A device and method for producing a jet of straight-corkscrew mixed ice particles on the spot by means of flash evaporation of a high-pressure superheated liquid

Abstract

The application belongs to the technical field of ice particle jet, and particularly relates to a device and a jet method for preparing straight-rotation mixed ice particle jet by using high-pressure superheated liquid flash evaporation, which comprises a high-pressure superheated liquid supply system and a water supply system, the high-pressure superheated liquid supply system and the water supply system are respectively connected with a straight-rotation mixed ice particle generation jet, the straight-rotation mixed ice particle generation jet system is connected with a recovery system, the recovery system is connected with the high-pressure superheated liquid supply system through a pipeline, the straight-rotation mixed ice particle generation jet system comprises a double-layer sleeve, the inner layer of the double-layer sleeve is connected with the water supply system, the outer layer is connected with the high-pressure superheated liquid supply system, an impeller is arranged at the outlet of the double-layer sleeve, a convergent atomizing nozzle is arranged at the outlet of the impeller, a protective shell is arranged outside the convergent atomizing nozzle, the convergent atomizing nozzle and the impeller center line are coincided with the inner layer, and the superheated liquid flash evaporation in the application has high refrigeration power and high speed, and can complete ice particle preparation in a short time.

Description

Technical Field

[0001] This invention belongs to the field of ice particle jet technology, and particularly relates to an apparatus and jetting method for instantaneous preparation of direct-swirl mixed ice particle jets using high-pressure superheated liquid flash evaporation. Background Technology

[0002] Ice particle jetting is a new, environmentally friendly process used for cleaning, descaling, rust removal, and paint removal. It's a type of sandblasting paint stripping that uses ice particles instead of abrasives, forming a high-speed particle stream under the action of high-speed gas. Ice particles have moderate hardness and are considered non-corrosive abrasives, causing minimal damage to the workpiece. The residue on the workpiece surface consists only of water and solid paint residue, greatly reducing the negative impact of paint stripping on the working environment. Furthermore, the process does not alter the mechanical, physical, or chemical properties of the material, thus broadening its applicability.

[0003] Because air jets have low abrasiveness, the abrasive performance of ice particles determines the treatment effect of ice particle jets. Ice particle preparation and jetting are crucial for erosion operations. Currently, the main method for ice particle preparation is direct contact freezing with refrigerant, such as the Chinese patent CN114434336A, entitled "An apparatus and jetting method for the immediate preparation and utilization of ice particles." This method uses a droplet generator to generate droplets of different sizes, which are injected onto the outer wall of an ice-forming chamber containing liquid nitrogen. The droplets fall into a collection chamber via a scraper, and a high-pressure airflow erodes the workpiece through an ejector pipe. However, using a syringe to generate water droplets is inefficient, and ice particles may aggregate within the ice particle collection chamber, affecting the quality and quantity of ice formation. Furthermore, using high-speed airflow to accelerate the ice particle erosion process increases energy consumption.

[0004] This device employs an atomizing nozzle based on the direct contact freezing method. Water and superheated liquid converge in the nozzle's acceleration zone before being sprayed out. The refrigerant passes through the impeller and comes into direct contact with the water flow in the nozzle's acceleration zone. The application of direct swirling mixing jet technology allows for more uniform mixing of the superheated liquid and water droplets, thereby improving ice-making efficiency. Utilizing the superheated liquid flash evaporation method, the temperature drops rapidly to generate ice particles. After flash evaporation, the superheated gas expands rapidly, generating pressure. Under pressure, the ice particles regain velocity, accelerating them and thus eroding the workpiece. The equipment is simple and reduces energy consumption. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus and method for instantaneous preparation of a swirling mixed ice particle jet using high-pressure superheated liquid flash evaporation. The invention primarily uses superheated liquid as a coolant, and employs a double-layered sleeve and a double-layered contractile atomizing nozzle to fully accelerate the droplets. The superheated liquid reaches the impeller through the sleeve. The gas after flash evaporation at the impeller outlet is in a swirling motion. Compared to a conventional jet without swirling, the swirling jet expands more rapidly after exiting the nozzle, with enhanced entrainment effect. This helps to enhance the mixing effect near the inner nozzle outlet and prevents the flashed, rotating superheated gas ice particles from adhering to the inner wall of the nozzle. The flash evaporation of the superheated liquid at the atomizing nozzle outlet has two advantages: firstly, the temperature drops sharply at the nozzle outlet, rapidly reducing the droplet temperature below the freezing point; secondly, the pressure gradient force formed by the expansion of the superheated liquid during flash evaporation further accelerates the ice particles. These two points reduce system energy consumption, improve ice particle generation efficiency, effectively solve the problem of ice particle storage and transportation, and achieve integration of ice particle preparation and ice particle jetting.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An apparatus for instantaneous preparation of a swirling mixed ice particle jet using flash evaporation of a high-pressure superheated liquid includes a high-pressure superheated liquid supply system and a water supply system. The high-pressure superheated liquid supply system and the water supply system are respectively connected to a swirling mixed ice particle jet generation system. The swirling mixed ice particle jet generation system is connected to a recovery system, which is connected to the high-pressure superheated liquid supply system via a pipeline. The swirling mixed ice particle jet generation system includes a double-layered pipe; the inner layer of the double-layered pipe is connected to the water supply system, and the outer layer is connected to the high-pressure superheated liquid supply system. The outlet of the inner layer of the double-layered pipe is welded together. The equipment is simple and... The sleeve outlet can be replaced as needed. The threaded connection end of the impeller corresponds to the outlet of the double-layer sleeve. An impeller is located at the outlet of the double-layer sleeve, and a contractile atomizing nozzle is located at the outlet of the impeller. A flow field region is formed within the contractile atomizing nozzle. High-pressure superheated liquid enters the contractile atomizing nozzle after the impeller rotates. Because the nozzle is connected to the outside, the temperature inside the nozzle has reached the boiling point of the superheated liquid. The resulting rotating gas carries ice particles into the flow field. The flow field region is divided into an initial stage and a second stage. The initial stage of the flow field region includes two-phase gaseous carbon dioxide and water droplets. In this stage, some liquid carbon dioxide flashes and becomes gaseous carbon dioxide. The ambient temperature is -73°C. The ambient temperature reaches the freezing point, but due to the short residence time of water droplets in the initial stage, ice particles have not yet formed, and liquid carbon dioxide partially flashes away. The second stage of the flow field region includes gaseous carbon dioxide, ice particles formed by water droplets after cooling, and dry ice. After the liquid carbon dioxide completely flashes away, its volume expands by about 450 times, and the high-speed airflow accelerates the ice particles to erode the workpiece again. The shrinking atomizing nozzle and impeller are both located on the inner wall of the outer layer, and their centerlines coincide with the inner layer of the double-layer sleeve. The superheated liquid and water are respectively transported to the inner and outer layers of the impeller in the ice particle generating jet system, and the two converge at the outlet of the inner layer of the shrinking atomizing nozzle. The high-pressure rotating superheated gas accelerates the water droplets along the axial direction at the outlet of the inner layer of the nozzle. After reaching the outer layer outlet, the superheated liquid flashes away to generate low temperature, and the water droplets cool into ice particles and form an ice particle jet under high-speed motion.

