RU2759763C1 - Method for fog dispersion - Google Patents

Abstract

FIELD: meteorological technology.

SUBSTANCE: invention relates to the field of changing weather conditions, in particular the dispersion of fog over various ground objects. The method for fog dispersion consists in the displacement of fog from a controlled area by an air stream cleared of fog droplets by exposing them to an electric field. The process of exposure of fog droplets to an electric field is carried out in the area of the advance of a pre-formed air flow through a porous filter element with open pores. The air flow is formed as a jet moving at a speed of at least 3 m/s.

EFFECT: proposed method of fog dispersion provides an increase in the efficiency of separation of liquid droplets from the gas stream, which generally increases the efficiency of fog dispersion.

1 cl, 2 dwg

Description

The invention relates to the field of technology intended for dispersing fog over various ground objects, which include airfields, high-speed roads, seaports, etc. various sports and entertainment events.

A known method of dispersing fog, based on the evaporation of fog droplets and the formation of ascending air flows by burning fuel in a controlled area (FIDO project, see, for example, https://habr.com/post/391039/). The device for dispersing the fog, which implements the known method, consisted of three pipes laid on both sides of the runway of the airfield. Two were lying on the ground, the upper one was located above them; holes were made in the lower pipes. Fuel was pumped into the upper pipeline, which flowed into the lower pipes and through the holes beat up in streams. The jets of fuel were ignited, the upper pipe warmed up, the fuel evaporated in it, and the system went into operation: not liquid, but gasoline vapors were poured out of the holes, forming torches 60-180 cm high. The heat from the flame heated the air in the surrounding space. The mist droplets evaporated, air currents formed, and the fog dissipated. The known device has been successfully applied in practice and ensured the landing of aircraft in conditions of powerful fogs. However, the known device is characterized by high energy consumption (more than 100 liters of fuel per second) and has not found wide application.

Methods of electrical action on fog are known. Thus, in US patent No. 4671805, published June 09, 1987, describes a method of dispersing fog using an ion cloud. NASA report 3481 from 1981 (see http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19820008785_1982008785.pdf,) presents research materials on the creation of ion generators. However, the practical application of ion generators for dispersing fog is not presented in published sources.

There is a known method of dispersing fog and clouds, which consists in generating electric charges into the atmosphere by connecting corona wires to a high voltage source fixed through insulators on supports near the earth's surface (see "Journal of Geophysical Research", Cambridge, Massachusetts, March 1962, vol. 67, pp. 1073-1082). Information about this method is reflected in the domestic technical literature (see L. G. Kachurin "Physical foundations of the impact on atmospheric formations", Gidrometeoizdat, Leningrad, 1978, pp. 287-293). The work on testing this method, carried out with the participation of the authors, showed that the dispersion of fog by this method has a statistically significant result. See V.B. Lapshin, A.A. Paley. Results of field experiments to assess the effect of corona discharge on fog density. Meteorology and Hydrology 2006, No. 1, pp. 41-47.

Known device for dispersing fog, the description of which is set forth in the patent of the Russian Federation No. 2124288 C1, class. E01H 13/00, 19.12.1997, published 10.01.1999, bull. # 1. The known device contains wires connected to the current source with a small radius of curvature of the surface, fixed on the insulators of the supports parallel to the electrically conductive mesh mounted in a vertical plane passing through the axes of symmetry of the adjacent supports.

The known technical solution quite successfully solves the problem of fog dispersing.

See for example https://www.youtube.com/watch?v=3HnMTvwBOXk, https://www.youtube.com/watch?v=PGGkdaVStXs. The corona discharge generated by the corona wires creates an ionic wind that is directed from the corona wires to the grounded grid. The fog cloud, passing through the corona discharge region, receives an electric charge and is directed to the grounded grid by the ionic wind, as well as by the external wind flow. Passing through the cells of the grounded grid, electrically charged fog drops are separated from the wind flow, and the wind flow cleared of fog is directed to the area of the space protected from fog. At the same time, the stability of corona discharge combustion, and, consequently, the efficiency of the device operation largely depends on the accuracy of the gap between the corona wires and the grounded grid. Where the gap is less than the design value, electrical breakdown occurs and the entire corona system is shut down. In places where the gap is greater than the design value, the intensity of the corona discharge is insufficient to effectively dissipate the fog. Providing the required flatness characteristics of the mesh surface is a very difficult technical problem.

