Composite multi-body hydrodynamic cavitation device

Abstract

The present invention discloses a composite multi-body hydrodynamic cavitation device, which includes an inlet outer casing. The bottom of the inlet outer casing is fixedly connected to an outlet outer casing. The inlet outer casing and the outlet outer casing are hollow inside. A spiral cone body is arranged inside the inlet outer casing. A cavitation generator is provided at the bottom of the spiral cone body. The cavitation generator is located inside the inlet outer casing. A stepped hydrophobic body is fixedly connected to the bottom of the cavitation generator. The stepped hydrophobic body is located inside the outlet outer casing. After the fluid enters the device from the inlet outer casing, due to the guiding action of the spiral cone body, it flows into the spiral cone body to form a jet and enters the cavity between the cavitation generator and the inlet outer casing. The fluid forms a swirling flow around the outer wall of the cavitation generator, making the dissolution of sewage solutes more sufficient, reducing the TDS and TSS in the fluid, so as to improve the efficiency of degrading organic wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrodynamic cavitation, and particularly to a composite multi-body hydrodynamic cavitation device. Background Art

[0002] The most serious problem currently existing in the water environment is water body organic pollution, especially persistent and difficult-to-degrade organic pollutants. Such organic pollutants have characteristics such as strong toxicity, great treatment difficulty, and long-term nature, posing a serious threat to people's health. Therefore, the degradation technology of persistent and difficult-to-degrade organic pollutants in water bodies has attracted much attention from the environmental protection circles at home and abroad. Among the industrial wastewater discharges in China, organic dye wastewater accounts for the majority. The traditional treatment processes for difficult-to-degrade organic substances are already difficult to adapt to the current increasing dye wastewater. Developing an efficient and energy-saving device for degrading organic dye wastewater is of great significance.

[0003] Cavitation technology can be divided into hydrodynamic cavitation, ultrasonic cavitation, photo-induced cavitation, etc. Its principle is a series of phenomena such as the generation, growth, expansion, contraction, and finally collapse of cavitation bubbles caused by the vaporization that occurs when the local pressure inside the liquid decreases to the current saturated vapor pressure of the liquid. Hydrodynamic cavitation is that the liquid passes through a fixed mechanical structure, and under the limitation of the mechanical structure, the local pressure of the liquid rapidly decreases. When the local pressure drops to the saturated vapor pressure of the current liquid temperature, vaporization will occur, thereby cavitation occurs. When hydrodynamic cavitation occurs, mechanical effects and chemical effects, etc. will be generated. The huge shear force and a large number of hydroxyl free radicals generated by the collapse of cavitation bubbles can break the carbon chains of some macromolecules and rupture the cell walls of microorganisms, which achieves the purpose of degrading organic pollutants and killing microorganisms. Hydrodynamic cavitation has obvious effects in the application of wastewater, such as applications in dye degradation, solvent degradation, ammonia nitrogen removal, etc. Hydrodynamic cavitation technology mainly includes vortex cavitation technology and jet cavitation technology. Comparing the two technologies, the vortex cavitation technology can generate cavitation without too high an inlet pressure, meeting the energy-saving requirements. Therefore, the vortex cavitation technology has great development potential and broad application prospects in degrading toxic and difficult-to-degrade organic wastewater.

[0004] The application of hydrodynamic vortex cavitation technology in the treatment of organic difficult-to-degrade wastewater is relatively backward. Therefore, there is an urgent need for a new type of composite multi-body hydrodynamic cavitation device to solve the above problems. Summary of the Invention

[0005] The object of the present invention is to provide a composite multi-body hydrodynamic cavitation device to solve the problems existing in the prior art.

[0006] To achieve the above object, the present invention provides the following solution: The present invention provides a composite multi-body hydrodynamic cavitation device, including an inlet housing, the bottom of the inlet housing is fixedly connected with an outlet housing, the inlet housing and the outlet housing are hollow, a spiral cone is arranged in the inlet housing, a cavitation generator is arranged at the bottom of the spiral cone, the cavitation generator is located in the inlet housing, and a stepped hydrophobic body is fixedly connected to the bottom of the cavitation generator, and the stepped hydrophobic body is located in the outlet housing.