[0008] Furthermore, the impeller includes an inner tube located at the center and an outer tube outside the inner tube. The inner tube is connected to the inner layer of the double-layer sleeve, and the outer tube is threadedly connected to the outer layer of the double-layer sleeve. Multiple arc-shaped strips are evenly distributed tangentially on the outer circumference of the inner tube. Each arc-shaped strip is arranged along the outer tangential direction of the inner tube, and the inner tube and the outer tube are connected by the arc-shaped strips.

[0009] Furthermore, the contractile atomizing nozzle includes a tapered outer shell with a gradually tapering cross-section, an inner channel located at the center of the outer shell and connected to the inner tube of the impeller, and an acceleration tube located at the end of the inner channel. The smallest diameter of the outer shell is connected to the acceleration tube. The outlet diameter of the inner channel is 1 mm, and the outlet diameter of the outer shell is 3 mm. The outlet of the inner layer of the nozzle and the outlet of the outer layer are 10 cm apart, forming a space as an acceleration zone, where high-pressure direct-rotation carbon dioxide fully accelerates and swirls the droplets. Atomizing nozzles of different diameters are installed according to the required parameters such as different atomized particle diameters, nozzle flow rates, and spray angles. The contractile atomizing nozzle is equipped with a protective shell, the outer diameter of which is the same as that of the outer layer.

[0010] Furthermore, the superheated liquid is selected as liquid carbon dioxide. The high-pressure superheated liquid supply system includes a carbon dioxide cylinder, a pneumatic booster pump connected to the outlet of the carbon dioxide cylinder, a high-pressure pipeline connecting the outlet of the carbon dioxide cylinder to the inlet of the pneumatic booster pump with a one-way valve on the pipeline, a cold bath connected to the outlet of the pneumatic booster pump, a high-pressure pipeline connecting the outlet of the pneumatic booster pump to the inlet of the cold bath with a one-way valve on the pipeline, an outlet pipeline of the cold bath connected to the inlet of the storage tank, a circulation pump between the cold bath and the storage tank, a coiled pipe inside the cold bath, and a jacket outside the storage tank. Antifreeze is stored in both the coiled pipe and the jacket. The circulation pump is connected to the coiled pipe and the inlet pipeline of the jacket, respectively, and draws antifreeze from the cold bath into the jacket of the storage tank for continuous cooling. The outlet pipeline of the storage tank is connected to the inlet of the plunger pump, and the outlet pipeline of the plunger pump is connected to the outer layer of the double-layered sleeve. There are two carbon dioxide cylinders, each with a cylinder pressure of 6 MPa, to ensure the supply of carbon dioxide. At room temperature, the carbon dioxide inside the carbon dioxide cylinder is liquid, and its pressure is constant at a certain temperature. As the gas in the gas phase space is used, the liquid carbon dioxide begins to vaporize, replenishing the gas phase pressure and thus providing carbon dioxide. A one-way valve is used to prevent carbon dioxide backflow. Antifreeze is injected into the cold bath until it submerges the pipes inside the cold bath. The antifreeze used in this experimental setup is an ethylene glycol-based diluent, which can ensure that the minimum temperature is reduced to -5 ℃. Temperature sensors and pressure gauges are installed in the storage tank to monitor the temperature and pressure of carbon dioxide, and a temperature controller is installed to precisely regulate the temperature, ensuring that the antifreeze temperature is maintained at 2 ℃. An electromagnetic flowmeter is installed at the outlet of the storage tank, which is a high-precision and reliable device for measuring fluid flow.

