A spatial droplet generator based on laser modulation of droplet diameter

Abstract

The present invention discloses a spatial droplet generator based on laser modulation of droplet diameter. A liquid cavity is communicated with a liquid storage chamber via a pipeline. A nozzle plate is arranged at the bottom of the liquid storage chamber, and a pump is arranged on the pipeline for pressurizing the liquid in the liquid cavity and pumping it into the liquid storage chamber, and causing a jet liquid column to be generated when the liquid passes through the nozzle plate. A laser emitter is used to emit laser, and the direction of the laser emitted by the laser emitter is perpendicular to the direction of the jet liquid column. A focusing lens is located at the front end of the laser emitter for focusing the laser emitted by the laser emitter on the jet liquid column to cause the jet liquid column to disintegrate and form droplets. Tens of thousands of large numbers of uniform and stable micro-droplets can be simultaneously generated in the liquid jet through laser thermal perturbation, and the droplet diameter can be controlled from two aspects of the laser frequency and the size of the nozzle holes of the nozzle plate, and the regulation is convenient.

Description

Technical Field

[0001] The present invention relates to the field of space radiation heat exchangers, and particularly to a space droplet generator based on laser modulation of droplet diameter. Background Art

[0002] With the continuous advancement of human exploration of the universe, various high-power spacecraft, in-space and nuclear-powered thrusters are urgently in need of development. And the greater the power, the more waste heat is generated. Since the cosmic environment is a vacuum and heat transfer mainly relies on radiative heat transfer, a space radiation heat exchanger is required.

[0003] The space radiation heat exchanger uses its droplet generator to generate thousands of tiny and uniform droplets for radiative heat transfer with the cosmic environment. However, the droplets generated by traditional droplet generators such as piezoelectric, pneumatic, and electromagnetic ones have poor uniformity, a small number of droplets, it is difficult to change the droplet diameter, and the structure is complex, which is not convenient for processing and space transportation.

[0004] Therefore, the traditional droplet generators used in the existing space radiation heat exchangers still need to be improved and developed. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a space droplet generator based on laser modulation of droplet diameter, which can generate a large number of uniform tiny droplets with adjustable diameters.

[0006] The technical solution of the present invention is as follows: A space droplet generator based on laser modulation of droplet diameter includes a liquid chamber, a pump, a liquid storage chamber, a nozzle plate, a focusing lens, and a laser emitter; the liquid chamber is connected to the liquid storage chamber via a pipeline, the nozzle plate is arranged at the bottom of the liquid storage chamber, the pump is arranged on the pipeline for pressurizing the liquid in the liquid chamber and pumping it into the liquid storage chamber, and making the liquid generate a jet liquid column when passing through the nozzle plate; the laser emitter is used to emit laser, and the direction of the laser emitted by the laser emitter is perpendicular to the direction of the jet liquid column; the focusing lens is located in front of the laser emitter for focusing the laser emitted by the laser emitter on the jet liquid column to cause the jet liquid column to disintegrate into droplets.

[0007] For the space droplet generator based on laser modulation of droplet diameter, wherein: the nozzle plate is a single-layer orifice plate, on which a 100×100 orifice array with orifice diameters of 100 to 300 microns is evenly distributed, and chamfers are provided at the openings on the side of all orifices facing the liquid storage chamber.

[0008] For the space droplet generator based on laser modulation of droplet diameter, wherein: the nozzle plate is formed by stacking two or more multi-layer orifice plates, the orifice diameters of different layers of orifice plates are different, and adjacent layers of orifice plates can be slightly moved to generate misalignment.

[0009] The described spatial droplet generator based on laser modulation of droplet diameter, wherein: a flow meter and a pressure gauge are provided on the pipeline between the pump and the liquid storage chamber. The flow meter is used to display and monitor the liquid flow rate or velocity flowing into the liquid storage chamber in real time, and the pressure gauge is used to display and monitor the liquid pressure flowing into the liquid storage chamber.

[0010] The described spatial droplet generator based on laser modulation of droplet diameter, wherein: a filter membrane is provided on the pipeline between the pump and the liquid storage chamber for filtering the liquid flowing into the liquid storage chamber.

[0011] The described spatial droplet generator based on laser modulation of droplet diameter, wherein: the laser emitter is connected to an oscilloscope through a signal transmission line and is used to adjust the frequency of the laser emitted by the laser emitter within the frequency range of 2000 - 5500 Hz.

[0012] The described spatial droplet generator based on laser modulation of droplet diameter, wherein: the laser emitter is connected to an oscilloscope through a signal transmission line and is used to adjust the power of the laser emitted by the laser emitter between 0.15 - 3.38 W.

[0013] The described spatial droplet generator based on laser modulation of droplet diameter, wherein: the pump is a gear pump.

