Supercooling large water drop nozzle and spraying device

Abstract

The invention discloses a supercooled large water drop nozzle and a spraying device, and belongs to the technical field of nozzle spraying. The supercooling large water drop nozzle comprises a body, an air inlet and a water inlet are formed in one end of the body, and an air inlet pipe and a water inlet pipe are arranged in the body and connected through an air mixing pipe. The other end of the body is provided with a plurality of nozzles, and the gas mixing pipe is connected with the nozzles through connecting pipelines. The connecting pipeline comprises N-stage branch pipes which are sequentially connected end to end, an outlet of the gas mixing pipe is connected with one end of a first-stage branch pipe of the N-stage branch pipes, the other end of the first-stage branch pipe is connected with inlets of a plurality of second-stage branch pipes, an outlet of a (N-1) th-stage branch pipe is connected with inlets of a plurality of Nth-stage branch pipes, and an outlet of the Nth-stage branch pipe is connected with the nozzle. By the adoption of the supercooled large water drop nozzle and the spraying device, the problems that the diameter and the liquid water content of supercooled large water drops sprayed by an existing nozzle are not uniform, and control is not easy can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of nozzle spraying, and in particular to a supercooled large-droplet nozzle and a spraying device. Background Art

[0002] High-altitude icing poses a serious threat to the safe flight of aircraft. SLD generally refers to super-large-diameter water droplets with an average diameter of water droplets in the cloud greater than 100 μm and a temperature below the freezing point. The icing environment containing such water droplets has characteristics such as a relatively large average diameter of water droplets (medium volume diameter, MVD) and a high liquid water content (liquid water content, LWC). The unique kinetic characteristics of SLD cause SLD to bypass the anti-icing and de-icing devices of the wing leading edge and engine components and freeze, resulting in the failure of the anti-icing and de-icing devices, a sharp decline in the aerodynamic performance of the aircraft. In particular, the SLD icing of the engine will reduce the air intake efficiency of the air intake duct, affect the thrust, and in severe cases, ice shedding may occur, damaging the blades and even causing the engine to flame out, posing a great threat to flight safety.

[0003] With the release of new airworthiness conditions and the increasing importance of research on the icing state of aircraft and anti- / de-icing devices under SLD icing conditions, new requirements have also been put forward for the analysis and experimental verification methods of SLD icing conditions. The icing wind tunnel experiment is an important means to test the aerodynamic performance of aircraft and the effectiveness of anti-icing and de-icing devices under icing conditions. The icing wind tunnel can more realistically simulate the icing conditions under various temperature, altitude, and flight speed conditions by configuring a spray system, a refrigeration system, and an altitude simulation system in the loop. The spray device mainly generates clouds that meet the test requirements through a two-fluid atomizing nozzle. Generally, the spray system of an icing wind tunnel includes a spray section tunnel body, a spray rake (including a bracket, a spray rod, and a fairing), a nozzle, pipelines, and control valves. The water supply and air supply systems provide pure water and pure compressed air at a certain temperature to the spray device, which are transported to the nozzle through the spray rod and control valve in the spray device, and water-air mixing is achieved at the nozzle to make it reach the similarity degree of clouds.

[0004] Existing icing wind tunnel experiments all have good simulation capabilities for the icing conditions in Appendix C, but there are still obvious deficiencies in the simulation capabilities for SLD icing conditions. In recent years, the simulation of SLD icing conditions has become one of the huge challenges and urgent research topics faced by icing wind tunnels.

[0005] The particle size distributions in the four SLD icing conditions defined in Appendix O of CFR14 - Part 25 all exhibit typical bimodal distribution characteristics. To meet the requirements of the bimodal distribution characteristics of the droplet size spectrum in the SLD icing conditions, a commonly used method is to mix and spray with two nozzles with different particle size ranges in the icing wind tunnel, so as to form a particle size distribution with "bimodal" characteristics in the downstream test section. However, the droplet size distribution generated by this method is uneven, so it is very difficult to predict the true particle size distribution characteristics downstream of the spray section using statistical methods, and the currently used nozzles cannot complete specific test conditions (high LWC, low MVD). Therefore, a new design idea is needed for the SLD icing wind tunnel spray system to support the icing simulation of SLD in the icing wind tunnel test. Summary of the Invention

[0006] The purpose of the present invention is to provide a supercooled large droplet nozzle and a spraying device, which solve the problems that the diameters and liquid water contents of the supercooled large droplets ejected by the existing nozzles are uneven and difficult to control.

