A method and a spreading device for artificial rainfall using silver iodide nanoparticles

Abstract

The application relates to the field of artificial rainfall, and relates to a method for artificial rainfall by using silver iodide nanoparticles and a scattering device. The main purpose is to overcome the problems of low nucleation efficiency caused by the dependence of traditional artificial rainfall technology on explosives, low utilization rate of silver iodide and uncontrollable particle size. The main scheme comprises the following steps: generating a pulsed laser beam by a laser generator; adjusting the energy density of the laser beam to 1-100 J / cm 2 , the pulse width is nanosecond to femtosecond level, the pulse repetition frequency is 10-100 kHz, the laser beam is focused on the surface of a silver iodide target material; the transient photo-thermal effect of the laser beam is utilized to cause the silver iodide target material to be non-decomposable gasified to generate silver iodide vapor; the silver iodide vapor is condensed into 10-1000 nm silver iodide nanoparticles in the air through high-altitude low-temperature high-speed airflow to form artificial condensation nuclei; and the silver iodide nanoparticles are released to the top or inside of a target cloud layer to promote the condensation of water vapor in the cloud and the formation of precipitation.

Description

Technical Field

[0001] This invention relates to the field of artificial rainfall, specifically a method and a seeding device for artificial rainfall using silver iodide nanoparticles. Background Technology

[0002] Weather modification technologies (such as artificial rainmaking and hail suppression) are important means of coping with meteorological disasters and alleviating water shortages. Among these, silver iodide (AgI) is widely used in cold cloud catalysis operations due to its excellent ice-nucleating properties. Currently, mainstream technologies release silver iodide particles primarily through the following two methods:

[0003] 1. Combustion-type cigarette sticks

[0004] Silver iodide powder is mixed with gunpowder and pressed into cylindrical smoke sticks, which are then transported to the operational area by aircraft and ignited. The high temperature generated by the combustion of the gunpowder causes the silver iodide to sublimate and vaporize, forming aerosol particles that diffuse into the clouds with the airflow. However, this method has significant drawbacks:

[0005] Dependence on explosives: Smoke sticks are classified as civilian explosives, and their production, storage, and transportation require approval from the local armed forces department, a process that is complex and time-consuming.

[0006] Low proportion of effective ingredients: The silver iodide content in a single cigarette is only a dozen grams, and the rest of the ingredients are gunpowder and binders, which limits the catalytic efficiency.

[0007] Poor particle uniformity: Temperature fluctuations during combustion result in a wide size distribution of silver iodide particles (from hundreds of nanometers to tens of micrometers), affecting the efficiency of ice nucleation.

[0008] 2. Spreading by anti-aircraft artillery / rocket shells

[0009] Silver iodide is loaded into the projectile warhead, and the catalyst diffuses through the explosion. While this method can quickly cover a large area, it has drawbacks such as strict ammunition control, high operating costs (over 10,000 yuan per launch), and safety risks.

[0010] In recent years, laser technology has been explored for meteorological intervention due to its precise and controllable characteristics. For example, femtosecond lasers can induce local condensation by ionizing air, but this method relies on the inherent moisture in clouds and cannot actively introduce condensation nuclei, limiting its applicability. Other studies have proposed using lasers to ablate metal targets to generate aerosols, but their objectives are air purification or material synthesis, and they do not involve the vaporization control of silver iodide or adaptation to artificial rainmaking scenarios.

[0011] Summary of existing technological bottlenecks:

[0012] The reliance on explosives complicates operational approvals and makes it difficult to meet the needs of emergency weather intervention.

[0013] Silver iodide has low utilization rate and high catalytic cost;

[0014] Traditional combustion / explosion methods produce particles with uncontrollable size distribution and unstable ice nucleation rates.

[0015] Emerging laser technologies have not yet been effectively integrated with the silver iodide catalytic mechanism, and there is a lack of targeted solutions. Summary of the Invention

[0016] The technical problem to be solved is to overcome the problems of dependence on pyrotechnics, low utilization rate of silver iodide, and low nucleation efficiency caused by uncontrollable particle size in traditional artificial rainmaking technology, and to provide a safe, efficient, and precise laser-catalyzed artificial rainmaking method and device that can generate nanoscale condensation nuclei.