[0007] Preferably, a flow guiding surface is arranged on the top surface of the spiral cone, a shunt cone is arranged on the top surface of the flow guiding surface, spiral cone narrow slit inlets are symmetrically arranged on both sides of the top surface of the spiral cone respectively, spiral cone narrow slit outlets are symmetrically arranged on both sides of the bottom surface of the spiral cone, the spiral cone narrow slit inlets and the spiral cone narrow slit outlets on the same side of the spiral cone are communicated, and the spiral cone narrow slit outlets are respectively located on both sides of the cavitation generator.

[0008] Preferably, the top surface of the cavitation generator is fixedly connected to the bottom surface of the spiral cone, a cavitation generator jet cavity is arranged in the center of the cavitation generator, a plurality of spiral flow channel outlets are communicated with the cavitation generator jet cavity, a spiral flow channel inlet is arranged on the side far away from the cavitation generator of the spiral flow channel outlet, and an eddy current cavity is arranged between the spiral flow channel outlet and the spiral flow channel inlet.

[0009] Preferably, a plurality of lateral inlets are arranged at the bottom of the cavitation generator, a plurality of lateral outlets are arranged at the bottom of the cavitation generator, and the lateral inlets and the lateral outlets on the same side of the cavitation generator are communicated.

[0010] Preferably, the area of the spiral flow channel inlet is 42.1 mm 2 , and the area of the spiral flow channel outlet is 1 mm 2 .

[0011] Preferably, the area of the lateral inlet is 6 mm 2 , and the area of the lateral outlet is 6.55 mm 2 .

[0012] The present invention discloses the following technical effects: After the fluid enters the device from the inlet housing, due to the guiding effect of the spiral cone, it flows into the spiral cone to form a jet and enters the cavity between the cavitation generator and the inlet housing, and the fluid forms a swirling flow around the outer wall of the cavitation generator, making the dissolution of sewage solutes more sufficient, reducing the TDS and TSS in the fluid, so as to improve the efficiency of degrading organic wastewater. Description of the Drawings

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0014] Figure 1 Structural schematic diagram of the composite multi-body hydrodynamic cavitation device of the present invention;

[0015] Figure 2 Structural schematic diagram of the spiral cone;

[0016] Figure 3 Structural schematic diagram of the bottom surface of the spiral cone;

[0017] Figure 4 Structural schematic diagram of the cavitation generator;

[0018] Figure 5 Structural schematic diagram of the bottom hole structure of the cavitation generator;

[0019] Figure 6 Structural schematic diagram of the top hole structure of the cavitation generator;

[0020] Figure 7 Distribution diagram of the relative velocity gradient of the fluid in the cavitation cross-section;

[0021] Figure 8 Distribution diagram of the pressure gradient of the fluid in the cavitation cross-section;

[0022] Figure 9 Distribution diagram of the pressure gradient of the fluid at the cavitation chamber;

[0023] Detailed implementation manners

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0025] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Referring to Figures 1-9 , the present invention provides a composite multi-body hydrodynamic cavitation device, including an inlet housing 1, the bottom of the inlet housing 1 is fixedly connected to an outlet housing 2, the interiors of the inlet housing 1 and the outlet housing 2 are hollow, a spiral cone 3 is provided inside the inlet housing 1, a cavitation generator 4 is provided at the bottom of the spiral cone 3, the cavitation generator 4 is located inside the inlet housing, and the bottom of the cavitation generator 4 is fixedly connected to a stepped hydrophobic body 5, and the stepped hydrophobic body 5 is located inside the outlet housing 2.

[0027] After the fluid enters the device from the inlet housing 1, due to the guiding action of the spiral cone 3, it flows into the spiral cone 3 to form a jet and enters the cavity between the cavitation generator 4 and the inlet housing 1. The fluid forms a swirling flow around the outer wall of the cavitation generator 4, making the dissolution of sewage solutes more sufficient, reducing the TDS and TSS in the fluid, so as to improve the efficiency of degrading organic wastewater.

