A crosswind spray test system and test method

Abstract

The present invention provides a crosswind spray test system and method, including an air compressor, a high-pressure air tank, a uniform airflow generating device, an optical test module and an observation room; the air compressor is connected to the high-pressure air tank through an air intake pipe; the high-pressure air tank is connected to the air intake end of the uniform airflow generating device through a connecting pipe; the air intake end of the observation room is connected to the air outlet end of the uniform airflow generating device; the air outlet end of the observation room is connected to the exhaust pipe; the optical test module is connected to the observation room; the present invention uses a uniform airflow generating device to generate an airflow with a uniform velocity field distribution to study the influence of gas flow on the atomization characteristics of engine fuel spray. The fuel is sprayed into the crosswind, and on the one hand, the influence of the crosswind airflow on the macroscopic structure and development of its spray is measured; on the other hand, the local droplet size and velocity distribution of the spray and the spatial distribution of SMD in the entire macroscopic spray are measured. These data have important guiding value for the verification and improvement of actual engine spray models.

Description

Technical Field

[0001] The invention belongs to the technical field of engine spray testing, and in particular relates to a crosswind spray testing system and a testing method. Background Art

[0002] Fuel injection in gas phase crosswind is a common working mode in the combustion chambers of aircraft engines and automotive engines, which require rapid fuel penetration, evaporation, mixing and ignition. The crosswind injection method enhances flame stability, increases combustion efficiency and thus reduces pollutant emissions. In the diesel engine exhaust aftertreatment system, the urea SCR system is the core of controlling diesel engine exhaust NOx emissions. In the SCR system, the nozzle sprays urea aqueous solution into the exhaust pipe to form a urea aqueous solution spray. The entire spray process will be affected by the lateral exhaust gas, and the crosswind effect cannot be ignored.

[0003] However, most of the current spray test experiments are carried out in a constant volume bomb, that is, the fuel is sprayed into still air, ignoring the influence of airflow, so it is necessary to improve the existing spray test technology. Summary of the invention

[0004] In view of the above technical problems, one of the purposes of one embodiment of the present invention is to provide a crosswind spray test system, which uses a uniform airflow generating device to generate an airflow with a uniform velocity field distribution, simulating the crosswind airflow and back pressure conditions in the actual engine combustion chamber or diesel engine exhaust treatment device during operation. The fuel is injected into the crosswind, and on the one hand, the effect of the crosswind airflow on the macroscopic structure and development of the spray is measured; on the other hand, the local droplet size and velocity distribution of the crosswind spray and the spatial distribution of SMD in the entire macroscopic crosswind spray are measured. These data have important guiding value for the verification and improvement of the actual engine spray model.

[0005] One of the purposes of one embodiment of the present invention is to provide a testing method for the crosswind spray test system, which is used to perform a crosswind spray test in the crosswind spray test system to measure the local droplet size and velocity distribution of the spray and the spatial distribution of SMD in the entire macro spray.

[0006] Note that the description of these objectives does not prevent the existence of other objectives. One embodiment of the present invention does not need to achieve all of the above objectives. Objectives other than the above objectives can be extracted from the description of the specification, drawings, and claims.

[0007] The present invention achieves the above technical objectives through the following technical means.

[0008] A crosswind spray test system, comprising an air compressor, a high-pressure air storage tank, a uniform airflow generating device, an optical test module and an observation room;

[0009] The air compressor is connected to the high-pressure air tank through an air inlet pipe; the high-pressure air tank is connected to the air inlet end of the uniform airflow generating device through a connecting pipe; the air inlet end of the observation room is connected to the air outlet end of the uniform airflow generating device; the air outlet end of the observation room is connected to the exhaust pipe; and the optical test module is connected to the observation room.

[0010] In the above scheme, the uniform airflow generating device comprises a diffusion section, a rectifying section and a contraction section connected in sequence;

[0011] A plurality of evenly arranged guide vanes are arranged in the diffusion section; a plurality of screens are arranged in the front section of the rectifying section, and the sizes of the screen holes decrease from the front to the back.