[0017] This invention provides a method for artificial rainmaking using silver iodide nanoparticles, comprising the following steps: A laser generator and a silver iodide target are mounted on an aircraft.

[0018] (a) A pulsed laser beam generated by a laser generator;

[0019] (b) Adjust the energy density of the laser beam to 1–100 J / cm², the pulse width to nanosecond to femtosecond level, and the pulse repetition frequency to 10–100 kHz, so that the laser beam is focused on the surface of the silver iodide target.

[0020] (c) The transient photothermal effect of the laser beam is used to cause the silver iodide target to undergo non-decompositional vaporization, generating silver iodide vapor;

[0021] (d) The silver iodide vapor is condensed in the air into silver iodide nanoparticles of 10–1000 nm by a high-altitude, low-temperature, high-speed airflow, forming artificial condensation nuclei;

[0022] (e) The silver iodide nanoparticles are released into the top or interior of the target cloud to promote water vapor condensation and precipitation formation in the cloud.

[0023] The present invention also provides a spreading device for implementing the method of claim 1, comprising:

[0024] Laser generator module: Outputs nanosecond laser beams with pulse energy of 1–100 J / cm²;

[0025] Target compartment: It is equipped with target material and laser output module. The transient photothermal effect generated by the output laser beam of the laser output module causes non-decomposition vaporization of the silver iodide target material, generating silver iodide vapor. The cold air during flight is compressed and accelerated through the flared air inlet. The accelerated cold air will rapidly cool and condense the silver iodide vapor to form silver iodide particles, which are then released into the target cloud through the flared air outlet.

[0026] In the above technical solution, the laser output from the laser generator module is introduced into the laser output module through an optical fiber. The laser is collimated inside the laser output module and focused onto the target material by an adjustable reflector.

[0027] In the above technical solution, a target material vaporization section is provided between the air inlet and the air outlet of the target chamber horn-shaped structure. The bottom of the target material vaporization section is used to set the target material, and a protective window is provided at the top of the target material vaporization section. A laser output module is set on the protective window.

[0028] In the above technical solution, a target material gasification section is provided between the air inlet and the air outlet of the target chamber funnel structure. A target material rotation device is provided on the axis of the target material gasification section, and the target material is sleeved and fixed on the fixed cylinder of the target material rotation device.

[0029] In the above technical solution, a front rotating device installation structure is provided at the inlet of the target gasification section, including:

[0030] The threaded ring is fixed to the inner wall of the gasification section of the target material by the first fixed support, and the axis of the threaded ring coincides with the axis of the gasification section of the target material.

[0031] In the above technical solution, a rear rotation device installation structure is provided at the outlet of the target gasification section, including:

[0032] It includes a bearing fixing ring, which is fixed to the inner wall of the target material gasification section by a second fixing support. A bearing is fixed inside the bearing fixing ring, and the axis of the bearing coincides with the axis of the target material gasification section.

[0033] In the above technical solution, the target rotation device includes:

[0034] The front-end motor mounting structure has a threaded post along the direction of the motor's output shaft. The threaded post is fixed in place with a threaded ring. The motor's output shaft extends from the center of the threaded post and is inserted into the bearing hole after passing through the axis of the fixed post.

[0035] In the above technical solution, the laser output module includes a guide rail parallel to the axis of the target vaporization section, a moving platform is mounted on the guide rail, the moving platform is driven by a drive motor to move along the guide rail, a focusing mirror and a second reflecting mirror are set on the moving platform, as well as a collimating mirror and a first reflecting mirror. The collimating mirror collimates the light transmitted from the optical fiber and transmits it to the first reflecting mirror. The first reflecting mirror reflects the laser to the second reflecting mirror. The second reflecting mirror reflects the laser to the focusing mirror, which focuses it and then passes through the protective window before hitting the target.

[0036] In the above technical solution, the laser between the first and second reflectors is parallel to the guide rail.

[0037] Because the present invention employs the above-mentioned technical means, it has the following beneficial effects:

[0038] 1. Precise control of silver iodide particle size: By precisely controlling the laser energy density (1–100 J / cm²), pulse repetition frequency, and pulse width (nanosecond to femtosecond level), combined with the rapid condensation process of cold air, silver iodide nanoparticles of 10–1000 nm can be stably generated. Their size is highly matched with the nucleation requirements of supercooled water droplets in clouds, significantly improving the ice nucleation efficiency.

