A method for preventing sand and dust in electrolytic cells based on the Coenda effect

Abstract

This invention discloses a method for preventing sand and dust in electrolytic cells based on the Coanda effect. It includes the following steps: S1: Forming a surrounding dust cover structure that flexibly contacts or maintains a non-contact gap with the electrolytic cell around a fully load-bearing mobile bracket; S2: Airflow sealing, continuously filling the inner chamber surrounded by the dust cover structure with gas to separate external sand and dust; S3: Coanda adhesion acceleration, guiding the laminar gas flow to a continuously variable curvature Coanda surface, utilizing the gradual curvature of the Coanda surface to generate a wall adhesion effect, increasing the gas velocity and forming a jet air curtain. By using a continuously variable curvature Coanda surface, the airflow velocity is increased through the wall adhesion effect, forming a laminar air curtain, achieving curvature-velocity coupling optimization. Compressed air is injected through a narrow-slit nozzle, leveraging ambient air to form a high-flow-rate air curtain. The measured air curtain coverage area is 3.2 times that of a traditional guide plate, and the unit energy consumption is reduced by 57%.

Description

Technical Field

[0001] This invention relates to the field of auxiliary devices for electrolytic cells, and specifically to a method for preventing sand and dust in electrolytic cells based on the Coenda effect. Background Technology

[0002] As a key pathway for clean energy production, water electrolysis hydrogen production technology, and filter press electrolyzers as an important technological branch in the field of water electrolysis hydrogen production, have always been a focus of technological innovation in terms of the improvement and structural optimization of their supporting equipment.

[0003] During the operation of a filter press water electrolyzer, the electrode plates, due to long-term exposure to gravity, may exhibit phenomena such as sinking in the middle section and outward flipping of the left and right end plates. The vertical displacement of the electrode plates due to gravity leads to their sinking, which affects the uniformity of the electrode spacing inside the electrolyzer and reduces the electrolysis efficiency.

[0004] Our prior utility model application (ZL202322792604.1) discloses an electrolytic cell support unit and a fully load-bearing movable bracket thereof. The electrolytic cell support unit includes a top support device, a support device, and a sliding device. An adjusting bolt is provided at the connection between the support device and the sliding device, allowing adjustment of the tilt angle and height of the top support device. The fully load-bearing movable bracket includes several of these electrolytic cell support units, which are placed on a foundation or structural steel frame, with insulated rollers positioned below the electrolytic cell electrode plates.

[0005] This invention solves the problems of sinking, slippage, and outward flipping of the end plates in electrolytic cells caused by gravity. Simultaneously, the electrolytic cell body expands and contracts radially with temperature changes. Therefore, the aforementioned support unit has the function of radial movement. The sliding device allows the electrolytic cell support unit to generate a certain sliding margin, adapting to changing environments and avoiding rigid deformation. Furthermore, the toothed grooves allow the gaskets between the plates to be squeezed into the grooves during thermal expansion and deformation, providing deformation space and preventing excessive compression of the plates by the gaskets.

[0006] Many hydrogen production projects are built in windy and sandy environments. If the electrolyzer is disturbed by wind and sand during operation, the support unit is directly exposed to this environment. A single roof cannot completely and effectively shield the electrolyzer body. In particular, sand or large particles of dust such as pebbles will be drawn into the support unit without obstruction. Over time, a large amount of pollutants accumulate at the rollers where the support unit moves radially, causing the support unit to malfunction. During operation, it is impossible to continuously provide uniform support force to the electrolyzer, and it is also impossible to solve the problem of support misalignment caused by thermal expansion of the electrolyzer during use, increasing the risk of leakage, especially at both ends of the electrolyzer.