A device for dispersing fog is known according to RF patent 2516988 Ru C1, IPC A01G 13/00 (2006/01), published on May 27, 2014, bull. No. 15. This device contains a grounded electrically conductive grid mounted on a frame, on top of which electrically conductive rods are installed with a certain pitch, along the surfaces of which corona electrodes connected to a high-voltage power supply and connected to a high-voltage power supply are installed with a gap. The stability of the gap of the discharge gap between the corona electrodes and the grounded surface in the known device is ensured by rigid attachment of the elements of the grounded surface to the frame. Also rigidly on the brackets fixed to the frame, guides with corona electrodes fixed on them are installed through the insulators. The guarantee of the accuracy of the value of the gap of the discharge gap in the known device is ensured by the fact that both grounded conductive rods and corona electrodes are rigidly fixed to the frame. Favorable conditions are created for the formation of a stable corona discharge with predetermined parameters, and the effective operation of the fog dispersing device is ensured. At the same time, the generated wind flow, which is directed to the area of the space protected from fog and ensures the displacement of fog from it, is determined by the ionic wind, the value of the speed of which in the known method is insignificant (1-2 m / s). Fog dispersion is provided only in conditions of complete calm, or only in the leeward space. And to disperse fog over a large area, for example, on a highway, it is required to install such a device almost along the entire line of its length.

A known method of dispersing fog by forming a jet of heated and dried air (patents for inventions 2174301 Ru, 2164368 Ru, 2160001 Ru, KR 201550121909, KR 20120088177). These methods provide the formation of a jet with a high speed, which allows you to adjust the direction of the jet and ensure the displacement of fog over large areas. At the same time, these technical solutions are distinguished by significant energy consumption.

The closest method to the proposed is the method of dispersing the fog, set forth in the patent 2661765 Ru. This method of dispersing fog consists in exposing the fog droplets to an electric field formed on the windward side of the controlled object. The process of affecting fog droplets with an electric field is preceded by the generation of a corona discharge in the volume of the fog passing through the region of the acting electric field. This method does not consume much energy. However, this method is limited in its consumption. Its implementation is possible only under conditions of protection of the controlled area, when fog flows into the controlled area. In calm conditions, however, it has a very low efficiency, and the implementation of this method is impossible.

The closest fog dispersing device to the proposed one can be attributed to the fog dispersing device presented in the patent 2610315 Ru. This device contains a frame free for the passage of the purified gas flow, in which the filter material with open pores is mounted, made in the form of belts installed one above the other with overlapping. In the space between the belts, partitions are installed at an angle to the horizon, which are made impermeable for the liquid to be separated. Partitions impermeable to the liquid to be separated, installed between the belts of the filtering material, ensure the removal of the separated liquid from the device separately from each belt of the filtering material. Separated droplets from the overlying layers do not fall on the underlying layers, do not overlap their pores, which ensures high efficiency of the entire device.

At the same time, in this device, only those drops are separated from the flow, which, during the flow of the flow, touch the surfaces of the structural elements of the filter material. The air flow, when passing through the pores of the filter material, flows around the structural elements, and since the fog drops are small, the aerodynamic forces, which are proportional to the square of the droplet size, significantly exceed the inertial forces, which are proportional to the cube of the droplet size.

where F _v - aerodynamic force;

F _i - inertial force;

r is the characteristic droplet size;

k, k ₁ , k ₂ are constant coefficients.

For a small drop, the size of which is r → 0, the value k → ∞

That is, small droplets of fog are, as it were, frozen into a stream and flow around the obstacle practically along the streamlines of air movement. Considering the low velocities of movement of air masses through the pores of the filter material and the small size of droplets, only a small part of finely dispersed droplets, due to turbulent eddies, can fall on the rear part of the streamlined surface. The theory of inertial deposition, see, for example, Vetoshkin A.G. Fundamentals of Environmental Engineering. - M: Infra-Engineering, 2019. - 452 p., Shows that small-sized particles mostly follow the streamlines of air movement and do not come into contact with the frontal (front) part of the streamlined body. Fog droplets are small, the radius of fog droplets usually ranges from 1 to 30 microns. Most of the droplets have a radius of 5-15 microns at positive air temperatures and 2-5 microns at negative temperatures (https://m.wikipedia.org/wiki/%D0%A2%D1%83%D0%BC%D0%B0% D0% BD). Thus, in the known device, a significant part of the mist droplets flows around the structural elements of the porous filter material and goes out into the controlled space. This reduces the effectiveness of the known device. Increasing the efficiency of separating mist droplets by reducing the pore size of the filter material significantly increases the aerodynamic resistance of the device. Natural air flow simply flows around it. And the use of forced air flow through the filter material in which the pore size is reduced, for example, using a fan and a restrictive passage to move the filter air flow increases power consumption, which also reduces the efficiency of the known device.

The purpose of the present invention is to improve efficiency.