[0007] To achieve the above purpose, the present invention provides a supercooled large droplet nozzle, which includes a body. An air inlet and a water inlet are arranged at one end of the body. An air inlet pipe connected to the air inlet and a water inlet pipe connected to the water inlet are arranged inside the body. The air inlet pipe and the water inlet pipe are connected through a mixing pipe. A plurality of spray nozzles are arranged at the other end of the body. The mixing pipe and the spray nozzles are connected through connecting pipelines. The diameters of the air inlet pipe and the water inlet pipe are 100μm - 1000μm.

[0008] Preferably, the connecting pipeline includes N - level branch pipes connected end to end in sequence. The outlet of the mixing pipe is connected to one end of the first - level branch pipe of a plurality of N - level branch pipes. The other end of the first - level branch pipe is connected to the inlet of a plurality of second - level branch pipes. The outlet of the (N - 1) - level branch pipe is connected to the inlet of a plurality of N - level branch pipes. The outlet of the N - level branch pipe is connected to the spray nozzle. The diameter of the connecting pipeline is 10μm - 500μm.

[0009] Preferably, the first - level branch pipe, the second - level branch pipe and the N - level branch pipe all include an inclined pipe and a horizontal pipe. The inclined pipe is the inlet pipe of the N - level branch pipe, and the horizontal pipe is the outlet pipe of the N - level branch pipe.

[0010] Preferably, the diameters of the spray nozzles are equal.

[0011] Preferably, the diameters of the spray nozzles are different. The diameters of the spray nozzles gradually decrease from the center of the body to the edge of the body. The spray nozzles with the same diameter are arranged in a circumferential array on the body.

[0012] A spray device includes a number of spray units. Each spray unit includes the above-mentioned supercooled large water droplet nozzle. The nozzles are arranged in a linear array on a spray rod, and the spray rod is arranged inside a housing. The spray rods are arranged in a linear array inside the housing, and pipelines for supplying air and water to the nozzles are arranged inside the spray rod.

[0013] Preferably, the pipelines include a water supply pipe and an air supply pipe. The air supply pipe and the water supply pipe are respectively connected to an external air source and a water source through an air pipe and a water pipe. Pressure regulating valves and flow regulating valves for regulating air pressure, gas flow rate, water pressure, and water flow rate are respectively arranged on the air pipe and the water pipe. Air supply branches corresponding to the nozzles one by one are arranged on the air supply pipe, and the air supply branches are connected to the air inlet pipes inside the nozzles. Water supply branches corresponding to the nozzles one by one are arranged on the water supply pipe, and the water supply branches are connected to the water inlet pipes inside the nozzles.

[0014] Preferably, a support rod for supporting the nozzles is fixed at one end of the spray rod where the nozzles are arranged. Grooves for installing the nozzles are arranged on the support rod, and through holes corresponding to the nozzles one by one and allowing the nozzles to pass through are arranged on the grooves.

[0015] Preferably, fixing rods for supporting the air supply branches, the water supply branches, and the nozzle ends are arranged inside the spray rod.

[0016] Preferably, a heating wire for heating the nozzles is wound around the outer surface of the nozzles, and the heating wire is connected to an external power source through a wire.

[0017] The advantages and positive effects of the supercooled large water droplet nozzle and the spray device of the present invention are as follows: 1. The present invention arranges a multi-stage flow channel type connection pipeline inside the nozzle, which can promote the mixing of water and gas, improve the generation rate of micro-droplets and the stability of droplet flow, and obtain micro-droplets with stable and uniform sizes. By arranging nozzles with different diameters on the nozzle, micro-droplets with different particle size compositions are obtained, and the size and water content of the micro-droplets are easier to control.

[0018] 2. The spray device of the present invention is applied in an icing wind tunnel experiment; it can also calibrate particle diameter measuring instruments with different principles, such as a laser phase Doppler particle analyzer (PDPA), a laser particle size analyzer, etc., by generating micro-droplets with a constant and known particle diameter.