[0007] In view of the above, it is necessary to propose a method for preventing sand and dust in electrolytic cells based on the Coanda effect to solve the above problems. Summary of the Invention

[0008] The purpose of this invention is to overcome the defects in the existing technology and provide a method for preventing sand and dust in electrolytic cells based on the Coanda effect.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows: A method for preventing sand and dust in electrolytic cells based on the Coanda Effect includes the following steps: S1: A dust cover structure is formed around the periphery of the fully load-bearing mobile bracket, which is either in flexible contact with the electrolytic cell or maintains a non-contact gap. The dust cover structure forms a semi-enclosed protective structure between the foundation and the electrolytic cell. S2: Airflow seal, gas is continuously filled into the inner chamber surrounded by the dust cover structure, or gas flow is formed in the dust cover structure and sprayed out from a specific part to generate an air curtain, so that the dust cover structure separates external sand and dust. S3: Coanda wall-attached acceleration guides the laminar flow of gas to a continuously variable curvature Coanda surface. The gradual curvature of the Coanda surface causes the gas to have a wall-attached effect, which increases the gas velocity and forms a jet gas curtain.

[0010] Furthermore, the dust cover structure includes at least a vertical enclosure wall set on the side of the fully load-bearing mobile bracket, with the bottom of the vertical enclosure wall connected to the foundation and the top of the enclosure wall in flexible contact with the electrolytic cell or forming a non-contact gap.

[0011] Furthermore, the dust cover structure is provided with a through-vent forming in the preset gas outflow direction, and the through-vent has a gas jet outlet at least at the gas outflow end.

[0012] Furthermore, the ventilation opening forms a gas intake at the end away from the gas jet outlet, and the dust cover structure includes vertical enclosure walls on both sides of the ventilation opening. The vertical enclosure walls form a Coanda surface on one side of each other. The Coanda surface includes a curved convex part formed on the side away from the gas jet outlet. The curved convex part transitions smoothly towards the gas jet outlet to form an inclined surface, and the openings formed by the inclined surfaces on both sides face the gas jet outlet.

[0013] Furthermore, the Kornda surface adopts a continuously variable curvature design, with the curvature radius R gradually changing from 50mm to 200mm.

[0014] Furthermore, the vertical enclosure has a cavity inside, and the cavity has a slit-shaped airflow nozzle on the front side of the curved convex part for gas to flow out in the tangential direction.

[0015] Furthermore, the dust cover structure includes an ion wind generating module, which includes an electrode array. The electrode array has an emitter and a collector, and an ionization region is set between the emitter and the collector. The emitter includes tungsten needle electrodes arranged on the front side of the curved convex part. The collector is a conductive silicon carbide layer plated on the convex surface of the Coanda curved surface, which is grounded to form an electric field gradient. The ionization region has an electrode spacing of 20-30mm and an electric field strength of E=7.5kV / cm. Corona discharge induces the formation of ion wind, and the ion wind flows through the Coanda curved surface and is further accelerated by the pressure gradient generated by its curvature.

[0016] Furthermore, a negative pressure pipe is provided on the vertical enclosure wall near the side of the fully load-bearing mobile bracket. The vertical enclosure walls arranged symmetrically on both sides form a throat section at the curved convex part. A tapering pipe is formed on the front side of the throat section and a expanding pipe is formed on the rear side. One end of the negative pressure pipe is connected to the throat section, and the other end is connected to the inside of the semi-enclosed protective structure.

[0017] Furthermore, the dust cover structure is made of a transparent and visible material.

[0018] Furthermore, the dust cover structure is made of a material resistant to alkali corrosion.

[0019] The advantages and beneficial effects of this invention are as follows: 1. This invention provides a sand and dust prevention method for electrolytic cells based on the Coanda Effect. The vertical enclosure and the electrolytic cell are connected by flexible brushes or a non-contact gap, allowing for ±5mm-level expansion and contraction displacement of the electrolytic cell due to temperature changes, thus mitigating the risk of support misalignment caused by thermal stress. The upper and lower rows of brushes are staggered and bonded together to form a progressive interception layer. Experimental data shows that the interception rate for 1mm sand particles reaches 100%, and the blocking efficiency for 0.1mm fine dust is 98.7%, while maintaining an air gap heat dissipation channel, controlling the internal temperature rise to <3℃.