[0039] 2. Avoid dependence on explosives: Laser gasification replaces traditional gunpowder combustion or explosive dispersal methods, eliminating the need for approval of civilian explosives, simplifying the operation process and reducing safety risks.

[0040] 3. Improve silver iodide utilization: Through non-decomposition gasification process and target rotation device design, uniform gasification of target material is achieved, avoiding ineffective loss, and the amount of catalyst per operation is increased by more than 10 times compared with combustion method.

[0041] 4. Dynamically adapt to complex airflow environment: The compression acceleration design of the horn-shaped air inlet (2) and air outlet (7), combined with the high-speed movement of the aircraft, can enhance the mixing efficiency of silver iodide vapor and cold air, ensuring that particles are evenly diffused into the cloud layer.

[0042] 5. Fixed-focus vaporization, reducing costs: The coordinated control of the mobile platform (3-3) and the target rotation device enables the laser spot to dynamically scan the target surface, realizing fixed-focus vaporization of silver iodide, which greatly reduces the implementation cost. Attached Figure Description

[0043] Figure 1 A simplified flowchart;

[0044] Figure 2 This is a simplified structural diagram of one embodiment.

[0045] Figure 3 for Figure 2 The left view;

[0046] Figure 4 This is a simplified structural diagram of one embodiment.

[0047] Figure 5 for Figure 4 A simplified structural diagram after removing the target rotation device;

[0048] Figure 6 The corresponding left and right views;

[0049] Figure 7 for Figure 6 A schematic diagram of the protection window displayed in the perspective view from the middle right.

[0050] Figure 8This is a schematic diagram of the assembled and disassembled target rotation device.

[0051] Explanation of reference numerals in the attached figures:

[0052] Fiber optic cable -1, horn-shaped air inlet -2, laser generator module -3, guide rail -3-1, drive motor -3-2, moving platform -3-3, second reflector -3-4, focusing lens -3-5, first reflector -3-6, collimating lens -3-7, target vaporization section -4, protective window -4-1, top of target vaporization section -4-2, bottom of target vaporization section -4-3, target -5, horn-shaped air outlet -7, threaded ring -9, first fixed support -8-1, bearing -10, second fixed support -8-2, front motor mounting structure -11, threaded column -11-1, motor output shaft -11-2, fixed cylinder -12, locking nut -12-1, positioning block -12-2, positioning groove -12-3, through hole -12-4, 6-laser beam. Detailed implementation method

[0053] The embodiments of the present invention will be described in detail below. Although the present invention will be described and illustrated in conjunction with some specific embodiments, it should be noted that the present invention is not limited to these embodiments. On the contrary, any modifications or equivalent substitutions made to the present invention should be covered within the scope of the claims of the present invention.

[0054] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art will understand that the present invention can be practiced without these specific details.

[0055] Example 1

[0056] This invention provides a method for artificial rainmaking using silver iodide nanoparticles, comprising the following steps: A laser generator and a silver iodide target are mounted on an aircraft (preferably a drone).

[0057] (a) A pulsed laser beam with a wavelength of 532nm-2000nm is generated by a laser generator; preferably 532nm, 1064nm, or 1550nm.

[0058] (b) Adjust the energy density of the laser beam to 1–100 J / cm², the pulse width to nanosecond to femtosecond level, and the pulse repetition frequency to 10–100 kHz, so that the laser beam is focused on the surface of the silver iodide target.

[0059] (c) The transient photothermal effect of the laser beam is used to cause non-decomposition vaporization of the silver iodide target surface, generating silver iodide vapor;

[0060] (d) The silver iodide vapor is condensed in the air into silver iodide nanoparticles of 10–1000 nm by a high-speed airflow, forming artificial condensation nuclei;

[0061] (e) The silver iodide nanoparticles are released into the target cloud to promote water vapor condensation and precipitation formation in the cloud.

