A performance test and analysis method for a piezoelectric fluid-driven pump based on solid-liquid coupling

Abstract

The present invention discloses a method for testing and analyzing the performance of a piezoelectric fluid-driven pump based on solid-liquid coupling, which relates to the field of piezoelectric fluid-driven pumps. By analyzing the main factors affecting its vibration characteristics and flow output characteristics, the influence law of the main factors of the electromechanical-hydraulic system on the performance of the piezoelectric fluid-driven pump and the reasonable system parameter matching relationship are obtained, the key structural parameters restricting the output performance of the piezoelectric fluid-driven pump are extracted, a three-dimensional model of the piezoelectric fluid-driven pump is constructed, the specific flow condition and pressure loss of the liquid medium inside the pump chamber are obtained, the key structural parameters and the nonlinear coupling law between fluids are analyzed, the optimal matching relationship between the system structure and parameters of the piezoelectric fluid-driven pump is sought, a test platform for output performance is constructed, the control variable method is used to conduct experimental tests on the test platform, and according to the experimental test data, the influence relationship between each key structural parameter and the output performance is obtained under the driving voltage and driving frequency.

Description

Technical Field

[0001] The present invention relates to the field of piezoelectric fluid-driven pumps, and particularly relates to a method for testing and analyzing the performance of a piezoelectric fluid-driven pump based on solid-liquid coupling. Background Technique

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

[0003] Currently, piezoelectric pumps in the prior art generally have common technical problems such as small flow rate and weak pumping ability. The improvement of existing structure piezoelectric pumps is mostly based on constructing a three-dimensional model of the piezoelectric pump by the finite element method, so as to optimize the design and improvement of its structural parameters. However, the existing methods lack a certain theoretical analysis basis and cannot conduct systematic scheme design and output performance detection on the output performance of existing piezoelectric pumps, so that the common technical problems of existing piezoelectric pumps mentioned above cannot be effectively solved. For this reason, we propose a method for testing and analyzing the performance of a piezoelectric fluid-driven pump based on solid-liquid coupling. Summary of the Invention

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

[0005] To achieve the above purpose, the technical solution adopted by the present invention is

[0006] A method for testing and analyzing the performance of a piezoelectric fluid-driven pump based on solid-liquid coupling, including:

[0007] Analyze the vibration characteristics and output characteristics of the piezoelectric vibrator, construct 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 law of the main factors of the electro-mechanical-hydraulic system on the performance of the piezoelectric fluid-driven pump and the reasonable system parameter matching relationship. Use multi-objective optimization and particle swarm algorithm to establish a mathematical model, and use the analytic hierarchy process to conduct global multi-layer parallel optimization selection according to the different importance degrees of each factor to the evaluation factors, and extract the key structural parameters that restrict the output performance of the piezoelectric fluid-driven pump; among them, 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. Among them, a dome composite structure with the key structural parameters is arranged in the internal pump cavity of the pump body, and the dome composite structure includes:

[0010] A dome structure arranged at the pump cavity facing the liquid inlet;

[0011] The dome structure is used to reduce the pressure loss generated during the forward impact of the liquid medium. When the liquid enters the pump cavity from the liquid inlet and impacts the front surface of the dome structure, the liquid medium will form a split flow 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 shrinking flow channels are formed on both sides of the trapezoidal structure. The flow velocity of the liquid flowing through the shrinking flow channels gradually increases, prompting more liquid media to flow through the flow channels. When the liquid medium flows backward from the liquid outlet into the pump cavity and impacts the rear vertical surface of the trapezoid, more pressure loss will be generated, resulting in a significant reduction in the backflow rate.

[0014] A fillet diversion structure arranged at the end of the pump cavity;

[0015] The fillet diversion structure can provide a better flow path for the liquid medium to flow out of the pump body;

[0016] When the liquid medium enters the pump cavity from the liquid inlet and impacts the apex angle of the dome structure, double-row vortices are formed on both sides of the dome structure, thereby changing the flow direction of the liquid and making it flow gradually along the flow channels on both sides of the trapezoidal structure to the end fillet diversion structure, and then being diverted 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] The unilateral angle of the trapezoidal structure;

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

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

[0022] The steps are used to relieve the backflow. When the backflow liquid medium impacts the steps, a large amount of pressure can be lost, and the backflow volume 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 trapezoid, it flows out of the pump body through the gaps between the two steps.

