Low-pressure wide-width gas-liquid two-phase atomizing nozzle and design method

Abstract

The invention relates to a low-pressure wide gas-liquid two-phase atomizing nozzle and a design method. The low-pressure wide gas-liquid two-phase atomizing nozzle is composed of an outer wall, a radial gas-phase inlet, a split liquid-phase inlet, a mixing cavity, a contraction accelerating cavity, a diffusion cavity and a nozzle outlet, and gas and liquid phases can be mixed in the nozzle and atomized to form fine mist spray to be sprayed out. According to the design method of the low-pressure wide-width gas-liquid two-phase atomizing nozzle, the optimal flow channel curved surface of the shrinkage acceleration cavity, the distribution angle of the shrinkage flow channel of the five-flow-channel diffusion cavity and the pressure working condition of the low-pressure wide-width gas-liquid two-phase atomizing nozzle under the given condition can be calculated. The gas-liquid two-phase atomizing nozzle has the advantages that liquid phase atomization is efficient and fine, the spraying flow and the fogdrop particle size are independently adjusted according to different operation scenes, the requirement for atomization pressure is low, atomization power consumption is low, atomization cost is low, and compared with a common gas-liquid two-phase atomizing nozzle, the number of the nozzles can be remarkably reduced.

Description

Technical Field

[0001] The present invention belongs to the field of plant protection atomizing nozzles, and relates to a low-pressure, wide-width gas-liquid two-phase atomizing nozzle and a design method. The nozzle has the characteristics of low gas phase pressure requirement, low atomization energy consumption, large atomization angle, wide spray width, small atomization particle size, etc., and is suitable for precise application of pesticides in various plant protection operation scenarios. Background Art

[0002] Nozzles have a wide range of applications in today's society, especially in the agricultural field. Nozzles can atomize and spray liquid agricultural chemicals such as pesticides and fertilizers to achieve precise fertilization of crops and pest control, thereby ensuring crop yield and quality. Improving the atomization efficiency of liquid medicine and achieving controllable atomization particle size is one of the important development directions of current plant protection spray nozzles. Existing pressure nozzles have the coupling of flow rate and droplet particle size parameters, and there are problems such as the inability to independently adjust the spray flow rate and droplet particle size.

[0003] The gas-liquid two-phase nozzle is different from the traditional atomizing nozzle in pressure atomization principle. It has the characteristics of independent control of flow rate and particle size and wide adjustable range. In actual plant protection operations, there are many operating scenarios that require small flow rate and fine droplets. The gas-liquid two-phase nozzle has a fine atomization particle size and a relatively uniform droplet distribution, which can well meet the needs of precise pesticide application and is very suitable for modern plant protection operations.

[0004] According to literature search, the Chinese invention patent "A water-medicine integrated gas-liquid two-phase atomizing nozzle", publication number CN107409958B, proposes a gas-liquid two-phase atomizing nozzle structure, where the liquid enters the nozzle from the central flow channel, passes through the buffer chamber and then enters the mixing chamber, where it is mixed with the coaxial gas phase to achieve the gas-liquid two-phase atomization process, and finally the two-phase mixed flow containing fine droplets is discharged from the nozzle. This structure does not fully utilize the gas energy, the gas-liquid two-phase mixing structure is simple, the size is short, and the two-phase atomization process is incomplete; due to the single nozzle structure of the nozzle, the high-speed airflow carrying the droplets will form an extremely fine spray beam, with a small spray angle and a small width of the atomized droplets.

[0005] In view of the problems of existing gas-liquid two-phase atomizing nozzles, such as high gas phase pressure requirement, unreasonable gas-liquid mixing structure design, and small spray angle, it is urgently necessary to invent a low-pressure and wide-width gas-liquid two-phase atomizing nozzle and design method to achieve the characteristics of low gas phase pressure requirement, low atomization energy consumption, wide spray width, and large atomization angle. Summary of the invention

[0006] In view of the above technical deficiencies, the present invention proposes a low-pressure and wide-width gas-liquid two-phase atomizing nozzle and a design method, which can achieve large atomization angle, wide width and small particle size spray under low gas phase pressure.

