A nanoscale cavitation generator and a design method thereof

Abstract

The application provides a nanoscale cavity generating device and a design method thereof, comprising a shell, an air inlet and a nozzle; a mixing chamber is arranged in the shell, a water suction chamber is arranged outside the mixing chamber, and the water suction chamber is used for communicating with a liquid medium; the mixing chamber and the water suction chamber are communicated through a guide hole, which is used for forming a rotational flow when the liquid medium enters the mixing chamber; the mixing chamber is provided with the air inlet, which is used for providing a gas medium into the mixing chamber; the liquid medium and the gas medium are mixed in the mixing chamber to generate nanoscale cavities; and the nozzle is arranged on the mixing chamber and used for outputting the nanoscale cavities. The mixed fluid of the application increases in speed after passing through the nozzle, and the mixed fluid leaving the nozzle directly impacts water wrapped outside the device, so that nanobubbles are formed under the impact and stored in the liquid.

Description

Technical Field

[0001] This invention relates to bubble generating devices, and particularly to a nanoscale cavitation generating device and its design method. Background Technology

[0002] Nanobubbles possess physical and chemical properties not found in conventional bubbles: long existence time, high surface energy, negative surface charge, high gas-liquid mass transfer rate, and the ability to spontaneously generate free radicals. These properties endow treated nanobubbles with unique functions, making them promising for widespread application in industrial and agricultural production, wastewater treatment, and hygiene.

[0003] Currently, there are four main methods for generating micro and nano bubbles: ultrasonic cavitation, hydrodynamic cavitation, optical cavitation, and microparticle cavitation. Among them, hydrodynamic cavitation equipment has simple requirements and is a commonly used method for generating micro and nano bubbles.

[0004] A Chinese patent discloses a micro / nano bubble generator. This device uses the combined action of a jet and a diffusion chamber to vigorously mix a gas-liquid mixture. Then, high-speed water flow in the diffusion chamber impacts the air bubbles, generating micro / nano bubbles. Increasing the flow rate intensifies the mixing of water and gas, and expanding the mixing volume allows the high-speed water flow to impact the gas, resulting in a greater number of micro / nano bubbles and higher efficiency. Due to the special cross-sectional area variation of the jet channel, the pressure and velocity of the gas-liquid mixture constantly change, achieving mixing. Further changes in the cross-sectional area of ​​the bubble-generating channel cause the gas and water to impact each other, rapidly forming a large number of bubbles. Another Chinese patent discloses a nanobubble generator that uses a compression cylinder to continuously pressurize and depressurize the liquid containing bubbles, compressing and expanding the liquid. When the pressure increases, the bubbles are compressed, causing them to shrink in volume; when the pressure decreases, they expand, causing them to enlarge in volume. During this process, the bubbles continuously split into new bubbles, reducing their diameter, thus becoming nanobubbles within the liquid. A third Chinese patent discloses a nanobubble generator that can filter impurities mixed in water and gas sources, preventing accumulation and clogging that could affect the device's lifespan and effectiveness.

[0005] Existing patents mainly use large-scale, externally powered bubble generating devices as nanobubble generators. These devices have many components and are bulky, making them difficult to use in environments with smaller requirements. Furthermore, they place high demands on the installation and operation of the devices. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a nanoscale cavitation generator and its design method. A high-pressure fluid can rotate at high speed within a mixing chamber. This high-speed rotation of the liquid provides a pathway for the gas along the central axis of the mixing chamber, allowing the gas to pass through and converge at the nozzle inlet. During entry into the nozzle, the liquid and gas are mutually compressed and thoroughly mixed to form a preliminary mixed fluid.

[0007] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0008] A nanoscale cavitation generator includes a housing, an air inlet, and a nozzle. The housing contains a mixing chamber, and an external water absorption chamber is provided for connecting a liquid medium. The mixing chamber and the water absorption chamber are connected via a guide hole to allow the liquid medium to enter the mixing chamber and form a swirling flow. The mixing chamber contains an air inlet for supplying a gaseous medium. The liquid and gaseous media mix within the mixing chamber to generate nanoscale cavitation. A nozzle is installed on the mixing chamber to output the nanoscale cavitation.