[0011] Furthermore, the water supply system includes a water supply tank, an outlet pipe of which is connected to a centrifugal booster pump, and an outlet pipe of which is connected to the inner layer of a double-walled pipe. There is only one water supply tank. A first electromagnetic flow meter is installed on the pipe between the water supply tank and the centrifugal booster pump to facilitate control of the number of subsequent water droplets generated. A third pressure gauge and valve are installed on the centrifugal booster pump and the double-walled pipe. The third pressure gauge is used to measure the pressure of the boosted water.

[0012] Furthermore, the recovery system includes a rust-removing pressure chamber. Inside the rust-removing pressure chamber, directly opposite the outlet of the accelerating tube, is a workpiece. The rust-removing pressure chamber has an outlet pipe connected to the inlet of a cyclone separator. The outlet of the cyclone separator is connected to the inlet of a gas separator. The outlet of the gas separator is connected to an analyzer. The analyzer's outlet pipe is divided into two paths: one connected to a cold bath chamber, and the other connected to the inlet of the cyclone separator. The analyzer is equipped with a display and an alarm. The gas separator consists of a molecular sieve and a polymer membrane (specific types of polymer membranes include polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVAc), which can isolate water vapor through carbon dioxide gas). Carbon dioxide gas and water vapor first pass through the molecular sieve and then through the specific membrane. The molecular sieve has selective adsorption properties, capable of separating specific components in the mixed gas based on the size, shape, and polarity of the molecules. For a mixture of carbon dioxide and water vapor, molecular sieves preferentially adsorb water molecules because water molecules are more polar than carbon dioxide molecules and are more easily adsorbed by the polar pores of the molecular sieve. The analyzer used is an infrared carbon dioxide analyzer, a device that uses infrared spectroscopy to detect the concentration of carbon dioxide in a gas. This analyzer typically consists of an infrared light source, an optical path, an infrared detector, circuitry, and software algorithms. Inside the analyzer is a specially designed infrared light source that emits infrared light of a specific wavelength. This infrared light passes through the gas being measured and is captured by the detector. The signal is then processed by the circuitry and software algorithms to obtain the carbon dioxide concentration value. The infrared light source emits infrared light in the wavelength range of 1-20 μm. This light is absorbed by a gas cell of a certain length, then passes through a narrow-band filter before finally reaching the infrared detector. The detector monitors the intensity of the transmitted infrared light of a specific wavelength to represent the concentration of CO2 gas.

[0013] Furthermore, the cyclone separator includes a shell, comprising a top cylindrical body and a bottom conical body. The top center of the cylindrical body has an outlet, and the upper part of the cylindrical body has a tangential gas inlet. The lower part of the cylindrical body has guide vanes, and the bottom outlet of the shell has a vortex stabilizer. The cyclone separator allows dust-laden gas to enter tangentially through the inlet, a design intended to create a strong rotating airflow inside. During rotation, due to the inertia of the particles, solid particles or droplets are thrown against the outer wall of the cyclone separator and slide down the wall to the dust discharge pipe for discharge. By installing guide vanes, vortex stabilizers, and other internal components inside the cyclone separator, most of the gas, after rotating and descending to the bottom of the cone, will generate an upward inward swirling flow due to the structural design. Finally, the purified gas leaves the cyclone separator from the top outlet. The guide vanes inside the cyclone separator cause the axially entering gas to rotate, helping to maintain the axial symmetry of the internal airflow, which is crucial for improving separation efficiency and reducing pressure loss. Spiral guide vanes effectively guide airflow and improve separation efficiency. They also affect the critical particle size of the separated particles, i.e., the smallest particle size that can be effectively separated. The vortex stabilizer at the bottom of the cyclone separator mainly stabilizes the airflow, reduces turbulence and eddies, and thus improves separation efficiency.

[0014] Furthermore, the high-pressure superheated liquid is carbon dioxide, each pipeline is equipped with a valve, the storage tank is equipped with a temperature sensor, a first pressure gauge and a temperature controller, the plunger pump outlet pipeline is equipped with a second pressure gauge and a first electromagnetic flow meter, the centrifugal booster pump outlet pipeline is also equipped with a third pressure gauge, the water supply tank outlet pipeline is also equipped with a second electromagnetic flow meter, and the rust removal pressure chamber outlet pipeline is also equipped with a constant pressure valve and a fourth pressure gauge.

[0015] A jetting method using an apparatus for instantaneous preparation of a direct-swirl mixed ice particle jet via flash evaporation of a high-pressure superheated liquid includes the following steps:

[0016] (1) Add distilled water to the water supply tank, check the gas cylinder content and the airtightness of each valve and pipe connection, and check whether each pressure gauge and temperature sensor can be used normally;

[0017] (2) Check if the analyzer is operating normally;

[0018] (3) Install the prepared shrinkable atomizing nozzle at the impeller outlet and place the workpiece in the rust removal pressure chamber;

[0019] (4) Adjust the diameter of the first electromagnetic flowmeter and the second electromagnetic flowmeter to ensure that the fluid flow through them is the same. Set the diameter of the two electromagnetic flowmeters to be the same to ensure that the inner and outer discharge control of the contractile atomizing nozzle is the same, the water droplets are cooled evenly, and the ice particle generation in the initial stage and the ice particle jet operation in the second stage are continuous.

[0020] (5) Open the outlet valve of the gas cylinder, then turn on the pneumatic booster pump and the circulation pump, and observe the temperature sensor and the first pressure gauge reading of the storage tank. When the first pressure gauge reading is 4 MPa and the temperature sensor reading is 2 ℃, open the valve and then turn on the plunger pump, and observe the second pressure gauge reading at the plunger pump.