[0020] 2. A continuously variable curvature Korndahl surface is used to increase airflow velocity through the wall effect, forming a laminar air curtain and achieving curvature-velocity coupling optimization. Compressed air is injected through a narrow slit nozzle, which agitates ambient air to form a high-flow-rate air curtain. The measured air curtain coverage area is 3.2 times that of a traditional guide vane, and the unit energy consumption is reduced by 57%.

[0021] 3. Ion wind-Kornda composite enhancement mechanism, corona discharge induced airflow: The tungsten needle electrode array generates ion wind under the electric field, with an initial wind speed of 4.5 m / s, which is accelerated by the Kornda curved surface and the flow rate is increased several times.

[0022] 4. The negative pressure self-driven circulation system utilizes the Venturi effect: the throat section (section contraction ratio 1:3.2) generates a local negative pressure of -1.2kPa, which automatically extracts the gas in the protective cover through the negative pressure pipe, achieving an air exchange rate of 12 times per hour without additional power consumption, saving 68% energy compared to active air supply. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an electrolytic cell sand and dust prevention device based on the Coanda effect according to the present invention; Figure 2 This is an exploded view of an electrolytic cell sand and dust prevention device based on the Coanda effect according to the present invention; Figure 3 This is a longitudinal cross-sectional schematic diagram of an electrolytic cell sand and dust prevention device based on the Coenda effect according to the present invention; Figure 4 This is the present invention. Figure 3 Schematic diagram of the AA section structure; Figure 5 This is a schematic diagram of the structure of Embodiment 3 of the present invention; Figure 6 This is a schematic diagram of the structure of Embodiment 4 of the present invention; Figure 7 This is a schematic diagram of the structure of Embodiment 5 of the present invention; Figure 8 This is a schematic diagram of the structure of Embodiment Six of the present invention; Figure 9 This is a schematic diagram of the structure of Embodiment Seven of the present invention; In the diagram: 1. Dustproof cover structure; 2. Support unit; 3. Vertical enclosure wall; 4. Foundation; 5. Electrolytic cell; 6. Flexible connection; 7. Gap distance; 8. Brush structure; 9. Lower row of brushes; 10. Upper row of brushes; 11. Non-contact gap; 12. Displacement chamber; 13. Compressed air supply pipe; 14. Air curtain; 15. Through-vent; 16. Gas jet outlet; 17. Cavity; 18. Coanda surface; 19. Gas inlet; 20. Curved convex part; 21. Inclined surface; 22. Airflow nozzle; 23. Through hole; 24. Ion wind generating module; 25. Electrode array; 26. Emitter; 27. Collector; 28. Ionization zone; 29. ​​Tungsten needle electrode; 30. Negative pressure pipe; 31. Throat section; 32. Converging tube; 33. Diverging tube; 34. Electro-silicon carbide layer. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention. Example 1:

[0025] A method for preventing sand and dust in electrolytic cells based on the Coanda Effect, such as... Figure 1 As shown, a dust cover structure 1 is formed around the periphery of the fully load-bearing mobile bracket, which flexibly contacts or maintains a non-contact gap 11 with the electrolytic cell 5. The dust cover structure 1 forms a semi-enclosed protective structure between the foundation 4 and the electrolytic cell 5. In actual use, the arrangement of the fully load-bearing mobile bracket is that the electrolytic cell 5 is set on the foundation or steel profile. Taking the steel profile as the foundation 4 for setting the electrolytic cell 5 as an example, several support units 2 of the electrolytic cell 5 are arranged in a row on the steel profile. The rolling rods at the bottom of the support units can roll to cope with the slight displacement of the electrolytic cell 5 caused by the additional stress brought to the gasket when the body of the electrolytic cell 5 expands and contracts due to temperature changes. It can be understood that the fully load-bearing mobile bracket is arranged at the bottom of the electrolytic cell 5 along its length.

[0026] Many hydrogen production projects are built in windy and sandy environments. If the electrolyzer 5 encounters wind and sand interference during operation, the support unit 2 is directly exposed to this environment. A single roof cannot completely and effectively shield the electrolyzer 5 body. In particular, sand or large particles of dust such as pebbles will be unimpeded and drawn into the support unit 2. Over time, a large amount of contaminants accumulate at the rollers where the support unit 2 moves radially, causing the support unit 2 to malfunction. During operation, it cannot continuously provide uniform support force to the electrolyzer 5, thus failing to solve the problem of support misalignment caused by thermal expansion of the electrolyzer 5 during use, increasing the risk of leakage, especially at both ends of the electrolyzer 5. In this embodiment, a semi-enclosed protective structure is set between the foundation 4-section steel and the electrolyzer 5.

