Multi-electrode electrostatic induction nozzle with online adjustable charge electric field and control method

Abstract

The invention discloses a multi-electrode electrostatic induction nozzle with an online adjustable charged electric field and a control method, and relates to the technical field of plant protection spraying, the multi-electrode electrostatic induction nozzle comprises a nozzle main body, a charged atomization area is arranged at a nozzle of the nozzle main body, and a plurality of charging electrodes are arranged in the charged atomization area; a nozzle and an airflow outlet are arranged adjacent to the charged atomization area, liquid medicine sprayed out of the nozzle forms a liquid film in the charged atomization area under the action of airflow sprayed out of the airflow outlet, and the charging voltage of the charging electrode is controlled according to the ideal electric field intensity at the mass point of the liquid film. The stable charge of liquid medicine fog drops is kept when the liquid film changes. A plurality of charging electrodes with independently adjusted voltage are adopted, the positions of the electrodes do not need to be changed, the charged electric field space distribution can be adjusted only by adjusting the charging voltage, the form change of a liquid film is tracked in real time, and stable charge of fog drops under different working conditions of variable spraying is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of plant protection spraying, and in particular to a multi-electrode electrostatic induction nozzle with online adjustable charging electric field and a control method thereof. Background Art

[0002] During agricultural electrostatic spraying, electrostatic forces induce a circling attraction phenomenon when charged droplets approach target crops, improving the droplet deposition rate on both sides of crop leaves. A higher droplet charge-to-mass ratio improves the charging effect and promotes more uniform droplet deposition. During inductive charging, the spatial charging field between the charging electrode and the liquid film is a key factor influencing droplet charging. During atomization, when the liquid film breakup front and the charging electrode are in the same plane, the charging field distribution is optimal, achieving optimal droplet charging. During precision variable-rate spraying, spray parameters must be dynamically adjusted based on factors such as crop growth and pest and disease severity. Atomization pressure, liquid flow rate, and auxiliary airflow rate all affect the liquid film size and the spatial position of the breakup front. However, existing fixed single charging electrodes cannot be adjusted in space, failing to meet the technical requirement of ensuring the liquid film breakup front and the charging electrode are in the same plane. Consequently, the charging field cannot be dynamically optimized based on the dynamic changes in the liquid film, resulting in unstable droplet charging and suboptimal deposition during actual operation. Therefore, in order to meet the technical requirements of efficient charging and deposition of droplets during precise spraying, there is an urgent need for an inductive electrostatic nozzle structure and control method that can track the dynamic changes of the liquid film and online regulate the spatial distribution of the charging electric field to achieve stable and efficient charging of droplets.

[0003] The Chinese invention patent, "A Pneumatic Atomization Electrostatic Sprinkler and Spray System," patent application number CN201810628110.0, discloses an electrostatic sprinkler that utilizes high-speed wind atomization. This invention fixes electrodes at the nozzle to charge the droplets. As the dosage changes, the position of the liquid film shifts, and the charging electric field of the fixed electrodes cannot effectively track the dynamic changes of the liquid film. The invention patent, "A Fan-Shaped Electrostatic Induction Atomizer Sprinkler with Automatically Adjustable Electrodes," patent application number CN201911250574.3, discloses an induction atomizer with adjustable electrode position for fan-shaped sprays. This invention utilizes a mechanical structure to adjust the spatial position of the electrodes in response to liquid pressure, enabling the electrodes to track the liquid film. The mechanical structure employed in this invention occupies a large space, increasing the complexity of compact nozzle layout and limiting its scope of application. Furthermore, the mechanical structure has a slow response speed, resulting in a significant time delay when tracking dynamic changes in the liquid film, making it difficult to ensure the dynamic stability of droplet charging.

[0004] In summary, during the precise variable spraying process, the existing induction electrostatic nozzle structure and control method cannot quickly adjust the spatial distribution of the charged electric field online according to the dynamic changes of the liquid film, making it difficult to achieve efficient and stable charging of the liquid droplets. Summary of the Invention

[0005] In order to solve the above technical problems, this application proposes the following technical solutions:

[0006] In the first aspect, an embodiment of the present application provides a multi-electrode electrostatic induction nozzle with an online adjustable charging electric field, comprising: a nozzle body, a charged atomization area is provided at the nozzle outlet of the nozzle body, and a plurality of charging electrodes are provided in the charged atomization area; a nozzle and an air flow outlet are provided adjacent to the charged atomization area, and the liquid medicine sprayed from the nozzle forms a liquid film in the charged atomization area under the action of the air flow sprayed from the air flow outlet, and the charging voltage of the charging electrode is controlled according to the ideal electric field strength at the particle point of the liquid film to ensure that the liquid medicine droplets maintain a stable charge when the liquid film changes.