[0007] The technical solution adopted by the present invention to solve its technical problems is that a low-pressure wide-width gas-liquid two-phase atomizing nozzle includes a nozzle housing, a radial gas inlet, a split liquid inlet, a transverse jet windward mixing chamber, a contraction acceleration chamber, a five-channel diffusion chamber, and a nozzle outlet.

[0008] The nozzle housing is integrally formed by an injection molding process and wraps the radial gas inlet, the split liquid inlet, the transverse jet windward mixing chamber, the contraction acceleration chamber, the five-channel diffusion chamber, and the nozzle outlet;

[0009] The radial gas inlet is located at the top of the side wall of the transverse jet windward mixing chamber, accesses the transverse jet windward mixing chamber in the radial direction, and is perpendicular to the split liquid inlet;

[0010] The split liquid inlet is located at the bottom of the side wall of the transverse jet windward mixing chamber, symmetrically accesses the transverse jet windward mixing chamber from both sides in the radial direction, and is perpendicular to the radial gas inlet;

[0011] The upper part of the side wall of the transverse jet windward mixing chamber is connected to the radial gas inlet, the bottom of the side wall is connected to the split liquid inlet, and the tail is connected to the contraction acceleration chamber;

[0012] The head of the contraction acceleration chamber is connected to the transverse jet windward mixing chamber, and the tail is connected to the five-channel diffusion chamber;

[0013] The curved surface of the contraction acceleration chamber presents a gradually contracting shape and is calculated by the design method of the low-pressure wide-width gas-liquid two-phase atomizing nozzle;

[0014] The five-channel diffusion chamber is composed of five contraction channels in the same plane, presenting a claw-shaped distribution, and the median angle between each channel is calculated by the design method of the low-pressure wide-width gas-liquid two-phase atomizing nozzle;

[0015] The nozzle outlet is respectively connected to each channel of the five-channel diffusion chamber and leads to the external atmosphere.

[0016] The radial gas inlet is located at the top of the nozzle housing and the transverse jet windward mixing chamber, penetrates the nozzle housing and is connected to the transverse jet windward mixing chamber, is arranged in the radial direction of the low-pressure wide-width gas-liquid two-phase atomizing nozzle, and the azimuth is located at the 90° direction of the low-pressure wide-width gas-liquid two-phase atomizing nozzle.

[0017] The split liquid inlet is located at the upper 1 / 3 of the nozzle housing and the bottom of the transverse jet windward mixing chamber, penetrates the nozzle housing and is connected to the transverse jet windward mixing chamber, is symmetrically arranged in the radial direction of the low-pressure wide-width gas-liquid two-phase atomizing nozzle, and the azimuth is located at the 0° and 180° directions of the low-pressure wide-width gas-liquid two-phase atomizing nozzle.

[0018] The described transverse jet windward mixing chamber is a cylindrical cavity. The diameter of the cavity is the same as the diameter of the inlet of the contraction-acceleration chamber. Its top is connected to the radial gas-phase inlet, its bottom is connected to the split liquid-phase inlet, and its tail is connected to the contraction-acceleration chamber.

[0019] The described contraction-acceleration chamber is connected to the end of the transverse jet windward mixing chamber. The fluid is continuously accelerated to the design limit in the contraction-acceleration chamber and enters the five-channel diffusion chamber. The curved surface equation of the contraction-acceleration chamber is calculated by the design method of the low-pressure wide-width gas-liquid two-phase atomizing nozzle.

[0020] The five-channel diffusion chamber is connected to the end of the contraction-acceleration chamber. The fluid is divided into five bundles by five channels and distributed in the spray plane. Each channel of the five-channel diffusion chamber is a contraction structure. The cross-section of the channel changes little in the front view, but significantly contracts in the side view, realizing the gradual contraction of the cross-section of the channel.