[0009] Furthermore, the water absorption chamber is an annular space, and the water absorption chamber is coaxial with the mixing chamber; the axis of the air inlet in the mixing chamber is coaxial with the mixing chamber, which is used to inject the gas medium into the center of the swirling liquid medium.

[0010] Furthermore, the housing is provided with a water inlet, the ratio of the inlet cross-section to the outlet cross-section of the water inlet is 2:1 to 3:1; the outlet of the water inlet is connected to the suction chamber. Simultaneously, the water inlet can effectively reduce the flow loss of high-pressure water before it enters the mixing chamber.

[0011] Furthermore, several sets of guide holes are evenly distributed axially on the wall of the mixing chamber, and several guide holes are evenly distributed circumferentially in each set of guide holes; the distance from the guide hole to the bottom of the mixing chamber is greater than 3 / 4 of the height of the mixing chamber, in order to avoid water deposition at the bottom of the device; the line connecting the center of the guide hole on the outer wall of the mixing chamber to the axis of the mixing chamber in the circumferential direction forms an angle α with the axis of the guide hole in the range of 30° to 60°, which enables the water flowing into the mixing chamber to rotate at high speed inside the mixing chamber.

[0012] Furthermore, an air inlet is installed at the center of the bottom of the mixing chamber, and a concave space is provided outside the center of the bottom of the mixing chamber, so that the cross-section of the bottom of the mixing chamber is ω-shaped, which reduces the impact of water on the wall when the water rotates in the mixing chamber and makes it smoother; the air inlet extends out of the bottom surface of the mixing chamber; the extended part of the air inlet is spherical or frustum-shaped, which is used to prevent water from accumulating at the air inlet outlet in the initial state, affecting the airflow speed or even blocking the air inlet.

[0013] Furthermore, the ratio of the volume of the gas medium entering the mixing chamber to the volume of the liquid medium entering the mixing chamber is between 1 / 50 and 1 / 10.

[0014] A design method for a nanoscale cavitation generator, given the number n and diameter d of the target micro / nano bubbles. i The intake air volume Q in the mixing chamber is determined according to the following formula. a The liquid inlet volume Q in the mixing chamber L :

[0015]

[0016] 50Q a ≥Q L ≥10Q a

[0017] In the formula:

[0018] n represents the number of target micro / nano bubbles;

[0019] d i The target micro / nano bubble diameter;

[0020] Q a Intake volume, L / s;

[0021] t is the ventilation time, in seconds;

[0022] Q L The influent flow rate is expressed in L / s.

[0023] k5 is the fifth empirical parameter.

[0024] Furthermore, the number n and diameter d of the target micro / nano bubbles are known. i The inlet diameter of the inlet is determined according to the following formula:

[0025] d1 = 2ck3n × 10 -6

[0026] In the formula:

[0027] d1 is the inlet diameter of the water inlet, in cm;

[0028] c represents the unit length, which is 1 cm.

[0029] k3 is the third empirical parameter, 0.9≤k3≤1.1;

[0030] Determine the diameter of the guide hole using the following formula:

[0031]

[0032] In the formula:

[0033] d3 is the diameter of the guide hole, in cm;

[0034] j represents the number of guide holes;

[0035] k1 is the first empirical parameter.

[0036] Furthermore, the water inlet velocity v2 of the guide hole satisfies the following condition with respect to α:

[0037]

[0038] In the formula:

[0039] r2 is the radius of the mixing chamber, in cm;

[0040] α is the angle formed between the line connecting the center of the guide hole located on the outer wall of the mixing chamber to the axis of the mixing chamber in the circumferential direction and the axis of the guide hole;

[0041] m is the mass of the liquid in the mixing chamber;

[0042] g is the acceleration due to gravity;

[0043] v2 is the water inlet velocity through the guide hole, in m / s. Sure.

[0044] Furthermore, the intake diameter d4 of the air intake nozzle is calculated according to the following formula:

[0045]

[0046] v3=φv1

[0047]

[0048] In the formula:

[0049] d4 is the diameter of the air intake port, in cm;

[0050] v3 is the intake speed, in m / s;

[0051] φ is the gas-liquid velocity ratio.

[0052] v1 is the velocity at the inlet of the water inlet, in m / s.

[0053] The diameter of the mixing chamber is d2 = k2d1, where k2 is a second empirical parameter;

[0054] The height of the mixing chamber is h = k4d2, where k4 is the fourth empirical parameter.

