and then increasing, which is similar to the influence of the driving frequency on the output flow. The optimal voltage range of dome structures of different sizes is 180V to 200V; when the dome size is 8mm, under the driving conditions of 190V voltage and 45Hz frequency, the output flow of the piezoelectric pump reaches a maximum value of 220.6ml / min. This shows that when the size of the dome structure is 8mm, the output flow of the piezoelectric pump can reach the optimal state.

[0109] The influence of the single-side angle of the trapezoid on the output flow

[0110] The single-side angle of the trapezoid can affect the contraction angle of the flow channels on both sides, thereby affecting the flow rate of the liquid and the output flow rate of the piezoelectric pump. Figure 6 The frequency-flow relationship diagram of the piezoelectric pump at different trapezoidal unilateral angles. It can be seen from the figure that in each flow curve, the output flow of the piezoelectric pump shows an overall change trend of first increasing and then decreasing. At the same time, when the driving frequency is between 70Hz and 75Hz, the pump output flow will have a second peak point, which is much lower than the output flow between 45Hz and 50Hz peak points. And as the unilateral angle increases, the output flow shows an increase first and then decrease. When the trapezoidal unilateral angle is 5°, under the action of the driving frequency of 45Hz, the output flow reaches the maximum value of 220.6ml / min.

[0111] Depend on Figure 7 From the voltage-frequency diagram of the piezoelectric pump at different trapezoidal unilateral angles, it can be seen that as the unilateral angle increases, the overall trend of the piezoelectric pump output flow rate gradually increases to the optimal point, and then rapidly decreases. When the trapezoidal unilateral angle is 5°, the pump output flow rate increases the fastest, and when the voltage exceeds 190V, the decline rate is also the fastest; when the trapezoidal unilateral angle is 7°, the piezoelectric pump output flow rate is the least, and the adjustable range is also the lowest; when the trapezoidal unilateral angle is 5°, the driving voltage is 190V, and the driving frequency is 45Hz, the piezoelectric pump output flow rate reaches the highest state of 220.6ml / min. The experimental results show that the output flow rate of the piezoelectric pump reaches the best state when the trapezoidal unilateral angle is 5°.

[0112] The influence of rounded corner guide structure on output flow

[0113] The rounded guide structure set at the tail end of the piezoelectric pump chamber can effectively reduce the pressure loss generated by the liquid and guide the liquid to the liquid outlet. In this process, the swirl and pressure loss of the liquid between the rounded structure cavities are reduced and the pump output flow rate is increased.

[0114] Figure 8The following is a graph showing the relationship between the driving frequency and flow rate of the piezoelectric pump under different sizes of fillet guide structures. When the fillet guide structure at the tail end is 0mm, it means that there is no fillet guide structure inside the pump chamber, which forms a control group in this experiment; with the change of the driving frequency, the pump flow rate generally shows a change that first increases and then decreases, and each pump flow rate will have a second peak at 65Hz~80Hz, which is caused by the change in the angle of the trapezoidal side; and with the increase of the radius of the tail end fillet, the output flow rate as a whole shows a trend of first increasing, then decreasing, and finally increasing again. When the size of the fillet structure at the tail end is 2mm, within the frequency range of 70Hz~80Hz, the output flow rate of the piezoelectric pump is much higher than the flow rate of other pumps with the same frequency.

[0115] according to Fig. 9 The flow rate diagram of the piezoelectric pump under different fillet diversion structure sizes shows that the pump output flow rate and voltage show a parabolic curve relationship that first increases and then decreases. However, when the fillet size is 1mm and 2mm, the output flow rate of the piezoelectric pump shows a positive correlation change law; and when the size of the fillet diversion structure increases, the pump output flow rate shows a trend of first increasing, then decreasing, and then increasing. Under the combined conditions of the dome structure size of 8mm, the trapezoidal single-side angle of 5°, and the radius of the fillet diversion structure of 6mm, the pump output flow rate reaches a maximum value of 220.6ml / min, and the driving conditions at this time are voltage 190V and frequency 45Hz.