[0027] Specifically, such as Figure 1 , 2As shown in Figure 3, a dust cover structure 1 consisting of a fence can be set on both sides of the foundation 4 based on steel profiles. The dust cover structure 1 includes at least a vertical fence wall 3 set on the side of the fully load-bearing mobile bracket. The bottom of the vertical fence wall 3 is connected to the foundation 4, and the top is in flexible contact with the electrolytic cell 5 or forms a non-contact gap 11. It is understandable that the vertical enclosure wall 3 can surround the perimeter of the fully load-bearing movable bracket composed of the support unit 2. The bottom of the vertical enclosure wall 3 is connected to the steel profile, thereby sealing the bottom of the dust cover structure 1. Since the operating temperature of the electrolytic cell 5 is around 60-100℃, the top of the vertical enclosure wall 3 should not be directly sealed to the surface of the electrolytic cell 5. Considering the following factors: first, heat dissipation of the surface of the electrolytic cell 5; second, expansion and contraction of the electrolytic cell 5 during operation; and third, the irregular shape and unevenness of the surface of the electrolytic cell 5, the top of the vertical enclosure wall 3 should not be sealed to the surface of the electrolytic cell 5 to form a barrier. In a preferred embodiment of this example, a flexible connection is established between the top of the vertical enclosure wall 3 and the electrolytic cell 5. Specifically, a gap distance 7 is set between the upper edge of the vertical enclosure wall 3 and the surface of the electrolytic cell 5, and the flexible connection 6 is set in this gap distance 7.

[0028] Specifically, such as Figure 4 As shown, the flexible connection 6 can be a brush structure 8 installed along the upper edge of the vertical enclosure wall 3. The brush structure 8 is set with a barrier at the gap distance 7 between the vertical enclosure wall 3 and the electrolytic cell 5, which has a good blocking effect on sand and dust, especially large sand and dust particles.

[0029] As an improvement, the brush structure 8 may include a lower row of brushes 9 and an upper row of brushes 10. The lower row of brushes 9 is positioned on the vertical enclosure wall 3, and the upper row of brushes 10 is positioned on the surface of the electrolytic cell 5, with the sides of the upper row of brushes 10 and the lower row of brushes 9 fitting together. The brushes create a barrier around the gap 7, thus blocking sand and dust. Its advantages are that it can accommodate the slight expansion and contraction of the electrolytic cell 5 while also providing good ventilation and heat dissipation, preventing heat buildup and temperature rise on the inner side of the dust cover structure 1. It is understood that at least one row of lower row brushes 9 and upper row brushes 10 should be provided. Furthermore, to improve the sand and dust blocking effect of the brush structure 8, multiple rows of lower row brushes 9 and upper row brushes 10 can be provided, and the rows of lower row brushes 9 and upper row brushes 10 should preferably be staggered. Example 2:

[0030] In specific implementation, the protective cover structure includes at least a vertical enclosure wall 3 set on the side of the full-load mobile bracket. The shape of the vertical enclosure wall 3 is not limited. It can be rectangular and can wrap and protect the support unit 2. Multiple vertical enclosure walls 3 are connected to form a ring enclosure that separates the full-load mobile bracket from the external space, thereby shielding and protecting against sand and dust.

[0031] Preferably, the material used to manufacture the protective cover structure should be resistant to alkaline corrosion. Since the electrolytic cell 5 is filled with alkaline electrolyte, there are certain requirements for the alkaline corrosion resistance of the protective cover structure. In actual use, polycarbonate (PC) or polymethyl methacrylate (acrylic) or any alkali-resistant material such as plexiglass can be used.

