Railway contact net icing reproduction supercooled liquid drop spraying device and design method

Abstract

The invention relates to the technical field of railway contact net icing tests, in particular to a railway contact net icing reproduction supercooled liquid drop spraying device and a design method, and the device comprises a nozzle array, a water supply pipeline, a water tank, a background wind field assembly, an auxiliary wind field assembly and a control system. According to the invention, the M-P distribution spectrum of natural freezing rain can be macroscopically reproduced, so that the icing physical process is highly real, the optimized array layout ensures that the rain field distribution of the test section is uniform, the test repeatability and precision are high, and the real pneumatic environment and liquid drop collision process during train operation can be controlled and simulated through the background wind field. In addition, in cooperation with the auxiliary wind field assembly, accurate control over the end speed when liquid drops impact the contact network is achieved, and the defect that in the prior art, liquid drop impact energy simulation is insufficient is overcome. The railway contact net icing reproduction supercooled liquid drop spraying device provided by the invention is high in design method scientificity and expansibility.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of railway catenary icing test, in particular to a railway catenary icing reproduction supercooled droplet spraying device and design method. BACKGROUND

[0002] The railway catenary is an important part of the electrified power supply system of high-speed railway, and its safe and stable operation is directly related to the power supply reliability of the train. Under the condition of freezing rain and other extreme weather, icing phenomenon is prone to occur on the surface of the catenary conductor, which leads to an increase in contact resistance and deterioration of the current collection relationship between the pantograph and the catenary. Severe icing can cause the pantograph to arc and break, and even cause power interruption, which seriously threatens the safety of train operation. In view of the catenary icing problem, existing research mainly focuses on two categories, one is numerical simulation method, and the other is test method. The test method usually simulates the freezing rain environment by artificial method to conduct icing test on a small section of contact line to observe the icing thickness and shape. However, such test is limited by site and equipment conditions, and it is difficult to reproduce complex wind and rain coupling conditions, especially it is difficult to restore the process of supercooled droplets icing on the surface of the catenary conductor.

[0003] Specifically, the spraying device of the artificial climate chamber for simulating catenary icing usually adopts simple pipe nozzle or ultrasonic atomizer. The water droplet particle size distribution produced by these spraying devices is single (mostly Gaussian distribution), which is far from the Marshall-Palmer exponential distribution of natural freezing rain environment, resulting in distortion of the icing shape, density and growth rate. Moreover, the design of the existing spraying device itself lacks scientific guidance and relies on experience, which leads to the lack of simulation fidelity from the design source. In addition, the existing spraying device is difficult to form a spatially uniform supercooled rain field in the test site, and cannot accurately control the rainfall intensity and droplet spectrum, so the fidelity and comparability of the simulation reproduction are poor. SUMMARY

[0004] The purpose of the present application is to provide a spraying device and corresponding design method for railway catenary icing test, which can more accurately simulate the impact of supercooled droplets, liquid film phase change and icing shape evolution.

[0005] In order to achieve the above purpose, the present application provides a railway catenary icing reproduction supercooled droplet spraying device, which comprises a nozzle array, a water supply pipeline, a water tank, a background wind field assembly, an auxiliary wind field assembly and a control system.

[0006] The nozzle array comprises a nozzle mounting frame, a plurality of nozzles connected with the nozzle mounting frame, and a mechanical adjustment assembly connected with the nozzle mounting frame, the nozzles have multiple specifications, each specification corresponds to generate liquid droplets of different particle sizes, the nozzles of different specifications are distributed on the nozzle mounting frame according to a preset rule, and the mechanical adjustment assembly is used for adjusting the position and angle of the nozzle mounting frame.

[0007] The water tank is used for storing water for forming liquid droplets.