[0021] (6) Simultaneously turn on the water supply tank switch, the centrifugal booster pump switch and the valve, and observe the reading of the third pressure gauge. Adjust the centrifugal booster pump to make the reading of the third pressure gauge 0.5 MPa.

[0022] (7) Adjust the plunger pump to make the second pressure gauge reading 45 MPa, and open its outlet pipeline valve;

[0023] (8) The water flow accelerated by liquid carbon dioxide turns into water droplets through the nozzle outlet. After the liquid carbon dioxide flashes, the lowest ambient temperature is -74 ℃, forming ice particles generated by the high-speed airflow, which then form an ice particle jet to erode the workpiece.

[0024] (9) After the workpiece erosion is completed, observe the fourth pressure gauge and the display, turn off the water supply tank switch and the centrifugal booster pump switch, and then turn off the carbon dioxide cylinder switch, the pneumatic booster pump switch and the circulation pump switch. The system will stop working.

[0025] The calculation process during operation is as follows: In this invention, the superheated liquid must be a gaseous fluid medium with high latent heat of vaporization, low specific heat capacity, and no toxicity or pollution under standard conditions (0 ℃, 101.325 kPa) to improve the flash boiling refrigeration efficiency. The technical solution is explained in detail below using carbon dioxide as an example:

[0026] Equations of state are fundamental functional relationships describing the temperature, pressure, and volume of a fluid. In calculations involving carbon dioxide, the BWR equation, as a multi-parameter equation for a real gas, can be extended from the gas phase to the liquid phase; therefore, this equation is used for calculations.

[0027]

[0028] Where P is pressure, T is temperature, and V is molar volume. A0, B0, C0, a, b, c, α, and γ are all empirical parameters that can be obtained from literature. For carbon dioxide, the parameters are as follows:

[0029] parameter <![CDATA[ A 0]]> <![CDATA[ B 0]]> <![CDATA[ C 0]]> unit <![CDATA[(cm 3 g mol -1 ) 2 bar]]> <![CDATA[cm 3 g mol -1 ]]> <![CDATA[(cm 3 g mol -1 ) 2 K 2 bar]]> <![CDATA[(cm 3 g mol -1 ) 3 bar]]> numerical values <![CDATA[2. 52730×10 6 ]]> <![CDATA[4. 32945×10 1 ]]> <![CDATA[1.43215×10 11 ]]> <![CDATA[1.30765×10 8 ]]> parameter unit <![CDATA[(cm 3 g mol -1 ) 2 ]]> <![CDATA[(cm 3 gmol -1 ) 3 K 2 bar]]> <![CDATA[(cm 3 g mol -1 ) 3 ]]> <![CDATA[(cm 3 g mol -1 ) 2 ]]> numerical values <![CDATA[4.18926×10 3 ]]> <![CDATA[1.33125×10 13 ]]> <![CDATA[6.47800×10 4 ]]> <![CDATA[4.48266×10 3 ]]>

[0030] Flash boiling phase transition occurs in a very short time, and the phase transition process can be considered adiabatic. When the ambient pressure is higher than the triple point (0.52 MPa), carbon dioxide flash boiling is a gas-liquid phase transition; when the ambient pressure is lower than 0.52 MPa, a gas-liquid-solid three-phase transition may occur due to the imbalance between the sensible heat and latent heat of carbon dioxide itself.

[0031] At atmospheric pressure of 0.103 MPa, liquid carbon dioxide cannot exist stably, while solid carbon dioxide can only be stably stored at 0.103 MPa pressure when the temperature is below -78.5℃. The phase transition relaxation time of carbon dioxide from metastable to steady state at environmental pressures below 0.52 MPa is extremely short; therefore, its phase transition process can be assumed to be an adiabatic expansion process. During the flash boiling of liquid carbon dioxide, the collapse of bubbles and the expansion work done by the vapor, along with the consumption of latent heat during bubble growth, cause a rapid temperature drop. When the temperature falls below the freezing point at the current environmental pressure, dry ice is formed. The heat released by the solidification of carbon dioxide is absorbed by the remaining liquid carbon dioxide, which continues to turn into a gaseous state until it enters the gas-solid two-phase equilibrium region at a certain distance from the nozzle. Assuming that the temperature of carbon dioxide in the gas-solid two-phase region is the condensation temperature corresponding to this environmental pressure, the specific volume v11 and enthalpy h11 of the gaseous carbon dioxide at this point can be calculated based on this temperature and environmental pressure, and then the expansion work W11 can be calculated. The main error in this method stems from treating the dry ice produced during the carbon dioxide phase transition as a gaseous state, thus overestimating the enthalpy of carbon dioxide at the end of the phase transition. As mentioned earlier, if the phase transition process of carbon dioxide from the nozzle into the environment is considered as adiabatic expansion, i.e., the enthalpy h1 = ht after the flash boiling of carbon dioxide ends, then the carbon dioxide phase transition energy can be calculated using the following formula:

[0032]

[0033] With Pin = 50 MPa, Tin = 303.15 K, Pamb = 1 MPa, and a tank capacity of 1 m³, 3 For example, the liquid density at this time is 1020 kg / m³. 3 Given an entropy s0 of 1.0115, and based on the pressure-enthalpy diagram, Pt = 3.61 MPa, Tt = 274.49 K, and ht = 203.28 kJ / kg, the gas-liquid two-phase density at the nozzle outlet is 87.378 kg / m³. 3 The volume expanded 11.7 times, that is, increased by 10.7 m³. 3 This expansion occurs under an ambient pressure of 1 MPa. The work done by the expansion is W = PSL = PV, where P is in Pa and S is the area in meters. 2 L is the distance, in meters. W = 10⁶ Pa * 10.7 m 3 =10700 kJ, meaning that 1L of liquid carbon dioxide can release 10.7kJ of energy.