[0032] Preferably, the dust cover structure 1 is made of a transparent and visible material. For example, a protective cover structure made of transparent acrylic forms a transparent and visible enclosure, which allows operators to directly observe the status of the fully load-bearing movable bracket inside from the outside, and also facilitates observation of the surface of the electrolytic cell 5, thus eliminating blind spots in the equipment. Example 3:

[0033] As another implementation, based on the gap distance 7 set in the aforementioned embodiment, the gap distance 7 is further reduced so that the vertical enclosure wall 3 is set close to the surface of the electrolytic cell 5 to maintain a small non-contact gap 11. Reducing the gap distance 7 can reduce the probability of sand and dust entering the dust cover structure 1 through the channel, thereby improving the protection effect on the support unit 2.

[0034] Furthermore, an airflow seal is provided at the aforementioned non-contact gap 11, specifically, as follows: Figure 5As shown, the fully load-bearing mobile bracket can be enclosed inside the dust cover structure 1, while the outside is the outdoor environment. In this embodiment, the inner side enclosed by the dust cover structure 1 is set as the replacement chamber 12. The bottom of the replacement chamber 12 is the mounting base 4 of the electrolytic cell 5, and the bottom of its vertical enclosure wall 3 can form a sealed connection with the base 4. The top of the replacement chamber 12 is the bottom side of the electrolytic cell 5, and a non-contact gap 11 is formed between the upper perimeter of the vertical enclosure wall 3 and the electrolytic cell 5. The aforementioned airflow seal can be formed at least at the non-contact gap 11. Specifically, in the setting scenario of the electrolytic cell 5, a compressed air supply pipe 13 or a nitrogen pipeline can be provided to supply the bracket. A compressed gas pipeline with a certain pressure is connected to the replacement chamber 12. Gas is continuously injected into the replacement chamber 12 through compressed gas, creating continuous displacement within the chamber. The displacement gas is then blown out from the non-contact gap 11, which also establishes a slightly positive pressure state relative to the outside environment within the replacement chamber 12. The narrow non-contact gap 11 serves two purposes: firstly, it increases the flow rate of the ejected gas, improving the effect of preventing sand and dust from entering; secondly, it reduces the gas flow rate. It is understood that establishing continuous displacement also helps to remove accumulated heat from the replacement chamber 12, thus avoiding the problem of a relative increase in temperature inside the dust cover structure 1. A blower can also be used to inject gas into the replacement chamber 12. A filter or washing device can be installed on the air inlet side of the blower to ensure the cleanliness of the gas entering the replacement chamber 12, preventing sand and dust from entering the rollers of the support unit 2 and causing them to jam. Example 4:

[0035] As another embodiment of forming an airflow seal, in this embodiment, gas flow is formed within the dust cover structure 1 and sprayed out from a specific location to generate an air curtain 14, thereby separating external sand and dust from the dust cover structure 1. This can be understood as spraying air curtain 14 at the flexible connection 6 or the non-contact gap 11. Based on the first embodiment 4, it is provided with a brush structure 8, and the lower row of brushes 9 can be further provided with gas outlets, i.e., specific locations, so that the brush structure 8 not only blocks sand and dust through the brush bristles, but also sprays out the air curtain 14 at the same time, thereby improving the sand and dust blocking effect at the flexible connection 6. A continuously sprayed air curtain 14 can also be formed at the non-contact gap 11, and the sand and dust can be blocked directly through the air curtain 14.

[0036] As one implementation method, such as Figure 6As shown, the dust cover structure 1 is provided with a through-vent 15 forming a preset gas outflow direction, and the through-vent 15 has a gas jet outlet 16 at least at the gas outflow end. Specifically, the interior of the vertical enclosure wall 3 is hollow, so its through-vent 15 is set towards the non-contact gap 11. Specifically, the through-vent 15 is set at the upper edge of the vertical enclosure wall 3, so that the cavity 17 inside the vertical enclosure wall 3 is connected to the upper through-vent 15. It can be understood that an air source as in Embodiment 3 can be used to connect the air source to the cavity, thereby forming a continuous airflow from the interior of the vertical enclosure wall 3 to the non-contact gap 11 to form an air curtain 14. Example 5:

[0037] As an improvement, this embodiment is based on the Coanda effect, causing the airflow to accelerate by adhering to the Coanda wall. Specifically, for example... Figure 7 As shown, the gas laminar flow is guided to the continuously variable curvature Coanda surface 18. The gradual curvature of the Coanda surface 18 is used to generate a wall-attachment effect in the gas, thereby increasing the gas flow rate and forming a jet gas curtain 14.