[0021] There are five nozzle outlets in total, which are respectively connected to the respective channels of the five-channel diffusion chamber and are connected to the external environment as the external of the channel outlets.

[0022] A design method of a low-pressure wide-width gas-liquid two-phase atomizing nozzle according to the present invention includes the following steps:

[0023] Step 1: Calculate the optimal channel curved surface of the contraction-acceleration chamber according to the given conditions:

[0024] The calculation formula for the optimal channel curved surface of the contraction-acceleration chamber in Step 1 is:

[0025]

[0026] Wherein, R is the cross-sectional radius of each axial section, z is the axial coordinate, A is the area of each cross-section of the channel, ρ is the fluid density, V is the fluid velocity, A cr is the area of the thinnest part of the channel, ρ cr is the fluid density at the thinnest part of the channel, V cr is the fluid velocity at the thinnest part of the channel, M is the Mach number, defined as the ratio of the fluid velocity to the local speed of sound v / c, and k is the adiabatic index of air;

[0027] The calculation results show that different from the contraction-expansion structure often used in high-pressure gas-liquid two-phase atomizing nozzles, the low-pressure wide-width gas-liquid two-phase atomizing nozzle should adopt a pure-contraction contraction-acceleration chamber channel structure. If a contraction-expansion structure is adopted, the mixed flow in the expansion section will decelerate due to insufficient pressure at the inlet, which is not conducive to droplet refinement. Therefore, a pure-contraction structure must be adopted;

[0028] The calculated optimal channel curved surface equation of the contraction-acceleration chamber is:

[0029]

[0030] Among them, ln is the logarithmic function, which is a basic elementary function.

[0031] Step 2: Calculate the distribution angle of the contraction channel of the five-channel diffusion cavity according to the given conditions:

[0032] The calculation formula for the distribution angle of the contraction channel of the five-channel diffusion cavity in Step 2 is:

[0033]

[0034] Among them, θ1 is the channel spray angle, θ2 is the included angle between the inner spray beams, θ3 is the included angle between the outer spray beams, and θ4 is the nozzle spray width condition;

[0035] The relationship between the included angle of the center lines of the inner and outer channels, the channel spray angle, and the nozzle spray width condition is calculated as:

[0036]

[0037] Among them, θ n is the included angle between the center lines of the inner channels, and θ w is the included angle between the center lines of the outer channels;

[0038] Step 3: Calculate the pressure working condition of the low-pressure wide-width gas-liquid two-phase atomizing nozzle according to the given conditions:

[0039] The calculation formula for the pressure working condition of the low-pressure wide-width gas-liquid two-phase atomizing nozzle in Step 3 is:

[0040]

[0041] Among them, P ext is the ambient pressure outside the low-pressure wide-width gas-liquid two-phase atomizing nozzle, P * is the total pressure of the fluid in the pipeline, which is the sum of the dynamic pressure and the static pressure, P 1s is the required pressure of the gas source, P y is the required pressure of the liquid pump, M1 is the Mach number of the fluid at the radial gas phase inlet, and M3 is the Mach number of the fluid at the nozzle outlet;

[0042] The calculated pressure working condition of the low-pressure wide-width gas-liquid two-phase atomizing nozzle is:

[0043]

[0044] The beneficial effects of the present invention are:

[0045] 1. The present invention adopts the principle of horizontal jet against the wind atomization, achieving high-efficiency atomization and ultra-fine atomization of the liquid phase;

[0046] 2. The present invention can independently control the nozzle flow rate and droplet size by adjusting the gas-liquid two-phase flow rate, realizing flexible and independent adjustment of the spray flow rate and the median diameter of the droplet size according to different operation scenarios and requirements;

[0047] 3. The present invention optimizes the nozzle flow channel for low-pressure conditions, realizing gas-liquid two-phase atomization under low-pressure conditions, and reducing the atomization energy consumption and atomization cost;