[0012] In the above scheme, the contraction curve satisfies the formula:

[0013]

[0014] Where: y is the distance from the profile curve to the central x-axis, y0 is the maximum cross-sectional half-length, y1 is the minimum cross-sectional half-length, L c is the length of the contraction section.

[0015] In the above solution, the inner surface of the uniform airflow generating device is polished.

[0016] In the above scheme, the air inlet pipe is provided with a valve I, the connecting pipe is provided with a valve II, and the exhaust pipe is provided with a valve III.

[0017] In the above solution, the connecting pipe is also provided with a T-shaped interface; the tracer particle generator is connected to the T-shaped interface.

[0018] In the above scheme, window steps are provided on both sides and the bottom of the observation room, and an observation window is provided on the window steps; and a window end cover is provided on the observation window;

[0019] A sealing groove is provided between the contact surface between the window step and the observation window, and a rubber ring is provided in the sealing groove; a polytetrafluoroethylene gasket is provided between the window end cover and the observation window.

[0020] In the above scheme, the upper part of the observation chamber is provided with an injector adapter, a hot wire wind speed probe and a pressure sensor; the observation chamber is provided with a step at the injector adapter, and the injector adapter is connected to the observation chamber housing; the injector adapter is provided with an injector, the injector nozzle extends into the observation chamber, and the injection direction of the spray generated by the injector is perpendicular to the upper surface of the observation chamber;

[0021] The hot wire wind speed probe is located in the center of the observation room and is used to detect the wind speed in the observation room; the pressure sensor is connected to the inside of the observation room shell and is used to detect the pressure in the observation room.

[0022] In the above scheme, the optical test module includes a hot wire anemometer, a PLC controller, a synchronous controller and an optical measurement system;

[0023] The hot wire anemometer is connected to the hot wire anemometer probe; the PLC controller is respectively connected to the hot wire anemometer, the pressure sensor and the synchronous controller; the synchronous controller is respectively connected to the injector, the PLC controller and the optical measurement system.

[0024] A method for testing a crosswind spray test system comprises the following steps:

[0025] Install the fuel injector: install the fuel injector adapter on the observation room, install the fuel injector into the fuel injector adapter, connect the fuel injector trigger signal line to the synchronous controller, set the trigger time and injection duration;

[0026] Build the optical test system: observe the interior of the observation chamber through the observation window; install the tracer particle generator into the T-type interface;

[0027] Connect the control system: connect the hot wire anemometer analog signal and the pressure sensor analog signal to the PLC controller, connect the PLC controller trigger signal to the synchronization controller, and set the wind speed and back pressure in the PLC controller;

[0028] Conduct the test: open valve I, close valve II and valve III, start the air compressor, and when the pressure in the high-pressure gas storage tank reaches the set pressure, close valve I, open valve III, start the tracer particle generator, quickly and completely open valve II, and wait for the system to automatically record data. After the data recording is completed, close valve II and turn off the tracer particle generator;

[0029] During the test, always pay attention to the observation window. If the observation window is blurred, close valve II, fully open valve III, and then clean the observation room.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] According to one embodiment of the present invention, a uniform airflow generating device can generate an airflow with a uniform velocity field distribution, which can effectively simulate the crosswind airflow and back pressure conditions during the operation of an engine combustion chamber or a diesel engine exhaust treatment device.

[0032] According to one embodiment of the present invention, fuel is injected into a crosswind in an observation room, so that on the one hand the effect of the crosswind airflow on the macroscopic structure and development of the spray can be measured; on the other hand, the local droplet size and velocity distribution of the spray and the spatial distribution of SMD in the entire macroscopic spray can be measured.

[0033] According to one embodiment of the present invention, the crosswind spray test system proposed in the present invention can effectively test the influence of airflow on spray atomization characteristics, and has important guiding value for the verification and improvement of actual engine spray models.