[0028] In a further optimized solution, a guiding surface 6 is provided on the top surface of the spiral cone 3, a splitting cone 7 is provided on the top surface of the guiding surface 6, spiral cone narrow-slit inlets 8 are symmetrically provided on both sides of the top surface of the spiral cone 3 respectively, spiral cone narrow-slit outlets 9 are symmetrically provided on both sides of the bottom surface of the spiral cone 3, the spiral cone narrow-slit inlet 8 and the spiral cone narrow-slit outlet 9 on the same side of the spiral cone 3 are communicated, and the spiral cone narrow-slit outlets 9 are respectively located on both sides of the cavitation generator 4.

[0029] In a further optimized solution, the top surface of the cavitation generator 4 is fixedly connected to the bottom surface of the spiral cone 3. A cavitation generator jet cavity 10 is provided at the center inside the cavitation generator 4. The cavitation generator jet cavity 10 is communicated with a plurality of spiral flow channel outlets 11. A spiral flow channel inlet 12 is provided on the side of the spiral flow channel outlet 11 away from the cavitation generator 4, and an eddy current cavity 13 is provided between the spiral flow channel outlet 11 and the spiral flow channel inlet 12.

[0030] In a further optimized solution, a plurality of lateral inlets 14 are provided at the bottom of the cavitation generator 4, and a plurality of lateral outlets 15 are provided at the bottom of the cavitation generator 4. The lateral inlets 14 and the lateral outlets 15 on the same side of the cavitation generator 4 are communicated.

[0031] When the fluid enters the lateral inlet 14 at the bottom of the cavitation generator 4, the slit of the lateral inlet 14 causes the fluid to form a tangential jet again. The gas nuclei in the fluid are blocked by the slit and collapse. At this time, the velocity of the fluid increases significantly. After passing through the lateral outlet at the bottom of the cavitation generator 4, the direction of the fluid changes suddenly and enters the vortex cavity 13 where cavitation occurs. The vortex motion in the vortex cavity 13 promotes the generation of a low-pressure area in the central region of the vortex cavity 13. The pressure of the fluid is less than the air separation pressure, resulting in the release of a large amount of air in the fluid and the generation of a large number of air bubbles. Whether the air bubbles can be generated normally is the key to whether cavitation can be achieved. Therefore, four radially distributed vortex cavities 13 are set up to provide better conditions for generating cavitation.

[0032] The top of the vortex cavity 13 is connected to a spiral flow channel leading to the central cavity, that is, the jet cavity 10 of the cavitation generator. The spiral flow channel 16 starts from the side wall of the vortex cavity 13, and at this time, the orifice cross-sectional area is the largest. As the fluid flows towards the jet cavity 10 of the cavitation generator, the cross-sectional area of the flow channel gradually decreases along the streamline direction. According to the relationship between the fluid and the flow area, the velocity of the fluid will increase sharply due to the change of the outlet area when it flows out of the outlet 11 of the spiral flow channel. It can be known from the Bernoulli equation that a local low pressure will be generated at the outlet, resulting in the expansion of the cavitation bubbles flowing through the fluid. When the fluid flows out of the outlet 11 of the spiral flow channel and enters the jet cavity 10 of the cavitation generator, the cross-sectional area suddenly increases, resulting in a pressure rise. The internal and external pressures of the cavitation bubbles are unbalanced, causing them to collapse, and the cavitation effect occurs. The instantaneous high temperature and high pressure cause the O-H bond of water molecules to break, generating -H and -OH free radicals. Subsequently, the OH free radicals react chemically with organic pollutants to achieve the purpose of degrading organic matter.

[0033] The fluids jet out from the four spiral flow channels 16 intersect and collide with each other. The tangential intersection and collision of the jets can convert 60% - 80% of the ineffective kinetic energy in the jets into collision and fragmentation energy, tearing the organic pollutants again. At this time, there may still be some cavitation bubbles in the jets that have not collapsed. Under the action of the jets, the fluid flows downward and enters the cavity between the stepped hydrophobic body 5 and the outlet housing 2. The stepped water body is in a sawtooth stepped shape, which acts on the water flow with multiple cross-sectional area mutations, and also makes the cavitation bubbles collapse as much as possible during multiple area mutations.