[0048] 4. The present invention adopts a diffusion structure, effectively expanding the spray angle of the low-pressure wide-width gas-liquid two-phase atomization nozzle, and significantly saving the number of nozzles used compared with general gas-liquid two-phase atomization nozzles. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is the front view sectional view of the low-pressure wide-width gas-liquid two-phase atomization nozzle;

[0050] Figure 2 is the side view sectional view of the low-pressure wide-width gas-liquid two-phase atomization nozzle;

[0051] Figure 3 is the three-dimensional sectional view of the low-pressure wide-width gas-liquid two-phase atomization nozzle;

[0052] Figure 4 is the flow chart of the design method of the low-pressure wide-width gas-liquid two-phase atomization nozzle;

[0053] Figure 5 is the physical diagram of the low-pressure wide-width gas-liquid two-phase atomization nozzle;

[0054] Figure 6 is the experimental schematic diagram of the droplet size of the low-pressure wide-width gas-liquid two-phase atomization nozzle;

[0055] Description of the reference numerals in the drawings: 1. Nozzle housing, 2. Radial gas inlet, 3. M12×1.5 pipe thread, 4. Split liquid inlet, 5. Horizontal jet against the wind mixing chamber, 6. Contraction acceleration chamber, 7. Five-channel diffusion chamber, 8. Nozzle outlet, 9. Test nozzle, 10. Liquid pipeline, 11. Gas pipeline, 12. Spray fan surface, 13. Diffraction laser particle size analyzer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0057] As Figure 1 , Figure 2 and Figure 3 shown, this embodiment includes a nozzle housing 1, a radial gas inlet 2, a split liquid inlet 4, a transverse jet windward mixing chamber 5, a contraction acceleration chamber 6, a five-channel diffusion chamber 7, and a nozzle outlet 8; the entire nozzle is integrally formed by an injection molding process. The internal cavity of the nozzle forms structures such as a radial gas inlet 2, a split liquid inlet 4, a transverse jet windward mixing chamber 5, a contraction acceleration chamber 6, a five-channel diffusion chamber 7, and a nozzle outlet 8, while the plastic entity forms structures such as a nozzle housing 1 and an M12*1.5 pipe thread 3.

[0058] Before the actual operation of this embodiment, the radial gas inlet 2 should be connected to a high-pressure gas source to provide high-pressure gas, and the two sides of the split liquid inlet 4 should be connected to the main liquid pipeline through a tee structure to provide pressurized liquid. The fluid pipeline should be connected to the radial gas inlet 2 and the split liquid inlet 4 using an M12*1.5 pipe thread, and the tightness of the relevant pipelines must be checked before starting the nozzle. When starting the nozzle, the gas flow must be turned on first and then the liquid flow to prevent liquid backflow and damage to the gas supply equipment.

[0059] During the working process of this embodiment, after the high-pressure gas enters the transverse jet windward mixing chamber 5 from the radial gas inlet 2, it will pass through a cavity to change the gas flow direction and stabilize the flow parameters before contacting the liquid phase; the liquid phase enters the transverse jet windward mixing chamber 5 from both sides of the split liquid inlet 4 and is evenly and vertically injected into the high-pressure gas, presenting a windward jet shape, and is mixed and sheared with the gas phase at the rear of the transverse jet windward mixing chamber 5 to form primary atomization; the gas-liquid mixed flow generated in the transverse jet windward mixing chamber 5 will continue to flow along the flow path and enter the contraction acceleration chamber 6 to be accelerated to the design limit. As the flow velocity increases, the shearing effect of the gas phase on the liquid phase will also increase accordingly, further refining and breaking the liquid phase to form secondary atomization; the high-speed gas-liquid mixed flow containing fine droplets will continue to flow along the flow path into the five-channel diffusion chamber 7, and the high-speed gas-liquid mixed flow is evenly divided into five bundles by the five channels, effectively expanding the spray angle of the low-pressure wide-width gas-liquid two-phase atomizing nozzle. Each channel of the five-channel diffusion chamber 7 is a contraction channel, which enables the mixed gas to continue to accelerate inside the nozzle and improves the atomization effect; finally, the five bundles of high-speed gas-liquid mixed flow are ejected from the nozzle outlet 8 to form a wide spray pattern and evenly distributed spray plane, and a large number of fine droplets move with the high-speed gas flow and finally deposit on the plants.