[0024] Using a fluid mechanics simulation tool, a three-dimensional model of the piezoelectric fluid-driven pump is constructed to obtain the specific flow conditions and pressure loss conditions of the liquid medium inside the pump cavity, analyze the key structural parameters and the non-linear 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] A test platform for output performance is constructed. Using the control variable method, experimental tests are carried out on the test platform. According to the experimental test data, the influence relationship between each key structural parameter and the output performance under the driving voltage and driving frequency is obtained.

[0026] Among them, the test platform includes: an AC power supply module, an output flow rate acquisition module, an output pressure acquisition module, a sinusoidal signal generation module, a fixing module, and a piezoelectric fluid-driven pump to be tested.

[0027] The piezoelectric fluid-driven pump to be tested is fixed through the fixing module.

[0028] The sinusoidal signal generation module outputs a sinusoidal driving signal and acts on the piezoelectric fluid-driven pump to be tested.

[0029] The output flow rate acquisition module and the output pressure acquisition module are respectively used to acquire the output flow rate 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 electric energy for the test process.

[0031] Among them, the theory of the piezoelectric fluid-driven pump mainly includes the volume change amount modeling and the analysis theory of the internal flow conditions of the pump cavity and the pump output flow rate analysis theory. The single crystal piezoelectric vibrator generates periodic reciprocating vibrations up and down under the excitation of a sinusoidal alternating current signal. The volume change amount generated by its movement in half a cycle is similar to the volume amount at the top of a sphere, and a sphere model as shown in Figure 3 can be established.

[0032] The volume formula of the 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]

[0047] The simultaneous equations (1-6 to 1-8) can be used to obtain the maximum pressure change inside the pump chamber:

[0048]

[0049] Where: P1 represents the standard atmospheric pressure; V1 is the volume inside the pump chamber when the piezoelectric vibrator is in a balanced state; P2 is the pressure change inside the pump chamber when the piezoelectric vibrator is deformed upward to the maximum displacement under the stimulation of the electrical signal.

[0050] 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:

[0051]

[0052] 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:

[0053] ΔP i =P i1 +P i2 +P i3 (1-11)

[0054] The reverse pressure loss of the liquid inside the pump chamber is:

[0055] ΔP o =P o1 +P o2 (1-12)

[0056]

[0057] In the formula: k i is the pressure loss coefficient; v2 is the flow velocity generated when the liquid enters the pump chamber; P i1 is the pressure loss generated when the liquid enters the pump chamber from the liquid inlet and impacts the dome structure; P i2 is the pressure loss generated during the process of the liquid flowing through the contraction channels on both sides of the trapezoid; P i3 is the pressure loss generated when the liquid flows through the end-rounding structure. P o1 is the pressure loss generated when the liquid flows from the liquid outlet into the pump chamber and impacts the vertical surface of the step; P o2 is the pressure loss generated when the liquid flows reversely through the contraction pipe. The pressure loss generated when the liquid enters the pump chamber can be obtained through formula (1-13).

[0058] The relationship between the pressure loss generated when the liquid impacts the dome structure and the half-angle at the top of the dome structure is a parabola opening downward, and can be expressed using the equation:

[0059] k1=-K1α 2 (0 ° <α<90 ° ) (1-14)

[0060] From the trigonometric relationship, it can be obtained that:

[0061]

[0062]

[0063] In the formula: l is the vertical length from the top of the dome to the front surface of the trapezoid; r is the radius of the bottom surface of the dome; ρ is the density of the working liquid.

[0064] 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:

[0065] k2=-K2α1 2 (0 ° <α1<90 ° ) (1-17)

[0066] 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:

[0067] k3=K3C (1-18)

[0068] Wherein: K1, K2, K3 are constants, α1 is the single-side angle of the trapezoid; C is the radius size of the fillet guide structure.

[0069] 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:

[0070]

[0071] According to the efficiency formula, the output flow of the piezoelectric pump can be obtained:

[0072] Q=fΔVη (1-20)

[0073] Where: η is the efficiency of the piezoelectric pump; f is the driving frequency of the piezoelectric pump.

