Dry ice air jet generation device and method

Abstract

The invention belongs to the technical field of dry ice air jet, particularly relates to a dry ice air jet generating device and method, and aims to form high-speed airflow by using compressed air and dry ice particles so as to be applied to the fields of industrial cleaning, surface treatment and the like. The main device comprises an air compressor, an air storage bottle, a high-pressure hose, a stop valve, a pressure release valve, a pressure gauge, a dry ice particle preparation system, an ejector and a self-oscillation nozzle. The method comprises the steps that the air compressor compresses air to high pressure and stores the air in the air storage bottle; the liquid carbon dioxide is pressurized and conveyed into the ice forming barrel through the plunger pump, and the liquid carbon dioxide is converted into dry ice through temperature and pressure changes; and the dry ice is cut into dry ice particles by the ultrasonic knife net. Then, the dry ice particles and compressed air are mixed in the ejector and accelerated to a high speed; and finally, spraying the mixture through a self-oscillation nozzle to form a high-speed dry ice air jet flow. By means of the method, the dry ice air jet can be efficiently and stably generated, and the method is suitable for various industrial applications such as cleaning, surface treatment and sand blasting. The device is simple in structure and convenient to operate, and has high application value.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of dry ice air jet, and particularly relates to a dry ice air jet generating device and method. BACKGROUND

[0002] With the increasing demand for industrial production and cleaning, dry ice blasting technology is widely used in surface treatment, cleaning and sandblasting due to its high efficiency, environmental protection and non-corrosion. The current preparation method of dry ice jet cleaning technology is intermittent ice supply and mechanical spraying method. For example, a Chinese patent with publication number CN 117206272A and the invention name of "an uninterrupted continuous ice supply grinding device for dry ice cleaning equipment" uses an independent ice maker to grind and supply dry ice, thereby realizing continuous supply of dry ice particles. However, this method uses finished dry ice, which has the problem of large loss of dry ice during transportation and storage. For example, a Chinese patent with publication number CN 117259350A and the invention name of "a dry ice cleaning method and a dry ice cleaning system" uses a fan combined with a spraying gun structure to realize dry ice spraying cleaning. The cleaning effect mainly depends on the airflow kinetic energy provided by the fan, but the airflow speed is low and the kinetic energy is insufficient, making it difficult to form a high-impact jet, which limits the cleaning efficiency.

[0003] In summary, the existing dry ice cleaning technology uses purchased finished dry ice, which is mechanically crushed and mixed with high-pressure air for spraying. This method has the problems of difficult transportation and storage, and large loss of dry ice. Therefore, there is an urgent need for a generation method and device that can instantly prepare dry ice, to better meet the dual needs of high efficiency and high reliability for industrial cleaning. Moreover, the traditional dry ice cleaning method usually relies on dry ice particles being sprayed by mechanical or gun, which has certain efficiency problems. SUMMARY

[0004] The purpose of the present application is to provide an instant preparation and high-speed spraying device for dry ice particles, which can fully mix dry ice particles with compressed air and accelerate the spraying to the target surface for efficient removal of dirt, coating or oxide.

[0005] To achieve the above purpose, the technical solution adopted by the present application is:

[0006] The dry ice air jet generating device comprises an air compressor, a gas storage cylinder connected with the air compressor, the air compressor being used for compressing air to a required high pressure and delivering the compressed air to the gas storage cylinder through a high-pressure hose for storage, the supply of the compressed air being controlled and monitored by a stop valve and a pressure gauge to ensure the stability of the air source; an ejector connected with the gas storage cylinder and a self-excited oscillation nozzle connected with the outlet of the ejector, and a dry ice particle preparation system connected with the inlet of the ejector; the dry ice particle preparation system comprises a liquid carbon dioxide tank, a plunger pump connected with the liquid carbon dioxide tank, a first Laval nozzle arranged at the outlet of the plunger pump, the outlet of the first Laval nozzle being connected with the tangential inlet of an ice-making cylinder, and the outlet of the ice-making cylinder being connected with the inlet of the ejector; the self-excited oscillation nozzle comprises an upstream nozzle, an oscillation cavity and a downstream nozzle which are communicated with each other; the liquid carbon dioxide is stored in a special gas cylinder and delivered to the dry ice preparation device after being pressurized by the plunger pump. The output pressure of the plunger pump is adjustable to ensure the stable injection of the liquid carbon dioxide and the completion of the phase change.