To achieve the stated goal in the known method of dispersing fog, which consists in the action of an electric field on electrically charged fog droplets, the process of affecting electrically charged fog droplets with an electric field is carried out in the region of advancement of a pre-formed air flow through a porous open-pore filter element installed in the air duct;

a known fog dispersing device containing waterproof plates installed one above the other at an angle to the horizon, in the gap between which a porous open-pored filter material is fixed, provided with electrodes connected by a high-voltage cable with a high-voltage source, electrically isolated between the grounded waterproof plates;

the electrodes are made in the form of pipes with walls made of electrical insulating material with internal reinforcement with an electrically conductive interlayer, hermetically connected to an electrically insulated current supply pipe, in the inner cavity of which, filled with an electrically insulating material, a high-voltage cable is laid, electrically connected to the electrically conductive pipe interlayers.

The technical effect is achieved due to the fact that the effect of an electric field on electrically charged droplets in the present invention is carried out in the pores of the filter element. If in the known method the droplets are removed in an open space, and in order to remove the fog droplets, it is necessary to provide the droplets with an electric field to move the droplets relative to the streamlines of the moving air stream over a considerable distance, measured by several meters. Then, in the proposed technical solution, the drops are removed by exposing them to an electric field in the pores of the filter element. The electric field is used for droplets to collide with filter structural elements. Further, the droplets are deposited on the surface of the filter structure and are separated from the air stream. A slight displacement by the electric field of the fog drops from the streamlines of the formed air flow, commensurate with the pore size of the filter element, measured in microns, is sufficient, which is much more efficient than in the known method.

The essence of the proposed method is as follows. Fog dispersion in the controlled area is carried out from the windward side of the object protected from fog. Fog from the controlled area is displaced by a jet of air stream purified from fog drops. As the laboratory experiments have shown, for reliable displacement of the fog, it is necessary to have a jet velocity of the air stream leaving the air duct of at least 3 m / s. A jet of an air stream purified from fog droplets is formed in two successive stages: the formation of an air stream and its subsequent purification from the fog droplets contained in it. The formation of an air stream is carried out from a fog approaching the controlled area, filled with electrically charged fog drops. See, for example, Jumanji V.A. Physical properties of an ordered water aerosol cluster. Dissertation for the degree of candidate of physical and mathematical sciences. FSBI Main Geophysical Observatory named after A.I. Voyeyky ". St. Petersburg. 2013. To increase the efficiency of fog dispersion in the area adjacent to the place where the fog is dispersed at a distance of at least 5 meters from the windward side, corona discharge is generated in the fog. Or, the corona discharge can be generated directly in the air flow shaping device. The formation of an air stream containing electrically charged mist droplets can be carried out:

in a natural way, the energy of a moving wind flow is used, which ensures the flow of fog onto the protected object;

with a fan;

using a special ion wind generator, see, for example, patent for invention No. 27345550.

The formed air flow with electrically charged mist droplets is directed into the air duct, the cross-section of which is blocked by a porous filter element installed in it and moves through its pores due to the dynamic pressure. Electrically charged droplets moving in the pores of the filter material are exposed to an electric field. Electrically charged droplets under the action of the forces of the electric field deviate from the current lines of the wind flow, collide with the elements of the filter structure, settle on their surface and are separated from the air flow. The air stream cleared of fog droplets leaves the air duct and displaces the fog from the controlled area with the dynamic pressure of its jet. As the laboratory experiments have shown, for reliable displacement of the fog, it is necessary to have a jet velocity of the air stream leaving the air duct of at least 3 m / s. If the energy of the incident flow is insufficient to provide such a speed, fans or special ionic wind generators are used, see, for example, patent for invention No. 27345550.

In fig. 1 shows a schematic diagram of a device that implements the proposed method of dispersing fog.

The fog dispersing device contains a frame free for the passage of the gas flow to be cleaned, made in the form of opposing racks 1. Inside the frame, between the partitions 2 fixed at an angle a to the horizon on racks 1, electrically isolated, for example, on insulators 3, electrodes 4 are installed, electrically connected to a high-voltage power supply 5. In the space of the frame between the partitions 2 and the electrodes 4, a filter material is mounted 6. If necessary, in case of insufficient rigidity, the filter material can be framed by a mesh 7, fixed on both sides between the posts 1 of the frame. The filter material 6 can be made of any filter materials available on the market. For example, metals, polymers, ceramic materials, fiberglass, carbon fiber, the so-called steel wool (in the literature it is also called "iron wool", "metal wool", "steel wool", "steel wool", "iron wool" , "Wire wool", "steel wire", "wire sponge".), Etc. The porosity of the filter material is determined at the design stage of the device, depending on its purpose and requirements for the degree of filtration. The porosity of the material is determined from the conditions for ensuring the free passage of fog through the device due to the dynamic pressure of the natural wind flow or the technical means used, a fan or an ionic wind generator. If it is necessary to increase the dynamic head of the wind flow, dynamic reflectors 8 can be mounted around the device, directing the natural wind flow from the space surrounding the device to pass it through the cross-section of the device. The size of the dynamic reflectors 8 is selected at the design stage and can be no more than 30% of the linear size of the device. Reflectors are installed at an acute angle β to the direction of the wind flow. Partitions 2 can be made of any material. The main requirement for partitions is impermeability to the separated liquid. The step of the baffles 2 and, accordingly, the step of the electrodes 4 is selected by experimental selection. The porosity of the filter material 6, its thickness, its permissible waterlogging, as well as the voltage of high-voltage power supplies 5, the dielectric strength of the insulators are taken into account 3. The angle of inclination of the partitions α to ensure stable drainage of accumulated moisture is at least 3 °. To increase the reliability of the withdrawal of the separated liquid from the device, partitions 2 can be installed at an acute angle γ towards one of the racks. The angle of inclination γ must also be at least 3 °. In this case, a groove 9 is made along the edge of the partition for draining the separated liquid.