[0055] The beneficial effects of this invention are as follows:

[0056] 1. The nanoscale cavitation generator and its design method described in this invention enable a high-pressure fluid to rotate at high speed within a mixing chamber under the structural action of the device itself. This high-speed rotation of the liquid provides a pathway for the gas along the central axis of the mixing chamber, allowing the gas to pass through the chamber and converge at the nozzle inlet. During entry into the nozzle, the liquid and gas are mutually compressed and thoroughly mixed to form a preliminary mixed fluid. The velocity of the mixed fluid increases after passing through the nozzle. The mixed fluid leaving the nozzle directly impacts the water surrounding the device, thereby forming nanobubbles within the liquid under the impact. This device has a simple structure, is easy to operate, has a small size, requires no external power source, and has low energy consumption.

[0057] 2. The nanoscale cavitation generator and its design method of the present invention feature a symmetrical semi-open inlet, with the ratio of the inlet cross-section to the outlet cross-section being 2:1 to 3:1. The outlet of the inlet is connected to the suction chamber. This symmetrical semi-open design allows for more uniform flow of high-pressure water before it enters the mixing chamber. Simultaneously, the inlet effectively reduces flow losses of the high-pressure water before it enters the mixing chamber.

[0058] 3. The nanoscale cavitation generator and its design method of the present invention, by providing a concave space outside the center of the bottom of the mixing chamber, makes the cross-section of the bottom of the mixing chamber ω-shaped, so that the water reduces the impact with the wall when rotating in the mixing chamber and thus flows more smoothly; the air inlet extends out of the bottom surface of the mixing chamber; the protruding part of the air inlet is spherical or frustum-shaped, which is used to prevent the water flow from accumulating at the air inlet outlet in the initial state, affecting the airflow speed or even blocking the air inlet.

[0059] 4. The nanoscale cavitation generator and its design method described in this invention can determine the air intake Q in the mixing chamber by the number n and diameter di of the target micro / nano bubbles. a The liquid inlet volume Q in the mixing chamber L This provides a basis for alternative designs. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For those skilled in the art, it is obvious that other drawings can be obtained from these drawings without creative effort.

[0061] Figure 1 This is a schematic diagram of the nanoscale cavitation generator described in this invention.

[0062] Figure 2 for Figure 1 AA sectional view.

[0063] Figure 3a This is a schematic diagram of the nozzle design 1 described in this invention.

[0064] Figure 3b This is a schematic diagram of the nozzle design 2 described in this invention.

[0065] Figure 3c This is a schematic diagram of the nozzle design 3 described in this invention.

[0066] Figure 4a This is a schematic diagram of the air intake nozzle design 1 according to the present invention.

[0067] Figure 4b This is a schematic diagram of the air intake nozzle design 2 described in this invention.

[0068] Figure 5a The nanoscale cavitation generator described in Example 1 Figure 1 BB cross-sectional view.

[0069] Figure 5b The nanoscale cavitation generator described in Example 2 Figure 1 BB cross-sectional view.

[0070] Figure 6 This is a particle size distribution of bubbles obtained from the sample experiment.

[0071] Figure 7 This is a bubble distribution diagram of the sample.

[0072] In the picture:

[0073] 100-Top cover; 200-Sealed outer shell; 300-Mixing chamber; 301-Guide hole; 400-Air inlet; 401-Air inlet nozzle; 500-Nozzle; 600-Water suction chamber; 601-Water inlet. Detailed Implementation

[0074] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0075] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0076] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0077] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0078] like Figure 1 and Figure 2 As shown, the nanoscale cavitation generator of the present invention includes a housing, an air inlet 400, and a nozzle 500.

[0079] The housing includes a top cover 100, a sealed outer shell 200, and a mixing chamber housing. The materials of the sealed outer shell 200, the top cover 100, and the mixing chamber housing should be transparent or semi-transparent as much as possible to facilitate observation of the internal reaction conditions of the device.