[0007] Further, the inner wall of the ice-making cylinder is provided with a spiral blade for preliminarily cutting the blocky dry ice formed after the expansion of the liquid carbon dioxide; the inner bottom of the ice-making cylinder is provided with a grid-shaped blade, and an ultrasonic vibration module is arranged on the grid-shaped blade, the module comprising a piezoelectric ceramic transducer, a variable amplitude rod and an ultrasonic generator; through high-frequency ultrasonic vibration, the grid-shaped blade generates micro-vibration when the dry ice passes through, so that the breaking and cutting capacity of the dry ice is enhanced, the particle adhesion is reduced, and the cutting uniformity is improved. The module adopts the piezoelectric ceramic driven ultrasonic transducer, and the required frequency and power are provided through the matching power module; in order to ensure the stable operation of the system under low-temperature working conditions, a low-temperature heat-conducting and heat-insulating layer is arranged outside the ultrasonic assembly, and an elastic connecting piece is arranged to avoid vibration transmission to the overall structure.

[0008] Further, the ejector comprises a main air flow channel, a dry ice inlet and a mixing cavity, and a second Laval nozzle is further arranged at the main air flow channel and the dry ice inlet, the outlet of the second Laval nozzle being communicated with the mixing cavity and connected with the self-excited oscillation nozzle through the outlet of the mixing cavity; the dry ice particles and the compressed air are mixed in the ejector. The ejector is composed of the main air flow channel, the dry ice inlet and the mixing cavity, a negative pressure is formed in the main channel to inhale the dry ice particles and realize uniform mixing. The ejector is made of low-temperature resistant and high-strength material to adapt to the high-speed flow field and low-temperature conditions; after mixing, the air flow enters the self-excited oscillation nozzle, the gas is further accelerated in the nozzle to form a supersonic jet, and the dry ice particles are sprayed at high speed to the target surface to produce an impact peeling effect.

[0009] Another object of the present application is to provide a jet flow method of the dry ice air jet generating device, comprising the following steps:

[0010] S1. Turn on the air compressor switch and compress air to the required high pressure; observe the pressure gauge on the air tank to ensure that the air pressure is stable within the set range, adjust the air flow through the stop valve, and ensure that the pressure relief valve is working properly to prevent overpressure;

[0011] S2. Open the liquid carbon dioxide bottle valve and start the plunger pump to transport liquid carbon dioxide from the storage tank to the ice cylinder for dry ice particle preparation. The liquid carbon dioxide is input into the ice cylinder at a pressure of 2 MPa under the action of the plunger pump, and suddenly expands to atmospheric pressure at the nozzle opening, with a pressure difference of 1.9 MPa. The liquid carbon dioxide undergoes adiabatic expansion, the temperature drops rapidly to form solid dry ice particles, which are cut into blocks by the spiral blade and then cut into uniform particles by the grid-shaped blade.

[0012] S3. The cut dry ice particles enter the ejector from the bottom of the ice cylinder, the air tank valve is opened, and high-speed compressed air flows into the tail of the ejector to form a negative pressure to attract the dry ice particles. The dry ice particles are fully mixed with the high-speed airflow to form a uniform dry ice-air mixture. The mixture flows from the ejector into the self-excited oscillating nozzle. In the convergent section of the nozzle, the mixture is compressed, the airflow velocity increases rapidly, and the mixture is further accelerated to supersonic speed in the divergent section of the nozzle, forming a high-impact dry ice-air jet.