[0034] Note that the description of these effects does not prevent the existence of other effects. One embodiment of the present invention does not necessarily have all of the above effects. Effects other than the above can be clearly seen and extracted from the description of the specification, drawings, claims, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the crosswind spray testing system according to one embodiment of the present invention.

[0036] Figure 2 It is a schematic diagram of the uniform airflow generating device according to one embodiment of the present invention.

[0037] Figure 3 It is a cross-sectional curve diagram of the contraction section of the uniform airflow generating device according to one embodiment of the present invention.

[0038] Figure 4 This is a cross-sectional view of the observation room according to one embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of the control system according to one embodiment of the present invention.

[0040] Figure 6 This is a calibration diagram of the crosswind velocity field in the observation room according to one embodiment of the present invention.

[0041] Figure 7 This is a calibration diagram of the relationship between pressure and wind speed over time in the observation room according to one embodiment of the present invention.

[0042] Figure 8 This is a macroscopic structure diagram of the spray under the action of crosswind airflow according to one embodiment of the present invention.

[0043] Fig. 9 This is a test diagram of spray microscopic particle size under the action of crosswind airflow according to one embodiment of the present invention.

[0044] Fig.10 This is a diagram of the distribution of spray microscopic particle sizes under the action of crosswind airflow according to one embodiment of the present invention.

[0045] In the figure: 1. air compressor, 2. valve I, 3. air intake pipe, 4. high-pressure air storage tank, 5. connecting pipe, 6. valve II, 7. T-type interface, 8. uniform air flow generating device, 9. optical test module, 10. observation room, 11. exhaust pipe, 12 valve III, 13. pressure gauge, 14. shell, 15. guide vane, 16. screen, 17. flange, 18. observation room shell, 19. injector, 20. adapter, 21. hot wire anemometer probe, 22. pressure sensor, 23. window, 24. reserved through hole, 25. window step, 26. window end cover, 27. hot wire anemometer, 28. PLC controller, 29. synchronous controller, 30. optical test system. DETAILED DESCRIPTION

[0046] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "front", "back", "left", "right", "up", "down", "axial", "radial", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are 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 cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0048] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] Embodiment 1:

[0050] Figure 1 The figure shows a preferred embodiment of the crosswind spray test system, which includes an air compressor 1, a high-pressure air storage tank 4, a uniform airflow generating device 8, an optical test module 9 and an observation room 10;

[0051] The air compressor 1 is connected to the high-pressure air tank 4 through the air inlet pipe 3; the high-pressure air tank 4 is connected to the air inlet end of the uniform airflow generating device 8 through the connecting pipe 5; the air inlet end of the observation chamber 10 is connected to the air outlet end of the uniform airflow generating device 8; the air outlet end of the observation chamber 10 is connected to the exhaust pipe 11; the optical test module 9 is connected to the observation chamber 10.

[0052] The uniform airflow generating device 8 comprises a diffusion section, a rectifying section and a contraction section connected in sequence;

[0053] The diffuser section is provided with a plurality of evenly arranged guide vanes 15; the front section of the rectifying section is provided with a plurality of screens 16, and the size of the screen holes of the screens 16 decreases from the front to the back.

[0054] The inner surface of the uniform airflow generating device 8 is polished.

[0055] The air inlet pipe 3 is provided with a valve I2, the connecting pipe 5 is provided with a valve II6, and the exhaust pipe 11 is provided with a valve III12.

[0056] The connecting pipe 5 is also provided with a T-shaped interface 7 ; the tracer particle generator is connected to the T-shaped interface 7 .

[0057] The observation chamber 10 is provided with window steps 25 on both sides and the bottom, and an observation window 23 is provided on the window steps 25; and a window end cover 26 is provided on the observation window 23;

[0058] A sealing groove is provided between the contact surface between the window step 25 and the observation window 23 , and a rubber ring is provided in the sealing groove; a polytetrafluoroethylene gasket is provided between the window end cover 26 and the observation window 23 .