[0014] The described spatial droplet generator based on laser modulation of droplet diameter, wherein: the time required for the thermal perturbation of the laser to grow from the initial intensity to the intensity required for the jet liquid column to disintegrate is t , and the distance between the irradiation point of the laser on the jet liquid column and the disintegration point where the jet liquid column begins to disintegrate is the disintegration length of the jet liquid column L b , and the relationship between the two L b = vt , v represents the jet velocity, and the radius of the droplet after the jet liquid column disintegrates , where R o is the radius of the nozzle hole on the nozzle plate, f is the frequency of the laser emitted by the laser emitter.

[0015] The described spatial droplet generator based on laser modulation of droplet diameter, wherein: the distance between two adjacent droplets , where v represents the jet velocity, f is the frequency of the laser emitted by the laser emitter.

[0016] A spatial droplet generator based on laser modulation of droplet diameter provided by the present invention can generate tens of thousands of uniform and stable micro-droplets simultaneously from a liquid jet through laser thermal perturbation, and the droplet diameter can be controlled from two aspects: the laser frequency and the size of the spray holes on the nozzle plate, which is convenient for regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the disclosure of the present invention in any way; the shapes and proportional dimensions of the components in the drawings are only schematic and are used to assist in understanding the present invention, rather than specifically defining the shapes and proportional dimensions of the components of the present invention; those skilled in the art can, under the teaching of the present invention, select various possible shapes and proportional dimensions according to specific circumstances to implement the present invention.

[0018] Figure 1 is a schematic diagram of the structural composition of the spatial droplet generator based on laser modulation of droplet diameter of the present invention;

[0019] Figure 2 is an enlarged schematic plan view of the plane structure of the nozzle plate used in the spatial droplet generator based on laser modulation of droplet diameter of the present invention;

[0020] Figure 3 is an enlarged schematic cross-sectional view of the nozzle plate used in the spatial droplet generator based on laser modulation of droplet diameter of the present invention;

[0021] Figure 4 is a comparison diagram of the droplet spacing generated by the spatial droplet generator of the present invention under laser irradiation at different frequencies;

[0022] Figure 5 is a comparison diagram of the droplet spacing generated by the spatial droplet generator of the present invention under laser irradiation at different powers.

[0023] Summary of the reference numerals in the drawings: liquid chamber 1, pump 2, flowmeter 3, pressure gauge 4, filter membrane 5, liquid storage chamber 6, nozzle plate 7, spray hole 7a, focusing lens 8, laser emitter 9, pipeline 11, signal transmission line 12. DETAILED DESCRIPTION OF THE INVENTION

[0024] The following will describe in detail the specific embodiments and examples of the present invention in conjunction with the drawings. The specific embodiments described are only used to explain the present invention and are not intended to limit the specific embodiments of the present invention.

[0025] As Figure 1As shown in the figure, a spatial droplet generator based on laser modulation of droplet diameter provided by the present invention includes a liquid chamber 1, a pump 2, a liquid storage chamber 6, a nozzle plate 7, a focusing lens 8, and a laser emitter 9. Among them, the liquid chamber 1 is communicated with the liquid storage chamber 6 via a pipeline 11. The nozzle plate 7 is arranged at the bottom of the liquid storage chamber 6, and the pump 2 is arranged on the pipeline 11, which is used to pressurize the liquid in the liquid chamber 1 and pump it into the liquid storage chamber 6, and make the liquid generate a jet liquid column when passing through the nozzle plate 7. The laser emitter 9 is used to emit laser, and the direction of the laser emitted by the laser emitter 9 is perpendicular to the direction of the jet liquid column. The focusing lens 8 is located at the front end of the laser emitter 9, which is used to focus the laser emitted by the laser emitter 9 on the jet liquid column, so that the jet liquid column disintegrates to form droplets.

[0026] When the laser emitted by the laser emitter 9 is focused and irradiated on the jet liquid column through the focusing lens 8, tiny thermal disturbances will be generated inside the jet liquid column, and these thermal disturbances will increase with time. According to Rayleigh's principle, the jet liquid column is unstable under the action of surface tension and is very likely to disintegrate. After testing, when the laser wavelength of the external disturbance is greater than the wetting perimeter of the jet liquid column and lasts for a certain period of time, the jet liquid column will disintegrate to form droplets.

[0027] In a specific embodiment of the spatial droplet generator based on laser modulation of droplet diameter of the present invention, as shown in combination with Figure 2 and Figure 3 When the nozzle plate 7 used is a single-layer orifice plate, it is evenly distributed with an array of 100×100 orifices 7a with a diameter of 100-300 microns, and chamfers are provided at the openings on the side of all orifices 7a facing the liquid storage chamber 6 to facilitate more fluid to enter the orifices 7a.