[0008] The water supply pipeline comprises a water supply main pipe and a plurality of independent water supply branch pipes, the water supply main pipe is communicated with the water tank, the water supply main pipe is provided with a driving pump, different water supply branch pipes are connected with nozzles of corresponding specifications to independently supply water, and the water supply branch pipes are provided with flow regulating valves and flow meters, the water supply pipeline further comprises a jacketed heat exchanger, the water supply branch pipes are arranged in the jacketed heat exchanger, and the jacketed heat exchanger is used for reducing the water temperature to a target supercooling degree.

[0009] The background wind field assembly is arranged in front of the nozzle array, is used for generating airflow with a direction parallel to the train running direction, a speed within a preset range and continuous adjustment, and simulates train wind generated when the train runs at a high speed.

[0010] The auxiliary wind field assembly is arranged directly above the nozzle array, is used for generating auxiliary airflow vertically downward, and provides additional axial acceleration for the liquid droplets generated by the nozzles.

[0011] The control system is electrically connected with the mechanical adjustment assembly, the driving pump, the flow regulating valve, the flow meter, the background wind field assembly and the auxiliary wind field assembly.

[0012] Further, the nozzles comprise large nozzles, medium nozzles and small nozzles.

[0013] Further, the large nozzles are used for generating liquid droplets with a particle size of 1.6-2.4 mm, the medium nozzles are used for generating liquid droplets with a particle size of 0.8-1.6 mm, and the small nozzles are used for generating liquid droplets with a particle size of 0.01-0.8 mm.

[0014] Further, the number ratio of the large nozzles, the medium nozzles and the small nozzles is 8:9:8.

[0015] Further, the nozzles are combined in a module form, the nozzles in each module are arranged in a rectangular array or a ring array, the large nozzles and the medium nozzles are arranged dispersedly, and the small nozzles are filled in the remaining positions.

[0016] Further, the water supply branch pipes include a first branch pipe, a second branch pipe and a third branch pipe, the first branch pipe corresponds to the large nozzle, the second branch pipe corresponds to the medium nozzle, and the third branch pipe corresponds to the small nozzle.

[0017] Further, the background wind field assembly includes a first fan and an air duct in communication with the first fan, the air duct is arranged to be angle-adjustable to simulate train wind with different angles with the train driving direction.

[0018] Further, the auxiliary wind field assembly includes a second fan and a plurality of nozzles in communication with the second fan, the nozzles are arranged one by one corresponding to the nozzles.

[0019] Further, the control system independently controls the flow of each water supply branch pipe according to the Marshall-Palmer distribution parameters of the target freezing rain environment, so that the overall characteristics of the droplets generated by all the nozzles meet the target particle size distribution and rainfall intensity.

[0020] The application also provides a design method of a railway overhead line system icing reproduction supercooled droplet spraying device, which designs the railway overhead line system icing reproduction supercooled droplet spraying device as described above, and includes the following steps:

[0021] S1, determining the Marshall-Palmer distribution parameters of the target freezing rain environment: according to the simulation requirements, determining the target rainfall intensity and the intercept parameter , obtaining the target droplet size distribution function , wherein the slope parameter ;

[0022] S2, calculating the water volume ratio of each particle size interval: dividing the droplet size range into large, medium and small intervals, and calculating the percentage of the total volume of each interval in the total volume by integrating the function in each interval, respectively represented by , ,

[0023] S3, determining the nozzle quantity ratio and working flow: preliminarily determining the total number of nozzles according to engineering experience, determining the number ratio of large, medium and small nozzles according to the water volume ratio calculated in S2, calculating the total water flow according to the target rainfall intensity and the test section area, and calculating the total working flow of each type of nozzle, ; ; , calculating the working flow of a single nozzle;

[0024] ​S4, determine the nozzle spacing and spatial layout: according to the nozzle spray cone angle And nozzle height , calculate the nozzle spacing according to the formula , wherein Is the overlap coefficient, the nozzle height Indicates the vertical distance from the nozzle to the conductor rail, and the spatial layout is optimized by adopting the dispersion principle, the large nozzle and the medium nozzle are dispersedly arranged, and the small nozzle is filled between the large nozzle and the medium nozzle, so that the uniform mixing of liquid droplets of different particle sizes in space is realized.

