Supercooled large water drop nozzle and spray device

Abstract

The present invention discloses a supercooled large water drop nozzle and a spray device, which belong to the field of nozzle spray technology. The supercooled large water drop nozzle includes a main body, one end of which is provided with an air inlet and a water inlet, and the interior of the main body is provided with an air inlet pipe and a water inlet pipe, and the air inlet pipe and the water inlet pipe are connected by a mixing pipe; the other end of the main body is provided with a plurality of nozzles, and the mixing pipe and the nozzles are connected by a connecting pipeline. The connecting pipeline includes N-level branches connected end to end in sequence, the outlet of the mixing pipe is connected to one end of the first-level branch of the plurality of N-level branches, the other end of the first-level branch is connected to the inlet of the plurality of second-level branches, the outlet of the N-1-th level branch is connected to the inlet of the plurality of N-th level branches, and the outlet of the N-th level branch is connected to the nozzle. The use of the supercooled large water drop nozzle and the spray device described in the present invention can solve the problem that the diameter and liquid water content of the supercooled large water droplets sprayed by the existing nozzle are uneven and difficult to control.

Description

Technical Field

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

[0002] High-altitude icing poses a serious threat to aircraft flight safety. SLDs typically refer to ultra-large droplets in clouds with an average diameter greater than 100 μm and temperatures below freezing. Icing environments containing these droplets are characterized by a large medium volume diameter (MVD) and high liquid water content (LWC). Due to their unique dynamic characteristics, SLDs can bypass anti-icing devices on wing leading edges and engine components, causing them to fail and dramatically degrade aircraft aerodynamic performance. In particular, SLD icing on engines can reduce inlet efficiency, impacting thrust, and in severe cases, ice can break off, damaging blades or even causing engine stall, posing a significant threat to flight safety.

[0003] With the release of new airworthiness requirements and the increasing importance of research on aircraft icing behavior and anti-icing / de-icing devices under SLD icing conditions, new requirements have been placed on the analysis and test verification methods for SLD icing conditions. Icing wind tunnel testing is a crucial means of evaluating aircraft aerodynamic performance and the effectiveness of anti-icing / de-icing devices under icing conditions. By configuring a spray system, cooling system, and altitude simulation system within the circuit, an icing wind tunnel can realistically simulate icing conditions under various temperature, altitude, and flight speed conditions. The spray system primarily utilizes a two-fluid atomizing nozzle to produce a cloud that meets test requirements. A typical icing wind tunnel spray system consists of a spray section, a spray rake (including a bracket, spray boom, and fairing), nozzles, piping, and control valves. The water and air supply systems provide the spray system with pure water and compressed air at a specific temperature. These water and compressed air are then delivered to the nozzles through the spray boom and control valves within the spray system, where they mix water and air to achieve a cloud-like consistency.

[0004] Existing icing wind tunnel experiments have good simulation capabilities for Appendix C icing conditions, but their simulation capabilities for SLD icing conditions are still significantly insufficient. In recent years, simulating SLD icing conditions has become a major challenge facing icing wind tunnels and one of the topics that urgently needs breakthroughs.

[0005] The particle size distribution under the four SLD icing conditions specified in Appendix O of CFR Part 14-25 all exhibit typical bimodal characteristics. To meet the bimodal droplet distribution requirements under SLD icing conditions, a common approach is to use two nozzles with different particle size ranges in the icing wind tunnel to mix and spray, thereby creating a "bimodal" particle size distribution in the downstream test section. However, this method produces an uneven droplet size distribution, making it difficult to use statistical methods to predict the actual particle size distribution characteristics downstream of the spray section. Furthermore, the currently used nozzles are unable to meet the specific test conditions (high LWC, low MVD). Therefore, new design ideas are needed for SLD ice wind tunnel spray systems to support ice wind tunnel testing of SLD icing simulations. Summary of the Invention

[0006] The purpose of the present invention is to provide a supercooled large water drop nozzle and a spray device to solve the problem that the diameter and liquid water content of the supercooled large water droplets sprayed by the existing nozzle are uneven and difficult to control.

[0007] To achieve the above objectives, the present invention provides a supercooled large droplet nozzle comprising a main body, one end of which is provided with an air inlet and a water inlet, and 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 being connected via an air mixing pipe; the other end of the main body is provided with a plurality of nozzles, and the air mixing pipe and the nozzles are connected by a connecting pipe. The diameter of the air inlet pipe and the water inlet pipe ranges from 100μm to 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 the multiple N-level branch pipes, the other end of the first-level branch pipe is connected to the inlet of the multiple second-level branch pipes, the outlet of the (N-1)-th level branch pipe is connected to the inlet of the multiple N-th level branch pipes, and the outlet of the N-th level branch pipe is connected to the nozzle; the diameter of the connecting pipeline is 10μm-500μm.