[0007] In one possible implementation, the plurality of charging electrodes are electrically connected to a voltage control module provided on one side of the interior of the nozzle body, a quick-connect plug is provided at the tail end of the nozzle body corresponding to the voltage control module, and a wire hole is provided between the quick-connect plug and the voltage control module. The plurality of charging electrodes are connected to the voltage control module via a plurality of wires, and the voltage control module is connected to the power supply end in the quick-connect plug. The voltage control module can provide a positive polarity high voltage to the charging electrode, and regulate the voltage values ​​of the plurality of independent electrodes of the charging electrode 6 online respectively, and dynamically adjust the spatial distribution of the charged electric field in the charged atomization area according to the principle of field strength superposition, so as to realize real-time tracking of the liquid film shattering front, and equivalently realize the optimal charged state in which a single charging electrode is always in the same plane as the liquid film shattering front, and dynamically maintain the efficient and stable charging of the droplets.

[0008] In one possible implementation, a gas inlet is provided in the middle position of the tail of the nozzle body, and the gas inlet is connected to the airflow outlet through a guide channel and a gas flow channel, the two ends of the guide channel are respectively connected to the gas inlet and the first end of the gas flow channel, and the second end of the gas flow channel is connected to the airflow outlet.

[0009] In one possible implementation, the guide channels and gas channels are provided in multiple groups, and the multiple groups of guide channels and gas channels are arranged around the axis of the nozzle body. The provision of multiple guide channels and gas channels can evenly distribute the airflow to the airflow outlet, ensuring the uniformity of the outlet airflow.

[0010] In one possible implementation, the nozzle body further includes a liquid inlet at the rear end, connected to the nozzle via a liquid medicine flow channel. After entering the nozzle body, the liquid medicine flows through the liquid medicine flow channel into the nozzle, where it atomizes the liquid medicine from a continuous fluid form into discrete droplets. This atomization process forms a liquid film, and the spatial region where the liquid film resides is the charged atomization zone.

[0011] In one possible implementation, a grounding electrode is disposed within the liquid medicine channel near the liquid inlet, and the grounding electrode is connected to a grounding terminal. The grounding electrode is embedded within the liquid medicine channel and connected to the grounding terminal via a wire. The grounding electrode is then grounded via an external grounding wire within the grounding terminal, thereby ensuring reliable grounding of the liquid medicine during the charged atomization process.

[0012] In a second aspect, an embodiment of the present application provides a method for controlling a multi-electrode electrostatic induction printhead with online adjustable charging electric field based on any possible implementation of the first aspect, comprising:

[0013] Determine the liquid film length and leading edge width in the charged atomization area based on the liquid parameters and nozzle control parameters;

[0014] Determine the distance between the liquid film rupture front and each charging electrode according to the liquid film length and the leading edge width;

[0015] Determine the ideal field strength of the liquid film rupture front under the condition of a single charging electrode and the combined field strength of the liquid film rupture front formed under the condition of multiple electrodes in combination with the distance between the liquid film rupture front and each charging electrode;

[0016] The charging voltage parameters of the multiple electrodes are determined by the ideal field strength and the combined field strength.

[0017] In one possible implementation, determining the liquid film length and leading edge width in the charged atomization area according to the liquid medicine parameters and the nozzle control parameters includes:

[0018] Determine the liquid pressure p, physical and chemical properties λ, nozzle type μ and air flow velocity v;

[0019] The liquid film length L=F(p,λ,μ,v) and the leading edge width D=G(p,λ,μ,v) are determined according to the liquid pressure p, physical and chemical properties λ, nozzle type μ and air flow velocity v.