[0062] Example 2

[0063] The present invention also provides a spreading device, comprising:

[0064] Laser generator module: outputs nanosecond laser with a wavelength of 1064±50 nm and a pulse energy of 1–100 J / cm²;

[0065] Target chamber: It is equipped with target material 5 and laser output module 3. The transient photothermal effect generated by the laser beam output by the laser output module causes non-decomposition vaporization of the surface of silver iodide target material 5, generating silver iodide vapor. The cold air during flight is compressed and accelerated through the flared air inlet 2. The accelerated cold air will rapidly cool and condense the silver iodide vapor to form silver iodide particles, which are then released into the target cloud through the flared air outlet 7.

[0066] In the above scheme, the laser output from the laser generator module is introduced into the laser output module 3 via optical fiber 1. The laser is collimated inside the laser output module 3 and focused onto the target material 5 by an adjustable reflector. Specifically, the laser beam passes through a galvanometer and is then focused onto the target material 5 by a field lens. Inside the galvanometer, a motor drives the reflector to move, thereby changing the position of the laser beam on the target surface. The field lens then performs focusing. The laser beam scans the target surface, and the movement of the galvanometer is controlled by software to achieve beam deflection and scanning rate.

[0067] This invention provides a target chamber structure. A target material vaporization section 4 is provided between the air inlet 2 and the air outlet 7 of the target chamber. The bottom 4-3 of the target material vaporization section is used to set the target material 5. The target material can be fixed to the bottom 4-3 of the target material vaporization section by means of adhesive or other bonding methods. A protective window 4-1 is provided at the top 4-2 of the target material vaporization section. A laser output module 3 is set on the protective window 4-1. The protective window 4-1 is generally made of fused silica glass.

[0068] It is worth noting that, such as Figure 2 , Figure 3 The laser output module 3 shown mainly uses existing mature technology, such as a galvanometer, to adjust the horizontal and vertical displacement of the laser output spot on the target material. It uses a field lens to focus the output laser to ensure that the laser has a focal point on the target material. Existing mature zoom technology is used here, so it will not be described in detail.

[0069] To achieve vaporization of silver iodide targets even under fixed-focus conditions, the equipment in fixed-focus mode has low requirements for intelligent control and lower implementation costs.

[0070] Example 3

[0071] The present invention also provides a spreading device, comprising:

[0072] Laser generator module: outputs nanosecond laser with a wavelength of 1064 nm and a pulse energy of 1–100 J / cm²;

[0073] Target chamber: It is equipped with target material 5 and laser output module 3. The transient photothermal effect of the laser beam output by the laser output module causes non-decomposition vaporization of the surface of silver iodide target material 5, generating silver iodide vapor. The cold air during flight is compressed and accelerated through the flared air inlet 2. The accelerated cold air will rapidly cool and condense the silver iodide vapor to form silver iodide particles, which are then released into the target cloud through the flared air outlet 7.

[0074] As one example, see Figure 4 A target material gasification section 4 is provided between the air inlet 2 and the air outlet 7 of the target chamber funnel structure. A target material rotation device is provided on the axis of the target material gasification section, and the target material is sleeved and fixed on the target material fixing cylinder 12 of the target material rotation device.

[0075] As another implementation method, see Figure 4 The present invention provides a target chamber structure, wherein a front rotating device mounting structure is provided at the inlet of the target material gasification section 4, including a threaded ring 9, the axis of the threaded ring 9 coincides with the axis of the target material gasification section 4, and the threaded ring 9 is fixed to the inner wall of the target material gasification section 4 by a first fixed support 8-1.

[0076] A rear rotation device mounting structure is provided at the outlet of the target material gasification section 4, including a bearing 10. The axis of the bearing 10 coincides with the axis of the target material gasification section 4, and the outer ring of the bearing 10 is fixed to the inner wall of the target material gasification section 4 by a second fixed support 8-2.

[0077] The target rotation device includes a front motor mounting structure 11. The front motor mounting structure 11 has a threaded post 11-1 along the direction of the motor output shaft. The threaded post 11-1 is threaded and fixed with the threaded ring 9. The output shaft 11-2 of the motor is led out from the center of the threaded post 11-1. The motor output shaft passes through the axis of the target fixing cylinder 12 and is inserted into the hole of the bearing 10.

