RU2466514C2 - Method to produce electric discharge in vapours of electrolyte and device for its realisation - Google Patents

Abstract

FIELD: information technologies.

SUBSTANCE: in the method to produce an electric discharge in vapours of electrolyte, consisting in ignition of a discharge between a solid-state anode and a liquid electrolyte sent into a discharge area via a solid body of a porous dielectric body, electrolyte is supplied into a discharge area by filling of a vertical through profiled channel in a porous dielectric body to the level of the ledge in the channel section. In the device to produce an electric discharge in vapours of electrolyte, comprising a solid-state current lead, a porous dielectric body, a liquid electrolyte as a cathode, a solid-state anode and a hydraulic system for electrolyte circulation, in the porous dielectric body there is a through cylindrical channel with a ledge, besides, the channel is aligned so that its section with a smaller diameter d is arranged at the side of the current lead, and the section with the large diameter D - at the side of the anode, and diameters of channel sections are selected within the following limits: d=(5÷15) mm - near a section with a smaller diameter; D=(1.2÷2.0)·d - near a section of a larger diameter.

EFFECT: increased active working area of a discharge.

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Description

The invention relates to methods for producing, researching and using low-temperature plasma and can be used in plasma chemistry, plasma processing technologies and plasma technology, in particular in plasma chemical reactors.

Known methods for producing an electric discharge in vapor of an electrolyte between a liquid electrolyte cathode and a solid-state anode, when the liquid electrolyte is either poured into an electrolytic bath [1] or is supplied in the form of a jet [2].

There is a method of producing an electric discharge in electrolyte vapors, when both electrodes (both the cathode and the anode) are liquid electrolytes and flow along the surfaces of solid-state current leads [3].

A disadvantage of the known methods is that with their help it is impossible to obtain a discharge at large interelectrode distances, i.e. it is impossible to increase the length of the discharge channel above a certain limit, which is about 20 mm and is practically independent of the composition of the electrolyte. Therefore, these methods have limited practical applications.

A known method of producing an electric discharge in electrolyte vapor, which consists in igniting a discharge inside a dielectric tube, the lower end of which touches the electrolyte poured into the electrolytic bath, and a solid-state anode is installed near the open upper end [4]. In this case, the electrolyte vapor rises in the vertical direction inside the tube, and this allows the discharge to be maintained at much larger (more than 20 mm) electrode distances.

This known method has the following disadvantages: there is no free access to the discharge region; there is no forced removal of heat from the electrolyte, as a result of which, during prolonged use, the electrolyte heats up and boils. Therefore, this method, like other known methods, has limited practical applications.

A device containing a solid-state current lead, a porous dielectric body, a liquid electrolyte as a cathode, a solid-state anode, and a hydraulic system for circulating the electrolyte are selected as a prototype of the device for implementing the method [5]. Due to the presence of electrolyte circulation, the prototype provides a gas discharge combustion for a sufficiently long time. In the prototype, the length of the interelectrode distance can be significantly increased, however, only to a certain limit. Depending on the chemical composition of the electrolyte used as a liquid cathode, the limiting length of the discharge gap can be in the range from 200 to 220 mm.

The invention is aimed at increasing the active working zone of the discharge.

This is achieved by the fact that in the method of producing an electric discharge in electrolyte vapors, which involves igniting a discharge between a solid-state anode and a liquid electrolyte passed into a discharge region through a solid body of a porous dielectric body, the electrolyte is fed into the discharge region by filling a vertical through profiled channel in a porous dielectric body to the level of the step in the channel section.

And in the device for producing an electric discharge in electrolyte vapors containing a solid-state current lead, a porous dielectric body, a liquid electrolyte as a cathode, a solid-state anode and a hydraulic system for circulating the electrolyte, a through cylindrical channel with a step is made in the porous dielectric body, while the channel is oriented so that its section with a smaller diameter d is located on the side of the current supply, and the section with a larger diameter D is on the side of the anode, and the diameters of the channel sections are selected in the range: d = (5 ÷ 15) mm ka with a smaller diameter; D = (1.2 ÷ 2.0) · d - in the area with a large diameter.

Figure 1 shows a device for implementing the method.

A device for implementing the method (Fig. 1) consists of a current lead 7, an electrolyte 2, which acts as a cathode, a porous dielectric body 3, a solid-state anode 4, made in the form of a ring, an insulator 5, a hydraulic system 6, which circulates the electrolyte. The current lead 1 and the anode 4 are connected to the terminals of the power supply 7 through a ballast resistor 8. The current lead 1 and the porous dielectric body 3 form a single cathode assembly with a cavity for the flow of electrolyte 2. In the porous dielectric body 3, a through channel 9 is made in the form of a cylindrical hole with a step 10 This channel connects the internal cavity of the cathode assembly with the combustion region of discharge 11. A section of the channel with a smaller diameter d is located on the side of the current lead 7, and its portion with a larger diameter D is located on the side of the anode 4.