[0038] This embodiment differs from Embodiment 4. In Embodiment 4, the vertical enclosure wall 3 can be understood as hollow inside, with a through-vent 15 at its top for air outlet, and its bottom and sides being a sealed structure. In this embodiment, the vertical enclosure wall 3 is still hollow inside. The difference is that the dust cover structure 1 in this embodiment includes two vertical enclosure walls 3 arranged in parallel, and the gap between the two vertical enclosure walls 3 is set as a through-vent 15. The side of the through-vent 15 near the non-contact gap 11 is a gas jet outlet 16, and the end of the through-vent 15 away from the gas jet outlet 16 forms a gas inlet 19.

[0039] The vertical enclosure walls 3 form a Coanda surface 18 on one side of their adjacent end faces. The Coanda surface 18 includes a curved protrusion 20 formed on the side away from the gas jet outlet 16. The curved protrusion 20 smoothly transitions towards the gas jet outlet 16 to form a slope 21, and the openings formed by the two slopes 21 face the gas jet outlet 16. Further, similar to Embodiment 4, the vertical enclosure has a cavity 17 inside. The difference is that the cavity 17 has a slit-shaped airflow nozzle 22 at the starting section on the front side of the curved protrusion 20, allowing gas to flow out tangentially. In this embodiment, the airflow nozzle 22 is on the lower side, while in Embodiment 4, the gas outlet is at the top. Compressed gas is introduced into the vertical enclosure wall 3, causing the gas to be ejected through the slit-shaped airflow nozzle 22. The gas ejected from the slit-shaped airflow nozzle 22 increases the gas flow velocity. The higher the gas flow velocity, the lower the pressure. The gas flows along the Coanda surface 18, forming a high-velocity, high-pressure environment. The effect of strong airflow creates a low-pressure area within the ventilation opening 15. This low-pressure area causes the air from the gas inlet 19 to converge towards the center of the ventilation opening 15. Consequently, the flow rate of the air jet from the gas jet outlet 16 on the other side increases several times compared to the original flow rate from the slit-like air jet nozzle 22. This allows a smaller flow rate to propel more gas through the ventilation opening 15 and out through the non-contact gap 11. In actual use, since the bottom of the vertical enclosure wall 3 is erected on the steel foundation 4, through holes 23 can be pre-set on the steel to connect with the gas inlet 19, allowing the ventilation opening 15 to be open vertically.

[0040] Specifically, the width of the through-vent 15 is 10~25mm; the protrusion height of the curved protrusion 20 is H=8mm (initial section) to H=0mm at the outlet section; the total length of the Coanda curved surface 18 is L=250mm~400mm, which meets the acceleration length requirement: L≥3D (D is the inlet equivalent diameter, D=45mm). Curvature parameter table

[0041] *Surface functions are based on the differential geometric continuity condition (C² continuity). Performance test data: Inlet wind speed: 1.5 m / s (corresponding flow rate Q = 0.12 m³ / s) Dust characteristics: particle size 0.1-1.0 mm, concentration 1.2 g / m³ (simulating desert conditions)

[0042] The Kornda surface adopts a continuously variable curvature design, with the curvature radius R gradually changing from 50mm to 200mm, and the surface roughness Ra≤0.8μm (after polishing); and the surface is set as a nano-alumina-polytetrafluoroethylene composite layer with a thickness of 30±5μm. Example 6:

[0043] Furthermore, the dust cover structure 1 includes an ion wind generating module 24, such as... Figure 8 As shown, the ion wind generating module 24 includes an electrode array 25, which has an emitter 26 and a collector 27. An ionization region 28 is set between the emitter 26 and the collector 27. The emitter 26 includes tungsten needle electrodes 29 arranged on the front side of the curved protrusion 20. The collector is a conductive silicon carbide layer 34 plated on the protrusion surface of the Coanda curved surface 18, which is grounded to form an electric field gradient. The ionization region 28 has an electrode spacing of 20-30 mm and an electric field strength E=7.5kV / cm. Corona discharge induces the formation of ion wind, and the ion wind flows through the Coanda curved surface 18 and is further accelerated by the pressure gradient generated by its curvature.

