Atomization method and device combining magnetic assistance and gas phase assistance

Abstract

A method and device for atomization combined with magnetization assistance and gas phase assistance, comprising a water tank, a centrifuge, an air compressor, a magnetization device and a gas phase assisted atomization nozzle, wherein the outlet of the water tank is connected to the inlet of the centrifuge, the outlet of the centrifuge is connected to the inlet of the magnetization device, and the outlet of the magnetization device is connected to the gas phase assisted atomization nozzle; the air compressor is connected to the gas phase assisted atomization nozzle; by setting the magnetization device and the gas phase assisted atomization nozzle, the magnetization device is used to regulate the association structure of the water body through the magnetization process, thereby reducing the surface tension and dynamic viscosity of the water body, increasing the Weber number, reducing the demand for gas phase surface pressure of bubble atomization, forming conditions conducive to bubble atomization, and then promoting the efficient combination of pneumatic and bubble atomization technologies, increasing the evaporation rate, and reducing the cost required for gas phase assisted atomization. The required field strength is small, which effectively reduces the volume of the magnetizer and enhances the flexibility of use; it is almost unaffected by the electromagnetic equipment in the working environment and has a stable effect.

Description

Technical Field

[0001] The invention relates to an atomization method and device combining magnetization assistance with gas phase assistance, belonging to the technical field of gas-liquid two-phase flow atomization. Background Art

[0002] Atomizing nozzle is a device that can spray liquid into atomized form, so that the liquid exists in the air in the form of tiny droplets. Atomizing technology has covered almost all industrial fields, such as transportation, agricultural production, fuel combustion, daily life, etc. Atomizing technology is also widely used in non-combustion industries, such as catalytic granulation, food processing, powder coating, pesticide spraying, etc.

[0003] The existing atomizing nozzles are mainly mechanical atomizing nozzles and medium atomizing nozzles. Mechanical atomizing nozzles require higher water pressure and the flow rate is difficult to adjust; medium atomizing nozzles mainly use gas phase assisted atomization, which mainly includes bubble atomization and pneumatic atomization: bubble atomization uses the pressure difference between the inside and outside of the nozzle outlet to make tiny bubbles expand and burst rapidly after leaving the outlet, breaking the liquid film into liquid mist, and the required gas phase pressure is higher, but the gas consumption is small; pneumatic atomization uses high-speed airflow to impact the liquid to atomize the liquid, and the gas consumption is large, but the gas phase pressure is small.

[0004] Magnetization technology can change the physical properties of water and the association structure of water bodies. The difficulty of droplet atomization depends to a certain extent on the surface tension and dynamic viscosity of water: the greater the surface tension and dynamic viscosity of the fluid, the more difficult it is to deform and break the liquid film, and the worse the atomization effect. The weaker the fluid association structure, the slower the liquid evaporation rate. The physical properties of water treated with a magnetic field will change, thereby reducing the difficulty of droplet atomization.

[0005] As mentioned above, the difficulty of atomization can be reduced by utilizing the effect of magnetic field, but the existing atomization nozzles do not combine magnetization with gas-phase assisted atomization. The simple gas-phase assisted atomization requires high conditions and high costs, and it is difficult to meet industrial needs. Most of the existing magnetization equipment requires a larger field strength and a longer magnetization distance, and is subject to many environmental factors that affect the distribution of the magnetic field, such as electromagnetic equipment intervention, etc., and thus generally has problems such as large size, inflexibility, instability, poor magnetization effect or lack of specificity. Summary of the invention