[0080] The top cover 100 is connected to both the sealing shell 200 and the mixing chamber shell. The mixing chamber shell and the top cover 100 together form a mixing chamber 300. The top cover 100, the sealing shell 200, and the outer wall of the mixing chamber shell together form a water absorption chamber 600. The top cover 100 provides fixed support for the mixing chamber 300, and a nozzle is embedded in the center of the top cover 100 as the outlet for the target product leaving the device. The sealing shell 200 isolates the entire device from the outside environment. Since the device operates underwater, the shell prevents external water from affecting its normal operation. The bottom of the sealing shell 200 has an inlet 601 for the water absorption chamber 600. The water absorption chamber 600 is used to connect the liquid medium; the mixing chamber 300 is connected to the water absorption chamber 600 through the guide hole 301, which is used to form a swirling flow when the liquid medium enters the mixing chamber 300; the mixing chamber 300 is provided with an air inlet 400, which is used to provide a gas medium into the mixing chamber 300; the liquid medium and the gas medium generate nanoscale cavitation bubbles after mixing in the mixing chamber 300.

[0081] like Figure 2 As shown, the water absorption chamber 600 is an annular space, and the water absorption chamber 600 is coaxial with the mixing chamber 300. The axis of the air inlet 400 inside the mixing chamber 300 is coaxial with the mixing chamber 300, which is used to inject the gas medium into the center of the swirling liquid medium. Several sets of guide holes are evenly distributed axially on the wall surface of the mixing chamber 300, and several guide holes are evenly distributed circumferentially in each set of guide holes. The distance from the guide hole to the bottom of the mixing chamber 300 is greater than 3 / 4 of the height of the mixing chamber 300 to avoid water deposition at the bottom of the device. The line connecting the center of the guide hole 301 on the outer wall of the mixing chamber 300 to the axis of the mixing chamber 300 in the circumferential direction forms an angle α with the axis of the guide hole 301, which is in the range of 30° to 60°, so that the water flowing into the mixing chamber can rotate at high speed inside the mixing chamber.

[0082] like Figure 1 and Figure 2 As shown, the shell is provided with a water inlet 601, which is a symmetrical semi-open type, that is, one end of the annular flow channel is the inlet, and the other end opposite the inlet is a blocking plate, thus turning the annular flow channel into a symmetrical semi-open flow channel. The outlet cross-section of the water inlet 601 is an annular cross-section intersecting with the suction chamber. The symmetrical semi-open water inlet allows the high-pressure water to flow more evenly before entering the mixing chamber. At the same time, the water inlet can effectively reduce the flow loss of high-pressure water before entering the mixing chamber. The ratio of the inlet cross-section to the outlet cross-section of the water inlet 601 is 2:1 to 3:1; the outlet of the water inlet 601 is connected to the suction chamber 600. The flow channel shape of the water inlet 601 is as follows. Figure 5a and Figure 5bAs shown, in an exemplary example, the selected symmetrical semi-open annular inlet structure 601 with a constant radius can improve the velocity vector field inside the suction chamber while meeting design requirements, such as... Figure 5a In another example, the symmetrical semi-open annular inlet 601 uses a flow channel with a gradually changing radius, as shown in Figure 5b.

[0083] An air inlet 401 is installed at the center of the bottom of the mixing chamber 300. A concave space is provided outside the center of the bottom of the mixing chamber 300, making the cross-section of the bottom of the mixing chamber 300 ω-shaped. This reduces the impact of water on the wall when it rotates in the mixing chamber, thus making the flow smoother. The air inlet 401 extends out of the bottom surface of the mixing chamber 300. The extended part of the air inlet 401 is spherical or frustum-shaped to prevent water from accumulating at the air inlet outlet in the initial state, affecting the airflow speed or even blocking the air inlet. Figure 4a As shown, the air intake 401 is designed as a spherical boss; as Figure 4b As shown, the air inlet 401 is designed as a frustum-shaped boss.

[0084] The ratio of the volume of gas medium entering the mixing chamber 300 to the volume of liquid medium entering the mixing chamber 300 is between 1 / 50 and 1 / 10, thus achieving a 10 6 Orders of magnitude of bubbles.