[0074] The combined formula can obtain the output flow rate of the piezoelectric pump:

[0075]

[0076] The present invention has the following beneficial effects:

[0077] 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;

[0078] Compared with the prior art, the technical solution of the present invention uses a hydrodynamic simulation tool to understand the specific flow conditions and pressure losses of the liquid inside the pump chamber of the piezoelectric fluid-driven pump, analyze the key structural parameters of the piezoelectric fluid-driven pump and the non-linear coupling law between fluids, seek the optimal matching relationship between the system structure and parameters of the piezoelectric fluid-driven pump, and thus establish a systematic theoretical model of the piezoelectric fluid-driven pump;

[0079] Compared with the prior art, the technical solution of the present invention uses the method of controlling variables to verify the reliability of the structure and simulation analysis, designs an experimental test platform for the output performance of the dome composite structure valve-less piezoelectric pump, realizes the construction of the platform, manufactures prototypes with different structural parameters and conducts test runs, tests the pump output flow and output pressure under different dome structures, different trapezoidal unilateral angles and different fillet diversion structure parameters, and analyzes the influence relationship of each parameter on the output performance;

[0080] 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. A dome structure is arranged at the pump chamber facing the liquid inlet to reduce the pressure loss generated during the forward impact of the liquid. When the liquid enters the pump chamber from the liquid inlet and impacts the front surface of the dome structure, the liquid will form a split flow state and then flow closely along the surface of the dome structure; a trapezoidal structure is connected behind the dome structure, and two gradually shrinking flow channels are formed on both sides of the trapezoidal structure. The flow velocity of the liquid increases gradually when flowing through the shrinking flow channels, promoting more liquid to flow through the flow channels. When the liquid flows reversely from the liquid outlet into the pump chamber and impacts the rear vertical surface of the trapezoid, more pressure losses will be generated, resulting in a significant reduction in the backflow volume; a fillet diversion structure is arranged at the end of the pump chamber, which can provide a better flow path for the liquid to flow out of the pump body, and can effectively solve the common technical problems such as the generally small flow rate and weak pumping ability of the piezoelectric pumps in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 is a flowchart 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;

[0082] Figure 2 is a schematic diagram of the working principle of the piezoelectric fluid-driven pump proposed by the present invention;

[0083] Figure 3 is a theoretical sphere model of the piezoelectric fluid-driven pump;

[0084] Figure 4 is a pump frequency-flow curve graph under the influence of different dome structure parameters;

[0085] Figure 5 is a pump voltage-flow graph under different dome structure parameters;

[0086] Figure 6 Frequency-flow relationship diagram of the piezoelectric pump at different trapezoidal unilateral angles;

[0087] Figure 7 Voltage-frequency diagram of the piezoelectric pump at different trapezoidal unilateral angles;

[0088] Figure 8 Relationship diagram of the driving frequency and flow rate of the piezoelectric pump at different rounded corner diversion structure sizes;

[0089] Figure 9 Pumped flow diagram of the piezoelectric pump at different rounded corner diversion structure sizes;

[0090] Figure 10 Structural schematic diagram of the piezoelectric fluid driving pump pressure proposed by the solution of the present invention;

[0091] Figure 11 Structural block diagram of the test platform proposed by the solution of the present invention. Specific implementation manners

[0092] The present invention will be further described below in conjunction with specific implementation manners. Among them, the attached drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and should not be construed as limiting the present invention. In order to better illustrate the specific implementation manners of the present invention, some components in the attached drawings will be omitted, enlarged or reduced, which do not represent the dimensions of the actual product.

[0093] Example 1

[0094] As Figures 1 - 11 shown, in this embodiment, the CFX module in the ANSYS simulation software is used for fluid simulation analysis. The piezoelectric fluid driving pump model is established using the three-dimensional drawing software Solidworks, and the model is imported into CFX, then the mesh is divided, and finally the flow field distribution diagram of the piezoelectric fluid driving pump is output.