[0034] The process by which the phase change potential energy is converted into impact kinetic energy mainly involves converting internal energy and pressure potential energy into expansion work. Therefore, if we consider the flash boiling of carbon dioxide as the work done by a high-pressure adiabatic expanding gas, assuming the initial state of carbon dioxide is 0 and the state after the phase change is 1, the phase change energy can be calculated using the following formula:

[0035]

[0036] The entropy of carbon dioxide inside the storage tank can be calculated using the following formula:

[0037]

[0038] Where S0, T0, and P0 are the parameter values ​​corresponding to carbon dioxide under standard conditions, VA and VB are the carbon dioxide volumes corresponding to temperatures T0 and T1, respectively, and the calculated isobaric heat capacity of carbon dioxide at 101.3 kPa is 44.141 JK. -1 ·mol -1 9.037 JK -1 ·mol -1 -8.535 JK -1 ·mol -1 And 0.

[0039] Enthalpy can be calculated using the following formula:

[0040]

[0041] in, The enthalpy under standard conditions is 484.89 KJ / Kg.

[0042] Because the phase transition relaxation time of carbon dioxide from metastable to steady state is extremely short, its flash boiling phase transition process can be assumed to be adiabatic. Carbon dioxide has low sensible heat and high latent heat of vaporization; the heat it carries is insufficient to meet its endothermic vaporization requirements, therefore, carbon dioxide is often used as a refrigerant. Assuming a carbon dioxide mass flow rate of m1 kg / min, temperature T0, and pressure P0, the initial carbon dioxide enthalpy h0(T0, P0) can be obtained using the property parameter lookup software REFPROP based on the temperature and pressure. In the actual experiment, the ambient pressure is P1 and the temperature is T1. The corresponding saturation temperature at the current ambient pressure is Ta (obtained from a table). Assuming that carbon dioxide undergoes complete adiabatic expansion to a saturated gaseous state, the saturation enthalpy of carbon dioxide at ambient pressure P1 can be calculated using REFPROP software. (Ta, P0); After the atomized water droplets are added, they mix with carbon dioxide in the near-field region. The temperature of the atomized water droplets decreases rapidly due to the endothermic effect of the carbon dioxide flash boiling phase change. Assuming the initial water conditions are temperature T2, pressure P2, and water spray flow rate is m2 kg / min, the isobaric specific heat capacity Cpw of the initial water is obtained using the REFPROP property parameter lookup software based on temperature and pressure. Then, the heat required for the carbon dioxide flash boiling phase change is... The droplet temperature can be calculated using the following formula: kJ / min.

[0043]

[0044] The time required for a water droplet to completely solidify can be calculated using the following formula:

[0045]

[0046] in, The density of ice particles; The latent heat of solidification of water; The droplet size of the water atomization liquid; is the thermal conductivity of ice; is the convective heat transfer coefficient.

[0047] The convective heat transfer coefficient is calculated using an empirical formula:

[0048]

[0049] The flow rate of the carbon dioxide flash boiling jet, as well as the inlet temperature and pressure conditions, are determined based on the actual water atomization particle size and flow rate during the operation to ensure that the atomized droplets solidify before impacting the target.

[0050] The advantages of this invention are:

[0051] 1. This invention uses superheated liquid as the refrigeration medium, which is simple to control parameters but has low storage and transportation costs;

[0052] 2. The direct-rotation mixing low-temperature ice particle preparation process proposed in this invention drives the water droplets to rotate, which can effectively avoid ice blockage inside the pipeline and nozzle;

[0053] 3. The superheated liquid flash refrigeration proposed in this invention has high power and fast speed, and can complete the preparation of ice particles in a short time;

[0054] 4. This device does not require an ejector device. The pressurization time of the superheated liquid using a plunger pump is short, and the high pressure generated by the flash boiling phase change expansion can also drive the ice particles to accelerate, which simplifies the equipment and reduces the energy consumption of using high-pressure equipment.

[0055] 5. The cyclone separator of the present invention can improve the internal flow stability without changing the structural dimensions of the cyclone separator, thereby improving the separation efficiency and reducing energy consumption;

[0056] 6. The gas separator used in this invention can perform double-layer filtration of the mixed gas, effectively improving the purity of carbon dioxide. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0058] Figure 2 This is a schematic diagram of the impeller structure in this invention.

[0059] Figure 3 This is a three-dimensional structural diagram of the atomizing nozzle and acceleration tube in this invention.

[0060] Figure 4 yes Figure 3 Cross-sectional view.

[0061] Figure 5 This is a schematic diagram of the flow field at the acceleration tube in this invention.

[0062] Figure 6 This is a schematic diagram of the cyclone separator in this invention.

