Vapor-doped super-cavitation noise reduction design method for electronic expansion valve

Abstract

The invention discloses a steam-doped super-cavitation noise reduction design method for an electronic expansion valve. Aiming at noise caused by two-phase flow of a refrigerant of an automobile heat pump air conditioner, a vapor-doping super-cavitation optimization strategy is provided, vapor-doping components are additionally arranged at an outlet section of an electronic expansion valve and an inlet section of an evaporator, and refrigerant gas is effectively led to an outlet of the electronic expansion valve by utilizing the pressure difference between the inlet section of the evaporator and the outlet of the electronic expansion valve; the local gas content near an outlet of the electronic expansion valve is increased, the pressure loss is reduced, and the cavitation phenomenon is restrained. Key structure parameters of the gas mixing component are proposed, and the optimal structure parameter value is obtained through a response surface optimization algorithm. The result shows that the noise is reduced by 9.95 dB by the optimized steam mixing component, and a theoretical basis and practical guidance are provided for the noise reduction design of an automobile heat pump air conditioning system.

Description

Technical Field

[0001] The present invention proposes a design method for steam-doped supercavitation noise reduction of an electronic expansion valve. The technical field to which it belongs is the field of optimized design of refrigeration systems and their components, and specifically involves solving the noise problem generated by electronic expansion valves during the refrigeration process through technical innovation. Steam-doped components are installed on both sides of the electronic expansion valve to increase the gas content at the outlet of the electronic expansion valve, reduce the inlet and outlet pressure difference, and inhibit cavitation. The key structural parameters of representative steam-doped components are proposed, and the optimal structural parameter values ​​are obtained through the response surface optimization algorithm, which significantly reduces the noise caused by two-phase flow. Background Art

[0002] With the continuous development of automobile technology, heat pump air conditioning systems have become an important part of new energy vehicles such as electric vehicles. However, the flow noise of the refrigerant, especially the noise at the electronic expansion valve, has always been an important factor affecting the comfort and user experience in the car. Therefore, reducing the noise in the heat pump air conditioning system, especially the noise at the electronic expansion valve, has important practical significance and application value.

[0003] At the entrance of the throttling valve core of the electronic expansion valve, the fluid encounters a sudden contraction of the aperture during the flow process. The reduction of the pipe diameter will have a certain obstruction effect on the fluid. According to the Bernoulli principle, part of the pressure potential energy is converted into kinetic energy, so that the fluid flows out at a high speed when passing through the throttling hole. When the liquid pressure drops below the saturated vapor pressure, a large number of cavitation bubbles are precipitated. When it flows to the high pressure, the bubbles burst and produce pressure pulsation, which leads to vibration and noise, which is the main cause of two-phase flow-induced noise. At the same time, due to the sudden contraction of the flow channel, the fluid produces extrusion and collision, and also generates heat energy and sound energy. In particular, the sound energy will be released in the form of radiation at the throttling point, thereby generating noise. This is the secondary part of the flow-induced noise.

[0004] Traditional electronic expansion valves are key components for regulating the flow of refrigerant in refrigeration systems, but their control accuracy, response speed and system adaptability still need to be improved. In the prior art, the control of electronic expansion valves mostly relies on simple feedback mechanisms, which are difficult to cope with complex and changing working conditions. In addition, the structural design of some electronic expansion valves is complex and the maintenance cost is high, which affects their widespread application.

[0005] Traditional noise reduction methods, such as using mufflers and optimizing pipeline design, can reduce noise to a certain extent, but they often have problems such as limited noise reduction effect, complex structure, and high cost. Especially in automotive heat pump air conditioning systems, the application of traditional noise reduction technology is greatly restricted due to factors such as limited space and complex working environment. Summary of the invention

[0006] The purpose of the present invention is to provide an electronic expansion valve steam-mixed supercavitation noise reduction control system and a structural design method thereof, which solves the problem of excessive noise caused by two-phase flow in an automobile heat pump air-conditioning system by integrating advanced control algorithms and optimized structural design, realizes accurate and rapid regulation of the refrigerant flow rate, and improves the overall performance of the refrigeration system.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A steam-mixing supercavitation noise reduction electronic expansion valve comprises an electronic expansion valve body, an electronic expansion valve inlet pipe, an electronic expansion valve outlet pipe and two steam-mixing components, wherein the steam-mixing components are divided into an inlet pipe and an outlet pipe.