[0034] For a further optimized scheme, the area of the spiral flow channel inlet 12 is 42.1 mm 2 , and the area of the spiral flow channel outlet 11 is 1 mm 2 .

[0035] For a further optimized scheme, the area of the lateral inlet 14 is 6 mm 2 , and the area of the lateral outlet 15 is 6.55 mm 2 .

[0036] The fluid flows from the vortex chamber to the spiral flow channel. Among them, the cross-section of the spiral flow channel is the largest at the vortex chamber body 13 and the smallest at the jet chamber. According to the relationship between the fluid and the flow area, when the fluid flows to the jet chamber, the gradient of the flow velocity increases due to the gradually decreasing area. While the fluid velocity is continuously increasing, its turbulence intensity is also greatly enhanced, thereby generating a cavitation effect. At this time, the relative velocity at the end of the spiral flow channel exceeds 31 m / s.

[0037] The fluid passes through the spiral flow channel with a gradually decreasing cross-sectional area, and the velocity gradually increases. According to Bernoulli's equation, a local low pressure will be generated at the outlet 11 of the spiral flow channel. When the pressure is lower than the saturation vapor pressure of the liquid at the current temperature, vaporization occurs and more gas nuclei are generated, resulting in the continuous expansion of the gas nuclei flowing through with the fluid, and the cavitation bubbles are fully developed. When the fluid flows out of the flow channel and enters the jet chamber 10 of the cavitation generator, the cross-sectional area suddenly increases, resulting in a pressure rise, and the internal and external pressures of the cavitation bubbles are unbalanced, causing them to collapse, thereby generating a cavitation effect.

[0038] Due to the sudden change in the pipeline through which the fluid flows, the flow velocity increases sharply, the pressure drops significantly, and the kinetic energy also increases. Then the pressure at the end of the spiral flow channel is the lowest. At this stage, there is a huge resistance loss in the turbulent pulsation, so that there will be a huge energy difference when the jet flow at the end of the spiral flow channel flows to the jet chamber. At the connection between the spiral flow channel and the jet chamber, local energy is released, and a large number of gas nuclei (cavitation bubbles) will appear in the liquid, forming a two-phase flow of vapor and liquid coexisting. Among them, the gas nucleus generation area is at the critical point of the saturation vapor pressure, corresponding to Figure 9 the pressure distribution at the cavitation occurrence point. The vapor volume fraction is one of the indicators to measure the occurrence of cavitation. However, if the gas nucleus density generated by the cavitation in the flow field is too large, resulting in the mutual contact of the gas nuclei, it will play a buffering effect at the moment when the gas nuclei break, resulting in a significant weakening of the cavitation intensity; the gas nuclei may also merge with each other to form a cavitation cloud, causing the incomplete collapse or shedding of the cavitation bubbles. This supercavitation phenomenon is also the reason why the cavitation intensity fails to meet expectations.

[0039] In the application of cavitation technology in sewage degradation, its chemical effect and mechanical effect are the main ones. While in the application of removing refractory organic compounds, its chemical effect plays a major role. Among them, there are mainly three reaction routes for the degradation of organic compounds by the cavitation chemical effect: free radical oxidation, supercritical water oxidation, and high-temperature pyrolysis. During the cavitation process, the dominant position of each reaction route is affected by the different positions of gas nuclei and the properties of organic pollutants. In particular, in the interfacial layer region near the bubble wall, when the solute concentration is high, high-temperature pyrolysis and supercritical water oxidation are the main processes; when the concentration is low, free radical oxidation is the main process. Four small slits are designed at the bottom of the spiral cone 3 to increase the fluid velocity to 10 m / s, thereby increasing the turbulent kinetic energy of the fluid, making the solute in the sewage dissolve more fully and making it possible to increase the solute concentration; the spiral cone 3 is designed to change the direction of the fluid entering the cavity, so that the fluid moves around the outer wall of the cavitation chamber to form a swirl, in order to increase the gas content rate of the fluid.