[0013] Another object of the present application is to provide an application of a dry ice-air jet generating device for industrial cleaning, removing dirt, coating or oxides in surface treatment.

[0014] The present application has the following advantages:

[0015] 1. The liquid carbon dioxide jet condensation method is used to convert dry ice. Through expansion cooling, instant dry ice preparation is achieved, avoiding the problems of low-temperature storage, easy sublimation loss and safety hazards in the storage and transportation process in traditional methods.

[0016] 2. The dry ice particle preparation device integrated with spiral blades and grid-shaped blades is designed. The blade system introduces an ultrasonic auxiliary vibration device to make the dry ice cutting process more efficient and uniform. Ultrasonic vibration enhances the cutting process through high-frequency micro-vibration, reduces the risk of particle adhesion and blockage, and improves the quality of dry ice particles and the overall system stability.

[0017] 3. The ejector is designed with a Venturi effect structure to achieve efficient mixing of compressed air and dry ice particles. The side inlet of dry ice particles is set to form a negative pressure suction mechanism under the action of high-speed airflow in the main channel, improving the suction efficiency and uniformity of dry ice particles. The structure of the ejector mixing chamber prevents particle deposition and realizes continuous and stable mixed flow output.

[0018] 4. The nozzle adopts a self-excited oscillation structure, and the self-excited oscillation nozzle generates a self-excited oscillation effect. Traditional dry ice cleaning mainly utilizes the difference in thermal expansion performance of stains and adhering materials to remove the adhering materials. However, the self-excited oscillation effect induced by the pulsed dry ice jet can force the target to produce high-frequency vibration on the basis of the above-mentioned effect, and the inherent frequency difference between the stains and adhering materials can further improve the removal efficiency of the stains, rust and coating. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The application is a dry ice air jet generation method and device.

[0020] Figure 2 The application is a structure diagram of an ice forming cylinder in a dry ice particle generation system.

[0021] Figure 3 The application is a structure diagram of a grid-shaped blade.

[0022] Figure 4 The application is a structure diagram of an ultrasonic generator.

[0023] Figure 5 The application is a structure diagram of a piezoelectric ceramic transducer.

[0024] Figure 6 The application is a structure diagram of an ejector.

[0025] Figure 7 The application is a structure diagram of a self-excited oscillation nozzle.

[0026] 1. Air compressor; 2. Stop valve; 3. Gas cylinder; 4. Pressure relief valve; 5. Pressure gauge; 6. Liquid carbon dioxide tank; 7. Plunger pump; 8. First Laval nozzle; 9. Spiral blade; 10. Grid-shaped blade; 11. Ice forming cylinder; 12. Ejector; 13. Self-excited oscillation nozzle; 14. Piezoelectric ceramic transducer; 15. Amplitude horn; 16. Ultrasonic generator; 17. Main airflow channel; 18. Dry ice inlet; 19. Second Laval nozzle; 20. Mixing chamber. DETAILED DESCRIPTION