[0025] The above scheme of the present application has the following beneficial effects:

[0026] The railway catenary icing reproduction supercooled droplet spraying device provided by the present application macroscopically reproduces the M-P distribution spectrum of natural freezing rain through the collaborative control of the array combination of three types of nozzles designed based on scientific methods and the control system of flow, spraying height, angle and the like, makes the icing physical process highly realistic, and the optimized array layout ensures uniform distribution of the rain field of the test section, high test repeatability and precision, and can simulate the real aerodynamic environment and droplet impact process when the train is running through the background wind field control, realizes the reproduction of the asymmetric dynamic icing shape of the railway catenary, and in addition, the auxiliary wind field assembly is used to realize the accurate control of the terminal speed of the droplet impacting the catenary, which makes up for the defects of the prior art in simulating the droplet impact energy.

[0027] The present application has strong parameter adjustability, and the rainfall intensity, raindrop spectrum, supercooling degree and wind speed can be flexibly and independently set through the control system, so that a set of device can simulate different intensity of freezing rain environment, has good universality, high integration degree, is managed by the central control system, realizes the collaborative control of the icing environment multi-physical parameters, and the simulation dimension and fidelity are significantly improved.

[0028] The present application can accurately control the supercooling degree of the droplet by setting the whole pipeline heat preservation layer and the sleeve type heat exchanger in front of the nozzle, ensures the stable generation and transportation of the supercooled droplet, and effectively avoids the nozzle blockage or droplet evaporation.

[0029] The design method of the railway catenary icing reproduction supercooled droplet spraying device provided by the present application is scientific and has strong expandability, the nozzle array design process is clear and the steps are clear, the target physical characteristics are accurately converted into engineering design parameters, the design efficiency and the first success rate of the device are significantly improved, the device can be distributed in a modular manner, can be flexibly expanded according to the test requirements, and has strong engineering adaptability.

[0030] Other beneficial effects of the present application will be described in detail in the subsequent specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1Fig. 1 is a schematic diagram of the overall structure of the device of the present application;

[0032] Figure 2 Fig. 2 is another schematic diagram of the overall structure of the device of the present application;

[0033] Figure 3 Fig. 3 is a flow chart of the design method of the present application.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS

[0035] 10 - nozzle array; 11 - nozzle mounting frame; 12 - large nozzle; 13 - medium nozzle; 14 - small nozzle; 20 - water supply pipeline; 21 - water supply main pipe; 22 - first branch pipe; 23 - second branch pipe; 24 - third branch pipe; 25 - drive pump; 26 - flow regulating valve; 27 - flow meter; 28 - jacketed heat exchanger; 30 - water tank; 40 - background wind field assembly; 50 - auxiliary wind field assembly; 60 - control system; 70 - catenary. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and advantages of the present application clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0037] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0038] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be a locking connection, or 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, or the communication between the two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] As Figure 1 , Figure 2 shown, the embodiment of the present application provides a device for spraying supercooled droplets to simulate icing of overhead contact system, which comprises a nozzle array 10, a water supply pipeline 20, a water tank 30, a background wind field assembly 40, an auxiliary wind field assembly 50 and a control system 60. The nozzle array 10 comprises a nozzle mounting frame 11 and a plurality of nozzles connected to the nozzle mounting frame 11. The nozzles are arranged in a specific pattern, and at least three types of nozzles are included: large nozzles 12 for generating droplets with a particle size of 1.6-2.4 mm, medium nozzles 13 for generating droplets with a particle size of 0.8-1.6 mm, and small nozzles 14 for generating droplets with a particle size of 0.01-0.8 mm. The number ratio of large nozzles 12, medium nozzles 13 and small nozzles 11 is preferably 8:9:8.