[0059] The upper part of the observation chamber 10 is provided with an injector adapter 20, a hot wire wind speed probe 21 and a pressure sensor 22;

[0060] The observation chamber 10 is provided with a step at the injector adapter 20, and the injector adapter 20 is connected to the observation chamber housing 18; the injector adapter 20 is provided with an injector 19, the injector 19 nozzle extends into the observation chamber 10, and the injection direction of the spray generated by the injector 19 is perpendicular to the upper surface of the observation chamber 10;

[0061] The hot wire wind speed probe 21 is located in the center of the observation room 10 and is used to detect the wind speed in the observation room 10;

[0062] The sensor 22 is in communication with the interior of the observation chamber housing 18 , and the pressure sensor 22 is used to detect the pressure in the observation chamber 10 .

[0063] The optical test module 9 includes a hot wire anemometer 27, a PLC controller 28, a synchronous controller 29 and an optical measurement system 30;

[0064] The hot wire anemometer 27 is connected to the hot wire anemometer probe 21; the PLC controller 28 is connected to the hot wire anemometer 27, the pressure sensor 22 and the synchronous controller 29 respectively; the synchronous controller 29 is connected to the injector 19, the PLC controller 28 and the optical measurement system 30 respectively.

[0065] According to this embodiment, preferably, the minimum configuration of the air compressor 1 is 30HP and the exhaust volume is 3.6m 3 / min. The air compressor 1 is used in conjunction with a high-pressure air storage tank 4 to ensure a stable output airflow.

[0066] The air compressor 1 and the high-pressure air storage tank 4 are connected through an air inlet pipe 3, and the valve I2 controls the opening and closing of the air inlet pipe 3. Preferably, the valve I2 adopts a DN40 stainless steel two-piece heavy-duty ball valve, which has small flow resistance and is easy to operate.

[0067] Preferably, the minimum configuration of the high-pressure gas storage tank 4 is a working pressure of 1.6 MPa, a design temperature of 150°C, and a volume of 2m 3 At the same time, the high-pressure gas storage tank 4 is equipped with a pressure gauge 13 to display the pressure in the tank in real time.

[0068] According to this embodiment, preferably, the uniform airflow generating device 8 is connected to the high-pressure gas storage tank 4 through the connecting pipe 5, and its function is to rectify the high-pressure air from the high-pressure gas storage tank 4 into a uniform transverse airflow. The valve II 6 controls the switch of the connecting pipe 5. Preferably, the valve II 6 adopts a DN40 stainless steel two-piece heavy-duty ball valve. In addition, a T-type interface 7 is reserved behind the valve II 6 on the connecting pipe 5 for placing tracer particles.

[0069] like Figure 2 As shown, the uniform airflow generating device 8 comprises a diffuser section, a rectifying section and a contraction section connected in sequence; flanges 17 are provided at both ends of the diffuser section, the rectifying section and the contraction section;

[0070] The diffuser section is provided with a plurality of evenly arranged guide vanes 15, and the front section of the rectifying section is provided with a plurality of screens 16, the mesh size of the screens 16 decreasing from front to back. Before the air reaches the screen 16, the guide vanes 15 can guide the air to a larger area, and after passing through the plurality of screens 16 in the front section of the rectifying section, an airflow with an evenly distributed velocity field is formed, so that the influence of the gas flow on the atomization characteristics of the engine fuel spray can be effectively studied.

[0071] The flow direction of the airflow inside the uniform airflow generating device 8 is as follows: Figure 2 As shown by the dashed arrow in the middle. According to this embodiment, preferably, the shell 14 of the uniform airflow generating device 8 is made of 316 stainless steel; the inner cavity of the shell is in contact with the airflow, which has a greater impact on the gas flow, and should be surface polished.

[0072] According to this embodiment, preferably, the number of the guide vanes 15 is 4, the number of the sieves 16 is 4, and the sizes of the sieve holes from front to back are 20 mm×20 mm, 10 mm×10 mm, 5 mm×5 mm, and 2 mm×2 mm, respectively.

[0073] The shape curve of the contraction section is very important for the velocity distribution at the outlet, and the transition curve should be smooth enough to reduce turbulence.