[0027] As Figures 1-7As shown, a dry ice air jet generating device includes an air compressor 1, a gas storage cylinder 3 connected to the air compressor, the air compressor being used to compress air to a required high pressure and deliver the compressed air to the gas storage cylinder through a high-pressure hose for storage, the supply of compressed air being controlled and monitored by a stop valve 2, a pressure gauge 5 and a pressure relief valve 4 to ensure the stability of the air source; an ejector 12 connected to the gas storage cylinder and a self-excited oscillating nozzle 13 connected to the outlet of the ejector, further comprising a dry ice particle preparation system connected to the inlet of the ejector; the dry ice particle preparation system comprises a liquid carbon dioxide tank 6, a plunger pump 7 connected to the liquid carbon dioxide tank, a first Laval nozzle 8 provided at the outlet of the plunger pump, the outlet of the first Laval nozzle being connected to the tangential inlet of an ice-making cylinder 11, and the outlet of the ice-making cylinder being connected to the inlet of the ejector; the self-excited oscillating nozzle comprises an upstream nozzle, an oscillating cavity and a downstream nozzle which are in communication with each other; the liquid carbon dioxide is stored in a special gas cylinder and delivered to the dry ice preparation device after being pressurized by the plunger pump; the output pressure of the plunger pump is adjustable to ensure stable injection of the liquid carbon dioxide and complete phase change. Further, the inner wall surface of the ice-making cylinder is provided with a spiral blade 9 for preliminarily cutting the block-shaped dry ice formed after the expansion of the liquid carbon dioxide; the inner bottom of the ice-making cylinder is provided with a grid-shaped blade 10, and an ultrasonic vibration module is arranged on the grid-shaped blade, the module comprising a piezoelectric ceramic transducer 14, an amplitude transformer 15 and an ultrasonic generator 16; through high-frequency ultrasonic vibration, the grid-shaped blade generates micro-vibration when the dry ice passes through, thereby enhancing the breaking and cutting capacity of the dry ice, reducing particle adhesion and improving cutting uniformity. The module adopts an ultrasonic transducer driven by a piezoelectric ceramic, and a required frequency and power are provided through a matching power module, in order to ensure stable operation of the system under low-temperature working conditions, an ultrasonic assembly is provided with a low-temperature heat-conducting and heat-insulating layer, and an elastic connecting piece is used to avoid vibration transmission to the overall structure. The ejector comprises a main airflow channel 17, a dry ice inlet 18 and a mixing cavity 20, and a second Laval nozzle 19 is further arranged at the main airflow channel and the dry ice inlet, the outlet of the second Laval nozzle being in communication with the mixing cavity and being connected to the self-excited oscillating nozzle 13 through the outlet of the mixing cavity; the dry ice particles and the compressed air are mixed in the ejector. The ejector is composed of the main airflow channel, the dry ice inlet and the mixing cavity, a negative pressure is formed in the main channel to suck in the dry ice particles and realize uniform mixing. The ejector is made of low-temperature-resistant and high-strength materials to adapt to high-speed flow field and low-temperature conditions; the mixed airflow enters the self-excited oscillating nozzle, the gas is further accelerated to form a supersonic jet in the nozzle, and the dry ice particles are sprayed at high speed to the target surface to produce an impact peeling effect.

[0028] A jet generating method of a dry ice air jet generating device, comprising the following steps:

[0029] First, turn on the air compressor switch and compress air to the required high pressure (e.g. 0.8 MPa). The compressed air is delivered to the air cylinder through a high-pressure hose. Observe the pressure gauge on the air cylinder to ensure that the air pressure is stable within the set range. Adjust the air flow through the shut-off valve and ensure that the pressure relief valve is working properly to prevent overpressure.

[0030] Next, open the valve of the liquid carbon dioxide cylinder and check the carbon dioxide storage pressure. Start the plunger pump and deliver the liquid carbon dioxide from the storage tank to the dry ice particle preparation device. Adjust the plunger pump output pressure as needed to ensure that the liquid carbon dioxide enters the ice-making cylinder at a stable flow rate. After the liquid carbon dioxide enters the ice-making cylinder, it is converted to dry ice through a rapid expansion and cooling process. Specifically, the liquid carbon dioxide is input into the ice-making cylinder at a pressure of about 2 MPa under the action of the plunger pump, and suddenly expands to atmospheric pressure (0.1 MPa) at the nozzle opening, with a pressure difference of about 1.9 MPa. During this expansion process, the liquid carbon dioxide undergoes adiabatic expansion, and the temperature drops rapidly, typically by about 50-60°C. According to thermodynamic data, when liquid CO2 undergoes adiabatic expansion below the critical point, a portion of it is converted to solid dry ice particles, and another portion is converted to gaseous CO2, absorbing the latent heat that drives the cooling of dry ice formation. This process relies primarily on the phase change latent heat of carbon dioxide and the adiabatic expansion mechanism. Under normal pressure conditions, the latent heat of vaporization of CO2 is about 571 kJ / kg, and its phase change cooling effect is sufficient to lower the local temperature to below -78.5°C, forming stable dry ice particles.