[0020] In one possible implementation, determining the ideal field strength of the liquid film rupture front under a single charging electrode condition and the combined field strength of the liquid film rupture front formed under a multi-electrode condition in combination with the distance between the liquid film rupture front and each charging electrode includes:

[0021] Assume that the voltages of N charging electrodes are u1, u2, u3...u N ;

[0022] Assume that a single charging electrode is located at an ideal position on the same plane as the liquid film rupture front, and the charging voltage of the electrode is u, forming the optimal spatial electric field distribution, then the charge surface density σ of the charging electrode is S for

[0023] The field strength at the front edge of the liquid film rupture is determined based on the charge surface density of the charging electrode and its spatial distance from the liquid film. for:

[0024] According to the The ideal field strength modulus for a single charging electrode is determined to be

[0025] In the electrode mode, the field strength of N electrodes on the front edge of the liquid film rupture is According to the principle of field strength superposition, the combined field strength at the front of the liquid film rupture is for:

[0026]

[0027] The final value of the combined field strength is Where: S is the charge surface density of a single charging electrode, ε is the dielectric constant of air, R is the distance between the charging electrode and the leading edge of the liquid film, is the surface charge density of the i-th electrode, R i is the distance between the ith electrode and the leading edge of the liquid film.

[0028] In a possible implementation, determining the recharging voltage parameters of the multiple electrodes by using the ideal field strength and the combined field strength includes:

[0029] Determine the condition E under which the charging effect under multi-electrode conditions is better than that under single electrode conditions 合 ≥E 理想 ;

[0030] Determine the multi-electrode charging voltage parameter value that meets the above charging conditions: u i =Φ i (L, D), where i is the number of charging electrodes, i = 1, 2, 3, ..., N.

[0031] In the embodiment of the present application, multiple charging electrodes with independently adjustable voltages are used. There is no need to change the electrode position. Only the charging voltage needs to be adjusted to adjust the spatial distribution of the charging electric field, and the morphological changes of the liquid film can be tracked in real time to ensure stable charging of droplets under different working conditions of variable spray. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A front view of a multi-electrode electrostatic induction nozzle with online adjustable charging electric field provided in an embodiment of the present application;

[0033] Figure 2 for Figure 1 AA direction cross-sectional view;

[0034] Figure 3 for Figure 1 BB direction cross-sectional view;

[0035] Figure 4 A three-dimensional diagram of a multi-electrode electrostatic induction nozzle with online adjustable charging electric field provided in an embodiment of the present application;

[0036] Figure 5 A flow chart of a method for controlling a multi-electrode electrostatic induction nozzle with online adjustable charging electric field provided in an embodiment of the present application;

[0037] Figure 6 This is a schematic diagram of the multi-electrode field strength superposition principle with online adjustable charging electric field;

[0038] Figure 7 Schematic diagram of online adjustable charging electric field tracking liquid film morphology provided in an embodiment of the present application;

[0039] Figure 1-7 In the symbol, it is represented as:

[0040] 1- nozzle body, 2- charged atomization area, 3- charging electrode, 4- nozzle, 5- air flow outlet, 6- voltage control module, 7- quick-connect plug, 8- wire hole, 9- gas inlet, 10- flow guide channel, 11- gas flow channel, 12- liquid inlet, 13- liquid flow channel, 14- ground electrode, 15- ground terminal. DETAILED DESCRIPTION

[0041] The present invention will be described below with reference to the accompanying drawings and specific implementation methods.

[0042] See also Figure 1-Figure 4 The multi-electrode electrostatic induction nozzle with online adjustable charging electric field provided in this embodiment comprises: a nozzle body 1, a charged atomization zone 2 provided at the nozzle opening of the nozzle body 1, and a plurality of charging electrodes 3 disposed within the charged atomization zone 2. A nozzle 4 and an airflow outlet 5 are disposed adjacent to the charged atomization zone 2. Liquid medicine sprayed from the nozzle 4 forms a liquid film in the charged atomization zone 2 under the action of the airflow from the airflow outlet 5. The charging voltage of the charging electrodes 3 is controlled according to the ideal electric field strength at the liquid film particles, ensuring that the charge of the liquid medicine droplets remains stable as the liquid film changes.