[0009] The working principle of the electronic expansion valve is based on electromagnetic induction and mechanical transmission. When the control system sends a pulse voltage signal, the coil part generates a magnetic field and drives the magnet rotor to rotate. The rotation of the magnet rotor drives the valve needle 12 to move up and down through the nut 14 and the shaft 17, thereby changing the opening degree of the throttle hole. As the opening degree of the throttle hole changes, the flow rate of the refrigerant also changes accordingly. In this way, the electronic expansion valve can achieve precise regulation and control of the refrigerant flow rate.

[0010] The electronic expansion valve body includes a valve core 11, a valve needle 12, a valve seat 13, a rotor, a nut 14, a valve needle spring, a spring support seat, a coil, a lower positioning structure 15, an upper positioning structure 16, a shaft 17, a shell 18 and a support seat 19. The shaft 17 is fixedly connected to the support seat 19, the valve needle 12 is top-connected to the spring support seat, and a fixing frame is provided outside the shell 18. The nut and the shaft cooperate with the valve needle through the spiral groove to realize the up and down movement of the valve needle. The main part of the electronic expansion valve is the core component of the electronic expansion valve. It adjusts the opening of the valve needle according to the magnetic field and pulse voltage signal generated by the coil part, thereby realizing precise control of the refrigerant flow.

[0012] The steam mixing component is connected to the outlet pipe of the electronic expansion valve by welding or integral molding, and the channels of the two are communicated.

[0013] The first connection point between the steam mixing component and the electronic expansion valve outlet pipe is located 5 mm from the electronic expansion valve body, and the second connection point is located 40 mm from the electronic expansion valve body. The steam mixing component and the pipeline center lines of the inlet and outlet pipes of the electronic expansion valve are located in the same plane.

[0014] The height H between the center line of the steam mixing component and the center line of the electronic expansion valve outlet pipe is 15 mm.

[0015] The connection between the steam mixing component and the electronic expansion valve body is in a hollow cylindrical shape.

[0016] The steam mixing component has an inner diameter that is 1 / 5 of the inner diameter of the outlet pipe of the electronic expansion valve.

[0017] The outer diameter of the steam mixing component is 1 / 4 of the inner diameter of the outlet pipe of the electronic expansion valve.

[0018] The distance between the center lines of the two connection points between the steam mixing component and the electronic expansion valve outlet pipe is 35 mm.

[0019] The angle α between the inlet pipe of the steam mixing component and the horizontal axis is 35°.

[0020] The diameter Φ of the steam mixing component is 2 mm.

[0021] The rounded corner of the transition part between the inlet pipe and the vertical pipeline of the steam mixing component is 5mm.

[0022] The key structural parameters of the steam mixing component are the steam mixing component inlet pipe angle α, the steam mixing component diameter Φ and the steam mixing component height H.

[0023] In an optional embodiment, the key structural parameters are selected as optimization design parameters, the level range of each single factor is obtained by a single-factor response surface optimization algorithm, the optimal parameter value of the structure is obtained by a multi-factor response surface optimization algorithm, and a response surface model is constructed with peak sound pressure level SPL peak and effective sound pressure level RMS as design target parameters.

[0024] In an optional embodiment, the method for constructing the response surface model includes:

[0025] (1) Select design points using Latin hypercube sampling method;

[0026] (2) obtaining an optimization target value corresponding to the design point;

[0027] (3) Based on the design point and the corresponding optimization target value, a functional relationship between the geometric structure parameters of the steam mixing component and the design target parameters is established:

[0028]

[0029] In the formula, y i represents the objective function; n is the number of design variables; x i 、x j is the design parameter for geometric structure optimization; β0 represents the constant term coefficient, β j represents the coefficient of the first-order term, β jj represents the coefficient of the quadratic term with the same parameter, β ij Represents the coefficient of the quadratic term between different parameters.

[0030] It can be seen from the above technical solutions that the advantages and positive effects of the noise reduction device design method proposed in this application are:

[0031] 1. Steam supercavitation noise reduction technology is based on a clear physical mechanism, that is, by introducing steam at the outlet of the electronic expansion valve, supercavitation is formed, thereby changing the local flow field characteristics, inhibiting the rupture of bubbles and the generation of noise. By adjusting the steam mixing parameters, the noise reduction effect can be accurately controlled, making the noise reduction process highly controllable.

[0032] 2. In the response surface optimization method, the relationship between the independent variable and the objective function is clear, and the response of the objective function can be predicted by adjusting the value of the independent variable.

[0033] 3. High computational efficiency. The fast iterative optimization process supported by this design method can significantly shorten the product development cycle. By adjusting the steam mixing parameters iteratively for multiple times, the optimal noise reduction solution can be quickly found.