[0085] Working principle:

[0086] In practical applications, the device operates underwater, surrounded by water. High-pressure water enters through the inlet and moves upward through the suction chamber 600. The mixing chamber remains stationary, and the high-pressure water enters through the guide hole 301. The high pressure provides a high initial velocity for the water flow. Due to centrifugal force, the high-speed rotating water flow converges in an area far from the central axis. Simultaneously, due to the fluid converging towards the wall, a region with lower pressure exists at the central axis. The airflow enters the mixing chamber 300 through the air inlet 400 and moves together with the internal water flow. Because other gases have a lower density than liquids, they converge on the central axis under centrifugal force. Similarly, due to the density difference, the gas continuously moves upward along the central axis. Water and airflow continuously enter the mixing chamber 300, and the fluids that enter first are inevitably compressed by the fluids that enter later. Under this action, the airflow and water flow continue to move until they rise to the inlet of the nozzle 500. The water and airflow are then forced into the nozzle 500. As the mixed fluid passes through nozzle 500, its higher static pressure energy is converted into kinetic energy, causing the fluid leaving the nozzle to have a lower pressure and a higher velocity compared to the fluid entering the nozzle. This high-speed mixed fluid leaving the nozzle directly impacts the water surrounding the device. The target product is obtained through this impact.

[0087] Nozzle 500 serves as the channel for fluid to leave the device and is also a crucial component in generating cavitation fluid. Changes in the nozzle's interface can alter the fluid's pressure and velocity, such as... Figure 3a , 3b Figures 3 and 3c are schematic diagrams of three example nozzle shapes. Figure 3a In the process, the nozzle 500 flow channel exhibits linear gradual expansion; Figure 3b In the process, the curvature of the nozzle 500 flow channel gradually increases and expands; Figure 3c In this nozzle 500, the curvature of the flow channel gradually decreases and expands. The nozzle can be implemented in many different forms and is not limited to the embodiments described herein.

[0088] Nozzle 500 is directly connected to the center opening of the top cover. As a key component in the production of the target product, the connection needs to have high sealing performance to withstand the impact of high-pressure fluid. In an exemplary example, a threaded connection, preferably a threaded thread, is used at the connection between nozzle 500 and the top cover to ensure sealing performance. Other thread types that can meet the sealing performance requirements are also available. At the same time, nozzle 500 is the main location where fluid leaves the device and interacts directly with external fluids, and will be subjected to significant forces; therefore, a material with high hardness, such as SUS301, should be used.

[0089] The design method of the nanoscale cavitation generator described in this invention is based on the known number n and diameter d of the target micro / nano bubbles. i The intake air volume Q in the mixing chamber 300 is determined according to the following formula. a The liquid inlet volume Q in the mixing chamber 300 L :

[0090]

[0091] 50Q a ≥Q L ≥10Q a

[0092] In the formula:

[0093] n represents the number of target micro / nano bubbles;

[0094] d i The target micro / nano bubble diameter;

[0095] Q a Intake volume, L / s;

[0096] t is the ventilation time, in seconds;

[0097] Q L The influent flow rate is expressed in L / s.

[0098] k5 is the fifth empirical parameter; generally, k5 is taken as 0.01-0.02, and a value of 0.02 is recommended.

[0099] Given the number n and diameter d of the target micro / nano bubbles. i The inlet diameter of inlet 601 is determined according to the following formula:

[0100] d1 = 2k3n × 10 -6

[0101] In the formula:

[0102] d1 is the inlet diameter of inlet 601, in cm;

[0103] k3 is the third empirical parameter; the range of k3 is 0.9≤k3≤1.1, and it is generally recommended to choose k3=1.

[0104] Determine the diameter of guide hole 301 using the following formula:

[0105]

[0106] In the formula:

[0107] d3 is the diameter of guide hole 301, in cm;

[0108] j represents the number of guide holes 301;

[0109] k1 is the first empirical parameter, and the range of k1 is 0.75≤k1≤1. It is generally recommended to choose k1=0.75.

[0110] The water inlet velocity v2 of the guide hole 301 satisfies the following condition with respect to α:

[0111]

[0112] In the formula:

[0113] r2 is the radius of the mixing chamber, in cm;

[0114] α is the angle formed between the line connecting the center of the guide hole 301 located on the outer wall of the mixing chamber 300 to the axis of the mixing chamber 300 in the circumferential direction and the axis of the guide hole 301;

[0115] m is the mass of the liquid in the mixing chamber 300;

[0116] g is the acceleration due to gravity;

[0117] v2 represents the water inlet velocity at guide hole 301, in m / s. Sure.