[0040] As a preferred embodiment, the nozzles in this embodiment preferably use pressure cyclone nozzles. Pressure cyclone nozzles are a kind of special nozzles that use the pressure of fluid (usually water or cleaning liquid) itself to produce rotational motion, thereby achieving large-area and high-efficiency impact coverage. Specifically, the fluid enters through the inlet of the pressure cyclone nozzle, and the path of the fluid in the pressure cyclone nozzle is usually through one or more eccentric holes, inclined channels or impact turbine blades, so that the jet direction of the fluid is not completely along the axis, but a tangential component is generated, which forms a torque to push the rotating parts (such as the nozzle head, rotor or turbine) of the nozzle to continuously rotate around its axis. And at the same time of rotation, the fluid is ejected at high speed from the nozzle hole, forming one or more continuously moving jet streams, thereby greatly expanding the coverage range of single-hole jet. Therefore, it does not need external motors or power sources, nor does it need additional control of the pressure cyclone nozzle itself.

[0041] In this embodiment, the nozzle mounting frame 11 is connected to a mechanical adjustment assembly, which can be driven by a linear drive mechanism such as an electric push rod and / or a rotary drive mechanism such as a servo motor, to realize continuous adjustment of the overall height and angle of the nozzle mounting frame, to optimize the spraying process and ensure comprehensive coverage of the complex structure of the overhead contact system 70.

[0042] In the embodiment, the nozzles of the nozzle array 10 are combined in a module form, and the nozzles in each module are arranged in a rectangular array, for example, a 5x5 array. The entire nozzle array 10 can be composed of one or several modules to cover test sections of different sizes. The embodiment is exemplified by a single module, and the layout principle is consistent for a single or combined modules and the nozzle layout within each module, that is, the large nozzles 12 and the medium nozzles 13 are dispersedly arranged at the edge and the center intersection of the rectangular array, and the small nozzles 14 are filled in the remaining positions of the rectangular array to achieve sufficient mixing of the droplets in space. In addition, a ring array can also be considered, each ring of the ring array is alternately and spacedly distributed by a plurality of large nozzles 12 and medium nozzles 13, or all by small nozzles 14, and then the two types of rings are alternately and spacedly distributed in turn, which can also achieve sufficient mixing of the droplets in space.

[0043] In the embodiment, the water supply pipeline 20 includes a water supply main pipe 21 and three independent water supply branch pipes, that is, a first branch pipe 22, a second branch pipe 23 and a third branch pipe 24. The water supply main pipe 21 is in communication with a water tank 30 for storing water used for forming supercooled droplets, which can be pre-cooled in the water tank 30, and the water tank 30 can be provided with a certain heat preservation capacity. The water supply main pipe 21 is provided with a driving pump 25, and the first branch pipe 22, the second branch pipe 23 and the third branch pipe 24 are in communication with the water supply main pipe 21 and are respectively used for independently supplying water to the large nozzles 12, the medium nozzles 13 and the small nozzles 14 to match the water amount corresponding to different nozzles. At the same time, a precision flow regulating valve 26 and a flow meter 27 are arranged on each branch pipe. The branch pipes are further provided with a sleeved heat exchanger 28, and then connected to the nozzle mounting frame 11 to reduce the water temperature 30 to a target supercooling degree, for example, -5℃, -10℃, -15℃, etc., through the sleeved heat exchanger 28 to simulate different phase state freezing rain environments, for example, frost ice state, mixed ice state, clear ice state, etc., to improve the reproduction authenticity of different icing types during the test. In addition, in order to realize pipeline protection and maintain the temperature inside the pipeline, the outer wall of all the pipelines is wrapped with heat preservation materials. It should be noted that the cold side of the sleeved heat exchanger 28 is connected to an external refrigeration unit to provide refrigeration to smoothly reduce the water in the branch pipes to the target supercooling degree.

[0044] In the embodiment, the background wind field assembly 40 is arranged in front of the nozzle array 10, for generating a stable and uniform airflow with a direction parallel to the train running direction and a speed in the range of 0-250 km / h and continuously adjustable, to simulate the train wind generated when the train runs at high speed. The background wind field assembly 40 can include a first fan and an air duct in communication with the first fan. The first fan sends air into the air duct, the air duct is aligned with the position of the nozzle array 10, and the air duct is arranged in parallel to form a stable and uniform airflow. In addition, a grille can be added inside the air duct or at the outlet position to simulate a specific turbulent flow field. Of course, the air duct can also be arranged to be angle-adjustable to simulate the train wind with different angles with the train running direction.