[0031] The ice-making cylinder is designed with a spiral blade and a grid-shaped blade:

[0032] The dry ice is initially cut into blocks by the spiral blade. The spiral blade is installed at an angle of 45 degrees relative to the direction of movement of the dry ice particles, which provides shear force and guides the dry ice to move downward along the spiral trajectory. This angle design ensures efficient primary cutting of the dry ice.

[0033] The block-shaped dry ice particles are further cut by the grid-shaped blade. To further improve the refinement effect and cutting efficiency of the dry ice particles, an ultrasonic vibration module is installed on the grid-shaped blade assembly. The module includes a piezoelectric ceramic transducer, an amplitude transformer, and an ultrasonic generator. When in operation, the transducer converts high-frequency electrical signals into mechanical vibrations, which act on the blade frame to produce micro-vibrations during the passage of the dry ice, effectively reducing the cutting resistance and improving the breaking rate and uniformity of the dry ice particles. The ultrasonic vibration frequency range is 20-40 kHz, and the amplitude is about 10-30 μm. Experiments show that this structure can make the final dry ice particle size distribution more concentrated, with an average particle size reduction of about 20%, and a significant decrease in particle clogging rate.

[0034] The cut dry ice particles enter the ejector from the bottom of the preparation device. The valve of the gas cylinder is opened, and high-speed compressed air flows into the tail of the ejector, forming a negative pressure to attract dry ice particles. In the ejector, dry ice particles are fully mixed with high-speed airflow to form a uniform dry ice-air mixture. The mixed gas stream flows from the ejector into the self-excited oscillating nozzle.

[0035] In the ejector, high-speed air forms a high-speed main flow through the converging section, and the dynamic pressure generates a Venturi effect, forming a local negative pressure at the dry ice side inlet. According to Bernoulli's law:

[0036]

[0037] The high-speed flow causes a drop in static pressure, generating a negative pressure that can attract and entrain dry ice particles. The negative pressure zone, together with the cross-sectional ratio of the mixing chamber and the flow velocity distribution, determines the ejector efficiency and particle delivery uniformity. Designing the angle between the gas inlet and the dry ice inlet at 30°, the length of the diffuser section, and the diameter of the mixing chamber can make the dry ice quickly wrapped, sheared, suspended, and uniformly forward after entering the mixing chamber. At the same time, the structure design of the mixing chamber avoids particle deposition or turbulent flow.

[0038] In the converging section of the nozzle, the mixed gas stream is compressed, and the airflow velocity rapidly increases. The mixed gas stream further accelerates to supersonic speed through the diverging section of the nozzle, forming a high-impact dry ice-air jet. The rectangular design of the nozzle ensures that the jet has a uniform velocity distribution, improving the cleaning effect.

[0039] Finally, the nozzle is aimed at the target surface, such as metal surfaces, molds, mechanical equipment, etc. Adjust the spray angle, spray distance, and flow rate to ensure that the jet acts on the target surface with the best effect. The high-speed jet uses the low temperature and impact force of dry ice particles to quickly remove dirt, grease, coatings, or oxides.

[0040] Equipment adjustment and optimization: Adjust the plunger pump pressure, grid blade density, and nozzle size to adapt to different cleaning objects and application scenarios.

[0041] Maintenance inspection: Regularly check the tightness of the air compressor and gas cylinder. Ensure the sharpness of the blades and the integrity of the grid-shaped blades. Maintain the nozzle to prevent blockage.

[0042] Safety precautions: Before use, check whether the equipment connection is firm to avoid high-pressure gas leakage. Wear protective equipment (such as goggles, earmuffs, gloves, etc.) when operating to prevent jet rebound injury. The working environment should be well ventilated to avoid high concentration of carbon dioxide accumulation.