[0063] Figure 7 yes Figure 6 Top view. Detailed Implementation

[0064] As shown in the figure, a device for instantaneous preparation of swirling mixed ice pellet jets using high-pressure superheated liquid flash evaporation mainly includes a high-pressure superheated liquid supply system, a water supply system, a swirling mixed ice pellet jet generation system, and a recovery system. The superheated liquid and water are respectively supplied to the inner and outer layers of the double-layered sleeve of the ice pellet jet generation system, and the two converge at the outlet of the contractile atomizing nozzle to generate ice pellets and form an ice pellet jet. Carbon dioxide is selected as the superheated liquid for illustration: The superheated liquid supply system includes carbon dioxide cylinders 1, a pneumatic booster pump 6, a cold bath chamber 10, a circulation pump 11, and a storage tank 12. There are two carbon dioxide cylinders 1, and their outlets converge into a main outlet pipe. This outlet is connected to the pneumatic booster pump 6, which transports the carbon dioxide gas to the cold bath chamber 10. The cold bath chamber is equipped with a coiled pipe 9. The outlet pipe of the cold bath chamber 10 is connected to the inlet of the storage tank 12. The circulation pump 11 is also connected between the cold bath chamber 10 and the storage tank 12. Several valves are installed on the outlet pipe of carbon dioxide cylinder 1 to control the amount of carbon dioxide discharged. Pneumatic booster pump 6 delivers the gas in carbon dioxide cylinder 1 to cold bath box 10. Cold bath box 10 is cooled by antifreeze 15. The interior has a spiral pipe 9 to increase the contact area between carbon dioxide and antifreeze 15. The outlet pipe of cold bath box 10 is connected to the inlet pipe of storage tank 12. Storage tank 12 is equipped with temperature sensor 14, first pressure gauge 13 and temperature controller 16. Temperature sensor 14 and first pressure gauge 13 are used to monitor the temperature and pressure inside the storage tank. Temperature controller 16 precisely adjusts the temperature of antifreeze to ensure that the storage tank 12 contains liquid carbon dioxide. The circulating pump 11 is a device that ensures the antifreeze 15 between the cold bath box 10 and the storage tank 12 flows between them and mixes them thoroughly, maintaining the low temperature conditions inside the storage tank. This completes the circulation of the antifreeze 15 and ensures that the temperature of the cold bath box 10 and the storage tank 12 is consistent. The outlet pipe of the storage tank 12 is connected to the inlet of the plunger pump 18, and a first valve 17 is installed on the pipe. The outlet of the plunger pump 18 has a second pressure gauge 19 and a first electromagnetic flowmeter 20 to detect the pressure of liquid carbon dioxide and control the flow rate, respectively. The water supply system includes a water supply tank 22 and a centrifugal booster pump 24. There is only one water supply tank 22. A second electromagnetic flowmeter 23 is installed on the outlet pipe to control the water flow rate and is connected to the centrifugal booster pump 24. A third pressure gauge 25 is installed on the outlet pipe of the centrifugal booster pump 24 to detect the pressure of the pressurized water, and a second valve 26 is installed to control the flow of the pressurized water. This outlet pipe is connected to the inner layer 28 of the double-layer casing.The ice particle generating jet system includes a double-layered sleeve 29, an impeller, and a contractile atomizing nozzle 31. The contractile atomizing nozzle includes a tapered outer shell with a gradually narrowing cross-section, an inner channel located at the center of the outer shell and connected to the inner tube of the impeller, and an acceleration tube located at the end of the inner channel. The minimum diameter of the outer shell is connected to the acceleration tube, which is the inner outlet flow field region 32 of the atomizing nozzle. A protective shell is provided outside the contractile atomizing nozzle, with the outer diameter of the protective shell being the same as that of the outer layer. Water flows through the inner layer 28 of the double-layered sleeve, and liquid carbon dioxide flows through the outer layer 27. The outlet of the double-layered sleeve 29 is connected to the impeller 30. The high-pressure superheated liquid enters the contractile atomizing nozzle 31 after the impeller 30 rotates. The outlet diameter of the inner channel of the atomizing nozzle is 1 mm, and the outlet diameter of the outer shell is 3 mm. The flow field region initially contains liquid carbon dioxide 52, partially gaseous carbon dioxide 53 after flash evaporation, and liquid water 51. The second stage contains ice particles 56, gaseous carbon dioxide 54, and dry ice 55. After the liquid carbon dioxide flashes, the pressure in the flow field region increases, providing velocity for the ice particles 56 to erode the workpiece. The recovery system includes a rust-removing pressure chamber 34, a cyclone separator 38, a gas separator 39, and an infrared carbon dioxide analyzer 44. The rust-removing pressure chamber 34 contains the workpiece 35. After erosion is completed, the dry ice 55 and ice particles 56 in the rust-removing pressure chamber 34 gradually evaporate, reacting with the generated... Gaseous carbon dioxide 54 enters the cyclone separator inlet 58 through the pipe containing the constant pressure valve 36. The cyclone separator includes a shell 60, which includes a cylindrical body at the top and a conical body at the bottom. The top center of the cylindrical body has an outlet, and the upper part of the cylindrical body has a tangential gas inlet. The lower part of the cylindrical body has guide vanes, and the bottom outlet of the shell has a vortex stabilizer. The guide vanes 59 and the vortex stabilizer 61 cause most of the gas to rotate and fall to the bottom of the cone, and then generate an upward internal swirling flow due to the structural design. Finally, the purified gas leaves the cyclone separator from the upper outlet 57.After being filtered by cyclone separator 38 to remove paint and rust residue, the gas enters gas separator 39 for further filtration. The gas separator consists of molecular sieve 40 and polymer membrane 41 (specific types of polymer membranes include polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVAc), which can isolate water vapor through carbon dioxide gas). Carbon dioxide gas and water vapor first pass through the molecular sieve and then through the specific membrane. Molecular sieve has selective adsorption characteristics and can separate specific components in the mixed gas according to the size, shape and polarity of molecules. For the mixed gas of carbon dioxide and water vapor, the molecular sieve can preferentially adsorb water molecules because water molecules are more polar than carbon dioxide molecules and are more easily adsorbed by the polar pore surface of the molecular sieve. The purified carbon dioxide flows through the pipeline into infrared carbon dioxide analyzer 44 to check the purity of carbon dioxide gas and observe the display 45. If the purity meets the standard, the third valve 48 will automatically open and the gas will flow back to the cold bath. If the alarm 46 sounds, the gas does not meet the standard, and the fourth valve 47 will automatically open and the gas will flow back to cyclone separator 38, and the molecular sieve 40 and specific membrane 41 will be checked.