[0060] As Figure 4 shown, a design method for a low-pressure wide-width gas-liquid two-phase atomizing nozzle in this embodiment includes the following steps:

[0061] Step 1: Calculate the optimal flow path surface of the contraction acceleration chamber according to the given conditions, and obtain the specific structures and dimensions of the transverse jet windward mixing chamber and the contraction acceleration chamber;

[0062] The calculation formula for the optimal flow channel surface of the contraction acceleration chamber is as follows:

[0063]

[0064] Among them, R is the cross-sectional radius of each axial section, z is the axial coordinate, A is the area of each cross-section of the flow channel, ρ is the fluid density, V is the fluid velocity, A cr is the area at the thinnest part of the flow channel, which is taken as 2.89 cm in this embodiment 2 ρ cr is the fluid density at the thinnest part of the flow channel, V cr is the fluid velocity at the thinnest part of the flow channel, M is the Mach number, defined as the ratio of the fluid velocity to the local speed of sound v / c, and k is the adiabatic index of air;

[0065] First, according to the area A cr at the thinnest part of the flow channel, determine the relationship between the flow channel diameter R and the axial distance z. Substitute the area A cr at the thinnest part of the flow channel into the above calculation formula, and the relationship between the flow channel diameter R and the axial distance z can be obtained;

[0066] Secondly, determine the value range of the axial coordinate z according to the fluid Mach number M1 at the radial gas phase inlet. Substitute the fluid Mach number M1 at the gas phase inlet and the fluid Mach number M3 at the nozzle outlet into the above calculation formula. Since the fluid Mach number M3 at the nozzle outlet is taken as 1 under the low-pressure condition during calculation, the range of the axial coordinate z of the contraction acceleration chamber is finally obtained;

[0067] Furthermore, by combining the relationship between the flow channel diameter R and the axial coordinate z with the value range of the axial coordinate z (in this embodiment, 0.3 < z < 5.1), the optimal flow channel surface equation of the contraction acceleration chamber can be obtained and the specific structure and dimensions of the contraction acceleration chamber can be determined. Its mathematical expression is (dimension unit: mm):

[0068]

[0069] Finally, add a cylindrical long cavity with the same diameter as the inlet of the contraction acceleration chamber at the front of the contraction acceleration chamber, and open split liquid phase inlets at 0° and 180° directions at the bottom of the cavity, and open a radial gas phase inlet at 90° direction at the top of the cavity, so as to determine the specific structure and dimensions of the transverse jet windward mixing chamber;

[0070] Step 2: Calculate the contraction flow channel distribution angle of the five-channel diffusion chamber according to the given conditions, and obtain the specific structure and dimensions of the five-channel diffusion chamber;

[0071] First, according to the outlet cross-section of the contraction acceleration chamber obtained in Step 1, divide it equally as the starting surface of each flow channel of the five-channel diffusion chamber;

[0072] Secondly, calculate the angles between the flow channels. The calculation formula for the distribution angle of the contraction flow channels of the five-channel diffusion chamber is as follows:

[0073]

[0074] Among them, θ1 is the spray angle of the flow channel, which is taken as 10° in this embodiment, θ2 is the included angle between the inner spray beams, θ3 is the included angle between the outer spray beams, and θ4 is the spray width condition of the nozzle, which is taken as 110° in this embodiment;

[0075] Substitute the flow channel spray angle θ1 and the spray width condition θ4 of the nozzle into the above formula to calculate the included angle θ n between the center lines of the inner flow channels, w and the included angle θ