[0044] The specific parameters of this composite dust cover structure 1 are as follows: taking the total length L=300mm of the Coanda curved surface 18 as an example, the spacing of the tungsten needle electrodes 29 is 5-25mm, the thickness of the silicon carbide conductive layer is about 80μm, and the resistivity is 10²Ω·cm; the surface potential gradient is ≤500V / mm (to prevent arc discharge); the ionization region 28 has a tapered flow channel expansion angle θ=8°, which enables the ion wind to accelerate in synergy with the Coanda curved surface 18.

[0045] Coanda surface co-design: Curvature-electric field coupling parameters

[0046] The corona current generated by the ion wind is approximately 2.1~2.4 mA; the ion wind velocity is not less than 4 m / s. The Coanda effect is triggered by the initial momentum of the ion wind (4.5 m / s), and the wall adhesion effect is used to achieve the following: airflow velocity doubling: 4.1 times (theoretical limit 4.8 times), and protection area expansion: 3.2 times.

[0047] In this embodiment, the specific structural layout is as follows: A row of tungsten needles (approximately 0.2 mm in diameter) is mounted on the leading edge of the curved protrusion at the emitter 26, with each needle spaced apart. These tungsten needle electrodes 29 are connected to a high-voltage power supply, and their tips discharge during operation. The collector 27 is made of conductive silicon carbide, used to receive the discharge from the tungsten needle electrodes 29. A conductive silicon carbide layer 34 is deposited on the entire surface of the curved protrusion to ground it. A 20-30 mm gap exists between the tungsten needles and the silicon carbide layer, where air is electrocuted in the ionization region 28, forming an ionized wind. The tungsten needle electrodes 29 point towards the curved protrusion, and the ionized particles adhere to the wall and flow down the Coanda curved surface 18, accelerating as they flow, thus creating an ionized wind. When the ionized wind reaches the curved surface, the curvature effect (Coanda effect) of the surface causes the airflow to accelerate close to the surface, much like water flowing down a slide. The original wind speed of 4 m / s can be increased to nearly 15-20 m / s after passing through a 300 mm long curved surface. Example 7:

[0048] Based on Embodiments 5 and 6, a negative pressure pipe 30 is provided on the vertical enclosure wall 3 near the side of the fully load-bearing movable bracket, such as... Figure 9 As shown, the vertical enclosure wall 3, which is symmetrically arranged on both sides, forms a throat section 31 at the curved protrusion 20. A tapered tube 32 is formed on the front side of the throat section 31 and a tapered tube 33 is formed on the rear side. One end of the negative pressure tube 30 is connected to the throat section 31, and the other end is connected to the inside of the semi-enclosed protective structure, that is, the inside of the dust cover structure 1.

[0049] In this embodiment, based on the principles of fluid dynamics, the vertical enclosure wall 3 is divided into a throat section 31, a converging pipe 32, and a diverging pipe 33. The throat section 31 utilizes the opposing arrangement of curved protrusions 20 to reduce its cross-section. The converging pipe 32 at its front gradually shrinks in cross-section, while the diverging pipe 33 gradually expands in cross-section. When the gas flows in the pipe, the mass flow rate remains constant. The reduced cross-sectional area (throat section 31) increases the flow velocity. The increased flow velocity (throat) leads to a decrease in static pressure, forming a low-pressure zone. Therefore, by connecting the negative pressure pipe 30 to the inside of the dust cover structure 1, the gas inside the dust cover structure 1 can be extracted, thereby achieving the effect described in Embodiment 3, such as displacing the inside of the dust cover structure 1 and preventing internal heat accumulation and temperature rise, without the need for an additional displacement gas source.