[0118] The intake diameter d4 of the 401 air intake nozzle is calculated using the following formula:

[0119]

[0120]

[0121]

[0122] In the formula:

[0123] d4 is the diameter of the air intake port of the 401 air intake nozzle, in cm;

[0124] v3 is the intake speed, in m / s;

[0125] The gas-liquid velocity ratio,

[0126] v1 is the velocity at the inlet of water inlet 601, in m / s.

[0127] The diameter of the mixing chamber 300 is d2 = k2d1, where k2 is a second empirical parameter; 1.5 ≤ k2 ≤ 2.5, and it is generally recommended to choose k2 = 2.

[0128] The height h of the mixing chamber 300 is h = k4d2, where k4 is the fourth empirical parameter. 1.5 ≤ k4 ≤ 2.5, and k4 = 2 is generally recommended.

[0129] Example

[0130] The number of target micro / nano bubbles, n, is known to be 1 × 10⁻⁶. 6 The target micro / nano bubble diameter d i It is 20 nanometers.

[0131] Calculation of the inlet diameter d1 of the suction chamber:

[0132] d1 = 2k3n × 10 -6 =2 (cm)

[0133] Intake volume Q a calculate:

[0134]

[0135] The recommended value is k5 = 0.02, Q a =0.0492 (L / s).

[0136] Inflow rate Q L calculate:

[0137] Calculate Q using the minimum influent flow rate that meets the requirements. L =10Q a ≈0.5 (L / s).

[0138] Calculation of wall opening diameter d3:

[0139]

[0140] Taking the recommended value k1 = 0.75, then d3 = 0.5cm. j is set to 12;

[0141] Calculation of water inflow velocity v2 through wall opening:

[0142]

[0143] The calculated value is v2 = 2 (m / s). α is 30 degrees, and the centripetal force is verified to meet the requirements.

[0144] Calculation of inlet velocity v1 of the suction chamber:

[0145]

[0146] The calculated value is v1 = 1.5 (m / s).

[0147] Intake speed v3 calculation:

[0148] Calculate using the lowest rate ratio that meets the requirements, i.e. The calculated value is v3 = 0.15 (m / s).

[0149] Calculation of inlet diameter d4:

[0150]

[0151] The calculation yields d4 = 2 (cm).

[0152] Calculation of the diameter d2 of the mixing chamber: d2 = k2d1, k2 is taken as the recommended value k2 = 2, then d2 = 4 (cm).

[0153] Calculation of the height of the mixed chamber: h = k4d2, k4 is taken as the recommended value k4 = 2, h = 2d2 = 8 (cm).

[0154] Based on the designed parameters of the nanoscale cavitation generator, namely, the inlet diameter of the water absorption chamber d1 = 2.0 (cm); the wall opening diameter d3 = 0.5 (cm); the air inlet diameter d4 = 2 (cm); the mixing chamber diameter d2 = 4 (cm); and the calculated mixing chamber height h = 8 (cm), the model is as follows: Figure 6 As shown.

[0155] Intake volume Q a =0.049 (L / S), influent flow rate Q L=0.47 (L / s), water pressure 0.4 MPa, air pressure 1 atm, experimental results: After the device stabilized, the device was stopped 15 seconds later and the count was performed. The count was performed at a distance of approximately 40 cm above the nozzle, 5-10 cm above the nozzle. 2 Product counting in the region: Counting area: 1.6 mm 2 .

[0156] like Figure 7 As shown, the total number of bubbles in the region is 1123. Considering the error in the edge region, 90% of the total number is considered the actual number of bubbles. Therefore, the actual number of micro / nano bubbles obtained is approximately 2.5 × 10⁻⁶. 6 The number is within the expected range.

