CN103294873B - A kind of analogy method of corona discharge space electrofluid - Google Patents

Abstract

The invention provides a method for simulating corona discharge space electrofluid. This method first establishes the model and determines the control equation, and obtains the electric field intensity distribution diagram and current density distribution diagram under different voltages in the discharge space through calculation and drawing, and then determines the wind source when simulating the electric fluid state through the electric field intensity distribution diagram in the discharge space range, and determine the radius of the wind source according to the current density distribution diagram of the discharge space. For different discharge voltages, the corresponding wind source radius is also different, and then calculate the wind speed of the wind source under different discharge voltages according to the corresponding calculation formula (ie initial wind speed). Therefore, in the subsequent simulation of the electrofluid, the state of the electrofluid under various discharge voltages can be more accurately reflected, making the simulation result closer to the theoretical value, thereby reducing the impact on the corona discharge space electrofluid. the simulation error.

Description

A Simulation Method of Corona Discharge Space Electrofluid

technical field

The invention relates to an electrofluid simulation method, in particular to a corona discharge space electrofluid simulation method.

Background technique

During corona discharge, two areas are formed in the discharge space: corona area and corona outer area. The field strength in the corona area is very strong, but it decays rapidly. In this area, due to the action of the strong electric field, the electrons released from the surface of the corona wire or near the ground move rapidly to the ground electrode. During the movement, the electrons will interact with gas atoms (or molecules) Collision makes atoms (or molecules) decompose into positive ions and electrons. This process occurs cyclically. The free electrons in the space increase rapidly, forming electron avalanche. Various ions move and collide under the action of electric field force, forming a certain airflow structure The electric fluid (also known as ion wind).

The positive and negative ions and electrons formed in the discharge space during corona discharge have a wide range of application values, such as electrostatic precipitators, high-speed printers, atomization and other fields. It is of great theoretical and practical value to understand the electric field distribution, ion state, and electrofluid formation in the discharge space, and the analysis of the electrofluid state is one of the important means to study the interaction between substances in the discharge space. In the prior art, fluid analysis software—Fluent software is usually used to simulate and analyze the state of the electric fluid in the discharge space. During the simulation, model establishment and parameter setting are required according to the discharge state.

The electrofluid is a high-speed ion jet starting from the discharge electrode. The shape of the jet source, the shape of the jet nozzle, and the initial velocity of the jet are the main factors affecting the flow characteristics of the electrofluid. The jet source of the electrofluid is the wind source in the simulation of the Fluent software. For example: in the electrostatic precipitator, the size of the discharge space during corona discharge is generally about 15cm, and the corona area near the corona line is approximately circular, with a size of about several millimeters, which is the injection area formed by the electrofluid. The main role is to accumulate the amount of charge and initial energy necessary for the formation of electric fluids.

In previous simulations, since the corona area is very small, which is similar to the scale of the corona wire, the entire corona wire is used as the wind source, and the same wind source radius and different initial wind speeds are set for simulation under different voltages. However, in the actual corona discharge process, the size of the corona area under different voltages is not the same, which determines that the radius of the wind source should be different under different voltages during simulation. There must be large errors in the simulation.

Contents of the invention

The purpose of the present invention is to provide a simulation method of corona discharge space electrofluid to solve the problem of large simulation errors caused by setting the same wind source radius under different voltages in the existing simulation methods.

The object of the present invention is achieved in that a kind of simulation method of corona discharge space electrofluid comprises the steps:

a. Establish a two-dimensional wire-plate discharge model and determine the potential Poisson equation and the current continuity equation in the electric field. Discretize the potential Poisson equation and the current continuity equation to obtain the potential discrete equation and the charge density discrete equation. According to the finite difference method Iteratively calculate the potential discrete equation and the charge density discrete equation in the discharge space, and draw the electric field intensity distribution diagram and current density distribution diagram under different voltages in the discharge space;

b. Determine the steep drop zone of the electric field in the discharge space according to the distribution diagram of the electric field intensity;