[0045] In the embodiment, the auxiliary wind field assembly 50 is arranged directly above the nozzle array 10, for generating an auxiliary airflow vertically downward, which acts on the liquid droplets just sprayed by the nozzle array 10, to provide additional axial acceleration to the liquid droplets, so as to improve the final speed of the liquid droplets when they hit the catenary 70, and achieve the purpose of more accurately simulating the actual freezing rain hitting the catenary 70. The auxiliary wind field assembly 50 can include a second fan and a plurality of air nozzles in communication with the second fan, which can be arranged one-to-one with the nozzles to better accelerate the liquid droplets.

[0046] In the embodiment, the control system 60 is electrically connected with the control units of the driving pump 25, the flow regulating valves 26, the flow meters 27, the mechanical adjusting assembly, the first fan, the second fan, etc., for controlling these components to adjust the supercooled liquid droplet spraying process. Specifically, according to the Marshall-Palmer distribution parameters of the target freezing rain environment, the flow rates of the three branches are independently controlled, so that the overall characteristics of the liquid droplets generated by all the nozzles meet the target particle size distribution and rainfall intensity; at the same time, the wind speed and direction generated by the background wind field assembly 40, the spraying height and angle of the nozzle array 10, and the airflow speed of the auxiliary wind field assembly 50 are controlled, so as to cooperatively achieve accurate control of the final speed of the liquid droplets when they hit the catenary 70.

[0047] It should be noted that, in order to realize high-fidelity reproduction of the dynamic process of the liquid droplets hitting the catenary 70, the control system 60 needs to accurately adjust the terminal speed of the liquid droplets, which is cooperatively realized in the embodiment by the following two ways:

[0048] The nozzle mounting frame 11 can realize continuous adjustment of the vertical height between the nozzle and the wire of the overhead contact line 70 through the mechanical adjustment assembly. According to the principle of fluid mechanics, liquid droplets accelerate in a constant wind field, and their speed tends to approach the terminal speed as the flight distance increases. By reducing the vertical height, the impact of small particle size droplets that do not reach the terminal speed in nature can be simulated; by increasing the vertical height, it can be ensured that all droplets impact the overhead contact line 70 at a speed close to their theoretical terminal speed. The adjustment range of the vertical height is generally set to 1.5m to 4m.

[0049] To further enhance the control ability, especially in the scenario of simulating super large particle size droplets or requiring droplets to impact at a speed exceeding their natural terminal speed, the auxiliary wind field assembly 50 is started to apply an additional vertical downward acceleration to the sprayed droplets, thereby actively increasing their impact speed, and the super large particle size droplets can accurately simulate the impact of the overhead contact line wire at the natural terminal speed, or the droplets impact the overhead contact line 70 at a speed exceeding their natural terminal speed.

[0050] As described above, the railway overhead contact line icing reproduction supercooled droplet spraying device provided by the embodiment solves the problems that the existing spraying device cannot generate supercooled droplets conforming to the natural frozen rain particle size distribution due to reliance on experience and lack of scientific methods, and the spraying uniformity is poor and the parameter control is not accurate. At the same time, it can solve the problem of poor spatial uniformity of the spraying area, and there are "stripes" or "holes" in the rain. It can realize flexible and accurate control of the rainfall intensity and the raindrop spectrum, and ensure the stable generation and transportation of supercooled droplets, avoiding nozzle blockage or droplet evaporation. In addition, it solves the technical problem that the existing test cannot reproduce the crescent-shaped asymmetric icing shape of the overhead contact line 70 wire under the "train wind" environment due to the lack of a background wind field simulating the train running speed, further improving the reproduction authenticity.