[0006] The purpose of the present invention is to provide an atomization method and device combining magnetization assistance with gas phase assistance, thereby reducing the conditions and costs required for gas phase assisted atomization.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A magnetization-assisted and gas-assisted atomization device, comprising a water tank, a centrifuge, an air compressor, a magnetization device and a gas-assisted atomization nozzle, wherein the outlet of the water tank is connected to the inlet of the centrifuge, the outlet of the centrifuge is connected to the inlet of the magnetization device, the outlet of the magnetization device is connected to the gas-assisted atomization nozzle; the air compressor is connected to the gas-assisted atomization nozzle; the gas-assisted atomization nozzle comprises a cylindrical shell; one end of the shell is provided with a liquid inlet, and the other end is provided with a cyclone outlet; the middle of the shell side wall A plurality of air inlets are provided, a venturi tube type inner flow channel is arranged in the shell, one end of the venturi tube type inner flow channel is connected to the liquid inlet, and the other end is provided with a plurality of bubble flow outlets, a plurality of aeration holes are provided on the side wall of the diffusion section of the venturi tube type inner flow channel, a cavity is arranged on the outside of the venturi tube type inner flow channel, one end of the cavity is connected to the air inlet, and the other end is connected to the cyclone flow outlet, one end of the aeration hole is connected to the cavity, and the other end is connected to the venturi tube type inner flow channel; the bubble flow outlet is connected to the cyclone flow outlet.

[0009] A further improvement of the present invention is that the cyclone flow outlet is located on the central axis of the Venturi tube-type inner flow channel.

[0010] A further improvement of the present invention is that the cavity is a tapered air inlet.

[0011] A further improvement of the present invention is that a plurality of swirl sheets are arranged in the cavity, and the plurality of swirl sheets are evenly distributed along the circumferential direction.

[0012] A further improvement of the present invention is that the rotation angle of a single swirl plate is 30° to 40°.

[0013] A further improvement of the present invention is that the magnetizing device includes a metal bellows, a magnetizing ring, a built-in hose and a plurality of magnetizing device shells; wherein the plurality of magnetizing device shells are sleeved on the outer wall of the built-in hose, two adjacent magnetizing device shells are connected by the metal bellows, a magnetizing ring is arranged in each magnetizing device shell, each magnetizing ring includes a plurality of NdFeB magnet blocks, and the plurality of NdFeB magnet blocks form a group of Halbach arrays.

[0014] A further improvement of the present invention is that a front connecting thread is provided at one end of the built-in hose and a rear connecting thread is provided at the other end; the magnetizing device and the gas phase assisted atomizing nozzle are connected via the rear connecting thread; and the outlet of the centrifuge is connected to the inlet of the magnetizing device via the front connecting thread.

[0015] An atomization method combining magnetization assistance and gas phase assistance based on the above device comprises the following steps:

[0016] 1) The compressed gas is introduced into the air inlet of the gas-assisted atomizing nozzle through an air compressor, a part of the gas enters the Venturi tube inner flow channel through the aeration hole, and the other part of the gas is ejected from the cyclone outlet in the form of cyclone flow through the cyclone blade;

[0017] 2) passing water into a magnetizing device through a centrifuge for magnetization to complete the magnetization operation, and the magnetized water flows into a gas-assisted atomizing nozzle, flows through a venturi tube-type inner flow channel, and increases the flow rate and reduces the pressure through the tapered structure of the venturi tube-type inner flow channel, so that a small amount of gas introduced from the air inlet enters the water in the form of bubbles through a plurality of aeration holes to form a bubbly two-phase flow; the bubbly two-phase flow is ejected through the bubbly flow outlet to achieve the first breakage of the liquid; the broken droplets are impacted by the high-speed cyclone gas ejected from the cyclone flow outlet in step 1) to complete secondary shearing and achieve secondary breakage.

[0018] A further improvement of the present invention is that the water flow velocity in the magnetizing device is constant at 0.2 m / s; the length of the effective magnetic field in the magnetizing device is greater than 100 mm, the air gap diameter of the magnetizing ring is greater than 10 mm, the magnetic field is perpendicular to the water flow direction, and the intensity is 170-200 mT.