[0019] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0020] Figure 1 It is a three-dimensional structural schematic diagram of the nozzle according to Embodiment 1 of the present invention; Figure 2 It is a schematic diagram of the internal pipeline structure of the nozzle according to Embodiment 1 of the present invention; Figure 3 Schematic diagram of the planar structure of the internal pipeline of the nozzle according to Embodiment 1 of the present invention; Figure 4 Schematic diagram of the three-dimensional structure of the spray unit according to Embodiment 3 of the present invention; Figure 5 Schematic diagram of the internal structure of the spray rod according to Embodiment 3 of the present invention; Figure 6 Schematic diagram of the partial structure of the spray rod according to Embodiment 3 of the present invention; Figure 7 Schematic diagram of the internal pipeline structure of the spray rod according to Embodiment 3 of the present invention; Figure 8 Schematic diagram of the partial structure of the internal pipeline of the spray rod according to Embodiment 3 of the present invention.

[0021] Reference numerals 1. Nozzle; 11. Body; 12. Spray orifice; 13. Air inlet pipe; 14. Water inlet pipe; 15. Air mixing pipe; 16. First-stage branch pipe; 17. Second-stage branch pipe; 18. Nth-stage branch pipe; 2. Spray unit; 21. Housing; 22. Spray rod; 23. Support rod; 24. Air supply pipe; 25. Water supply pipe; 26. Air supply branch pipe; 27. Water supply branch pipe; 28. Fixed rod; 29. Groove; 210. Heating wire; 211. Lead wire. Detailed implementation manners

[0022] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0023] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. In case of inconsistency, the meaning described in this specification or the meaning derived from the content recorded in this specification shall prevail. In addition, the terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application. In order to accurately describe the technical content in this application and to accurately understand the present invention, the following explanations or definitions are given to the terms used in this specification before describing the specific embodiments: The following will describe in detail the embodiments of the present invention with reference to the accompanying drawings.

[0024] Embodiment 1 As Figure 1 shown. A supercooled large-droplet nozzle includes a body 11, and an air inlet and a water inlet are provided at one end of the body 11. An air inlet pipe 13 connected to the air inlet and a water inlet pipe 14 connected to the water inlet are provided inside the body 11, and the air inlet pipe 13 and the water inlet pipe 14 are connected through a mixing pipe 15. External air and water enter the inside of the body 11 through the air inlet pipe 13 and the water inlet pipe 14 respectively, and then are mixed in the mixing pipe 15. The mixing pipe 15 is a horizontal pipe, and the air inlet pipe 13 and the water inlet pipe 14 are inclined pipes, and the air inlet pipe 13 and the water inlet pipe 14 are provided at one end of the mixing pipe 15. The pipe diameters of the air inlet pipe and the water inlet pipe are 100 μm - 1000 μm, and the specific pipe diameter sizes of the air inlet pipe and the water inlet pipe are specifically set according to actual needs.

[0025] As Figure 2 、 Figure 3 shown. A plurality of nozzles 12 are provided at the other end of the body 11, and the mixing pipe 15 and the nozzles 12 are connected through a connecting pipeline. The connecting pipeline includes N - stage branch pipes connected end to end in sequence. The outlet of the mixing pipe 15 is connected to one end of the first - stage branch pipe 16 of a plurality of N - stage branch pipes, the other end of the first - stage branch pipe 16 is connected to the inlet of a plurality of second - stage branch pipes 17, the outlet of the (N - 1) - th stage branch pipe is connected to the inlet of a plurality of N - th stage branch pipes 18, and the outlet of the N - th stage branch pipe 18 is connected to the nozzle 12. The pipe diameters of the branch pipes in the connecting pipeline are 10 μm - 500 μm. The acute - angle between the inclined pipe of the mixing pipe and the first branch pipe is 30° - 45°.

[0026] The first - stage branch pipe 16, the second - stage branch pipe 17, and the N - th stage branch pipe 18 all include an inclined pipe and a horizontal pipe. The inclined pipe is the inlet pipe of the N - th stage branch pipe 18, and the horizontal pipe is the outlet pipe of the N - th stage branch pipe 18. The pipe diameter of the (N - 1) - th stage branch pipe is not less than the pipe diameter of the N - th stage branch pipe 18. The acute - angle between the inclined pipe and the horizontal pipe is 30° - 45°, and the inner - wall roughness of the inclined pipe and the horizontal pipe is 0.1 μm - 0.5 μm.

[0027] The diameters of the nozzles 12 are different, and the diameter of the nozzle 12 gradually decreases from the center of the body 11 to the edge of the body 11. The nozzles 12 with the same diameter are arranged in a circumferential array on the body 11.