[0043] In this embodiment, the plurality of charging electrodes 3 are electrically connected to the voltage control module 6 provided on one side of the interior of the nozzle body 1. A quick-connect plug 7 is provided at the tail of the nozzle body 1 corresponding to the voltage control module 6, and a wire hole 8 is provided between the quick-connect plug 7 and the voltage control module 6. The plurality of charging electrodes 3 are connected to the voltage control module 6 through a plurality of wires, and the voltage control module 6 is connected to the power supply end in the quick-connect plug 7. The voltage control module 6 can provide a positive polarity high voltage to the charging electrode 3, and regulate the voltage values ​​of the plurality of independent electrodes of the charging electrode 3 online respectively, and dynamically adjust the spatial distribution of the charged electric field in the charged atomization area 2 according to the principle of field strength superposition, so as to realize real-time tracking of the liquid film breakup front, and equivalently realize the optimal charged state in which the single charging electrode 3 is always in the same plane as the liquid film breakup front, and dynamically maintain the efficient and stable charging of the droplets.

[0044] A gas inlet 9 is provided in the middle position of the tail of the nozzle body 1, and the gas inlet 9 is connected to the airflow outlet 5 through a guide channel 10 and a gas channel 11. The two ends of the guide channel 10 are respectively connected to the gas inlet 9 and the first end of the gas channel 11, and the second end of the gas channel 11 is connected to the airflow outlet 5.

[0045] The guide channels 10 and gas channels 11 are provided in multiple groups, and the multiple groups of guide channels 10 and gas channels 11 are arranged around the axis of the nozzle body 1. The provision of multiple guide channels 10 and gas channels 11 can evenly distribute the airflow to the airflow outlet 5, ensuring the uniformity of the outlet airflow.

[0046] In this embodiment, the tail of the nozzle body 1 is further provided with a liquid inlet 12, which is connected to the nozzle 4 via a liquid medicine flow channel 13. After the liquid medicine enters the nozzle body 1, it flows through the liquid medicine flow channel 13 into the nozzle 4. The nozzle 4 atomizes the liquid medicine from a continuous fluid form into discrete droplets. During the atomization process, a liquid film is formed. The spatial area where the liquid film is located is the charged atomization zone 2.

[0047] A grounding electrode 14 is provided near the liquid inlet 12 of the liquid medicine channel 13. The grounding electrode 14 is connected to a grounding terminal. The grounding electrode 14 is embedded in the liquid medicine channel 13 and connected to the grounding terminal 15 via a wire. The grounding electrode 14 is grounded via an external grounding wire within the grounding terminal 15 to ensure that the liquid medicine is reliably grounded during the charged atomization process.

[0048] Corresponding to the multi-electrode electrostatic induction nozzle with online adjustable charging electric field provided in the above embodiment, this embodiment further provides a control method for the multi-electrode electrostatic induction nozzle with online adjustable charging electric field.

[0049] See also Figure 5The present embodiment provides a method for controlling a multi-electrode electrostatic induction nozzle with an online adjustable charging electric field, comprising:

[0050] S101, determining the liquid film length and leading edge width in the charged atomization area according to liquid medicine parameters and nozzle control parameters.

[0051] Specifically, in this embodiment, the liquid medicine pressure p, physical and chemical properties λ, nozzle type μ, and airflow velocity v are first determined. Then, the liquid film length L = F(p, λ, μ, v) and the leading edge width D = G(p, λ, μ, v) are determined based on the liquid medicine pressure p, physical and chemical properties λ, nozzle type μ, and airflow velocity v.

[0052] S102 : determining the distance between the liquid film rupture front and each charging electrode according to the liquid film length and the front width.

[0053] S103 , determining the ideal field strength of the liquid film rupture front under a single charging electrode condition and the combined field strength of the liquid film rupture front formed under a multi-electrode condition, based on the distances between the liquid film rupture front and each charging electrode.