[0095] Among them, in this embodiment, the diameters of the inlet and outlet of the piezoelectric fluid driving pump are both set to 5 mm, the diameter of the single-chip piezoelectric vibrator is 35 mm, the diameter of the piezoelectric ceramic is 25 mm, the depth of the pump cavity is 6 mm, and the width of the rectangular flow channel is 12 mm. For the convenience of calculation, it is set in the simulation that the pressure change generated inside the pump cavity during the vibration of the single-chip piezoelectric vibrator is a fixed value. Since there is backflow in the piezoelectric fluid driving pump, 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 driving pump can perform backflow, thereby establishing a three-dimensional model of the piezoelectric fluid driving pump with a dome composite structure.

[0096] 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 relationship of the dome structure, trapezoidal unilateral angle, and rounded corner diversion structure with different parameters on the output performance. The specific values of the output performance of the piezoelectric pump can be obtained by adjusting the driving voltage and driving frequency.

[0097] The output performance test system of the piezoelectric pump includes the piezoelectric current-driven pump to be tested, and:

[0098] An AC power supply module for providing the electric energy required for the test process;

[0099] An output flow rate acquisition module for acquiring the output flow rate parameters of the liquid medium of the piezoelectric current-driven pump to be tested during the test process;

[0100] An output pressure acquisition module for acquiring the output pressure parameters of the liquid medium of the piezoelectric current-driven pump to be tested during the test process;

[0101] A sinusoidal signal generation module for outputting a sinusoidal driving signal acting on the piezoelectric current-driven pump to be tested;

[0102] A fixing module for fixing the piezoelectric current-driven pump to be tested;

[0103] In this embodiment, the output range of the driving voltage of the sinusoidal driving signal is set to 0 - 220V, and the driving frequency is 40Hz - 400Hz; the liquid medium is pure water;

[0104] The specific experimental test content and the obtained data results are as follows:

[0105] The influence of the dome structure size on the output flow rate

[0106] The dome structure can change the flow direction of the liquid entering the pump chamber, directly affecting the output performance of the piezoelectric pump. The parameter values of the dome structure are divided into 4 groups for testing, which are 2mm, 4mm, 6mm, and 8mm respectively. The parameter values of the trapezoidal unilateral angle are divided into 5 groups for testing, which are 1°, 3°, 5°, 7°, and 9° respectively. The parameter values of the rounded corner diversion structure are divided into 7 groups, and the parameter value range is 0 - 6mm.

[0107] During the test process, first fix the voltage and adjust the frequency, and observe the influence relationship of the change of the frequency on the output flow rate of the piezoelectric pump. The test range of the frequency starts from 40Hz and increases until the flow rate of the piezoelectric pump decreases to 0 and then the test ends.

[0108] The test method for the influence relationship between the driving voltage and the flow rate is as follows: In the frequency test, select the optimal driving frequency point, keep the frequency unchanged, and gradually change the voltage until the output flow rate is 0 to end the test. Since long-term operation causes great damage to the lifespan of the piezoelectric vibrator and the number of measurement tests is too large, a flow rate test is performed every 30 s for each piezoelectric pump.

[0109] Through testing, the pump frequency-flow rate curve diagrams under the influence of different dome structure parameters as shown in Figure 4 can be obtained. When the size of the dome structure increases, the overall trend of the output flow rate of the piezoelectric pump first decreases and then increases. In the flow rate curve at each size, as the frequency increases, the output flow rate first increases and then decreases; when the size of the dome structure is 4 mm, the output flow rate of the pump reaches the lowest value of 145.4 ml / min, and the adjustable range of the output flow rate is relatively low, only within the regulation range of 25 Hz. When the frequency reaches 65 Hz, the output flow rate is interrupted due to insufficient self-priming ability; as the size of the dome structure increases, the self-priming ability of the piezoelectric pump continuously enhances, resulting in a gradually increasing adjustable range of the piezoelectric pump. When the size of the dome structure is 8 mm, the driving frequency range of the piezoelectric pump is 40 Hz to 95 Hz.