[0034] 4. The design results are effective, reducing the peak sound pressure level by 9.95dB, improving the flow state of the refrigerant in the electronic expansion valve, and improving the refrigeration efficiency and stability of the system. By optimizing the flow field structure, reducing energy loss and vibration noise, the performance of the entire refrigeration system is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a three-dimensional schematic diagram of a steam-added supercavitation noise reduction electronic expansion valve.

[0036] Figure 2 This is a schematic diagram of the structure of a steam-added supercavitation noise reduction electronic expansion valve.

[0037] Figure 3 This is a cross-sectional view of the main body of a steam-added supercavitation noise reduction electronic expansion valve.

[0038] Figure 4 It is a partial cross-sectional view of the main valve core of a steam-added supercavitation noise reduction electronic expansion valve.

[0039] Figure 5 The present invention is a cross-sectional view of an outlet pipe and steam-mixing components of a steam-mixing supercavitation noise reduction electronic expansion valve.

[0040] Figure 6 The results are the single factor test results of the key index parameters of the steam-entrained components of a steam-entrained supercavitation noise reduction electronic expansion valve.

[0041] Figure 7 It is a benchmarking of the SPL predicted value and actual value of a steam-added supercavitation noise reduction electronic expansion valve.

[0042] Description of Figure Numbers:

[0043] Label name Label name 1 Electronic expansion valve body 3 Electronic expansion valve outlet pipe 11 Valve core 31 Electronic expansion valve outlet pipe inlet 12 Valve needle 32 Electronic expansion valve outlet pipe outlet 13 Valve Seat 4 Steam mixing components 14 Nuts 41 Steam mixing component 1 15 Lower positioning structure 411 Steam mixing component 1 inlet pipe 16 Upper positioning structure 412 Steam mixing component 1 outlet pipe 17 axis 42 Steam mixing component 2 18 shell 421 Steam mixing component 2 inlet pipe 19 Support seat 422 Steam mixing component 2 outlet pipe 2 Electronic expansion valve inlet pipe DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] See also Figure 1 , Figure 1 The invention discloses a three-dimensional schematic diagram of a steam-mixed supercavitation noise reduction electronic expansion valve, which comprises an electronic expansion valve body 1, an electronic expansion valve inlet pipe 2, an electronic expansion valve outlet pipe 3, and a steam-mixing component 4.

[0046] The working principle of the electronic expansion valve is based on electromagnetic induction and mechanical transmission. The evaporation temperature or superheat signal is collected by the temperature sensor and pressure sensor set at the outlet of the evaporator. These sensors send the collected data to the microprocessor. After receiving the electrical signal from the sensor, the microprocessor will perform a series of complex calculations. These processes include signal filtering, data analysis, comparison and judgment, etc., to determine the current load state of the refrigeration system and the refrigerant flow demand. According to the processing results, the microprocessor will generate corresponding control instructions. These instructions are usually output in the form of pulse voltage signals to control the opening of the electronic expansion valve. When the control system sends a pulse voltage signal, the coil part generates a magnetic field and drives the magnet rotor to rotate. The rotation of the magnet rotor drives the valve needle 12 to move up and down through the nut 14 and the shaft 17, converting the rotational motion into linear motion, thereby changing the opening of the throttle hole. As the opening of the throttle hole changes, the flow of the refrigerant also changes accordingly. In this way, the electronic expansion valve can achieve precise regulation and control of the refrigerant flow. At the same time, the position sensor on the valve body monitors the position of the valve needle in real time and feeds the position signal back to the microprocessor. The microprocessor continuously adjusts the output pulse voltage signal based on the comparison between the feedback signal and the preset target value to achieve precise control of the opening of the electronic expansion valve. This closed-loop control mechanism can further improve the stability and efficiency of the refrigeration system.

[0048] The main body of the electronic expansion valve includes a valve core 11, a valve needle 12, a valve seat 13, a rotor, a nut 14, a valve needle spring, a spring support seat, a coil, a lower positioning structure 15, an upper positioning structure 16, a shaft 17, a housing 18 and a support seat 19. The shaft 17 is fixedly connected to the support seat 19, the valve needle 12 is top-connected to the spring support seat, and a fixing frame is provided outside the housing 18. The nut and the shaft cooperate with the valve needle through the spiral groove to realize the up and down movement of the valve needle. At the same time, the movement stroke of the valve needle is limited by the upper and lower positioning structures, and it is only allowed to move within the range between the upper and lower positioning structures.