[0074] like Figure 3 As shown, the contraction curve satisfies the formula:

[0075]

[0076] Where: y is the distance from the profile curve to the central x-axis, y0 is the maximum cross-sectional half-length, y1 is the minimum cross-sectional half-length, L c is the length of the contraction section.

[0077] According to this embodiment, preferably, the maximum cross-sectional dimension of the contraction section is 200 mm × 200 mm, the minimum cross-sectional dimension is 100 mm × 100 mm, y0 is the maximum cross-sectional half length = 100 mm, y1 is the minimum cross-sectional half length = 50 mm, L c The contraction section length = 150 mm. According to this embodiment, preferably, a sealing groove is processed on the contact surface of the flange 17, a rubber ring is placed in the sealing groove, and a polytetrafluoroethylene gasket is placed around it. When the bolts distributed along the flange 17 are tightened, the flange 17 is squeezed against each other to form a sealing surface with the rubber ring and the polytetrafluoroethylene gasket, thereby playing a sealing role.

[0078] like Figure 4 As shown, the upper part of the observation room 10 is provided with an injector adapter 20, a hot wire wind speed probe 21, a pressure sensor 22 and a reserved through hole 24; the observation room 10 is connected to the uniform airflow generating device 8 through a flange 17, and the uniform crosswind generated by the device 8 is directly introduced into the observation room 10. At the same time, the observation room 10 is connected to the exhaust pipe 12 for exhausting the exhaust gas. The switch of the exhaust pipe 12 is controlled by the valve III 12. Preferably, the valve III 12 adopts a DN40 stainless steel electric flange butterfly valve, and the opening can be accurately adjusted electrically.

[0079] According to this embodiment, preferably, the observation chamber shell 18 is made of 316 stainless steel forging, has an inner size of 100 mm×100 mm, a designed pressure resistance of 2 MPa, and can withstand a high temperature of nearly 500K.

[0080] According to this embodiment, preferably, the injector adapter 20 is fixed to the upper wall of the observation chamber 10 by bolts. The bottom surface of the injector adapter 20 is at the same level as the inner upper surface of the observation chamber 10, and each end face joint adopts a stepped design. The sealing ring is pressed on the joint through the stepped structure, thereby ensuring the sealing effect of the joint. The injector adapter 20 is responsible for fixing the injector 19, and the sealing between the injector 19 and the injector adapter 20 is achieved by the rubber ring provided by the injector 19.

[0081] Different types of fuel injectors 19 need to design the inner cavity of the adapter separately, and the final effect is to achieve: 1. Ensure the sealing between the fuel injector adapter 20 and the fuel injector 19; 2. The incident direction of the spray generated by the fuel injector 19 should be perpendicular to the upper surface of the observation chamber 10; 3. The nozzle of the fuel injector 19 is exposed 3 to 5 mm from the upper surface of the observation chamber shell 18, that is, it extends 3 to 5 mm into the observation chamber 10. Preferably, the fuel injector 19 adopts a GDI fuel injector, and the angle between the GDI fuel injector nozzle and the upper surface of the observation chamber shell 18 is 25°, so as to ensure that the sprayed oil beam is perpendicular to the upper surface of the observation chamber 10.

[0082] According to the present embodiment, preferably, the hot-wire wind speed probe 21 is used to detect the wind speed in the observation room 10. Preferably, the hot-wire wind speed probe 21 is configured at a minimum with a range of 0.1m / s to 100m / s, a resolution of 0.01m / s, an operating temperature of 0 to 50°C, and a response time of 0.01ms. The hot-wire wind speed probe 21 is installed in the central position of the observation room 10, where the turbulence effect is small and the wind speed is more stable. The pressure sensor 22 is connected to the inner cavity through a through hole on the upper surface of the observation room 10. Preferably, the pressure sensor 22 is configured at a minimum with a measurement range of -0.1 to 2MPa, an accuracy of 0.25, and a response frequency of 1KHz. Preferably, the reserved through hole 24 can be used to install a temperature sensor, which is used to detect the temperature in the observation room 10.