The description of the device is presented for its use as a means for dispersing fog, cleaning natural moving air masses (fog) from droplets contained in them. When using a device for the purification of gas streams, where special devices for the formation of gas streams are used, the frame can be made in the form of a surface covering the formed gas stream in order to exclude leakage of the purified gas due to excessive pressure from the gas flow blower, for example, it can be made in the form cylinder.

In fig. 2 shows a schematic diagram of a device that implements the proposed method of dispersing fog, in which the electrodes are made in the form of pipes with walls made of electrically insulating material with internal reinforcement with an electrically conductive layer. As such pipes, polypropylene pipes widely available on the market, with internal aluminum reinforcement, can be used. See, for example, https://www.fdplast.ru/polipropilenovye-truby/armirovannye-alyuminiem/. The device includes a frame free for the passage of the gas flow to be cleaned, made in the form of racks 1 standing opposite each other. Inside the frame, between the partitions 2 fixed at an angle a to the horizon on racks 1, electrodes 3 are installed, made of pipes with walls made of electrical insulating material with internal reinforcement with an electrically conductive interlayer 4. At one end, each pipe is hermetically sealed with a plug 5, and the other end through a tee 6 is hermetically connected to the current supply pipe 7. The plug 5, the tee 6 and the current supply pipe 7 are made of electrical insulating material, for example, in the same way as electrode 3, made of polypropylene. The tightness of the connection of the pipes of the electrodes 3 with plugs 5 and through the tees 6 with the current supply pipe 7 can be carried out by welding, which is widely used in the installation of heating systems from polypropylene pipes. See, for example, https://trubanet.ru/plastikovye-truby/svarka-polipropilenovykh-trub-video-uroki.html. The electrically conductive layers 4 of the electrodes 3 inside the current supply pipe 7 are electrically connected to the high-voltage cable 8, laid through the mounting hole made in the plug 9 installed at one of the ends of the current supply pipe 7. 11. The space inside the frame, between the opposing posts 1, partitions 2, and electrodes 3 is filled with filter material 12. If necessary, in case of insufficient rigidity, the filter material can be framed with a mesh 13. The proposed devices operate as follows.

The proposed device is installed between the oncoming fog stream and the protected object. The incident flow W under the action of the excess pressure formed by the high-speed pressure passes through the pores of the filter material. The electrically charged liquid droplets contained in the stream to be cleaned, under the action of inertial forces and electrostatic forces, deviate from the streamlines of the air flow advancing in the pores, contact the fibers of the filtering material and settle on their surface. As the droplets grow larger, they flow down to the partition 2 under the action of gravitational forces and are then removed from the device. The stream cleared of droplets displaces the fog from the controlled area and provides the task of dispersing the fog in the vicinity of the protected object. When using the device in treatment paths, the scheme of operation of the proposed device is similar. Since the cleaning schemes provide for the formation of excess pressure using a special device (for example, a fan), it is necessary to provide for the connection points of the proposed device with a gas pipeline supplying the generated air flow to the device to be cleaned.

In the proposed technical solution, the separation of mist droplets is carried out in the pores of the filter element. The electric field is used for droplets to collide with filter structural elements. Exposing electrically charged mist droplets to an electric field increases the likelihood of their collision with the structural elements of the porous filter element. Further, the droplets are deposited on the surface of the filter structure and are separated from the air flow. A slight displacement by the electric field of the fog drops from the streamlines of the formed air flow, commensurate with the pore size of the filter element, measured in microns, is sufficient, which is much more efficient than in the known method.

Thus, the proposed technical solution, due to new previously unknown features, provides an increase in the efficiency of separating droplets from a gas stream, which increases the efficiency of the proposed method of dispersing fog and allows you to achieve the goal of the proposed invention.

Claims (1)

A method of dispersing fog, which consists in displacing fog from a controlled area with an air stream purified from fog drops by exposing them to an electric field, characterized in that the process of affecting fog drops with an electric field is carried out in the area of advancement of a pre-formed air flow through a porous filtering with open pores element, while the air flow is formed in the form of a jet moving at a speed of at least 3 m / s.

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