[0028] Furthermore, when the nozzle plate 7 is composed of two, three or more layers of orifice plates stacked together, the orifice diameters of the orifices 7a between different layers of orifice plates are different, and adjacent layers of orifice plates can be slightly moved to generate misalignment. Thus, the fine adjustment of the orifice diameter of the orifices 7a of the nozzle plate 7 can be achieved by adjusting the position between adjacent orifice plates.

[0029] Furthermore, a flow meter 3, a pressure gauge 4, and a filter membrane 5 are sequentially arranged on the pipeline 11 between the pump 2 and the liquid storage chamber 6. The flow meter 3 is used to display and monitor the liquid flow rate or velocity flowing into the liquid storage chamber 6 in real time. The pressure gauge 4 is used to display and monitor the liquid pressure flowing into the liquid storage chamber 6. The filter membrane 5 is used to filter the liquid flowing into the liquid storage chamber 6 to prevent the orifices 7a from being blocked.

[0030] Furthermore, the laser emitter 9 is connected to an oscilloscope 10 through a signal transmission line 12, which is used to adjust the frequency and power of the laser emitted by the laser emitter 9 within the frequency range of 2000-5500 Hz.

[0031] Specifically, the power of the laser emitter 9 is between 0.15 and 3.38 W, and the wavelength of the emitted laser is 532 nm; the focal length of the focusing lens 8 preferably focuses the laser focus emitted by the laser emitter 9 to about 20 microns.

[0032] Preferably, the pump 2 is a gear pump, which is small in volume and can pump out fluid under the condition of a large pressure difference between upstream and downstream.

[0033] In the specific embodiment of the spatial droplet generator based on laser modulation of droplet diameter of the present invention, specifically, assuming that the time required for the thermal disturbance of the laser to grow from the initial intensity to the intensity required for the jet liquid column to disintegrate is t , the distance between the irradiation point where the laser irradiates the jet liquid column and the disintegration point where the jet liquid column begins to disintegrate is the disintegration length of the jet liquid column L b , the relationship between the two L b = vt , v represents the jet velocity. Assuming that the radius of the droplet after the jet liquid column disintegrates is R d , according to the law of conservation of mass, , where R o is the radius of the nozzle hole 7a of the nozzle plate 7, f is the frequency of the laser emitted by the laser emitter 9; when changing the radius of the nozzle hole 7a and / or the laser frequency, the droplet radius can be correspondingly changed to R d ; assuming that the distance between two adjacent droplets is d , , when adjusting the laser frequency f , the droplet spacing d will also change accordingly.

[0034] Example 1: The pump 2 using a gear pump pressurizes the fluid pressure in the pipeline 11 to between 0.4 and 0.8 Mpa, and keeps the fluid velocity in the pipeline 11 between 1 and 10 m / s. It can be monitored in real time through the flow meter 3 and the pressure gauge 4 on the pipeline 11. The fluid in the pipeline 11 flows into the liquid storage chamber 6 after being filtered by the filter membrane 5, and becomes a jet liquid column array and sprays out through the 100×100 nozzle holes 7a with a diameter of 100 to 300 microns on the nozzle plate 7. The laser emitter 9 emits a rectangular surface laser source with a wavelength of 532 nm and an energy between 0.1 and 3.3 W. After being focused by the focusing lens 8 to 20 microns, it irradiates on the jet liquid column array. As the internal thermal disturbance grows, it finally breaks into uniformly sized and stable droplets, causing the jet liquid column array to break into a micro-droplet array; when the nozzle plate 7 uses a multi-layer orifice plate, the relative position between the multi-layer orifice plates can be adjusted to change the size of the nozzle holes 7a of the nozzle plate 7, so as to achieve the purpose of changing the droplet size; when the nozzle plate 7 uses a single-layer orifice plate, the frequency of the laser emitted by the laser emitter 9 can be adjusted by the oscilloscope 10, and the purpose of changing the droplet size can also be achieved; by reasonably adjusting the laser frequency, power and the diameter of the nozzle holes 7a of the nozzle plate 7, a uniform and stable droplet array can be continuously generated.

[0035] Example 2: The flow rate of a single nozzle hole 7a of the nozzle plate 7 is 1.37 ml / min, the diameter of the jet liquid column is 115.6 microns, the velocity of the jet liquid column is 2.18 m / s, the laser power is 3.38 W, and the laser wavelength λ = 532 nm. The frequency of the laser emitted by the laser emitter 9 is adjusted by the oscilloscope 10 between 2000 Hz and 5500 Hz. As Figure 4 shown, it can be observed by the naked eye that uniformly stable droplets can be generated, and the greater the frequency, the smaller the droplet spacing and the smaller the droplet diameter, but the distance from the droplet splitting point to the nozzle does not change significantly.