[0009] Preferably, 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.

[0010] Preferably, the nozzles have the same diameter.

[0011] Preferably, the nozzles have different diameters, and the diameter of the nozzles gradually decreases from the center of the body to the edge of the body, and nozzles of the same diameter are distributed in a circular array on the body.

[0012] A spray device includes several spray units, each of which includes the above-mentioned supercooled large water droplet nozzles. The nozzles are arranged in a linear array on a spray rod, which is arranged inside a shell. The spray rods are arranged in a linear array inside the shell, and pipelines for supplying air and water to the nozzles are provided inside the spray rod.

[0013] Preferably, the pipeline includes a water supply pipe and an air supply pipe, which are connected to the external air source and water source through the air pipe and water pipe respectively, and the air pipe and water pipe are respectively provided with a pressure regulating valve and a flow regulating valve for regulating the air pressure, gas flow and regulating the water pressure, water flow; the air supply pipe is provided with an air supply branch pipe corresponding one-to-one to the nozzle, and the air supply branch pipe is connected to the air inlet pipe inside the nozzle; the water supply pipe is provided with a water supply branch pipe corresponding one-to-one to the nozzle, and the water supply branch pipe is connected to the water inlet pipe inside the nozzle.

[0014] Preferably, one end of the spray rod provided with the nozzle is fixed with a support rod for supporting the nozzle, the support rod is provided with a groove for mounting the nozzle, and the groove is provided with a through hole corresponding to the nozzle one by one and allowing the nozzle to pass through.

[0015] Preferably, a fixing rod for supporting the air supply branch pipe, the water supply branch pipe and the nozzle end is provided inside the spray rod.

[0016] Preferably, 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 via a wire.

[0017] The advantages and positive effects of the supercooled large water droplet nozzle and spray device of the present invention are:

[0018] 1. The present invention incorporates a multi-stage flow channel connecting pipeline within the nozzle, which promotes the mixing of water and gas, increases the rate of microdroplet generation and the stability of droplet flow, and produces microdroplets of stable and uniform size. By providing nozzles of varying diameters on the nozzle, microdroplets with varying particle sizes are produced, making the size and water content of the microdroplets more easily controllable.

[0019] 2. The spray device of the present invention is used in icing wind tunnel experiments. It can also generate micro-droplets with a constant and known particle size to calibrate diameter measuring instruments based on different principles, such as laser phase Doppler particle analyzers (PDPAs), laser particle size analyzers, and other instruments for measuring particle diameters.

[0020] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the three-dimensional structure of the nozzle of Example 1 of the present invention;

[0022] Figure 2This is a schematic diagram of the internal piping structure of the nozzle according to Example 1 of the present invention;

[0023] Figure 3 This is a schematic diagram of the planar structure of the internal pipeline of the nozzle of Example 1 of the present invention;

[0024] Figure 4 This is a schematic diagram of the three-dimensional structure of the spray unit according to Example 3 of the present invention;

[0025] Figure 5 This is a schematic diagram of the internal structure of the spray rod according to Example 3 of the present invention;

[0026] Figure 6 This is a schematic diagram of the partial structure of the spray rod according to Example 3 of the present invention;

[0027] Figure 7 This is a schematic diagram of the internal piping structure of the spray rod according to Example 3 of the present invention;

[0028] Figure 8 This is a schematic diagram of the partial structure of the internal pipeline of the spray rod of Example 3 of the present invention.

[0029] Reference numerals

[0030] 1. Nozzle; 11. Main body; 12. Nozzle; 13. Air inlet pipe; 14. Water inlet pipe; 15. Mixing pipe; 16. First-stage branch pipe; 17. Second-stage branch pipe; 18. Nth-stage branch pipe;

[0031] 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. Fixing rod; 29. ​​Groove; 210. Heating wire; 211. Wire. DETAILED DESCRIPTION

[0032] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the inventive product is usually placed when in use. These are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. In the description of the present invention, it should also be noted that, unless otherwise expressly specified and limited, the terms "setting", "installation" and "connection" 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 a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of 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 circumstances.