The method is as follows. A device for implementing the method is installed in a vertical position, as shown in figure 1. In this case, the cathode assembly, consisting of a current lead 1 and a porous dielectric body 3, is located at the bottom, and the anode 4 is at the top. Through the cavity formed between the current lead 7 and the porous dielectric body 3, the flow of electrolyte 2 is passed. Its direction is indicated by arrows in figure 1. The electrolyte flow rate is selected so that the electrolyte fills the channel 9 to the level of the ledge 10, as shown in figure 1. Then, using known methods, for example, by exploding a thin copper wire, discharge 11 is ignited between the liquid electrolyte 2 and the anode 4. The insulator 5, which covers the lower end of the anode 4 and its outer side surfaces prevents the anode spots from wandering around the outer surface of the anode and thereby helps to stabilize the discharge.

Under the influence of the energy flow coming from the discharge plasma, the electrolyte evaporates and enters the discharge region 11. Due to the fact that the thermal conductivity of the dielectric is much lower compared to the electrolyte, the porous dielectric body heats up more strongly, and the evaporation of the electrolyte occurs mainly inside the pores of the surface layer of the porous dielectric body . The electrolyte evaporates from the horizontal surface of the ledge 10 and from the walls of the channel 9 in its section with a large diameter D. The electrolyte vapor, leaving the pores under pressure, forms a flow directed towards the discharge region. Due to the electrolyte vapor coming from the vertical walls of the channel 9, the steam flow density increases, and a cumulative effect also arises. These factors contribute to the lengthening of the active working zone of the electric discharge in the vertical direction, thereby making it possible to increase the interelectrode distance l.

In the experiments, an electric discharge was obtained at an interelectrode distance l = 410 mm, which is almost two times the maximum interelectrode distance of the prototype. As in the case of the prototype, an aqueous solution of sodium chloride (NaCl) with a mass concentration of 30 kg / m ³ was used as a liquid electrolyte. Thus, the proposed method can significantly increase the interelectrode distance and, accordingly, the active working zone of the discharge.

The experiments showed that the greatest positive effect is achieved when performing a through channel in a porous dielectric body with the following geometric parameters: d = (5 ÷ 15) mm and D = (1,2 ÷ 2,0) d. At d more than 15 mm and D≥2.0 · d, the vapor flux density decreases and the length of the active working zone of the discharge decreases, and at d less than 5 mm, the discharge channel is compressed and contracted, which reduces the stability of the discharge burning.

Information sources

1. Gaysin F.M., Son E.E., Shakirov Yu.I. Volume discharge in a vapor-gas medium between solid and liquid electrodes. M .: Publishing house of VZPI. 1990. Pages 82-85.

2. Gaysin F.M., Khakimov R.G., Shakirov Yu.I. A discharge in a gas between a liquid stream and a solid electrode // Abstracts of the scientific and technical conference "Problems and Applied Problems of Physics" - Saransk. May 18-20, 1993. MGPI. Page 34.

3. Barinov Yu.A., Blinov I.O., Dyuzhev G.A., Shkolnik S.M. An experimental study of a discharge with liquid electrodes in air at atmospheric pressure // Materials of the conference “Physics and Plasma Engineering”, vol. 1, Minsk. Belarus. September 13-15, 1994. Pages 123-126.

4. AC No. 1088086 (USSR). Gaysin F.M., Gizatullina F.A., Dautov G.Yu. Device for producing a glow discharge at atmospheric pressure. 1983.

5. RF patent No. 2169443. Tazmeev B.Kh., Tazmeev Kh.K. A method of producing an electrolyte electric discharge and a device for its implementation. 2001.

Claims (2)

1. A method of producing an electric discharge in electrolyte vapor, which consists in igniting a discharge between a solid-state anode and a liquid electrolyte passed to a discharge region through a porous dielectric body, characterized in that the electrolyte is supplied to the discharge region by filling a vertical through profiled channel in a porous dielectric body to level of the ledge in the section of the channel. 2. The device for implementing the method according to claim 1, containing a solid-state current supply, a porous dielectric body, a liquid electrolyte as a cathode, a solid-state anode and a hydraulic system for circulating the electrolyte, characterized in that a through cylindrical channel with a step is made in the porous dielectric body, wherein the channel is oriented so that its section with a smaller diameter d is located on the side of the current supply, and the section with a larger diameter D is on the side of the anode, and the diameters of the channel sections are selected in the range: d = (5 ÷ 15) mm - at the section with less their diameter; D = (1.2 ÷ 2.0) · d - in the area with a large diameter.