[0040] Four radial slits are designed at the entrance of the eddy current cavity 13, which can greatly increase the fluid velocity to 18.6 m / s and form an eddy current motion in the eddy current cavity 13, so as to form a low-pressure area in the central region of the eddy current cavity, making the pressure of the fluid less than the air separation pressure and generating a large number of air bubbles. A stepped water drainage port is designed at the outlet, aiming at the cavitation bubbles that have not collapsed in the cavitation chamber to collapse during multiple area mutations, so as to improve the efficiency of single-pass cavitation.

[0041] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0042] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. Composite multi-body hydrodynamic cavitation device, characterized in that: It includes an inlet housing (1), the bottom of the inlet housing (1) is fixedly connected to an outlet housing (2), the interior of the inlet housing (1) and the outlet housing (2) is hollow, a spiral cone (3) is provided inside the inlet housing (1), a cavitation generator (4) is provided at the bottom of the spiral cone (3), the cavitation generator (4) is located inside the inlet housing (1), the bottom of the cavitation generator (4) is fixedly connected to a stepped hydrophobic body (5), and the stepped hydrophobic body (5) is located inside the outlet housing (2). The top surface of the spiral cone (3) is provided with a guiding surface (6), the top surface of the guiding surface (6) is provided with a splitting cone (7), spiral cone narrow-slit inlets (8) are symmetrically provided on both sides of the top surface of the spiral cone (3), spiral cone narrow-slit outlets (9) are symmetrically provided on both sides of the bottom surface of the spiral cone (3), the spiral cone narrow-slit inlets (8) and the spiral cone narrow-slit outlets (9) on the same side of the spiral cone (3) are connected, and the spiral cone narrow-slit outlets (9) are respectively located on both sides of the cavitation generator (4). The top surface of the cavitation generator (4) is fixedly connected to the bottom surface of the spiral cone (3), a cavitation generator jet cavity (10) is provided at the center inside the cavitation generator (4), a number of spiral flow channel outlets (11) are connected to the cavitation generator jet cavity (10), the spiral flow channel outlets (11) are connected to a spiral flow channel inlet (12) through a spiral flow channel (16), and the spiral flow channel inlet (12) is connected to a vortex cavity (13). A number of lateral inlets (14) are provided at the bottom of the cavitation generator (4), a number of lateral outlets (15) are provided at the bottom of the cavitation generator (4), the lateral inlets (14) and the lateral outlets (15) on the same side of the cavitation generator (4) are connected, and the lateral outlets (15) are connected to the vortex cavity (13). After the fluid enters the interior of the device from the inlet housing (1), due to the guiding effect of the spiral cone (3), it flows into the spiral cone (3) to form a jet and enters the cavity between the cavitation generator (4) and the inlet housing (1). When the fluid enters the lateral inlets (14) at the bottom of the cavitation generator (4), the slits of the lateral inlets (14) cause the fluid to form a tangential jet again. After passing through the lateral outlets (15) at the bottom of the cavitation generator (4), the fluid direction suddenly changes and enters the vortex cavity (13) of the cavitation generator (4). The top of the vortex cavity (13) is connected to a spiral flow channel (16) leading to the central cavity, that is, the cavitation generator jet cavity (10). The spiral flow channel (16) starts from the side wall of the vortex cavity (13). As the fluid flows towards the cavitation generator jet cavity (10), the cross-sectional area of the spiral flow channel (16) gradually decreases along the streamline direction. When the fluid flows out of the spiral flow channel outlets (11), the sudden change in the area of the spiral flow channel outlets (11) causes a sharp increase in the flow velocity of the fluid.

2. The composite multi-body hydrodynamic cavitation device according to claim 1, characterized in that: The area of the spiral flow channel inlet (12) is 42.1 mm 2 The outlet area of the spiral channel (11) is 1 mm 2 .

3. The composite multi-body hydrodynamic cavitation device according to claim 1, wherein: The area of the side inlet (14) is 6 mm 2 , and the area of the side outlet (15) is 6.55 mm 2 .

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