[0065] In practical use, place the workpiece 35, adjust the flow rate of the first electromagnetic flowmeter 20 and the second electromagnetic flowmeter 23 to ensure consistency, and install the atomizing nozzle 31 with the required structure according to the required ice particle diameter. Open valves 2 and 3 of carbon dioxide cylinder 1, as well as the main valve 4. Start the pneumatic booster pump 6 and the circulation pump 11. The pneumatic booster pump 6 transports carbon dioxide gas into the cold bath box 10. The circulation pump 11 circulates the antifreeze 15 between the cold bath box 10 and the storage tank 12. The temperature controller 16 in the storage tank 12 controls the antifreeze 15 at 2°C. Observe the readings of the temperature sensor 14 and the first pressure gauge 13 in the storage tank 12. At the same time, open the water supply tank 22 switch, the centrifugal booster pump 24 switch, and the second valve 26, and observe the reading of the third pressure gauge 25. Adjust the centrifugal booster pump 24 to make the reading of the third pressure gauge 25 0.5 MPa. When the reading of the first pressure gauge 13 is 4 MPa and the reading of the temperature sensor 14 is 2°C, open the first valve 17, start and adjust the plunger pump 18, and adjust the second pressure gauge 19 to 45°C. MPa, open the seventh valve 21, use high pressure liquid carbon dioxide 50 to axially accelerate the water flow 49 and increase the rotational force, and after the liquid carbon dioxide 52 is completely flashed, its volume expands again to accelerate the ice particles 56 to form an ice particle jet, which erodes the workpiece 35.

[0066] An apparatus and method for instantaneous preparation of ice pellet jets using superheated liquid flash evaporation, comprising the following steps:

[0067] (1) Add distilled water to the water supply tank 22, check the content of carbon dioxide cylinder 1 and the airtightness of each valve and pipe connection, and check whether each pressure gauge and temperature sensor can be used normally.

[0068] (2) Check whether the infrared carbon dioxide analyzer 44 is operating normally.

[0069] (3) Install the prepared shrinkable double-layer atomizing nozzle 31 at the outlet of the impeller 30, and place the workpiece 35 in the rust removal pressure chamber 34.

[0070] (4) Adjust the diameter of the first electromagnetic flowmeter 20 and the second electromagnetic flowmeter 23 to ensure that the fluid flow rate through them is the same.

[0071] (5) Open the fifth valve 2, the sixth valve 3 and the main valve 4, then open the pneumatic booster pump 6 and the circulation pump 11, observe the readings of the temperature sensor 14 and the first pressure gauge 13 of the storage tank 12. When the first pressure gauge 13 reads 4 MPa and the temperature sensor 14 reads 2 ℃, open the first valve 17 and then open the plunger pump 18, observe the second pressure gauge 19.

[0072] (6) Simultaneously turn on the water supply tank 22 switch, the centrifugal booster pump 24 switch and the second valve 26, and observe the reading of the third pressure gauge 25. Adjust the centrifugal booster pump 24 so that the reading of the third pressure gauge 25 is 0.5 MPa.

[0073] (7) Adjust the plunger pump 18 so that the reading of the second pressure gauge 19 is 45 MPa, and open the seventh valve 21.

[0074] (8) The water flow 49 accelerated by liquid carbon dioxide 50 turns into water droplets 51 through the nozzle outlet. After the liquid carbon dioxide 50 flash evaporates, the lowest ambient temperature is -74 ℃, forming ice particles 56 generated by the high-speed airflow, which then form an ice particle jet to erode the workpiece.

[0075] (9) After the workpiece erosion is completed, observe the fourth pressure gauge 37 and the display 45, turn off the water supply tank 22 switch and the centrifugal booster pump 24 switch, and then turn off the carbon dioxide cylinder 1 switch, the pneumatic booster pump 6 switch and the circulation pump 11 switch, and the system stops working.