[0028] Air and water are two immiscible substances. Water is the continuous phase and air is the discrete phase. Water and air enter their respective pipelines at fixed volume flow rates. When the two fluids meet at the intersection point, the flow velocity of the discrete-phase fluid is relatively slow. Under the shearing and squeezing actions of the continuous-phase fluid, due to the instability of the free interface, the liquid column breaks, manifested as the liquid column being "pinched off", and thus is dispersed in the continuous phase to form micro-droplets in the range of a few micrometers to a few hundred micrometers. The size, morphology and uniformity of the micro-droplets are good, thereby improving the uniformity of the droplet size ejected by the nozzle 1.

[0029] The internal connecting pipeline of the nozzle 1 is a hierarchical flow channel, and the connecting pipeline of the hierarchical flow channel can promote the mixing of fluids. Due to the continuous subdivision of the branch flow channels, the fluid is gradually divided into finer stream strands, increasing the contact area between the fluids. With the grading of the flow channels, the flow velocity and pressure distribution of the fluid in the branch flow channels change; in the finer branch flow channels, the flow velocity of the fluid is relatively high and the shear force increases, making it easier for the dispersed-phase fluid to be broken into small droplets, thereby realizing the regulation of the micro-droplet size. The hierarchical design of the flow channels increases the sites for droplet formation, enabling droplets to be formed simultaneously at multiple branches, improving the droplet generation rate. The structure of the hierarchical flow channel can also disperse the pressure of the fluid, reduce the influence of pressure fluctuations on droplet flow, and improve the stability of droplet flow.

[0030] In this embodiment, the flow velocity of water is 0.1 m / s - 0.15 m / s. As the continuous phase, the specific flow velocity of water is determined by the LWC of supercooled large water droplets. Air, as the discrete phase, is controlled by the solenoid valve of the microfluidic chip of the micro-droplet generator. To make the diameter of the supercooled large water droplets directly determined by the nozzle diameter in this embodiment, the solenoid valve frequency is set to 20 HZ - 40 HZ, the opening time is 0.5 ms - 1 ms, and the air pressure is 45 KPa - 60 KPa. In this way, droplets with uniform and stable particle sizes can be ejected through the nozzle, and the particle size of the droplets is 1.7 times - 1.9 times the size of the nozzle.

[0031] The nozzle 1 with nozzles 12 of different diameters can eject micro-droplets with different size compositions, so that the size of the droplets in the spray can be adjusted and controlled as needed by setting the sizes of different nozzles 12.

[0032] Embodiment 2 The difference between this embodiment and Embodiment 1 is that in this embodiment, the diameters of the nozzles 12 of the nozzle 1 are the same, and a nozzle 1 can eject a spray with uniform particle size.

[0033] Embodiment 3 As shown Figure 4 in the figure. A spray device includes a plurality of spray units 2, and the spray unit 2 includes the nozzle 1 in Embodiment 1 or Embodiment 2. The nozzles 1 are fixedly arranged in a linear array on the spray rod 22, and the spray rod 22 is fixedly arranged inside the housing 21. The spray rod 22 is arranged in a linear array inside the housing 21.

[0034] As shown Figure 5 , Figure 7 , Figure 8 in the figure. Inside the spray rod 22, there are pipelines for supplying air and water to the nozzle 1. The pipelines include a water supply pipe 25 and an air supply pipe 24. The air supply pipe 24 and the water supply pipe 25 are respectively connected to an external air source and a water source through an air pipe and a water pipe. Pressure regulating valves and flow regulating valves for regulating air pressure, gas flow rate, water pressure, and water flow rate are respectively arranged on the air pipe and the water pipe. An air supply branch pipe 26 corresponding to the nozzle 1 one by one is arranged on the air supply pipe 24, and the air supply branch pipe 26 is connected to the air inlet pipe 13 inside the nozzle 1. A water supply branch pipe 27 corresponding to the nozzle 1 one by one is arranged on the water supply pipe 25, and the water supply branch pipe 27 is connected to the water inlet pipe 14 inside the nozzle 1. By controlling the pressure regulating valve and the flow regulating valve, the flow rate and pressure of water and air entering the nozzle 1 are controlled, and the generation speed of micro-droplets and the spray mass flow rate are controlled to meet the requirements of different tests for the liquid water content LWC.

[0035] The control of the micro-droplet particle size can be obtained by adjusting the diameter of the nozzle orifice 12 of the nozzle 1. The single nozzle 1 described in Embodiment 1 can be used; or the nozzles 1 described in Embodiment 2 with different nozzle orifice 12 diameters can be used. By changing different types of nozzles 1, the droplet particle size distribution in the spray is adjusted to meet the experimental requirements.