[0050] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preventing sand and dust in electrolytic cells based on the Coanda effect, characterized in that, Includes the following steps: S1: A dust cover structure (1) is formed around the periphery of the fully load-bearing mobile bracket, which is in flexible contact with the electrolytic cell (5) or maintains a non-contact gap (11). The dust cover structure (1) forms a semi-enclosed protective structure between the foundation (4) and the electrolytic cell (5). The dust cover structure (1) includes at least a vertical enclosure wall (3) set on the side of the fully load-bearing mobile bracket. The bottom of the vertical enclosure wall (3) is connected to the foundation (4), and the top is in flexible contact with the electrolytic cell (5) or forms a non-contact gap (11). S2: Airflow seal, continuously filling the inner chamber surrounded by the dust cover structure (1) with gas, or forming a gas flow in the body of the dust cover structure (1) and spraying out from the gas jet outlet (16) to generate an air curtain (14), so that the dust cover structure (1) separates the external sand and dust. The dust cover structure (1) is provided with a through-vent (15) formed in the preset gas outflow direction, and the through-vent (15) is provided with a gas jet outlet (16) at least at the gas outflow end. S3: Coanda wall-attached acceleration guides the gas laminar flow to the continuous variable curvature Coanda surface (18). The gradual curvature of the Coanda surface (18) causes the gas to have a wall-attached effect, which increases the gas flow rate and forms a jet gas curtain (14). The ventilation opening (15) forms a gas intake port (19) at the end away from the gas jet outlet (16). The dust cover structure (1) includes vertical enclosure walls (3) set on both sides of the ventilation opening (15). The vertical enclosure walls (3) form a Coanda surface (18) on one side of each other. The Coanda surface (18) includes a curved protrusion (20) formed on the side away from the gas jet outlet (16). The curved protrusion (20) smoothly transitions to the gas jet outlet (16) side to form a slope (21). The opening direction formed by the slopes (21) on both sides faces the gas jet outlet (16).

2. The method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 1, characterized in that, The Coanda surface (18) adopts a continuously variable curvature design, with the curvature radius R gradually changing from 50mm to 200mm.

3. A method for preventing sand and dust in an electrolytic cell based on the Coanda effect, as described in claim 1 or 2, characterized in that, The vertical enclosure has a cavity (17) inside, and the cavity (17) has a slit-shaped airflow nozzle (22) on the front side of the curved protrusion (20) for gas to flow out in the tangential direction.

4. A method for preventing sand and dust in an electrolytic cell based on the Coanda effect, as described in claim 1 or 2, characterized in that, The dust cover structure (1) includes an ion wind generating module (24), which includes an electrode array (25). The electrode array (25) is provided with an emitter (26) and a collector (27). An ionization region (28) is set between the emitter (26) and the collector (27). The emitter (26) includes tungsten needle electrodes (29) arranged on the front side of the curved protrusion (20). The collector is a conductive silicon carbide layer (34) plated on the protrusion surface of the Coanda curved surface (18), which is grounded to form an electric field gradient. The ionization region (28) is provided with an electrode spacing of 20-30 mm. Corona discharge induces the formation of ion wind. The ion wind flows through the Coanda curved surface (18) and is further accelerated by the pressure gradient generated by its curvature.

5. A method for preventing sand and dust in an electrolytic cell based on the Coanda effect, as described in claim 1 or 2, characterized in that, A negative pressure pipe (30) is provided on the vertical enclosure wall (3) near the side of the fully load-bearing mobile bracket. The vertical enclosure walls (3) arranged symmetrically on both sides form a throat section (31) at the curved protrusion (20). A tapered pipe (32) is formed on the front side of the throat section (31) and a tapered pipe (33) is formed on the rear side. One end of the negative pressure pipe (30) is connected to the throat section (31), and the other end is connected to the inside of the semi-enclosed protective structure.

6. The method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 1, characterized in that, The dust cover structure (1) is made of transparent and visible material.

7. The method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 1, characterized in that, The dust cover structure (1) is made of a material resistant to alkali corrosion.

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