[0033] 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 art to which this application belongs. In the event of any inconsistency, the meaning described in this specification or the meaning derived from the contents 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 for the terms used in this specification before describing the specific embodiments:

[0034] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] Example 1

[0036] like Figure 1 As shown. A supercooled large water droplet nozzle includes a main body 11, and an air inlet and a water inlet are provided at one end of the main 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 main 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 main 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 arranged at one end of the mixing pipe 15. The diameters of the air inlet pipe and the water inlet pipe are 100μm-1000μm, and the specific diameters of the air inlet pipe and the water inlet pipe are set according to actual needs.

[0037] like Figure 2 、 Figure 3 As shown. Several nozzles 12 are provided at the other end of the body 11, and a mixing pipe 15 is connected to the nozzles 12 via a connecting pipeline. The connecting pipeline includes N-stage branch pipes connected end to end. The outlet of the mixing pipe 15 is connected to one end of the first-stage branch pipe 16 of the N-stage branch pipes. The other end of the first-stage branch pipe 16 is connected to the inlet of several second-stage branch pipes 17. The outlet of the (N-1)-stage branch pipe is connected to the inlet of several N-stage branch pipes 18. The outlet of the N-stage branch pipe 18 is connected to the nozzle 12. The diameter of each branch pipe in the connecting pipeline is 10μm-500μm. The acute angle between the mixing pipe and the inclined pipe of the first branch pipe is 30°-45°.

[0038] The first-stage branch pipe 16, the second-stage branch pipe 17, and the Nth-stage branch pipe 18 all include an inclined pipe and a horizontal pipe. The inclined pipe serves as the inlet pipe of the Nth-stage branch pipe 18, and the horizontal pipe serves as the outlet pipe of the Nth-stage branch pipe 18. The diameter of the (N-1)th-stage branch pipe is no less than that of the Nth-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 and horizontal pipes is 0.1μm-0.5μm.

[0039] The diameters of the nozzles 12 are different. The diameter of the nozzles 12 gradually decreases from the center of the body 11 to the edge of the body 11 . The nozzles 12 of the same diameter are distributed in a circular array on the body 11 .

[0040] Air and water are two immiscible substances, with water as the continuous phase and air as the discrete phase. Water and air enter their respective pipes at fixed volume flow rates. When the two fluids meet at the intersection, the flow velocity of the discrete phase fluid is relatively slow. Under the shear and extrusion of the continuous phase fluid, the liquid column breaks due to the instability of the free interface, which manifests as the liquid column being "pinched off" and thus dispersed in the continuous phase to form micro-droplets ranging from a few microns to hundreds of microns in size. The size, morphology and uniformity of the micro-droplets are good, thereby improving the uniformity of the droplet size sprayed by the nozzle 1.

[0041] The internal connecting pipes of the nozzle 1 are graded flow channels, and the connecting pipes of the graded flow channels can promote the mixing of fluids. Due to the continuous subdivision of the branch flow channels, the fluid is gradually divided into smaller streams, increasing the contact area between the fluids. As the flow channels are graded, 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 achieving the regulation of the size of the microdroplets. The graded design of the flow channels increases the sites for droplet formation, allowing droplets to form simultaneously at multiple branches, thereby increasing the droplet generation rate. The structure of the graded flow channels can also disperse the pressure of the fluid, reduce the impact of pressure fluctuations on droplet flow, and improve the stability of droplet flow.

[0042] In this embodiment, the flow rate of water is 0.1m / s-0.15m / s. The specific flow rate of water as the continuous phase is determined by the LWC of the supercooled large water droplets. Air is controlled by the solenoid valve of the microfluidic chip of the microdroplet generator as the discrete phase. To achieve the supercooled large water droplet diameter, which is directly determined by the nozzle diameter of this embodiment, the solenoid valve frequency is set to 20Hz-40Hz, the opening time is 0.5ms-1ms, and the air pressure is set to 45kPa-60kPa. In this way, droplets with uniform and stable particle size can be ejected through the nozzle, and the particle size of the droplets is 1.7-1.9 times the nozzle size.

[0043] The nozzle 1 has nozzle openings 12 of different diameters and can spray out micro-droplets with different sizes. Thus, by setting different sizes of the nozzle openings 12, the size of the droplets in the spray can be adjusted and controlled as needed.

[0044] Example 2

[0045] The difference between this embodiment and embodiment 1 is that the nozzles 12 of the nozzles 1 in this embodiment have the same diameter, and one nozzle 1 can spray out a spray with uniform particle size.

[0046] Example 3

[0047] like Figure 4 A spray device includes a plurality of spray units 2, each of which includes the nozzles 1 of Example 1 or Example 2. The nozzles 1 are fixedly arranged in a linear array on a spray rod 22, which is fixedly arranged inside a housing 21. The spray rods 22 are arranged in a linear array inside the housing 21.