c. Set the minimum discharge voltage that can make the electric fluid in the discharge space have a vortex structure as the reference voltage, and the radius of the wind source under the reference voltage is the radius r of the corona wire. From the current density distribution diagram corresponding to the reference voltage Find the current density ρ ₀ at the outer edge of the corona wire, and find the distance from the point with the current density ρ ₀ to the center of the corona wire from the current density distribution diagram corresponding to other discharge voltages. Wind source radius R under voltage;

d. According to the relationship v=0.0246(u-14.81) ² between the ion wind speed v at the outer edge of the corona wire and the discharge voltage u, calculate the wind source wind speed v ₀ under the reference voltage;

e. According to the radius r of the wind source under the reference voltage, the wind speed v ₀ of the wind source under the reference voltage and the radius R of the wind source under other discharge voltages, calculate the wind speed v′ of the wind source under other discharge voltages, where,

f. According to the radius of the wind source and the wind speed of the wind source corresponding to different discharge voltages, the motion state of the electric fluid in the discharge space is simulated.

The present invention uses a computer to execute the above simulation calculation steps to simulate the corona discharge space electrofluid.

When step a is executed, Matlab software is used for iterative calculation, and electric field intensity distribution diagrams and current density distribution diagrams under different voltages in the discharge space are drawn.

When step f is executed, the radius of the wind source and the wind speed of the wind source corresponding to different discharge voltages are input into the Fluent software, and the movement state of the electric fluid in the discharge space is simulated by the Fluent software.

There are two main factors affecting the formation and state of the electrofluid in atmospheric air: 1. The magnitude of the electric field strength acting on the space charge; 2. The energy of the space charge, which is specifically expressed as the number and moving speed of the space charge. Therefore, the present invention selects the distribution of the space electric field intensity to determine the range of the wind source, and determines the radius of the wind source through the distribution of the current density; for different discharge voltages, the corresponding wind source radius is also different, and then calculate according to the corresponding calculation formula The wind speed of the wind source (that is, the initial wind speed) under different discharge voltages is obtained. Therefore, when using Fluent software to simulate the electric fluid in the future, it can more accurately reflect the state of the electric fluid under various discharge voltages, making the simulation result closer to the theoretical value, thereby reducing the impact on the corona Simulation errors for discharge space electrofluids.

Description of drawings

Fig. 1 is a schematic diagram of a two-dimensional wire-plate discharge model established by the present invention.

Fig. 2 is a simulation diagram of electric field intensity distribution in the discharge space obtained under discharge voltages of 30kV and 50kV.

FIG. 3 is a simulation diagram of the current density distribution in the discharge space obtained at a discharge voltage of 30 kV.

Fig. 4 is a simulation diagram of the current density distribution in the discharge space obtained at a discharge voltage of 50 kV.

Fig. 5 is a wind speed curve obtained by actual measurement, simulation and theoretical calculation of point F in Fig. 1 under different discharge voltages by the existing simulation method.

Fig. 6 is a wind speed curve obtained from the actual measurement, simulation and theoretical calculation of point F in Fig. 1 by the simulation method of the present invention under different discharge voltages.

Detailed ways

The invention provides a method for effectively simulating the movement state of space electric fluid under different discharge voltages during corona discharge. The method is to carry out the following steps by means of a computer to simulate the corona discharge space electric fluid, and the specific steps are:

1. Determine the model and governing equations

In the electrostatic precipitator, the most commonly used is the line-plate type dust collector. The commonly used line-plate spacing is 15cm, and the discharge space is symmetrical. Accordingly, the present invention establishes a two-dimensional line-plate discharge model, as shown in Figure 1, the corona wire radius r is 0.75mm, the line-plate spacing OF=15cm, the discharge channel length AD=BC=40cm, and the discharge voltage is 30-50kV .

In the electric field, the general solution equations are the potential Poisson equation and the current continuity equation. The two equations are coupled with each other, specifically expressed as:

Poisson's equation for electric potential: $\frac{{\∂}^{2}V}{\∂x^2}+\frac{{\∂}^{2}V}{\∂{\mathrm{the\; y}}^2}=-\frac{\mathrm{\ρ}}{{\mathrm{\ϵ}}_0}$

Current continuity equation: $\frac{\∂V}{\∂x}\&Center\; Dot;\frac{\∂\mathrm{\ρ}}{\∂x}+\frac{\∂V}{\∂\mathrm{the\; y}}\·\frac{\∂\mathrm{\ρ}}{\∂\mathrm{the\; y}}=\frac{{\mathrm{\ρ}}^2}{{\mathrm{\ϵ}}_0}$