[0049] The electronic expansion valve outlet pipe 3 and the steam-mixing component 4 are connected by welding or integral molding to form a branch pipe for the flow of refrigerant. After the gas-liquid two-phase refrigerant enters the outlet pipe 3, part of the gaseous refrigerant flows into the inlet pipe of the steam-mixing component 4 along the pipe wall and flows out from the outlet pipe of the steam-mixing component to form a small cycle.

[0050] The steam-added supercavitation noise reduction electronic expansion valve operates in a cooling mode.

[0051] The refrigerant passes through the electronic expansion valve inlet pipe 2, enters the electronic expansion valve body 1, and then enters the electronic expansion valve outlet pipe 3 and the steam-mixing component 4. When the refrigerant flows through the electronic expansion valve core 11, it becomes a gas-liquid mixture. The liquid is in the shape of a jet along the center of the electronic expansion valve outlet pipe 3, and the gas penetrates into the steam-mixing component outlet pipes 412 and 422 along the pipe wall and flows out from the inlet pipe. This process is a transient process. After the internal flow field gradually stabilizes, the pressure at the steam-mixing component outlet pipe is lower than that at the steam-mixing component inlet pipe. Therefore, the gas at the outlet 32 ​​of the electronic expansion valve outlet pipe enters the steam-mixing component inlet pipes 411 and 421 along the pipe wall and flows out from the steam-mixing component outlet pipe, increasing the gas content and pressure at the inlet 31 of the electronic expansion valve outlet pipe, forming a supercavitation phenomenon, increasing the local pressure, reducing the cavitation number, inhibiting the generation of cavitation bubbles, and significantly reducing the noise caused by bubble bursting.

[0052] The key structural parameters of the steam mixing component, namely the inlet pipe angle α, the diameter Φ of the steam mixing component and the height H of the steam mixing component, are proposed. The height of the steam mixing component not only affects the transmission distance of the gas, but also affects the flow state of the gas. A certain inlet pipe angle α makes it easier for the gas to flow into the bypass pipe and reduce the pipeline resistance, but a larger bending angle will increase the flow resistance at the bend of the pipeline and even cause eddy currents and turbulence, thus affecting the steam mixing effect and the stability of the flow field. The inlet pipe angle of the steam mixing component will affect the flow direction and velocity distribution of the gas. A larger height H will increase the flow resistance and give the gas more time and space for energy conversion and mixing; a smaller height H will cause the newly flowing gas to impact the pipe wall, resulting in vibration and noise. The diameter of the steam mixing component directly affects the gas flow capacity. A larger diameter Φ can reduce the resistance of the gas flow and increase the flow rate, which may affect the steam mixing effect and the formation speed and quality of the supercavitation flow field.

[0053] The response surface optimization method is based on experimental design and statistical analysis. Through a limited number of experiments, an approximate response surface model is established to replace the real complex system or process, and then the model is optimized and solved. This method uses mathematical and statistical techniques to express the relationship between the response of the system and the influencing factors with a mathematical model, and then finds the optimal solution through the optimization algorithm. Different structural parameters of steam mixing components will form different flow fields. According to the structural design and layout of steam mixing components, the key indicator parameters H, Φ and α are extracted, and the responses are SPL peak and RMS, and the design parameters are optimized by response surface.

[0054] See also Figure 6 First, the steam mixing component inlet pipe angle α ranges from 20° to 50°, the steam mixing component diameter Φ ranges from 1mm to 3mm, and the steam mixing component height H ranges from 10mm to 25mm, and the influence of single factors on the sound pressure level is studied. The horizontal ranges of the three key structural parameters are determined through single factor optimization, with the α horizontal range of 30-40°, the Φ horizontal range of 1.5-2.5mm, and the H horizontal range of 10-20mm.

[0055] Then, the three-factor three-level response surface optimization was performed with the minimum peak sound pressure level and the minimum effective sound pressure level as the optimization targets. The relationship between the independent variables and the response values ​​was established through the quadratic regression model, as shown in equations (1) and (2). The value ranges of H, Φ, and α in the equations are the value ranges determined by the single factor optimization. A variance analysis was then performed, see Figure 7 , which shows the comparative relationship between the actual value and the predicted value of SPL. The horizontal axis is the actual value, and the vertical axis is the predicted value calculated by the quadratic regression equation. All the points are distributed close to a straight line, indicating that the model has a strong predictive ability and the deviation between the predicted value and the actual value is small. SPL(dB)=230.0925-7.19275α-38.45Φ-5.08075H-0.341αΦ-0.0548αH+0.067ΦH+0.1225α 2 +12.82Φ 2 +0.2205 H 2 (1) RMS(dB)=259.84375-10.07975α-42.8625Φ-3.4425H-0.022αΦ-0.0199αH+0.399ΦH+0.1494α 2 +9.64Φ 2 +0.1169H 2 (2)

[0056] As shown in Table 1, Design Expert 13 was used to predict the minimum SPL and RMS of the second-order regression model and obtain the corresponding structural parameter values. The optimal dimensions α were 36°, D was 2 mm, and H was 16 mm. The optimal dimension model was verified, and the model prediction results were compared with the original model and the single factor optimization results. The single factor optimization reduced the peak sound pressure level by 9.85 dB, and the response surface optimization reduced the peak sound pressure level by 9.95 dB, verifying the effectiveness of optimizing the sound pressure level by refining the key structural parameters of the steam injection component and constructing the response surface method.