[0036] As shown Figure 6 in the figure. At one end of the spray rod 22 where the nozzle 1 is arranged, there is a support rod 23 for supporting the nozzle 1. A groove 29 for installing the nozzle 1 is arranged on the support rod 23, and through holes corresponding to the nozzles 1 one by one and allowing the nozzles 1 to pass through are arranged on the groove 29.

[0037] Inside the spray rod 22, there is a fixing rod 28 for supporting the air supply branch pipe 26, the water supply branch pipe 27, and the end of the nozzle 1.

[0038] A heating wire 210 for heating the nozzle 1 is wound around the outer surface of the nozzle 1, and the heating wire 210 is connected to an external power source through a wire 211. The nozzle 1 is heated by the heating wire 210 to prevent the nozzle 1 from freezing.

[0039] Therefore, by using the supercooled large water droplet nozzle and the spray device of the present invention, the problems that the diameters and liquid water contents of the supercooled large water droplets ejected by the existing nozzles are uneven and difficult to control can be solved.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A supercooled large water drop nozzle, characterized in that: It includes a main body, one end of which is provided with an air inlet and a water inlet, the interior of the main body is provided with an air inlet pipe connected to the air inlet and a water inlet pipe connected to the water inlet, the air inlet pipe and the water inlet pipe are connected through an air mixing pipe; the other end of the main body is provided with a plurality of nozzles, the air mixing pipe and the nozzles are connected through a connecting pipeline.

2. The supercooled large water drop nozzle according to claim 1, characterized in that: The connecting pipeline comprises N-stage branch pipes connected end to end in sequence, the outlet of the mixing pipe is connected to one end of a first-stage branch pipe of the plurality of N-stage branch pipes, the other end of the first-stage branch pipe is connected to the inlet of the plurality of second-stage branch pipes, the outlet of the (N-1)-stage branch pipe is connected to the inlet of the plurality of N-stage branch pipes, and the outlet of the N-stage branch pipe is connected to the nozzle; the pipe diameter of the connecting pipeline is 10μm-500μm.

3. The supercooled large water drop nozzle according to claim 2, characterized in that: The first-stage branch pipe, the second-stage branch pipe and the N-th-stage branch pipe all include an inclined pipe and a horizontal pipe, the inclined pipe is the inlet pipe of the N-th-stage branch pipe, and the horizontal pipe is the outlet pipe of the N-th-stage branch pipe.

4. The supercooled large water drop nozzle according to claim 1, characterized in that: The nozzles have equal diameters.

5. The supercooled large water drop nozzle according to claim 1, characterized in that: The nozzles have different diameters, and the diameters of the nozzles gradually decrease from the center of the body to the edge of the body. The nozzles with the same diameter are distributed in a circular array on the body.

6. A spray device, characterized in that: It comprises a plurality of spray units, the spray units comprising the supercooled large water drop nozzles according to any one of claims 1 to 5, the nozzles being arranged in a linear array on a spray rod, the spray rod being arranged inside a shell, the spray rod being arranged in a linear array inside the shell, and pipelines for supplying air and water to the nozzles being arranged inside the spray rod.

7. A spray device according to claim 6, characterized in that: The pipeline includes a water supply pipe and an air supply pipe, which are connected to an external air source and water source through an air pipe and a water pipe respectively, and the air pipe and the water pipe are respectively provided with a pressure regulating valve and a flow regulating valve for regulating air pressure and gas flow and regulating water pressure and water flow; the air supply pipe is provided with air supply branches corresponding to the nozzles one by one, and the air supply branch is connected to the air inlet pipe inside the nozzle; the water supply pipe is provided with water supply branches corresponding to the nozzles one by one, and the water supply branch is connected to the water inlet pipe inside the nozzle.

8. A spray device according to claim 6, characterized in that: A support rod for supporting the nozzle is fixed to one end of the spray rod provided with the nozzle, a groove for installing the nozzle is provided on the support rod, and a through hole corresponding to the nozzle one by one and allowing the nozzle to pass through is provided on the groove.

9. A spray device according to claim 6, characterized in that: A fixing rod for supporting the air supply branch pipe, the water supply branch pipe and the nozzle end is arranged inside the spray rod.

10. A spray device according to claim 6, characterized in that: A heating wire for heating the nozzle is wound around the outer surface of the nozzle, and the heating wire is connected to an external power source through a wire.

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