[0043] Data support and calculation process:

[0044] To verify the working performance of the device, the key process parameters are theoretically calculated and analyzed to support the design rationality and technical implementation feasibility of the device. Performance analysis of compressed air system:

[0045] The output pressure of the air compressor is set to 0.8 MPa (gauge pressure), i.e. 0.9 MPa (absolute pressure). When the ambient temperature is 25°C, the density of compressed air under ideal gas state is estimated as:

[0046]

[0047] Assuming that the nozzle inlet diameter is 10 mm and the air flow rate is the sound speed (340 m / s), the area A ≈ 7.85 × 10 -5 m 2 The corresponding air mass flow rate is:

[0048]

[0049] In the dry ice preparation process, liquid carbon dioxide is suddenly released from a high pressure state of 2 MPa to a normal pressure of 0.1 MPa through a nozzle, resulting in a violent adiabatic expansion. Since there is no heat exchange with the outside during the expansion process (Q = 0), according to the first law of thermodynamics ΔU = Q - W, the internal energy of liquid CO2 decreases due to the work done on the outside, resulting in a rapid temperature drop, with a local temperature drop to below -78.5°C, which promotes the direct solidification of part of CO2 into dry ice. The theoretical temperature change of this process can be approximately calculated by the adiabatic expansion relationship of ideal gas:

[0050]

[0051] where T1 is the temperature before expansion, T2 is the temperature after expansion, P1 and P2 are the pressures before and after expansion, respectively, and γ is the adiabatic index of CO2 (about 1.3). Taking the normal temperature (about 273 K) and pressure change 2 MPa → 0.1 MPa as an example, the calculated gas temperature after ejection is about 205 K (-68°C), which is sufficient to drive the phase change to generate solid dry ice. Therefore, the present application realizes the phase change conversion of liquid carbon dioxide to dry ice under low temperature conditions through adiabatic expansion, without the need for an additional refrigeration system.

[0052] In the dry ice production process, liquid carbon dioxide (LCO2) is ejected into the atmosphere or low pressure environment by means of adiabatic expansion, in which process part of the gasification absorbs heat and becomes gaseous carbon dioxide, and part of the condensation becomes dry ice. This process can be regarded as an ideal adiabatic process, and according to the principle of energy conservation, the maximum mass ratio of liquid carbon dioxide converted into dry ice can be estimated. The relevant thermal property parameters of liquid CO2 at normal pressure are as follows: specific enthalpy of liquid CO2 (hl) ≈ 100 kJ / kg (-18℃); specific enthalpy of gaseous CO2 (hg) ≈ 398 kJ / kg (0.1 MPa); and specific enthalpy of dry ice (solid CO2) (h) ≈ 0-100 kJ / kg.

[0053] Theoretical conversion rate estimation:

[0054] Suppose 1 kg of liquid CO2 is adiabatically expanded, which is divided into two parts: one part with mass ms is condensed into dry ice; and one part with mass mg = 1-ms is vaporized into gas. According to the energy conservation equation:

[0055] h l =m s ·h s +(1-m s )·h g

[0056] Numerical estimation:

[0057]

[0058] Therefore, under ideal adiabatic conditions, at most about 74.9% of liquid CO2 can be converted into dry ice. However, in actual applications, due to factors such as heat loss, gas mixing, and nozzle structure, the conversion rate of dry ice usually fluctuates between 50% and 70%. With the use of high-efficiency nozzle structure and rapid expansion separation design, the conversion rate can reach about 70%. (Theoretical calculation of conversion rate)

[0059] Dry ice particle generation efficiency estimation:

[0060] The output pressure of the plunger pump is 2 MPa, and the liquid supply rate is 0.1 L / s. The mass conversion rate of liquid CO2 converted into dry ice is 70%, i.e.:

[0061]

[0062] Dry ice and air mixing mass mixing ratio:

[0063]

[0064] Maintaining the mixing ratio between 0.2 and 0.3 can achieve good jet stability and impact effect.