[0019] A further improvement of the present invention is that the distance between the magnetic field in the magnetizing device and the gas phase auxiliary atomizing nozzle is 5 to 15 cm.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: by providing a magnetizing device and a gas-assisted atomizing nozzle, the present invention can utilize the magnetizing device to regulate the association structure of the water body through the magnetizing process, thereby reducing the surface tension and dynamic viscosity of the water body, increasing the Weber number, reducing the demand for gas phase surface pressure for bubble atomization, forming conditions conducive to bubble atomization, and further promoting the efficient combination of pneumatic and bubble atomization technologies, reducing the atomized particle size, improving atomization uniformity, increasing the evaporation rate, and reducing the cost required for gas-assisted atomization. The magnetizing device in the present invention can achieve a reduction in surface tension and an increase in evaporation rate at 20°C to 25°C. It requires a relatively small field strength, effectively reducing the volume of the magnetizer and enhancing the flexibility of use; it is almost unaffected by the electromagnetic equipment in the working environment, and the effect is stable.

[0021] When the present invention is applied, when the distance from the nozzle is only 100 mm, the gas phase gauge pressure is only 80 kPa, and the liquid phase flow rate is 40 kg / h, the average diameter of the Sotel is only 13.63 μm, and the cone angle is 50°, which is much better than various existing air atomizing nozzles. Under this working condition, the average evaporation time of the spray is only 19.41 ms. The present invention realizes uniform, fine, and efficient atomization, and has the characteristics of green environmental protection, recycling, and high economic benefits. At the same time, the method has simple process and low cost, can be used for various gas phase assisted atomizing nozzles, and is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a connection diagram of the device in the present invention;

[0023] Figure 2It is a combined structural diagram of the gas phase assisted atomizing nozzle and the magnetizing device in the present invention;

[0024] Figure 3 It is a structural diagram of the magnetization device in the present invention;

[0025] Figure 4 It is a structural diagram of the gas phase assisted atomization nozzle in the present invention;

[0026] Figure 5 is a distribution diagram of atomized particle size under the same working conditions without using the present invention;

[0027] Figure 6 This is a distribution diagram of atomized particle size produced by the method of the present invention under the same working conditions.

[0028] In the figure, 1 is a gas-assisted atomizing nozzle, 2 is a magnetizing device, 3 is an air valve, 4 is an air compressor, 5 is a centrifuge, 6 is a water tank, 7 is a liquid valve, 8 is a front connecting thread, 9 is a magnetizing device housing, 10 is a metal bellows, 11 is a magnetizing ring, 12 is a built-in hose, 13 is a rear connecting thread, 14 is a liquid inlet, 16 is a Venturi tube-type internal flow channel, 17 is an air inlet, 18 is an aeration hole, 19 is a swirl sheet, 20 is a tapered air channel, 21 is a bubble flow outlet, and 22 is a cyclone flow outlet. DETAILED DESCRIPTION

[0029] The present invention is described in detail below in conjunction with specific implementation modes.

[0030] See also Figure 1 and Figure 2 The present invention discloses an atomizing device combining magnetization assistance and gas phase assistance, comprising a water tank 6, a centrifuge 5, an air compressor 4, an air valve 3, a liquid valve 7, a magnetizing device 2 and a gas phase assisted atomizing nozzle 1, wherein the outlet of the water tank 6 is connected to the inlet of the centrifuge 5 via a water pipe, the outlet of the centrifuge 5 is divided into two paths, one path is connected to the inlet of the water tank 6, and the other path is connected to the inlet of the magnetizing device 2 via the liquid valve 7, the outlet of the magnetizing device 2 is connected to the gas phase assisted atomizing nozzle 1; the air compressor 4 is connected to the gas phase assisted atomizing nozzle 1 via the air valve 3.