[0048] like Figure 5 、 Figure 7 、 Figure 8 As shown. The interior of the spray rod 22 is provided with pipelines for supplying air and water to the nozzle 1. The pipelines include an air supply pipe 25 and a water supply pipe 24, and the air supply pipe 24 and the water supply pipe 25 are connected to the external air source and water source through an air pipe and a water pipe respectively. The air pipe and the water pipe are respectively provided with a pressure regulating valve and a flow regulating valve for regulating air pressure, gas flow and regulating water pressure and water flow. The air supply pipe 24 is provided with an air supply branch pipe 26 corresponding one-to-one to the nozzle 1, and the air supply branch pipe 26 is connected to the air inlet pipe 13 inside the nozzle 1. The water supply pipe 25 is provided with a water supply branch pipe 27 corresponding one-to-one to the nozzle 1, and the water supply branch pipe 27 is connected to the water inlet pipe 14 inside the nozzle 1. The flow rate and pressure of water and air entering the nozzle 1 are controlled by the pressure regulating valve and the flow regulating valve, and the speed of micro-droplet generation and the spray mass flow rate are controlled to meet the requirements of different tests for liquid water content LWC.

[0049] The droplet size can be controlled by adjusting the diameter of the nozzle 12 of the nozzle 1. A single nozzle 1 as described in Example 1 can be used; alternatively, multiple nozzles 1 as described in Example 2 with different nozzle 12 diameters can be used. By varying the nozzle 1 type, the droplet size distribution in the spray can be adjusted to meet experimental requirements.

[0050] like Figure 6 As shown, the spray rod 22 is provided with a nozzle 1 and a support rod 23 is fixed at one end thereof to support the nozzle 1. The support rod 23 is provided with a groove 29 for mounting the nozzle 1, and the groove 29 is provided with a through hole corresponding to the nozzle 1 one by one and allowing the nozzle 1 to pass through.

[0051] A fixing rod 28 is provided inside the spray rod 22 to support the air supply branch pipe 26 , the water supply branch pipe 27 and the end of the nozzle 1 .

[0052] A heating wire 210 is wound around the outer surface of the nozzle 1 to heat the nozzle 1. The heating wire 210 is connected to an external power source via a wire 211. The nozzle 1 is heated by the heating wire 210 to prevent the nozzle 1 from icing or freezing.

[0053] Therefore, the use of the supercooled large water droplet nozzle and the spray device of the present invention can solve the problem that the diameter and liquid water content of the supercooled large water droplets sprayed by the existing nozzle are uneven and difficult to control.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A supercooled large water drop nozzle, characterized by: The device comprises a main body, one end of which is provided with an air inlet and a water inlet, an air inlet pipe connected to the air inlet and a water inlet pipe connected to the water inlet are provided inside the main body, and the air inlet pipe and the water inlet pipe are connected via an air mixing pipe; the other end of the main body is provided with a plurality of nozzles, and the air mixing pipe and the nozzles are connected via a connecting pipe; The connecting pipeline includes N-stage branch pipes connected end to end in sequence, the outlet of the mixing pipe is connected to one end of the 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 diameter of the connecting pipeline is 10 μm-500 μm; 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; 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.

2. A spray device, characterized in that: The invention comprises a plurality of spray units, each of which comprises the supercooled large water drop nozzle according to claim 1, wherein the nozzles are arranged in a linear array on a spray rod, the spray rod is arranged inside the housing, the spray rod is arranged in a linear array inside the housing, and a pipeline for supplying air and water to the nozzles is provided inside the spray rod; 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.

3. A spray device according to claim 2, characterized in that: The pipeline includes a water supply pipe and an air supply pipe, which are connected to the external air source and water source through the air pipe and water pipe respectively. The air pipe and water pipe are respectively provided with a pressure regulating valve and a flow regulating valve for regulating the air pressure, gas flow and regulating the water pressure and water flow; the air supply pipe is provided with an air supply branch pipe corresponding one-to-one to the nozzle, and the air supply branch pipe is connected to the air inlet pipe inside the nozzle; the water supply pipe is provided with a water supply branch pipe corresponding one-to-one to the nozzle, and the water supply branch pipe is connected to the water inlet pipe inside the nozzle.

4. A spray device according to claim 2, characterized in that: One end of the spray rod provided with the nozzle is fixed with a support rod for supporting the nozzle, the support rod is provided with a groove for installing the nozzle, and the groove is provided with a through hole corresponding to the nozzle one by one and allowing the nozzle to pass through.

5. A spray device according to claim 2, 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.

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