[0110] From Figure 5 the pump voltage-flow rate diagrams under different dome structure parameters, it can be seen that in the dome structure of each specific size, as the driving voltage increases, the output flow rate first shows a linear growth trend and reaches the maximum value, and then rapidly decreases; when the size of the dome structure increases, the output flow rate of the piezoelectric pump also shows a trend of first decreasing and then increasing, which is similar to the influence relationship of the driving frequency on the output flow rate. The optimal voltage range for different sizes of dome structures is between 180 V and 200 V; when the dome size is 8 mm, under the driving conditions of 190 V voltage and 45 Hz frequency, the output flow rate of the piezoelectric pump reaches the highest value of 220.6 ml / min. This indicates that when the size of the dome structure is 8 mm, the output flow rate of the piezoelectric pump can reach the optimal state.

[0111] Influence of the trapezoidal unilateral angle on the output flow rate

[0112] The trapezoidal unilateral angle can affect the contraction angle of the two side channels, thereby affecting the liquid flow velocity and the output flow rate of the piezoelectric pump. Figure 6It is a graph of the frequency-flow rate relationship of a piezoelectric pump at different trapezoidal unilateral angles. It can be seen from the graph that in each flow rate curve, the output flow rate of the piezoelectric pump shows an overall changing trend of first increasing and then decreasing. At the same time, when the driving frequency is between 70 Hz and 75 Hz, a second peak point will appear in the pump output flow rate. This peak point is much lower than the output flow rate between 45 Hz and 50 Hz, and as the unilateral angle increases, the output flow rate shows a trend of first increasing and then decreasing. When the trapezoidal unilateral angle is 5°, under the action of a driving frequency of 45 Hz, the output flow rate reaches the highest value of 220.6 ml / min.

[0113] From Figure 7 It can be seen from the voltage-frequency graph of the piezoelectric pump at different trapezoidal unilateral angles that as the unilateral angle increases, the overall trend of the output flow rate of the piezoelectric pump shows a gradual increase to the optimal point first, and then a rapid decrease. And when the trapezoidal unilateral angle is 5°, the growth rate of the pump output flow rate is the fastest, and the decrease rate is also the fastest when the voltage exceeds 190 V; when the trapezoidal unilateral angle is 7°, the output flow rate of the piezoelectric pump is the least, and the adjustable range is also the lowest; when the trapezoidal unilateral angle is 5°, when the driving voltage is 190 V and the driving frequency is 45 Hz, the output flow rate of the piezoelectric pump reaches the highest state of 220.6 ml / min. The test results prove that the output flow rate of the piezoelectric pump reaches the optimal state when the trapezoidal unilateral angle is 5°

[0114] The influence of the rounded corner diversion structure on the output flow rate

[0115] The rounded corner diversion structure set at the end of the pump chamber of the piezoelectric pump can effectively reduce the pressure loss generated by the liquid, and can play a role in guiding the liquid to the liquid outlet. In this process, the swirling and pressure loss of the liquid between the rounded corner structure cavities are reduced, and the pump output flow rate is increased.

[0116] Figure 8 It is a graph of the relationship between the driving frequency and the flow rate of the piezoelectric pump under different rounded corner diversion structure sizes. When the rounded corner diversion structure at the end is 0 mm, it means that there is no rounded corner diversion structure inside the pump chamber, which forms a control group in this test; as the driving frequency changes, the pump flow rate generally shows a changing situation of first increasing and then decreasing, and each pump flow rate will have a second peak at 65 Hz - 80 Hz, which is caused by the change of the trapezoidal unilateral angle; and as the radius of the rounded corner at the end increases, the overall output flow rate shows a trend of first increasing, then decreasing, and finally increasing again. When the size of the rounded corner structure at the end is 2 mm, in the frequency range of 70 Hz - 80 Hz, the output flow rate of the piezoelectric pump is much higher than that of other pumps at the same frequency.

[0117] According to Figure 9From the pump output flow diagram of the piezoelectric pump under different sizes of the rounded-corner flow guiding structure, it can be seen that the pump output flow and voltage show a parabolic-like curve relationship of first increasing and then decreasing. However, when the rounded-corner sizes are 1 mm and 2 mm, the output flow of the piezoelectric pump shows a positive correlation change rule; and when the size of the rounded-corner flow guiding structure increases, the pump output flow shows a trend of first increasing, then decreasing, and then increasing again. Under the combined conditions of the dome structure size of 8 mm, the trapezoidal unilateral angle of 5°, and the radius of the rounded-corner flow guiding structure of 6 mm, the pump output flow reaches a maximum value of 220.6 ml / min, and the driving conditions at this time are a voltage of 190 V and a frequency of 45 Hz.