[0051] Based on the same inventive concept, the embodiment also provides a railway overhead contact line icing reproduction supercooled droplet spraying device design method, as shown in Figure 3 , comprising the following steps:

[0052] S1, determining the Marshall-Palmer distribution parameters of the target frozen rain environment: according to the simulation requirements, determining the target rainfall intensity (mm / h) and the intercept parameter (m -3 mm -1 ), so as to obtain the target droplet size distribution function , wherein the slope parameter .

[0053] S2, calculate the water volume proportion of each particle size interval: divide the droplet particle size range into three intervals of large, medium and small. For example: large, 1.6-2.4mm; medium, 0.8-1.6mm; small: 0.01-0.8mm. Calculate the water volume proportion of each interval by integrating the function in each interval to obtain the water volume proportion of large, medium and small particle size droplets, which are represented by , , respectively.

[0054] S3, determine the nozzle number ratio and working flow: according to engineering experience, such as uniformity requirement, cost, etc., preliminarily determine the total number of nozzle array 10, for example, 5x5=25. According to the water volume proportion calculated in S2, determine the number ratio of large, medium and small nozzles, in order to ensure spatial uniformity, the number ratio of large, medium and small nozzles is preferably large: medium: small=8:9:8. Calculate the total water flow according to the target rainfall intensity and the test section area. Calculate the total working flow of each type of nozzle: ; ; . Calculate the working flow of a single nozzle, specifically divide the total working flow of each type of nozzle by the number of nozzles of that type to obtain the working flow of a single nozzle, which is used for subsequent flow control.

[0055] S4, determine the nozzle spacing and spatial layout: according to the nozzle spray cone angle and the nozzle height , calculate the nozzle spacing according to the formula , wherein is the overlap coefficient, usually taken as 1.2-1.5 to ensure that the droplets overlap sufficiently, and the nozzle height represents the vertical distance from the nozzle to the contact net conductor. Adopt the dispersion principle to optimize the spatial layout, disperse the large nozzles and medium nozzles at the edge and center intersection positions of the array grid, and fill the small nozzles in the remaining grid positions to achieve uniform mixing of droplets of different particle sizes in space.

[0056] The railway contact net icing reproduction supercooled droplet spraying device design method provided in the embodiment has the same inventive concept and beneficial effects as the spraying device described above, and will not be described here.

[0057] The technical features of the above embodiments can be combined in any way. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present disclosure.

[0058] The above embodiments only express several implementation ways of the present application, and the description is specific and detailed, but it should not be understood as a limitation to the scope of the application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A spray device for reproducing supercooled droplets icing on railway overhead contact lines, characterized in that, It includes nozzle arrays, water supply pipelines, water tanks, background wind field components, auxiliary wind field components, and control systems; The nozzle array includes a nozzle mounting frame, multiple nozzles connected to the nozzle mounting frame, and a mechanical adjustment component connected to the nozzle mounting frame. The nozzles have various specifications, each of which produces droplets of different sizes. The nozzles of different specifications are distributed on the nozzle mounting frame according to a preset pattern. The mechanical adjustment component is used to adjust the position and angle of the nozzle mounting frame. The water tank is used to store water that forms droplets; The water supply pipeline includes a main water supply pipe and multiple independent water supply branch pipes. The main water supply pipe is connected to the water tank and is equipped with a drive pump. Different water supply branch pipes are connected to nozzles of corresponding specifications for independent water supply, matching the water volume corresponding to different nozzle specifications. The water supply branch pipes are equipped with flow regulating valves and flow meters. The water supply pipeline also includes a shell-and-tube heat exchanger. The water supply branch pipes pass through the shell-and-tube heat exchanger, which is used to reduce the water temperature to the target subcooling degree. The background wind field component is positioned in front of the nozzle array to generate an airflow that is parallel to the direction of train travel, with a speed within a preset range and continuously adjustable, in order to simulate the train wind generated when the train is running at high speed. The auxiliary airflow assembly is positioned directly above the nozzle array to generate a vertically downward auxiliary airflow, providing additional axial acceleration to the droplets generated by the nozzles. The control system is electrically connected to the mechanical adjustment component, the drive pump, the flow regulating valve, the flow meter, the background wind field component, and the auxiliary wind field component.