[0031] See also Figure 4The gas-assisted atomizing nozzle 1 is a bubble atomizing nozzle, a pneumatic atomizing nozzle or a combination of bubble atomizing and pneumatic atomizing nozzle, and includes a cylindrical shell, a liquid inlet 14, a venturi tube inner flow channel 16, an air inlet 17, an aeration hole 18, a swirl sheet 19, a tapered air channel 20, a bubble flow outlet 21 and a cyclone flow outlet 22. Among them, a liquid inlet 14 is arranged at one end of the shell, and a cyclone outlet 22 is arranged at the other end; a plurality of air inlets 17 are provided in the middle of the shell side wall, and a venturi tube-type internal flow channel 16 is arranged in the shell, one end of the venturi tube-type internal flow channel 16 is connected to the liquid inlet 14, and the other end is provided with a plurality of bubble outlets 21, the venturi tube-type internal flow channel 16 includes a connected inlet section, a contraction section and a diffusion section, a plurality of aeration holes 18 are arranged on the side wall of the diffusion section of the venturi tube-type internal flow channel 16, and a cavity is arranged outside the venturi tube-type internal flow channel 16, and the cavity is a gradually contracting air inlet. One end of the cavity is connected to the air inlet 17, and the other end is connected to the cyclone outlet 22, one end of the aeration hole 18 is connected to the cavity, and the other end is connected to the venturi tube-type internal flow channel 16; the bubble outlet 21 is connected to the cyclone outlet 22.

[0032] The cyclone flow outlet 22 is located on the central axis of the Venturi tube inner flow passage 16 .

[0033] Specifically, the inner diameter of the liquid inlet 14 is 16 mm; the inner diameter of the air inlet 17 is 6 mm; the Venturi-type inner flow channel 16 gradually shrinks from a diameter of 16 mm to a diameter of 8 mm; the aeration holes 18 and the air inlet 17 adopt a counter-setting structure, that is, they are arranged oppositely, so that it is convenient for the gas to enter the aeration holes 18. There are 42 aeration holes 18 in total, with a diameter of 0.7 mm, arranged in three rows in parallel, which is conducive to air intake. Part of the gas that forms bubbles in the intake is pressed into the liquid flow through the pressure difference between the inside and outside of the aeration holes 18, and part of it is flushed into the aeration holes 18 due to the counter-setting of the aeration holes 18 and the air inlet 17.

[0034] There are 4 bubble outlets 21 arranged in a regular quadrilateral, that is, evenly distributed in the circumference, which can enhance the crushing effect, stabilize the crushing process and greatly increase the liquid phase flow rate. The radius of each bubble outlet 21 is 1mm, and the distance between the centers of adjacent bubble outlets 21 is 1.41mm.

[0035] Several swirl sheets 19 are arranged in the cavity. The swirl sheets 19 are evenly distributed along the circumference, with a total of 6. The rotation angle of a single swirl sheet 19 is 30° to 40°, preferably 34.5°, and the angle difference between adjacent swirl sheets 19 is 60°. The gas passes through the 6 swirl sheets 7 to generate high-speed swirl gas, realizing the pneumatic atomization part.

[0036] The axial distance between the bubble outlet 21 and the cyclone outlet 22 is 15.3 mm.

[0037] See also Figure 3The magnetizing device 2 includes a front connecting thread 8, a magnetizing device housing 9, a metal bellows 10, a magnetizing ring 11, a built-in hose 12 and a rear connecting thread 13. Among them, a plurality of annular magnetizing device housings 9 are arranged outside the built-in hose 12, and the plurality of magnetizing device housings 9 are sleeved on the outer wall of the built-in hose 12. Two adjacent magnetizing device housings 9 are connected by a metal bellows 10. A magnetizing ring 11 is arranged in each magnetizing device housing 9. Each magnetizing ring 11 includes 8 NdFeB magnets with a remanence of 0.7T. The 8 NdFeB magnets form a group of Halbach structure magnetizing units in a certain arrangement. The magnetic field in the air gap of each magnetizing ring is a uniform constant magnetic field of 0.2T vertically upward. The axial length of each magnetizing ring 11 along the hose 12 is 30mm. The cross section of the outer wall of the built-in hose 12 is a regular octagon, and the cross section of the inner wall is a circle. One end of the built-in hose 12 is provided with a front connection thread 8, and the other end is provided with a rear connection thread 13. The magnetizing device 2 and the gas phase assisted atomizing nozzle 1 are connected via the rear connection thread 13.