Among them, V—discharge space potential, V;

ρ——space charge density, C/m ³ ;

ε ₀ ——free space dielectric permittivity, ε ₀ =8.85×10 ^-12 C/(V·m);

The above two governing equations are discretized to obtain the potential discretization equation:

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; [</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;x</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;y</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ]</span>}<span\; class="notranslate">\; [</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;x</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;y</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;x</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;y</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}}{{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; ]</span>$

Discrete equation for charge density:

${\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}}{\mathrm{<span\; class="notranslate">\; \&Delta;x</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}}{\mathrm{<span\; class="notranslate">\; \&Delta;y</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\sqrt{{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}}{\mathrm{<span\; class="notranslate">\; \&Delta;x</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}}{\mathrm{<span\; class="notranslate">\; \&Delta;y</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}}{\mathrm{<span\; class="notranslate">\; \&Delta;x</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}}{\mathrm{<span\; class="notranslate">\; \&Delta;y</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; )</span>}$

Δx and Δy are the grid step size in the direction of x-axis and y-axis respectively, and i and j are the serial numbers of node coordinates.

Because of the symmetry of the discharge, the OEBF is selected as the analysis object for the area in Figure 1, and other areas are symmetrical to this area. The specific method is as follows: use Matlab software to iterate the discrete equations of the potential and charge density in the OEBF area according to the finite difference method Calculation, the initial position of the iterative calculation starts from the outer edge of the corona wire, and finally the electric field intensity distribution simulation diagram (as shown in Figure 2) and the current density distribution simulation diagram (as shown in Figure 3 and Figure 4) can be obtained .

2. Field strength distribution in discharge space under different discharge voltages

As shown in Figure 2, the electric field strength in the OEBF area has a downward trend as shown in the figure under different discharge voltages. The point 0.00 represents the point O on the outer edge of the corona line. Within a short distance from the corona line, the field strength appears Decrease rapidly, about an order of magnitude (from 10 ⁷ to 10 ⁶ ). The change range of the field strength steep drop zone is about 0-5mm, so the range from the outer edge of the corona wire to the outer edge 5mm is defined as the range of the jet source, which is the range of the wind source when the Fluent software is used to simulate the state of the electric fluid. Since the radius r of the corona wire is 0.75mm, the range of the wind source is an annular area 0.75-5.75mm away from the center of the corona wire.

3. Current density distribution in discharge space under different discharge voltages

The energy of the space charge is determined by the quantity and speed of the charge, so the energy of the space charge per unit length can be represented by the current density, and the current density has a great influence on the motion state of the electrofluid.

In previous simulations, it was found that when the discharge voltage is small, the electrofluid does not present a vortex-like structure, and only when the discharge voltage reaches a certain value, the electrofluid presents a vortex-like structure. Therefore, the present invention will enable the electrofluid to present a vortex-like structure The minimum discharge voltage of the structure is set as the reference voltage. The reference voltage is 30kV obtained through multiple experiments, so in the present invention, the radius of the wind source under different discharge voltages is determined based on the current density when the discharge voltage is 30kV.

As shown in Figure 3, when the discharge voltage is 30kV, the current density at the outer edge of the corona wire (that is, point O in Figure 3) is 5.8×10 ^-3 A/m ² , the equivalent values in Figure 3 and Figure 4 The line scales are the same. From Figure 4, the distance between the point where the current density is 5.8×10 ^-3 A/m ² and the point O is 3.3mm when the discharge voltage is 50kV, so the radius of the wind source is 4.05mm when the discharge voltage is 50kV (corona The line radius r is 0.75mm, 0.75mm+3.3mm=4.05mm), according to this rule, the wind source radii at discharge voltages of 35kV, 40kV, and 45kV are found to be 1.45mm, 2.1mm, and 2.7mm respectively. The radius of the wind source when the discharge voltage is 30kV is the corona wire radius r0.75mm.