[0078] As one example, see Figure 8To facilitate the mounting of the fixed cylinder 12 on the output shaft 11-2, a through hole 12-4 is provided on the target fixing cylinder 12, and a positioning groove 12-3 is provided on the left end of the fixing cylinder 12. The positioning groove 12-3 cooperates with the positioning block 12-2 provided on the left end of the output shaft 11-2 to prevent rotation between the output shaft 11-2 and the target fixing cylinder 12. In use, the output shaft 11-2 passes through the through hole 12-4 on the target fixing cylinder 12 and is pressed and fixed by the locking nut 12-1. A corresponding thread 11-3 is provided on the output shaft 11-2 at the corresponding position.

[0079] As an example of assembly, the following further explanation is provided on how to install the silver iodide target onto the target rotation device, to facilitate understanding by those skilled in the art:

[0080] 1. Insert the cylindrical silver iodide target into the target fixing cylinder 12, and apply a slight interference fit;

[0081] 2. Then align the central axis of the through hole of the target fixing cylinder 12 with the central axis of the threaded ring 9;

[0082] 3. Insert the motor output shaft 11-2 on the front motor mounting structure 11 through the threaded ring 9 into the through hole of the target fixing cylinder 12, then rotate the front motor mounting structure 11 to lock the threaded cylinder 11-1 with the threaded ring 9, and finally insert the output shaft 11-2 into the bearing 10 to complete the fixing of the device.

[0083] As one example, see Figure 4 , Figure 5 The laser output module 3 includes a guide rail 3-1 parallel to the axis of the target vaporization section 4. A moving platform 3-3 is mounted on the guide rail. The moving platform 3-3 is driven by a drive motor 3-2 to move along the guide rail. A focusing lens 3-5 and a second reflecting mirror 3-4 are set on the moving platform. It also includes a collimating lens 3-7 and a first reflecting mirror 3-6. The collimating lens collimates the light transmitted from the optical fiber and transmits it to the first reflecting mirror 3-6. The first reflecting mirror reflects the laser to the second reflecting mirror 3-4. The second reflecting mirror 3-4 reflects the laser to the focusing lens 3-5, which focuses it and then passes through the protective window 4-1 before hitting the target.

[0084] It is worth noting that the laser between the first reflector and the second reflector 3-4 needs to be set parallel to the guide rail 3-1. This ensures that the laser can still be reflected to the focusing lens 3-5 after passing through the first reflector 3-6 and the second reflector 3-4 during the movement of the moving platform 3-3.

[0085] As one embodiment, by setting a fixed rotational speed of the motor output shaft and then coordinating with the uniform speed movement of a certain platform, fixed-coke vaporization of silver iodide can be achieved. A target material is used to fix the cylinder 12 to the cylindrical silver iodide target. The target material can be fixed by a slight interference fit, without the need for adhesives or other auxiliary fixing structures.

[0086] In summary, this invention achieves non-decompositional vaporization of silver iodide targets through the transient photothermal effect of laser. Combined with target chamber structure design and optimized airflow dynamics, it overcomes the technical bottleneck of traditional combustion / explosion methods for releasing silver iodide particles. Specifically, precise control of laser parameters (wavelength 1064 nm, energy density 1–100 J / cm²) ensures that silver iodide undergoes only surface vaporization rather than chemical decomposition. The generated vapor is rapidly condensed by high-speed cold air (compression acceleration effect increases flow rate by 3-5 times) introduced through the flared inlet, forming uniform nanoparticles of 100–1000 nm. This particle size range is optimally matched to the size of supercooled water droplets in clouds (10–20 μm), and a single silver iodide particle can provide multiple nucleation sites.

[0087] The innovative design of the device significantly improves operational safety and economy: the rotating target structure (including the motor drive system and bearing fixing components) rotates axially at a uniform speed (adjustable speed range 5–30 rpm) to create a spiral scanning trajectory of the laser beam on the target surface. Combined with the linear displacement of the moving platform (guide rail accuracy ±0.1 mm), the utilization rate of the target surface is maximized (up to 92%), and the effective release of silver iodide in a single operation is 2-5 times higher than that of a fixed target. In addition, the entire system requires no explosives, bypassing the approval process for civil explosives, and the operation response time is shortened from the traditional 72 hours to within 4 hours, making it particularly suitable for rapid intervention in sudden meteorological disasters.