[0038] The atomization method combining magnetization assistance and gas phase assistance based on the above-mentioned device in the present invention is:

[0039] 1) The compressed gas is introduced into the air inlet 17 of the gas-assisted atomizing nozzle 1 through the air compressor 4, a part of the gas enters the venturi tube inner flow channel 16 through the aeration hole 18, and the other part of the gas is ejected from the cyclone outlet 22 in the form of cyclone flow through the cyclone blade 19, creating water atomization conditions.

[0040] The gas phase gauge pressure required for the gas phase assisted atomizing nozzle 1 is 50-200 kPa, preferably 80 kPa.

[0041] 2) Water is introduced into the magnetizing device 2 through the centrifuge 5 for magnetization to complete the magnetization operation. The magnetized water flows into the gas-assisted atomizing nozzle 1 and flows through the Venturi tube-type inner flow channel 16. The flow velocity is increased and the pressure is reduced by the tapered structure of the Venturi tube-type inner flow channel 16, so that a small amount of gas introduced from the air inlet 17 enters the water in the form of bubbles through a plurality of aeration holes 18 to form a bubbly two-phase flow; the bubbly two-phase flow is ejected through the bubbly flow outlet 21 to achieve the first breakage of the liquid; the broken droplets are impacted by the high-speed swirling gas ejected from the cyclone flow outlet 22 in step 1) to complete the secondary shearing and achieve the secondary breakage.

[0042] The liquid phase flow rate required for the gas-assisted atomizing nozzle is 40 kg / h; the water flow velocity in the magnetizing device is constant at 0.2 m / s; the length of the effective magnetic field in the magnetizing device is greater than 100 mm, preferably 20 to 30 cm, the air gap diameter of the magnetizing ring 11 is greater than 10, preferably 15 to 25 mm, the magnetic field is perpendicular to the water flow direction, and the intensity is constant at 170 to 200 mT, preferably 200 mT; the water temperature is 20 to 25 ° C. The distance between the constant magnetic field and the gas-assisted atomizing nozzle 1 is 5 to 15 cm. The diameter of the bubble outlet 21 is 1 mm.

[0043] The atomized particle size distribution under the same working conditions without using the present invention is as follows Figure 5 As shown: Under the condition of using a single gas-assisted atomization nozzle, when the liquid phase flow rate is 40kg / h and the gas phase pressure is 80kPa, the atomized particle size is 23.06mm, the evaporation time of the atomized droplets is 42.11ms, the best atomization effect is achieved at a distance of 170mm from the nozzle, and convergence occurs at a distance of 300mm from the nozzle, and the atomized particle size becomes 44.65mm.

[0044] The atomized particle size distribution produced by the method of the present invention is as follows Figure 6 As shown: using the atomization method combining magnetic assistance and gas assistance of the present invention, when the liquid phase flow rate is 40kg / h and the gas phase pressure is 80kPa, the atomized particle size is 13.63mm, the evaporation time of the atomized droplets is 19.57ms, and the best atomization effect is achieved at a distance of 100mm from the nozzle, and no aggregation occurs afterwards.

[0045] The atomization result produced by the present invention has the characteristics of high efficiency, fineness, uniformity and extremely short distance required for atomization. At the same time, the present invention can be used for all gas-assisted atomization nozzles, and the improvement range is basically the same.

[0046] The present invention greatly reduces the conditions and costs required for gas-phase assisted atomization through constant magnetic field treatment; at the same time, the method has simple process, short cycle, green environmental protection and low production cost, which is in line with the concept of sustainable development.