[0054] Assume that the voltages of N charging electrodes are u1, u2, u3...u N ;

[0055] Assume that a single charging electrode is located at an ideal position on the same plane as the liquid film rupture front, and the charging voltage of the electrode is u, forming the optimal spatial electric field distribution, then the charge surface density σ of the charging electrode is S for

[0056] The field strength at the front edge of the liquid film rupture is determined based on the charge surface density of the charging electrode and its spatial distance from the liquid film. for:

[0057] According to the The ideal field strength modulus for a single charging electrode is determined to be

[0058] In the electrode mode, the field strength of N electrodes on the front edge of the liquid film rupture is According to the principle of field strength superposition, the combined field strength at the front of the liquid film rupture is for:

[0059]

[0060] The final value of the combined field strength is Where: S is the charge surface density of a single charging electrode, ε is the dielectric constant of air, R is the distance between the charging electrode and the leading edge of the liquid film, is the surface charge density of the i-th electrode, R i is the distance between the ith electrode and the leading edge of the liquid film.

[0061] S104: Determine charging voltage parameters of multiple electrodes according to the ideal field strength and the combined field strength.

[0062] Determine the condition E under which the charging effect under multi-electrode conditions is better than that under single electrode conditions 合 ≥E 理想 ;

[0063] Determine the multi-electrode charging voltage parameter value that meets the above charging conditions: u i =Φ i (L, D), where i is the number of charging electrodes, i = 1, 2, 3, ..., N.

[0064] The following is a simple example of the above control method using three electrodes as an example:

[0065] Combined with the liquid film morphology parameters determined by S101, the three electrodes and the liquid film front are abstractly simplified into particles, such as Figure 6 Assume that the width of the charged atomization area is M, the leading edge of the liquid film is located between any two electrodes, and the horizontal distances from the two electrodes are L1 and L2 respectively. Then the distance from the third electrode is (L1+2L2), and the vertical distance between the leading edge of the liquid film and the line connecting the three electrodes is d.

[0066] In the multi-electrode structure, assuming that the charges of the three electrodes are q1, q2, and q3, the electric field strengths of the three electrodes at the front edge of the liquid film rupture are:

[0067]

[0068] Where M is the width of the charged atomization area, and the electric field strength of the three electrodes at the front edge of the liquid film rupture obtained above is determined.

[0069] In order to ensure that the droplets can still maintain efficient and stable charging when the liquid film changes dynamically, E 合 ≥E 理想 From the above, we can see that E 合 It is closely related to the liquid film morphology parameters L and D. Assuming that the upper limit of the charging voltages u1, u2, and u3 of the three independent electrodes is the charging voltage u of a single electrode, then E 合 ≥E 理想 The optional interval of the liquid film rupture front is as follows Figure 7 As shown, when the front edge of the liquid film rupture is located at Figure 7 When the spatial range ① is within, it is possible to solve the problem that satisfies E 合 ≥E 理想 The charging voltage parameter combination of the three independent electrodes is Figure 7 When the space range ② is within, there is no 合 ≥E 理想 Charging voltage parameter combination.

[0070] Therefore, within the spatial range ①, if the spatial position of the liquid film front edge is known, the liquid film morphology parameters L′ and D′ can be determined, and the equation satisfying E can be obtained. 合 ≥E 理想 The parameter values ​​u of the charging voltages u1, u2, and u3 of the three independent electrodes i =Φ i (L,D),i=1,2,3.

[0071] In the embodiments of the present application, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0072] The above description is merely a specific embodiment of the present application. Any person skilled in the art may easily conceive of variations or substitutions within the technical scope disclosed in this application, and such variations or substitutions shall be within the scope of protection of this application. The scope of protection of this application shall be subject to the scope of protection of the claims.

Claims

1. A multi-electrode electrostatic induction nozzle with online adjustable charging electric field, characterized in that: include: A nozzle body, wherein a charged atomization area is provided at the nozzle opening of the nozzle body, and a plurality of charging electrodes are provided in the charged atomization area; A nozzle and an air flow outlet are provided adjacent to the charged atomization area. The liquid medicine sprayed from the nozzle forms a liquid film in the charged atomization area under the action of the air flow sprayed from the air flow outlet. The charging voltage of the charging electrode is controlled according to the ideal electric field strength at the particles of the liquid film to ensure that the liquid medicine droplets are stably charged when the liquid film changes.

2. The multi-electrode electrostatic induction nozzle with online adjustable charging electric field according to claim 1, characterized in that: The plurality of charging electrodes are electrically connected to a voltage control module arranged on one side of the interior of the nozzle body. A quick-connect plug is provided at the tail of the nozzle body corresponding to the voltage control module, and a wire hole is provided between the quick-connect plug and the voltage control module.