[0118] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A performance test and analysis method for a piezoelectric fluid-driven pump based on solid-liquid coupling, characterized in that Including: Analyze the vibration characteristics and output characteristics of the piezoelectric vibrator, construct 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 rate output characteristics; Obtain the influence law of the main factors of the electromechanical-hydraulic system on the performance of the piezoelectric fluid-driven pump and the reasonable system parameter matching relationship. Use multi-objective optimization and particle swarm algorithm to establish a mathematical model, and use the analytic hierarchy process to perform global multi-layer parallel optimization selection according to the different importance degrees of each factor to the evaluation factors, and extract the key structural parameters that restrict the output performance of the piezoelectric fluid-driven pump; Use fluid mechanics simulation tools to construct a three-dimensional model of the piezoelectric fluid-driven pump, obtain the specific flow conditions and pressure loss conditions of the liquid medium inside the pump chamber, analyze the key structural parameters and the non-linear coupling law between fluids, seek the optimal matching relationship between the system structure and parameters of the piezoelectric fluid-driven pump, and establish a systematic theoretical model of the piezoelectric fluid-driven pump; Construct a test platform for output performance, and use the control variable method to conduct experimental tests on the test platform. According to the experimental test data, obtain the influence relationship between each key structural parameter and the output performance under the driving voltage and driving frequency; The components of the piezoelectric fluid-driven pump include a liquid inlet, a liquid outlet, and a pump body. Among them, the internal pump chamber of the pump body is provided with a dome composite structure with the key structural parameters. The dome composite structure includes: A dome structure provided at the pump chamber facing the liquid inlet; The dome structure is used to reduce the pressure loss generated when the liquid medium impacts forward. When the liquid enters the pump chamber from the liquid inlet and impacts the front surface of the dome structure, the liquid medium will form a split flow 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 shrinking flow channels are formed on both sides of the trapezoidal structure. The flow velocity of the liquid flowing through the shrinking flow channels gradually increases, prompting more liquid media to flow through the flow channels. When the liquid medium flows back into the pump chamber from the liquid outlet and impacts the rear vertical surface of the trapezoid, more pressure loss will be generated, resulting in a significant reduction in the backflow rate; A fillet diversion structure provided at the end of the pump chamber; The fillet diversion structure can provide a better flow path for the liquid medium to flow out of the pump body; When the liquid medium enters the pump chamber from the liquid inlet and impacts the apex angle of the dome structure, double-row vortices are formed on both sides of the dome structure, thereby changing the flow direction of the liquid, making it flow gradually along the flow channels on both sides of the trapezoidal structure to the fillet diversion structure at the end, and then being diverted to the liquid outlet and flowing out of the pump body.

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

3. A performance test analysis method of a piezoelectric fluid-driven pump based on solid-liquid coupling according to claim 1, characterized in that The trapezoidal structure is provided with two steps with different heights at the end, where: The steps are used to relieve the backflow. When the backflowing liquid medium impacts the steps, a large amount of pressure can be lost, and the backflow rate 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 trapezoid, it flows out of the pump body through the gap between the two steps.

4. A performance test analysis method for 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 rate acquisition module, an output pressure acquisition module, a sinusoidal signal generation module, a fixing module, and a fluid driving pump to be tested for pressure; The fluid driving pump to be tested for pressure is fixed by the fixing module; The sinusoidal signal generation module outputs a sinusoidal driving signal and acts on the fluid driving pump to be tested for pressure; The output flow rate acquisition module and the output pressure acquisition module are respectively used to acquire the output flow rate parameter and the output pressure parameter of the liquid medium of the fluid driving pump to be tested for pressure during the test; The AC power supply module is used to provide the electric energy required for the test process.

5. A method for performance test and analysis of a piezoelectric fluid-driven pump based on solid-liquid coupling according to claim 1, characterized in that The output performance includes the output flow rate and the output pressure.

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