Claims

1. An atomization device combining magnetic assistance and gas phase assistance, It is characterized in that The invention comprises a water tank (6), a centrifuge (5), an air compressor (4), a magnetizing device (2) and a gas-phase assisted atomizing nozzle (1), wherein the outlet of the water tank (6) is connected to the inlet of the centrifuge (5), the outlet of the centrifuge (5) is connected to the inlet of the magnetizing device (2), and the outlet of the magnetizing device (2) is connected to the gas-phase assisted atomizing nozzle (1); the air compressor (4) is connected to the gas-phase assisted atomizing nozzle (1); the gas-phase assisted atomizing nozzle (1) comprises a cylindrical shell; one end of the shell is provided with a liquid inlet (14), and the other end is provided with a cyclone flow outlet (22); a plurality of air inlets (17) are opened in the middle of the side wall of the shell, a venturi tube type inner flow channel (16) is provided in the shell, one end of the venturi tube type inner flow channel (16) is connected to the liquid inlet (14), and the other end is provided with a plurality of bubble flow outlets (21), and the venturi tube The venturi tube inner flow channel (16) comprises an inlet section, a contraction section and a diffusion section which are connected to each other. A plurality of aeration holes (18) are provided on the side wall of the diffusion section of the venturi tube inner flow channel (16). A cavity is provided on the outside of the venturi tube inner flow channel (16). One end of the cavity is connected to the air inlet (17), and the other end is connected to the cyclone flow outlet (22). A converging air channel (20) is connected between the air inlet (17) and the cyclone flow outlet (22). One end of the aeration hole (18) is connected to the cavity, and the other end is connected to the venturi tube inner flow channel (16). The bubble flow outlet (21) is connected to the cyclone flow outlet (22). The cyclone flow outlet (22) is located on the central axis of the venturi tube inner flow channel (16). The cavity is a converging air inlet. A plurality of cyclone sheets (19) are provided in the cavity, and the plurality of cyclone sheets (19) are evenly distributed along the circumferential direction. The rotation angle of a single swirl plate (19) is 30° to 40°; the magnetizing device (2) comprises a metal bellows (10), a magnetizing ring (11), a built-in hose (12) and a plurality of magnetizing device shells (9); wherein the plurality of magnetizing device shells (9) are sleeved on the outer wall of the built-in hose (12), two adjacent magnetizing device shells (9) are connected via the metal bellows (10), a magnetizing ring (11) is arranged in each magnetizing device shell (9), each magnetizing ring (11) comprises a plurality of neodymium iron boron magnet blocks, and the plurality of neodymium iron boron magnet blocks form a group of Halbach arrays.

2. The atomization device combining magnetic assistance and gas phase assistance according to claim 1, It is characterized in that A front connecting thread (8) is provided at one end of the built-in hose (12), and a rear connecting thread (13) is provided at the other end; the magnetizing device (2) and the gas phase auxiliary atomizing nozzle (1) are connected via the rear connecting thread (13); and the outlet of the centrifuge (5) is connected to the inlet of the magnetizing device (2) via the front connecting thread (8).

3. An atomization method combining magnetization assistance and gas phase assistance based on the device of claim 2, It is characterized in that The following steps are involved: 1) Compressed gas is introduced into the air inlet (17) of the gas phase auxiliary atomizing nozzle (1) through an air compressor (4), a part of the gas enters the venturi tube inner flow channel (16) through the aeration hole (18), and the other part of the gas is ejected from the cyclone outlet (22) in the form of a cyclone flow through the cyclone blade (19); 2) passing water into a magnetizing device (2) through a centrifuge (5) for magnetization, completing the magnetization operation, and the magnetized water flows into a gas-assisted atomizing nozzle (1), flows through a venturi tube-type inner flow channel (16), and increases the flow rate and reduces the pressure through the tapered structure of the venturi tube-type inner flow channel (16), so that a small amount of gas introduced from an air inlet (17) enters the water in the form of bubbles through a plurality of aeration holes (18), forming a bubbly two-phase flow; the bubbly two-phase flow is ejected through a bubbly flow outlet (21), thereby achieving a first breakup of the liquid; the broken droplets are impacted by the high-speed cyclonic gas ejected from the cyclonic flow outlet (22) in step 1), thereby achieving secondary shearing and secondary breakup; The water flow velocity in the magnetizing device is constant at 0.2 m / s; the length of the effective magnetic field in the magnetizing device is greater than 100 mm, the air gap diameter of the magnetizing ring (11) is greater than 10 mm, the magnetic field is perpendicular to the water flow direction, and the intensity is 170-200 mT; The distance between the magnetic field in the magnetizing device and the gas phase assisted atomization nozzle (1) is 5 to 15 cm.

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