Claims

1. An apparatus for instantaneous preparation of a direct-swirl mixed ice particle jet using high-pressure superheated liquid flash evaporation, characterized in that: The system includes a high-pressure superheated liquid supply system and a water supply system, both of which are connected to a swirling ice particle generating jet system. The swirling ice particle generating jet system is connected to a recovery system, which is connected to the high-pressure superheated liquid supply system via a pipeline. The swirling ice particle generating jet system includes a double-layered casing. The inner layer of the double-layered casing is connected to the water supply system, and the outer layer is connected to the high-pressure superheated liquid supply system. An impeller is located at the outlet of the double-layered casing, and a contractile atomizing nozzle is located at the outlet of the impeller. The contractile atomizing nozzle, the impeller, and the centerline of the inner layer of the double-layered casing coincide and are all connected by threads. A flow field region is formed within the contractile atomizing nozzle. The impeller includes an inner tube located at the center and an outer tube outside the inner tube. The inner tube is connected to the inner layer of the double-layered casing, and the outer tube is threadedly connected to the double-layered casing. The outer circumference of the inner tube is tangentially... The system comprises multiple evenly distributed arc-shaped strips, each arranged tangentially along the outer side of the inner tube, and the inner and outer tubes are connected by these arc-shaped strips. The shrinking atomizing nozzle includes a tapered outer shell with a gradually tapering cross-section, an inner channel located at the center of the outer shell and connected to the inner tube of the impeller, and an acceleration tube located at the end of the inner channel. The outer shell is connected to the acceleration tube at its smallest diameter. A protective shell is provided outside the shrinking atomizing nozzle, with the outer diameter of the protective shell being the same as that of the outer layer. The recovery system includes a rust-removing pressure chamber, in which a workpiece is placed directly opposite the outlet of the acceleration tube. An outlet pipe is provided on the rust-removing pressure chamber, which is connected to the inlet of a cyclone separator. The outlet of the cyclone separator is connected to the inlet of a gas separator, and the outlet of the gas separator is connected to an analyzer. The analyzer outlet pipe is divided into two paths: one connected to a cold bath box, and the other connected to the inlet of the cyclone separator. The analyzer is equipped with a display and an alarm.

2. The apparatus for instantaneous preparation of a direct-swirl mixed ice particle jet using high-pressure superheated liquid flash evaporation as described in claim 1, characterized in that: The high-pressure superheated liquid supply system includes a gas cylinder, a pneumatic booster pump connected to the outlet of the gas cylinder, a cold bath box connected to the outlet of the pneumatic booster pump, an outlet pipe of the cold bath box connected to the inlet of the storage tank, a circulation pump between the cold bath box and the storage tank, a coiled pipe inside the cold bath box, a jacket outside the storage tank, antifreeze inside both the coiled pipe and the jacket, and the circulation pump connected to the coiled pipe and the inlet pipe of the jacket respectively; the outlet pipe of the storage tank is connected to the inlet of the plunger pump, and the outlet pipe of the plunger pump is connected to the outer layer of the double-layer casing.

3. The apparatus for instantaneous preparation of a direct-swirl mixed ice particle jet using high-pressure superheated liquid flash evaporation as described in claim 2, characterized in that: The water supply system includes a water supply tank, the outlet pipe of which is connected to a centrifugal booster pump, and the outlet pipe of the centrifugal booster pump is connected to the inner layer of a double-layered casing.

4. The apparatus for instantaneous preparation of a direct-swirl mixed ice particle jet using high-pressure superheated liquid flash evaporation as described in claim 3, characterized in that: The cyclone separator includes a shell, which comprises a top cylindrical body and a bottom conical body. The top center of the cylindrical body has an air outlet, the upper part of the cylindrical body has a tangential gas inlet, the lower part of the cylindrical body has guide vanes, and the bottom outlet of the shell has a vortex stabilizer.

5. The apparatus for instantaneous preparation of a direct-swirl mixed ice particle jet using high-pressure superheated liquid flash evaporation as described in claim 4, characterized in that: The high-pressure superheated liquid is carbon dioxide. Each pipeline is equipped with a valve. The storage tank is equipped with a temperature sensor, a first pressure gauge and a temperature controller. The plunger pump outlet pipeline is equipped with a second pressure gauge and a first electromagnetic flow meter. The centrifugal booster pump outlet pipeline is also equipped with a third pressure gauge. The water supply tank outlet pipeline is also equipped with a second electromagnetic flow meter. The rust removal pressure chamber outlet pipeline is also equipped with a constant pressure valve and a fourth pressure gauge.

6. The jetting method of the apparatus for instantaneous preparation of a direct-swirl mixed ice particle jet using the flash evaporation of a high-pressure superheated liquid as described in claim 5, characterized in that, Includes the following steps: (1) Add distilled water to the water supply tank, check the gas cylinder content and the airtightness of each valve and pipe connection, and check whether each pressure gauge and temperature sensor can be used normally; (2) Check if the analyzer is operating normally; (3) Install the prepared shrinkable atomizing nozzle at the impeller outlet and place the workpiece in the rust removal pressure chamber; (4) Adjust the diameter of the first electromagnetic flowmeter and the second electromagnetic flowmeter to ensure that the fluid flow rate through them is the same; (5) Open the outlet valve of the gas cylinder, then turn on the pneumatic booster pump and the circulation pump, and observe the temperature sensor and the first pressure gauge reading of the storage tank. When the first pressure gauge reading is 4 MPa and the temperature sensor reading is 2 ℃, open the valve and then turn on the plunger pump, and observe the second pressure gauge reading at the plunger pump. (6) Simultaneously turn on the water supply tank switch, the centrifugal booster pump switch and the valve, and observe the reading of the third pressure gauge. Adjust the centrifugal booster pump to make the reading of the third pressure gauge 0.5 MPa. (7) Adjust the plunger pump to make the second pressure gauge reading 45 MPa, and open its outlet pipeline valve; (8) The water flow accelerated by liquid carbon dioxide turns into water droplets through the nozzle outlet. After the liquid carbon dioxide flashes, the lowest ambient temperature is -74 ℃, forming ice particles generated by the high-speed airflow, which then form an ice particle jet to erode the workpiece. (9) After the workpiece erosion is completed, observe the fourth pressure gauge and the display, turn off the water supply tank switch and the centrifugal booster pump switch, and then turn off the carbon dioxide cylinder switch, the pneumatic booster pump switch and the circulation pump switch. The system will stop working.

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