[0116] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A piezoelectric fluid driven pump performance test and analysis method based on solid-liquid coupling, characterized in that: include: Analyze the vibration characteristics and output characteristics of the piezoelectric vibrator, build a mathematical model of the mutual coupling of the flow field, stress field and electric field in the system, and analyze the main factors affecting its vibration characteristics and flow output characteristics; The influence of the main factors of the electromechanical-hydraulic system on the performance of the piezoelectric fluid-driven pump and the reasonable matching relationship of system parameters are obtained. The mathematical model is established using multi-objective optimization and particle swarm algorithm. The hierarchical analysis method is used to perform global multi-layer parallel optimization selection according to the different importance of each factor to the evaluation factor, and the key structural parameters that restrict the output performance of the piezoelectric fluid-driven pump are extracted. Using fluid mechanics simulation tools, a three-dimensional model of a piezoelectric fluid-driven pump is constructed to obtain the specific flow conditions and pressure loss of the liquid medium inside the pump chamber, analyze the key structural parameters and the nonlinear coupling law between fluids, seek the optimal matching relationship between the structure and parameters of the piezoelectric fluid-driven pump system, and establish a systematic theoretical model of the piezoelectric fluid-driven pump; A test platform for output performance is constructed, and experimental tests are carried out on the test platform using a control variable method. Based on the experimental test data, the influence relationship between each of the key structural parameters and the output performance under the driving voltage and driving frequency is obtained.

2. A method for testing and analyzing the performance of a piezoelectric fluid-driven pump based on solid-liquid coupling according to claim 1, characterized in that: The components of the piezoelectric fluid driven pump include a liquid inlet, a liquid outlet and a pump body, wherein the internal pump cavity of the pump body is provided with a dome composite structure having the key structural parameters, and the dome composite structure includes: A dome structure is provided at the pump chamber directly opposite to the liquid inlet; The dome structure is used to reduce the pressure loss caused by the forward impact of the liquid medium. When the liquid enters the pump chamber from the liquid inlet and hits the front surface of the dome structure, the liquid medium will form a diversion state and then flow closely along the surface of the dome structure. a trapezoidal structure connected to the rear of the dome structure; Two gradually contracting flow channels are formed on both sides of the trapezoidal structure. When the liquid flows through the contracting flow channels, the flow velocity gradually increases, which causes more liquid medium to flow through the flow channels. When the liquid medium flows into the pump chamber from the liquid outlet in the opposite direction and hits the rear end vertical surface of the trapezoid, more pressure loss will be generated, resulting in a significant reduction in the reflux volume. A rounded flow guide structure is provided at the rear end of the pump chamber; The rounded flow guide structure can provide a better flow route for the liquid medium to flow out of the pump body; When the liquid medium enters the pump chamber from the liquid inlet and hits the top corner of the dome structure, double rows of vortices are formed on both sides of the dome structure, thereby changing the flow direction of the liquid, causing it to gradually flow along the flow channels on both sides of the trapezoidal structure to the rounded guide structure at the tail end, and then be guided to the liquid outlet to flow out of the pump body.

3. A piezoelectric fluid driven pump performance test and analysis method based on solid-liquid coupling according to claim 1 or 2, characterized in that: The key structural parameters include: The radius of the dome structure; One-side angle of the trapezoidal structure; The fillet radius of the fillet guide structure.

4. The method for testing and analyzing the performance of a piezoelectric fluid-driven pump based on solid-liquid coupling according to claim 2, characterized in that: The trapezoidal structure is provided with two steps of different heights at the tail end, wherein: The steps are used to alleviate backflow. When the backflowing liquid medium hits the steps, a large amount of pressure can be lost, and the backflow amount can be reduced; The steps are also used to increase the output flow rate. When the liquid medium flowing into the pump body from the liquid inlet flows through the flow channels on both sides of the ladder, it flows out of the pump body through the gap between the two steps.

5. The method for testing and analyzing the performance of a piezoelectric fluid-driven pump based on solid-liquid coupling according to claim 1, characterized in that: The test platform includes: an AC power supply module, an output flow acquisition module, an output pressure acquisition module, a sinusoidal signal generation module, a fixing module, and a piezoelectric fluid drive pump to be tested; The piezoelectric fluid driven pump to be measured is fixed by the fixing module; The sinusoidal signal generating module outputs a sinusoidal driving signal to act on the piezoelectric fluid driving pump to be tested; The output flow acquisition module and the output pressure acquisition module are used to respectively acquire the output flow parameter and the output pressure parameter of the liquid medium of the piezoelectric fluid driven pump to be tested during the test process; The AC power supply module is used to provide the required electrical energy for the testing process.

6. The method for testing and analyzing the performance of a piezoelectric fluid-driven pump based on solid-liquid coupling according to claim 1, characterized in that: The output performance includes output flow and output pressure.

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