4. Determination of inlet wind speed under different discharge voltages

Based on the discharge condition at a discharge voltage of 30kV, the plane under the same current density (5.8×10 ^-3 A/m ² ) is determined as the inlet of the wind source, and the velocity value of the inlet of the wind source when simulated by Fluent software needs to be determined . Assuming that the radius of the wind source at 30kV is r, and the radius of the wind source at 50kV is R, r<R, then the ratio of the perimeter of the inlet of the wind source at 50kV and 30kV is So when the current density (the energy of the charge per unit length) is the same, then the ratio of the total energy of the charge is also Since the electric fluid is the result of the collective movement of ions, the inlet wind speed is determined by the total energy of the charge at the wind source, so the inlet wind speed at 50kV is that at 30kV times.

The specific solution process of the inlet wind speed at 30kV is as follows:

In the embodiment of the present invention, the line-to-plate spacing OF=15cm, and for different line-to-plate spacings, the volt-ampere characteristics during corona discharge are nonlinearly fitted by Origin software, and it is found that when the discharge voltage is greater than or equal to a certain value u ₀ , the relationship between the effective current of the ion wind and the voltage applied by the corona wire is as follows:

I=K(uu ₀ ) ² (1)

For different line-to-plate spacings, the value of K in formula (1) varies slightly around 0.1, and formula (1) has universal applicability to different line-to-plate discharge devices.

In the process of corona discharge, the change law of ion wind speed with discharge voltage is also very stable as its relationship with its volt-ampere characteristics, and is similar to the change law of corona discharge volt-ampere characteristics. Therefore, according to the formation mechanism of ion wind combined with current formation formula:

I=nvqS (2)

Where n is the carrier density passing through the cross section, v is the velocity of the carrier vertical to the cross section, q is the charged amount of each carrier, and S is the area of the cross section. It can be seen that the discharge current increases with the increase of the charge quantity and the charge movement speed. The higher the discharge current is, the more charges pass through a certain cross-section per unit time, and the faster the directional movement of charges is, so the more violent the electrofluid movement is, the greater the ion wind speed will be.

According to the above analysis, it can be imagined that there is a simple linear relationship between the ion wind speed and the discharge current at the plate (point F in Figure 1), namely:

v=AI (3)

From the formula (1) can get:

v=AI=Ak(uu ₀ ) ² (4)

Since A and k are both constants, let Ak be equal to the constant B, then formula (4) can be transformed into

v=AI=B(uu ₀ ) ² (5)

In order to verify whether the assumption is true, the quadratic function nonlinear fitting was performed on the ion wind velocity at the plate with the discharge voltage. The fitting results are in good agreement with the experimental results, which is the same as the discharge volt-ampere characteristic.

The above conclusions draw the relationship between the ion wind speed at the plate and the discharge voltage at different line-plate spacings. In order to deeply study the relationship between the ion wind speed at the corona line and the discharge voltage and the vector distribution state of the ion wind at each point of the discharge channel, the dynamic wind is used to replace the ion wind, and the mathematical simulation model is established by using Fluent software for numerical simulation analysis.

When using Fluent software for electrofluid simulation, the value of the dynamic wind speed input at the corona wire corresponds to the voltage applied at the corona wire. Assuming that the formula (5) is also applicable to the corona wire, it is measured by experiments that under the condition that the distance between the wire and the plate is 15cm, the critical value of the no-load spark discharge of a single corona wire is 70kV. The ion wind speed near the halo line is 75m/s, according to formula (5) and combined with the above conditions, B=0.0246 can be obtained. Therefore, it is concluded that the ion wind speed and the discharge voltage u at the corona wire meet the following variation rules:

v=0.0246 (u-14.81) ² (6)

Among them, u>14.81kV.

The ion wind speed at the corona line corresponding to different discharge voltages can be calculated from the formula (6) when the distance between the wire and the plate is 15cm. The results are shown in Table 1.

Table 1:

Discharge voltage (kV) Ion wind speed at corona wire (m/s) 30 5.68 35 10.03 40 15.61 45 22.42 50 30.46

In the present invention, when the discharge voltage is 30kV, the inlet wind velocity value of the wind source is the ion wind velocity 5.68m/s at the corona line when the discharge voltage is 30kV in Table 1.