[0076]

[0077] between the center lines of the outer flow channels. Its mathematical expression (dimension unit: °) is: n and the included angle θ w between the center lines of the outer flow channels. Finally, in the front view plane, extend the starting surfaces of the flow channels of the five-channel diffusion chamber along the included angles θ

[0078] between the center lines of the inner flow channels and the included angle θ

[0079] Step 3: Calculate the pressure working conditions of the low-pressure wide-width gas-liquid two-phase atomizing nozzle according to the given conditions;

[0080]

[0081] Among them, P ext is the ambient pressure outside the low-pressure wide-width gas-liquid two-phase atomizing nozzle, which is taken as 1 atmospheric pressure in this embodiment, P * is the total pressure of the fluid in the pipeline, which is the sum of the dynamic pressure and the static pressure, P 1s is the required pressure of the gas source, P y is the required pressure of the liquid pump, M1 is the Mach number of the fluid at the radial gas-phase inlet, and M3 is the Mach number of the fluid at the nozzle outlet, which is taken as 1 under low-pressure conditions;

[0082] Substitute the Mach number M1 of the fluid at the radial gas-phase inlet and the Mach number M3 of the fluid at the nozzle outlet calculated in Step 1 into the above calculation formula to obtain the required pressure P 1s of the gas source. The required pressure of the liquid pump should be slightly greater than the gas source pressure, about 1.2 times P 1s Finally, determine the pressure working conditions of the low-pressure wide-width gas-liquid two-phase atomizing nozzle;

[0083] The pressure operating conditions of the low-pressure wide-width gas-liquid two-phase atomizing nozzle in this embodiment are calculated, and its mathematical expression (dimension unit: Pa) is:

[0084]

[0085] In order to verify the effectiveness and superiority of the low-pressure wide-width gas-liquid two-phase atomizing nozzle and its design method of the present invention, a physical nozzle was designed and processed, as Figure 5 shown. To clarify the atomization performance of the low-pressure wide-width gas-liquid two-phase atomizing nozzle, various methods were used to conduct spray performance tests on the low-pressure wide-width gas-liquid two-phase atomizing nozzle. The test nozzle 9 was installed on the test bracket. The liquid-phase pipeline 10 was split into two through a tee to access the split liquid-phase inlet 4 to provide the liquid phase. The gas-phase pipeline 11 was directly connected to the radial gas-phase inlet 2 to provide the gas phase. During the test, the diffractive laser particle size analyzer measured the particle size data of the droplet population in the spray fan 12 through laser diffraction images. The experimental scenario is as Figure 6 shown. The experimental data shows that the atomization characteristics of the low-pressure wide-width gas-liquid two-phase atomizing nozzle can fully meet the requirements of ultra-fine atomization and achieve precise pesticide application in plant protection operations. The detailed experimental conditions and data are shown in Table 1 and Table 2.

[0086]

[0087]

[0088]

[0089] As mentioned above, the above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed in this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claimed rights.