[0036] Example 3: The flow rate of a single nozzle hole 7a of the nozzle plate 7 is 1.37 ml / min, the diameter of the jet liquid column is 115.6 microns, the velocity of the jet liquid column is 2.18 m / s, the laser frequency is 4500 Hz, and the laser wavelength λ = 532 nm. The power of the laser emitted by the laser emitter 9 is adjusted by the oscilloscope 10 between 0.15 W and 3.38 W. As Figure 5 shown, it can be observed by the naked eye that uniformly and stable droplets can also be generated, and as the laser power increases, the distance from the droplet splitting point to the nozzle becomes smaller and smaller, but the droplet spacing and the droplet diameter do not change significantly.

[0037] The content not described in detail in this specification belongs to the prior art well-known to those of ordinary skill in the art.

[0038] It should be understood that the above are only preferred embodiments of the present invention, and are not sufficient to limit the technical solutions of the present invention. For those of ordinary skill in the art, within the spirit and principles of the present invention, additions, deletions, substitutions, transformations or improvements can be made according to the above description, and all these technical solutions after the additions, deletions, substitutions, transformations or improvements should fall within the protection scope of the appended claims of the present invention.

Claims

1. A spatial droplet generator based on laser modulation of droplet diameter, characterized in that, It includes a liquid chamber (1), a pump (2), a liquid storage chamber (6), a nozzle plate (7), a focusing lens (8) and a laser emitter (9); the liquid chamber (1) is communicated with the liquid storage chamber (6) via a pipeline (11), the nozzle plate (7) is arranged at the bottom of the liquid storage chamber (6), the pump (2) is arranged on the pipeline (11) and is used to pressurize the liquid in the liquid chamber (1) and pump it into the liquid storage chamber (6), and to generate a jet liquid column when the liquid passes through the nozzle plate (7); the laser emitter (9) is used to emit laser, and the direction of the laser emitted by the laser emitter (9) is perpendicular to the direction of the jet liquid column; the focusing lens (8) is located at the front end of the laser emitter (9) and is used to focus the laser emitted by the laser emitter (9) on the jet liquid column to cause the jet liquid column to disintegrate into droplets; The nozzle plate (7) is a single-layer orifice plate, on which an array of 100×100 spray holes (7a) with a diameter of 100 to 300 microns is evenly distributed, and chamfers are provided at the openings on the side of all the spray holes (7a) facing the liquid storage chamber (6); The nozzle plate (7) is formed by stacking two or more multi-layer orifice plates, the aperture sizes of the spray holes (7a) between different layers of orifice plates are different, and adjacent layers of orifice plates can be slightly moved to generate misalignment; The time required for the thermal disturbance of the laser to increase from the initial intensity to the intensity required for the jet liquid column to disintegrate is t The distance between the irradiation point where the laser irradiates the jet liquid column and the disintegration point where the jet liquid column begins to disintegrate is the disintegration length of the jet liquid column L b The relationship between the two L b = vt , v represents the jet velocity, the droplet radius after the jet liquid column disintegrates wherein, R o is the radius of the nozzle hole 7a of the nozzle plate (7), f is the frequency of the laser emitted by the laser emitter (9).

2. The spatial droplet generator based on laser modulation of droplet diameter according to claim 1, wherein: A flowmeter (3) and a pressure gauge (4) are arranged on the pipeline (11) between the pump (2) and the liquid storage chamber (6). The flowmeter (3) is used to display and monitor the liquid flow rate or velocity flowing into the liquid storage chamber (6) in real time, and the pressure gauge (4) is used to display and monitor the liquid pressure flowing into the liquid storage chamber (6).

3. The spatial droplet generator based on laser modulation of droplet diameter according to claim 1, wherein: A filter membrane (5) is arranged on the pipeline (11) between the pump (2) and the liquid storage chamber (6) and is used to filter the liquid flowing into the liquid storage chamber (6).

4. The spatial droplet generator based on laser modulation of droplet diameter according to claim 1, wherein: The laser emitter (9) is connected to an oscilloscope (10) through a signal transmission line (12) and is used to adjust the frequency of the laser emitted by the laser emitter (9) within the frequency range of 2000 to 5500 Hz.

5. The spatial droplet generator based on laser modulation of droplet diameter according to claim 1, characterized in that: The laser emitter (9) is connected to an oscilloscope (10) through a signal transmission line (12) and is used to adjust the power of the laser emitted by the laser emitter (9) between 0.15 and 3.38 W.

6. The spatial droplet generator based on laser-modulated droplet diameter according to claim 1, wherein: The pump (2) is a gear pump.

7. The spatial droplet generator based on laser modulation of droplet diameter according to claim 1, characterized in that: The distance between adjacent droplets , where v represents the jet velocity, f is the frequency of the laser emitted by the laser emitter (9).

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