[0157] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0158] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A nanoscale cavitation generator, characterized in that, The system includes a housing, an air inlet (400), and a nozzle (500). The housing contains a mixing chamber (300), and the outside of the mixing chamber (300) contains a water absorption chamber (600) for connecting a liquid medium. The mixing chamber (300) and the water absorption chamber (600) are connected by a guide hole (301) to allow the liquid medium to form a swirling flow when it enters the mixing chamber (300). The mixing chamber (300) contains an air inlet (400) for supplying a gaseous medium to the mixing chamber (300). The liquid and gaseous media mix in the mixing chamber (300) to generate nanoscale cavitation bubbles. A nozzle (500) is installed on the mixing chamber (300) to output the nanoscale cavitation bubbles. The mixing chamber (300) has several sets of guide holes evenly distributed axially on its wall surface, and each set of guide holes has several guide holes evenly distributed circumferentially; the distance from the guide hole to the bottom of the mixing chamber (300) is greater than 3 / 4 of the height of the mixing chamber (300); the line connecting the center of the guide hole (301) on the outer wall of the mixing chamber (300) to the axis of the mixing chamber (300) in the circumferential direction forms an angle α with the axis of the guide hole (301) ranging from 30° to 60°. An air inlet (401) is installed at the center of the bottom of the mixing chamber (300), and a concave space is provided outside the center of the bottom of the mixing chamber (300), so that the cross section of the bottom of the mixing chamber (300) is ω-shaped; the air inlet (401) extends out of the bottom surface of the mixing chamber (300); the extended part of the air inlet (401) is spherical or frustum-shaped.

2. The nanoscale cavitation generator according to claim 1, characterized in that, The water absorption chamber (600) is an annular space, and the water absorption chamber (600) is coaxial with the mixing chamber (300); the axis of the air inlet (400) in the mixing chamber (300) is coaxial with the mixing chamber (300), and is used to inject the gas medium into the center of the swirling liquid medium.

3. The nanoscale cavitation generator according to claim 1, characterized in that, The housing is provided with a water inlet (601), and the ratio of the inlet cross section to the outlet cross section of the water inlet (601) is 2:1 to 3:1; the outlet of the water inlet (601) is connected to the water suction chamber (600).

4. The nanoscale cavitation generator according to claim 1, characterized in that, The ratio of the volume of gas medium entering the mixing chamber (300) to the volume of liquid medium entering the mixing chamber (300) is between 1 / 50 and 1 / 10.

5. A design method for a nanoscale cavitation generator according to any one of claims 1-4, characterized in that, Given the number n and diameter d of the target micro / nano bubbles. i The intake air volume Q in the mixing chamber (300) is determined according to the following formula. a The liquid inlet volume Q in the mixing chamber (300) L : ， 50Q a ≥Q L ≥10Q a , In the formula: n represents the number of target micro / nano bubbles; d i The target micro / nano bubble diameter; Q a This refers to the intake air volume, in L / s. t is the ventilation time, in seconds; Q L The influent flow rate is expressed in L / s. k5 is the fifth empirical parameter.

6. The design method of the nanoscale cavitation generator according to claim 5, characterized in that, Given the number n and diameter d of the target micro / nano bubbles. i The inlet diameter of the inlet (601) is determined according to the following formula: ， In the formula: d1 is the inlet diameter of the inlet (601), in cm; c represents the unit length, which is 1 cm. k3 is the third empirical parameter; The diameter of the guide hole (301) is determined according to the following formula: ， In the formula: d3 is the diameter of the guide hole (301), in cm; j represents the number of guide holes (301); k1 is the first empirical parameter.

7. The design method of the nanoscale cavitation generator according to claim 5, characterized in that, The water inlet velocity v2 of the guide hole (301) satisfies the following condition with respect to α: ， In the formula: r2 is the radius of the mixing chamber, in cm; α is the angle formed between the line connecting the center of the guide hole (301) located on the outer wall of the mixing chamber (300) to the axis of the mixing chamber (300) in the circumferential direction and the axis of the guide hole (301); m is the mass of the liquid in the mixing chamber (300); g is the acceleration due to gravity; v2 is the water inlet velocity through the guide hole (301), in m / s. Sure.

8. The design method of the nanoscale cavitation generator according to claim 5, characterized in that, The intake diameter d4 of the air inlet (401) is calculated according to the following formula: ， ， ， In the formula: d4 is the diameter of the air inlet of the (401) nozzle, in cm; v3 is the intake speed, in m / s; φ is the gas-liquid velocity ratio. v1 is the velocity at the inlet of the inlet (601), in m / s; The diameter of the mixing chamber (300) is d2=k2d1, where k2 is a second empirical parameter; The height h of the mixing chamber (300) is h=k4d2, where k4 is the fourth empirical parameter.

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