Claims

1. A low-pressure, wide-width gas-liquid two-phase atomizing nozzle, characterized in that: It includes a nozzle shell, a radial gas phase inlet, a split liquid phase inlet, a transverse jet windward mixing chamber, a contraction acceleration chamber, a five-channel diffusion chamber, and a nozzle outlet; The nozzle housing is integrally formed by injection molding and envelops the radial gas phase inlet, the split liquid phase inlet, the transverse jet windward mixing chamber, the contraction acceleration chamber, the five-channel diffusion chamber, and the nozzle outlet; The radial gas phase inlet is located at the top of the side wall of the transverse jet windward mixing chamber, connected to the transverse jet windward mixing chamber from the radial direction, and is perpendicular to the split liquid phase inlet; The split liquid phase inlet is located at the bottom of the side wall of the transverse jet windward mixing chamber, symmetrically connected to the transverse jet windward mixing chamber from both sides in the radial direction, and perpendicular to the radial gas phase inlet; The upper part of the side wall of the transverse jet windward mixing chamber is connected to the radial gas phase inlet, the bottom of the side wall is connected to the split liquid phase inlet, and the tail is connected to the contraction acceleration chamber; The head of the contraction acceleration chamber is connected to the transverse jet windward mixing chamber, and the tail is connected to the five-channel diffusion chamber; The shrinkage acceleration cavity curved surface presents a gradually shrinking shape and is calculated by a low-pressure wide-band gas-liquid two-phase atomizing nozzle design method; The five-channel diffusion chamber is composed of five contraction channels in the same plane, showing a claw-shaped distribution, and the midline angle between the channels is calculated by the design method of the low-pressure wide-band gas-liquid two-phase atomizing nozzle; The nozzle outlets are respectively connected to the flow channels of the five-channel diffusion chamber and lead to the external atmosphere.

2. The design method of a low-pressure wide-width gas-liquid two-phase atomizing nozzle as claimed in claim 1, characterized in that: The steps include: Step 1: Calculating the optimal flow channel surface of the contraction acceleration cavity according to given conditions; Step 2: Calculate the distribution angle of the contraction channel of the five-channel diffusion cavity according to given conditions; Step 3: Calculate the pressure working conditions of the low-pressure wide-range gas-liquid two-phase atomizing nozzle according to given conditions.

3. The design method of the low-pressure wide-width gas-liquid two-phase atomizing nozzle according to claim 2, characterized in that: In step 1, the calculation formula for the optimal flow channel surface of the contraction acceleration chamber is: Where R is the cross-sectional radius of each axial cross section, z is the axial coordinate, A is the area of ​​each cross section of the flow channel, ρ is the fluid density, V is the fluid velocity, and A cr is the area of ​​the narrowest part of the flow channel, ρ cr is the density of the fluid at the thinnest part of the flow channel, V cr is the velocity of the fluid at the narrowest part of the flow channel, M is the Mach number, which is defined as the ratio of the fluid velocity to the local speed of sound v / c, and k is the adiabatic index of the air; The optimal flow channel surface equation of the contraction acceleration chamber is calculated as follows: Among them, ln is a logarithmic function, which is a basic elementary function.

4. The design method of the low-pressure wide-width gas-liquid two-phase atomizing nozzle according to claim 2 is characterized in that: In step 2, the calculation formula for the distribution angle of the contraction channel of the five-channel diffusion cavity is: Among them, θ1 is the flow channel spray angle, θ2 is the inner spray beam angle, θ3 is the outer spray beam angle, and θ4 is the nozzle spray width condition; The relationship between the calculated inner and outer flow channel midline angles and the flow channel spray angle and nozzle spray width conditions is: Among them, θ n is the angle between the center lines of the inner flow channels, θ w It is the angle between the center lines of the outer flow channels.

5. The design method of the low-pressure and wide-width gas-liquid two-phase atomizing nozzle according to claim 2, characterized in that: In step 3, the calculation formula for the pressure working condition of the low-pressure wide-range gas-liquid two-phase atomizing nozzle is: Among them, P ext is the ambient pressure outside the low-pressure wide-range gas-liquid two-phase atomizing nozzle, P * is the total pressure of the fluid in the pipeline, which is the sum of dynamic pressure and static pressure, P 1s is the required pressure of the gas source, P y is the pressure required by the liquid pump, M1 is the Mach number of the fluid at the radial gas phase inlet, and M3 is the Mach number of the fluid at the nozzle outlet; The pressure working condition of the low-pressure wide-range gas-liquid two-phase atomizing nozzle is calculated as follows: The Mach number M1 of the fluid at the radial gas phase inlet and the Mach number M3 of the fluid at the nozzle outlet are calculated by step 1 of the low-pressure wide-width gas-liquid two-phase atomizing nozzle design method.

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