3. The multi-electrode electrostatic induction nozzle with online adjustable charging electric field according to claim 1, characterized in that: A gas inlet is provided in the middle position of the tail of the nozzle body, and the gas inlet is connected to the airflow outlet through a guide channel and a gas flow channel. The two ends of the guide channel are respectively connected to the gas inlet and the first end of the gas flow channel, and the second end of the gas flow channel is connected to the airflow outlet.

4. The multi-electrode electrostatic induction nozzle with online adjustable charging electric field according to claim 3, characterized in that: The guide flow channels and the gas flow channels are provided in multiple groups, and the multiple groups of guide flow channels and the gas flow channels are arranged around the axis of the nozzle body.

5. The multi-electrode electrostatic induction nozzle with online adjustable charging electric field according to claim 1, characterized in that: The tail of the nozzle body is also provided with a liquid inlet, and the liquid inlet is connected to the nozzle through a liquid medicine flow channel.

6. The multi-electrode electrostatic induction nozzle with online adjustable charging electric field according to claim 5, characterized in that: A grounding electrode is provided at a position of the liquid medicine flow channel close to the liquid inlet, and the grounding electrode is connected to the grounding terminal.

7. A method for controlling a multi-electrode electrostatic induction printhead with online adjustable charging electric field according to any one of claims 1 to 6, characterized in that: include: Determine the liquid film length and leading edge width in the charged atomization area based on the liquid parameters and nozzle control parameters; Determine the distance between the liquid film rupture front and each charging electrode according to the liquid film length and the leading edge width; Determine the ideal field strength of the liquid film rupture front under the condition of a single charging electrode and the combined field strength of the liquid film rupture front formed under the condition of multiple electrodes in combination with the distance between the liquid film rupture front and each charging electrode; The charging voltage parameters of the multiple electrodes are determined by the ideal field strength and the combined field strength.

8. The method for controlling a multi-electrode electrostatic induction nozzle with online adjustable charging electric field according to claim 7, characterized in that: The method of determining the liquid film length and leading edge width in the charged atomization area according to the liquid medicine parameters and the nozzle control parameters includes: Determine the liquid pressure p, physical and chemical properties λ, nozzle type μ and air flow velocity v; The liquid film length L=F(p,λ,μ,v) and the leading edge width D=G(p,λ,μ,v) are determined according to the liquid pressure p, physical and chemical properties λ, nozzle type μ and air flow velocity v.

9. The method for controlling a multi-electrode electrostatic induction nozzle with online adjustable charging electric field according to claim 8, characterized in that: The step of determining the ideal field strength of the liquid film rupture front under a single charging electrode condition and the combined field strength of the liquid film rupture front formed under a multi-electrode condition in combination with the distance between the liquid film rupture front and each charging electrode comprises: Assume that the voltages of N charging electrodes are u1, u2, u3...u N ; Assume that a single charging electrode is located at an ideal position on the same plane as the liquid film rupture front, and the charging voltage of the electrode is u, forming the optimal spatial electric field distribution, then the charge surface density σ of the charging electrode is S for The field strength at the front edge of the liquid film rupture is determined based on the charge surface density of the charging electrode and its spatial distance from the liquid film. for: According to the The ideal field strength modulus for a single charging electrode is determined to be In the electrode mode, the field strength of N electrodes on the front edge of the liquid film rupture is According to the principle of field strength superposition, the combined field strength at the front of the liquid film rupture is for: The final value of the combined field strength is Where: S is the charge surface density of a single charging electrode, ε is the dielectric constant of air, R is the distance between the charging electrode and the leading edge of the liquid film, is the surface charge density of the i-th electrode, R i is the distance between the ith electrode and the leading edge of the liquid film.

10. The method for controlling a multi-electrode electrostatic induction nozzle with online adjustable charging electric field according to claim 9, characterized in that: The determining of the charging voltage parameters of the multiple electrodes by using the ideal field strength and the combined field strength includes: Determine the condition E under which the charging effect under multi-electrode conditions is better than that under single electrode conditions 合 ≥E 理想 ; Determine the multi-electrode charging voltage parameter value that meets the above charging conditions: u i =Φ i (L, D), where i is the number of charging electrodes, i = 1, 2, 3, ..., N.

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