[0088] The innovative structural design brings multiple technological advantages: the double-ended flared structure generates a negative pressure zone through the Venturi effect, accelerating the mixing and condensation process of silver iodide vapor and cold air (residence time <50ms) and inhibiting particle agglomeration; the combined design of the protective window (fused silica glass) and the optical fiber transmission system allows the laser module to be kept away from the high-temperature vaporization area, avoiding contamination of optical components; the positioning groove and locking nut structure of the target fixing cylinder enable rapid target replacement (operation time <2 minutes), significantly improving the maintainability of the device.

Claims

1. A device for artificial rainfall using silver iodide nanoparticles, characterized in that, The application relates to a laser generator and an iodized silver target material, and belongs to the technical field of spaceflight. The laser generator comprises a laser generator module and a target warehouse. The target warehouse comprises a target material (5) and a laser output module (3), and the laser beam output by the laser output module generates a transient photo-thermal effect to cause non-decompositional gasification of the surface of the iodized silver target material (5) and generate iodized silver vapor; cold air in the flight process is compressed and accelerated through a horn structure air inlet (2), the accelerated cold air rapidly cools and condenses the iodized silver vapor to form iodized silver particles, and the iodized silver particles are released into a target cloud layer through a horn structure air outlet (7). A target material gasification section (4) is arranged between the horn structure air inlet (2) and the horn structure air outlet (7), and a target material rotating device is arranged on the axis of the target material gasification section. The laser output module (3) comprises a guide rail (3-1) parallel to the axis of the target material gasification section (4), a moving platform (3-3) is arranged on the guide rail, the moving platform (3-3) is driven to move along the guide rail by a driving motor (3-2), a focusing mirror (3-5) and a second reflecting mirror (3-4) are arranged on the moving platform, and the laser output module (3) further comprises a collimating mirror (3-7) and a first reflecting mirror (3-6); the collimating mirror collimates the light transmitted from an optical fiber and transmits the collimated light to the first reflecting mirror (3-6); the first reflecting mirror reflects the laser to the second reflecting mirror (3-4); and the second reflecting mirror (3-4) reflects the laser to the focusing mirror (3-5) to focus the laser and then pass through a protection window (4-1) to hit the target material.

2. The spreading device according to claim 1, characterized in that A front rotating device mounting structure is arranged at the entrance of the target material gasification section (4) and comprises a threaded ring (9) fixed to the inner wall of the target material gasification section (4) by a first fixed support (8-1), and the axis of the threaded ring (9) is coincident with the axis of the target material gasification section (4). A rear rotating device mounting structure is arranged at the exit of the target material gasification section (4) and comprises a bearing fixed ring fixed to the inner wall of the target material gasification section (4) by a second fixed support (8-2), and a bearing (10) is fixed in the bearing fixed ring, and the axis of the bearing (10) is coincident with the axis of the target material gasification section (4).

3. The spreading device of claim 1, wherein The target material rotating device comprises a front motor mounting structure (11) provided with a threaded column (11-1) in the direction of the output shaft of the motor, the threaded column (11-1) is fixed to the threaded ring (9) in a threaded mode, the center of the threaded column (11-1) leads out the output shaft of the motor, and the output shaft of the motor is inserted into the hole of the bearing (10) after penetrating the axis of the fixed cylinder (12). The laser between the first reflecting mirror and the second reflecting mirror (3-4) is parallel to the guide rail (3-1).

4. The spreading device of claim 3, wherein The laser generator and the iodized silver target material are carried on a spacecraft, and the method comprises the following steps: (a) generating a pulsed laser beam by the laser generator; 5. The spreader of claim 1, wherein (b) adjusting the energy density of the laser beam to 1-100 J / cm2, the pulse width is nanosecond to femtosecond, and the pulse repetition frequency is 10-100 kHz, so that the laser beam is focused on the surface of the iodized silver target material.

6. A method for artificial rainfall using a device for artificial rainfall using silver iodide nanoparticles according to any one of claims 1 to 5, characterized in that, ​ ​ ​ (c) using the transient photo-thermal effect of the laser beam to cause non-decomposable gasification of the silver iodide target material to generate silver iodide vapor; (d) using high-altitude low-temperature high-speed airflow to cause the silver iodide vapor to condense into silver iodide nanoparticles of 10-1000 nm in air to form artificial condensation nuclei; (e) releasing the silver iodide nanoparticles to the top or inside of the target cloud layer to promote water vapor condensation in the cloud and precipitation formation.

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