According to the corresponding wind speed of the wind source at 30kV is 5.68m/s, combined with the discharge voltages of 35kV, 40kV, 45kV, and 50kV, the wind source radii are 1.45mm, 2.1mm, 2.7mm, and 4.05mm respectively. The ratio of the source wind speed is the ratio of the corresponding wind source radius. According to this rule, the wind source wind speed under different discharge voltages can be calculated, as shown in Table 2.

Table 2:

Discharge voltage (kV) Wind source radius (mm) Wind source wind speed (m/s) 30 0.75 5.68 35 1.45 10.98 40 2.1 15.9 45 2.7 20.45 50 4.05 30.67

Since the wind speeds obtained in Table 1 are the ion wind speeds at the corona wires, and in the prior art when simulating the discharge space electric fluid, the same wind source radius (that is, the corona wire radius) and different Therefore, according to the data in Table 1, the Fluent software is used to simulate the state of the electric fluid in the discharge space under different discharge voltages, and the simulated value of the ion wind speed at point F (see Figure 1) in the two-dimensional wire-plate discharge model is measured The comparison results with the measured wind speed value and theoretical wind speed are shown in Fig. 5.

However, when the present invention simulates the electric fluid in the discharge space, it has different wind source radii and different initial wind speeds for different discharge voltages. Therefore, according to the data in Table 2, Fluent software is used to simulate the discharge space under different discharge voltages. Fig. 6 shows the comparison results of the simulated value of the ion wind speed at point F (see Fig. 1) in the two-dimensional wire-plate discharge model, the measured wind speed value, and the theoretical wind speed.

By comparing Fig. 5 and Fig. 6, it can be seen that when the method of the present invention is used to simulate the electric fluid, the simulated value is more consistent with the experimental value and the theoretical value, so compared with the prior art, it can reduce The small simulation error makes the simulated value closer to the theoretical value.

Claims (4)

1. an analogy method for corona discharge space electrofluid, is characterized in that, comprises the steps:

A, set up two-dimensional line plate discharging model and determine the electromotive force Poisson equation in electric field and Current continuity equation, carry out discretely obtaining electromotive force discrete equation and electric density discrete equation to electromotive force Poisson equation and Current continuity equation, at discharge space, iterative computation is carried out to electromotive force discrete equation and electric density discrete equation according to method of finite difference, and paint to obtain electric-field intensity distribution figure under the different voltage of discharge space and current density distributing figure;

B, electric field Dou Jiang district according to electric-field intensity distribution figure determination discharge space, described electric field Dou Jiang district is wind regime scope during analog electrical fluid state;

C, the minimum sparking voltage that discharge space electrofluid can be made to be swirl shape structure are set to reference voltage, wind regime radius under described reference voltage is the radius r of corona wire, finds the current density ρ of corona wire outer edge from the current density distributing figure corresponding to reference voltage ₀, from the current density distributing figure corresponding to other sparking voltage, find current density also is respectively ρ ₀point apart from the distance at corona wire center, this distance is the wind regime radius R under different sparking voltage;

D, according to the relation v=0.0246 (u-14.81) between corona wire outer edge ion wind velocity v and sparking voltage u ², wherein, u > 14.81, calculates the wind regime wind speed v under reference voltage ₀;

E, according to the wind regime radius r under reference voltage, wind regime wind speed v under reference voltage ₀and the wind regime radius R under other sparking voltage, calculate the wind regime wind speed v ' under other sparking voltage, wherein, r < R;

F, wind regime radius corresponding to different sparking voltage and wind regime wind speed carry out analogue simulation to the motion state of discharge space electrofluid.

2. the analogy method of corona discharge space electrofluid according to claim 1, is characterized in that, utilizes computing machine to perform above-mentioned analog computation step, carries out the simulation of corona discharge space electrofluid.

3. the analogy method of corona discharge space electrofluid according to claim 2, it is characterized in that, when performing step a, be utilize Matlab software to carry out iterative computation, and paint to obtain electric-field intensity distribution figure under the different voltage of discharge space and current density distributing figure.

4. the analogy method of corona discharge space electrofluid according to claim 2, it is characterized in that, when performing step f, be by the wind regime radius corresponding to different sparking voltage and wind regime air speed value input Fluent software, by the motion state of Fluent software simulation discharge space electrofluid.