[0057] Table 1 Comparison of results of different optimization methods

[0058]

[0059] The specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A steam-mixing supercavitation noise reduction electronic expansion valve, comprising an electronic expansion valve body, an electronic expansion valve inlet pipe, an electronic expansion valve outlet pipe and two steam-mixing components, wherein the steam-mixing components are divided into an inlet pipe and an outlet pipe.

2. The electronic expansion valve with steam supercavitation noise reduction according to claim 1, characterized in that: The steam mixing component is connected to the outlet pipe of the electronic expansion valve by welding or integral molding, and the channels of the two are communicated.

3. The electronic expansion valve with steam-mixed supercavitation and noise reduction according to claim 1, characterized in that: The first connection point between the steam mixing component and the electronic expansion valve outlet pipe is located 5 mm away from the electronic expansion valve body, and the second connection point is located 40 mm away from the electronic expansion valve body.

4. The electronic expansion valve with steam supercavitation noise reduction according to claim 1, characterized in that: The height H between the center line of the steam mixing component and the center line of the electronic expansion valve outlet pipe is 16 mm.

5. The electronic expansion valve with steam-mixed supercavitation and noise reduction according to claim 1, characterized in that: The connection between the steam mixing component and the electronic expansion valve body is in a hollow cylindrical shape.

6. The electronic expansion valve with steam supercavitation noise reduction according to claim 2, characterized in that: The steam mixing component has an inner diameter that is 1 / 5 of the inner diameter of the outlet pipe of the electronic expansion valve.

7. The electronic expansion valve with steam-mixed supercavitation and noise reduction according to claim 2, characterized in that: The outer diameter of the steam mixing component is 1 / 4 of the inner diameter of the outlet pipe of the electronic expansion valve.

8. The electronic expansion valve with steam-mixed supercavitation and noise reduction according to claim 3, characterized in that: The distance between the center lines of the two connection points between the steam mixing component and the electronic expansion valve outlet pipe is 35 mm.

9. The electronic expansion valve with steam-mixed supercavitation and noise reduction according to claim 1, characterized in that: The angle α between the inlet pipe of the steam mixing component and the horizontal axis is 36°.

10. The electronic expansion valve with steam-mixed supercavitation and noise reduction according to claim 1, characterized in that: The diameter Φ of the steam mixing component is 2 mm.

11. The electronic expansion valve with steam-mixed supercavitation and noise reduction according to claim 1, characterized in that: The rounded corner of the transition part between the inlet pipe and the vertical pipeline of the steam mixing component is 5mm.

12. The electronic expansion valve with steam-mixed supercavitation and noise reduction according to claim 1, characterized in that: The key structural parameters of the steam mixing component are the steam mixing component inlet pipe angle α, the steam mixing component diameter Φ and the steam mixing component height H.

13. The electronic expansion valve with steam-mixed supercavitation noise reduction according to claim 12, characterized in that: The key geometric parameters of steam-blended components are selected as optimization design parameters. The level range of each single factor is obtained through the single-factor response surface optimization algorithm. The optimal parameter values ​​of the structure are obtained through the multi-factor response surface optimization algorithm. A response surface model with peak sound pressure level SPL peak and effective sound pressure level RMS as design target parameters is constructed.

14. The steam-mixed supercavitation noise reduction electronic expansion valve according to claim 13, characterized in that: The response surface model construction methods include: (1) Select design points using Latin hypercube sampling method; (2) obtaining an optimization target value corresponding to the design point; (3) Based on the design point and the corresponding optimization target value, a functional relationship between the geometric structure parameters of the steam mixing component and the design target parameters is established: In the formula, y i represents the objective function; n is the number of design variables; x i 、x j is the design parameter for geometric structure optimization; β0 represents the constant term coefficient, β j represents the coefficient of the first-order term, β jj represents the coefficient of the quadratic term with the same parameter, β ij Represents the coefficient of the quadratic term between different parameters.

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