[0065] Jet velocity and energy:

[0066] Nozzle exit velocity estimated at 450 m / s, mixed mass flow of 0.35 kg / s, kinetic energy:

[0067]

[0068] The jet of the device has sufficient kinetic energy for industrial cleaning and surface stripping operations.

[0069] Dry ice particle size control data: The blade mesh diameter is set to 0.3-1 mm. It is measured that the average diameter of the particles is 0.5 mm, and the variance is ±0.1 mm. Ensure that the dry ice particle size is uniform and smooth, avoid nozzle blockage, and improve system stability.

Claims

1. A dry ice air jet generating device characterized by: The device comprises an air compressor, an air tank connected to the air compressor, an ejector connected to the air tank, and a self-excited oscillation nozzle connected to the outlet of the ejector, and further comprises a dry ice particle preparation system connected to the inlet of the ejector; the dry ice particle preparation system comprises a liquid carbon dioxide tank, a plunger pump connected to the liquid carbon dioxide tank, a first Laval nozzle provided at the outlet of the plunger pump, a tangential inlet of an ice-making cylinder connected to the outlet of the first Laval nozzle, and an outlet of the ice-making cylinder connected to the inlet of the ejector; the self-excited oscillation nozzle comprises an upstream nozzle, an oscillation cavity, and a downstream nozzle which are in communication with each other.

2. The dry ice air jet generating device according to claim 1, wherein: The inner wall of the ice-making cylinder is provided with a spiral blade, and the inner bottom of the ice-making cylinder is provided with a grid-shaped blade, and an ultrasonic vibration module is arranged on the grid-shaped blade, the module comprising a piezoelectric ceramic transducer, an amplitude transformer, and an ultrasonic generator.

3. The dry ice air jet generating device according to claim 2, wherein: The ejector comprises a main airflow channel, a dry ice inlet, and a mixing chamber, and a second Laval nozzle is further arranged at the main airflow channel and the dry ice inlet, the outlet of the second Laval nozzle is in communication with the mixing chamber and connected to the self-excited oscillation nozzle through the outlet of the mixing chamber.

4. The dry ice air jet generating method of any one of claims 1 to 3, wherein The device comprises the following steps: S1. Turn on the air compressor switch and compress air to the required high pressure; Observe the pressure gauge on the air tank to ensure that the air pressure is stable within the set range, adjust the air flow through the stop valve, and ensure that the pressure relief valve is working properly to prevent overpressure; S2. Open the liquid carbon dioxide tank valve and start the plunger pump to transport the liquid carbon dioxide from the tank to the ice-making cylinder of the dry ice particle preparation system, the liquid carbon dioxide is input into the ice-making cylinder at a pressure of 2 MPa under the action of the plunger pump, and is suddenly expanded to atmospheric pressure at the nozzle opening, with a pressure difference of 1.9 MPa, the liquid carbon dioxide undergoes adiabatic expansion, the temperature drops rapidly to form solid dry ice particles, which are cut into blocks by the spiral blade and then cut into uniform particles by the grid-shaped blade; S3. The cut dry ice particles enter the ejector from the bottom of the ice-making cylinder, the air tank valve is opened, and high-speed compressed air flows into the ejector from the tail, forming a negative pressure to attract the dry ice particles, the dry ice particles are fully mixed with the high-speed airflow to form a uniform dry ice-air mixture, and the mixture flows from the ejector into the self-excited oscillation nozzle, in the converging section of the nozzle, the mixture is compressed, the airflow velocity increases rapidly, the mixture further accelerates to supersonic speed through the diverging section of the nozzle, and a high-impact dry ice-air jet is formed.

5. Use of a dry ice air jet generating device according to any one of claims 1 to 3, characterized in that: The device is used for removing dirt, coating or oxides in industrial cleaning and surface treatment.

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