2. The railway contact wire icing reproduction supercooled droplet spraying device according to claim 1, characterized in that, The nozzles include large nozzles, medium nozzles, and small nozzles.

3. The railway contact wire icing reproduction supercooled droplet spraying device according to claim 2, characterized in that, The large nozzle is used to generate droplets with a diameter of 1.6~2.4mm, the medium nozzle is used to generate droplets with a diameter of 0.8~1.6mm, and the small nozzle is used to generate droplets with a diameter of 0.01~0.8mm.

4. The railway contact wire icing reproduction supercooled droplet spraying device according to claim 3, characterized in that, The ratio of the number of large nozzles, medium nozzles, and small nozzles is 8:9:

8.

5. The railway contact wire icing reproduction supercooled droplet spraying device according to claim 2, characterized in that, The nozzles are combined in a modular form, and the nozzles in each module are arranged in a rectangular array or a ring array. The large nozzles and the medium nozzles are distributed separately, and the small nozzles fill the remaining positions.

6. The railway contact wire icing reproduction supercooled droplet spraying device according to claim 2, characterized in that, The water supply branch pipe includes a first branch pipe, a second branch pipe, and a third branch pipe. The first branch pipe corresponds to the large nozzle, the second branch pipe corresponds to the medium nozzle, and the third branch pipe corresponds to the small nozzle.

7. The railway contact wire icing reproduction supercooled droplet spraying device according to claim 1, characterized in that, The background wind field component includes a first fan and a wind duct connected to the first fan. The wind duct is configured to be angle-adjustable to simulate train wind with different angles to the direction of train travel.

8. The railway contact wire icing reproduction supercooled droplet spraying device according to claim 1, characterized in that, The auxiliary wind farm assembly includes a second fan and a plurality of air nozzles connected to the second fan, wherein the air nozzles are configured in a one-to-one correspondence with the nozzles.

9. The railway contact wire icing reproduction supercooled droplet spraying device according to claim 1, characterized in that, The control system independently controls the flow rate of each water supply branch pipe according to the Marshall-Palmer distribution parameters of the target freezing rain environment, so that the overall characteristics of the droplets generated by all nozzles conform to the target particle size distribution and rainfall intensity.

10. A design method for a railway catenary icing reproduction supercooled droplet spraying device, comprising the railway catenary icing reproduction supercooled droplet spraying device as described in any one of claims 1-9, characterized in that, Includes the following steps: S1, Determine the Marshall-Palmer distribution parameters for the target freezing rain environment: Determine the target rainfall intensity based on simulation requirements. and intercept parameter The target droplet size distribution function is obtained. Among them, the slope parameter ; S2, Calculate the water content percentage for each droplet size range: Divide the droplet size range into large, medium, and small intervals, and calculate the water content percentage for each droplet size range using the function. Integrate within each interval and calculate the percentage of the total droplet volume to the total volume in each interval, expressed as follows: , , express; S3, Determine the nozzle quantity ratio and working flow rate: Based on engineering experience, initially determine the total number of nozzles. Based on the water volume ratio calculated in S2, determine the ratio of large, medium, and small nozzles, and then determine the target rainfall intensity. The total water flow rate was calculated from the area of ​​the test section. Calculate the total working flow rate of various types of nozzles. ; ; Calculate the working flow rate of a single nozzle; S4, Determine nozzle spacing and spatial layout: based on nozzle spray cone angle and nozzle height According to the formula Calculate the nozzle spacing, where The overlap factor is the nozzle height. This indicates the vertical distance from the nozzle to the contact wire. The spatial layout is optimized by adopting the principle of dispersion, dispersing large and medium nozzles and filling the space between large and medium nozzles with small nozzles to achieve uniform mixing of droplets of different sizes in space.

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