[0083] According to this embodiment, preferably, window steps 25 are provided on both sides and the bottom of the observation chamber 10, and an observation window 23 is provided on the window steps 25; a window end cover 26 is provided on the observation window 23, and the window end cover 26 is connected to the observation chamber 10 by bolts; the window steps 25 can reduce the damage to the observation window 23 caused by frequent disassembly and assembly and reduce the sealing performance. Preferably, the observation window 23 is made of Pyrex heat-resistant glass, and the glass is applicable to the wavelength band of 220nm to 2500nm (completely covering the visible light band of 380nm to 780nm), so that the optical measurement system light path can pass through the window.

[0084] The contact surface between the window step 25 and the observation window 23 is provided with a sealing groove, in which a rubber ring is provided; a polytetrafluoroethylene gasket is provided between the window end cover 26 and the observation window 23 to prevent the observation window 23 from being damaged when tightening the bolts.

[0085] like Figure 5 As shown, the optical test module 9 includes a hot wire anemometer 27, a PLC controller 28, a synchronous controller 29 and an optical measurement system 30;

[0086] The hot-wire anemometer 27 is connected to the hot-wire anemometer probe 21; the PLC controller 28 is connected to the hot-wire anemometer 27, the pressure sensor 22 and the synchronous controller 29; the synchronous controller 29 is connected to the injector 19, the PLC controller 28 and the optical measurement system 30. In the crosswind spray test, the triggering of the injector 19 and the optical measurement system 30 needs to meet the two given conditions of the crosswind wind speed and the ambient back pressure in the observation room 10 at the same time, so the two signals need to be processed synchronously. The PLC controller 28 receives the analog signal of the hot-wire anemometer 27 and the analog signal of the pressure sensor 22, and converts them into digital signals. Before the test starts, the wind speed and pressure parameters are displayed as waiting for input on the display screen of the PLC controller 28. During the test, the wind speed and pressure conditions given by the test are input through the control panel. Only when these two parameter conditions are met at the same time, the PLC controller 28 will send a trigger signal to the synchronous controller 29.

[0087] The synchronous controller 29 is connected to the injector 19 and the optical measurement system 30 at the same time. When receiving the trigger signal from the PLC controller 28, the synchronous controller 29 will send a trigger signal to the injector and the optical measurement system 30 according to a specific timing.

[0088] The optical measurement system 30 may include a variety of optical measurement technologies or measuring instruments, such as high-speed photography, PIV (particle image velocimetry), particle microscopy, and phase Doppler particle analyzer, to obtain the macroscopic structure, velocity field, and local droplet size, velocity distribution, and spatial distribution of SMD of the crosswind spray.

[0089] The purpose of the uniform airflow generating device of the present invention is to provide a uniform and stable crosswind field for the observation room 10. Preferably, the effectiveness of the device is verified by PIV. During the test, the tracer particles are selected as magnesium oxide MgO, which has a particle size of micrometers and has good tracking characteristics. The tracer particle generator is connected to the T-type interface 7, and the tracer particles can enter the observation room 10 with the airflow. The PIV test results are shown in Figure 6The direction of the white arrow in the figure is the wind speed direction, and the size of the arrow represents the wind speed. It can be seen that except for the nozzle near the nozzle, which will affect the crosswind field, this is a normal phenomenon and does not affect the measurement of the spray. The speed distribution in the remaining area is uniform and parallel to the inner surface of the observation chamber 10, that is, perpendicular to the spray direction, proving the effectiveness of the uniform airflow generating device 8.

[0090] The method for obtaining the wind speed and the ambient back pressure in the observation room 10 of the present invention is:

[0091] Open valve I2, and the air is pressurized by air compressor 1 and stored in high-pressure air storage tank 4 to reach a specific pressure P1. At this time, valve III12 is in a partially open state, and the opening degree is set to K%, the closed state is 0%, and the fully open state is 100%. Then quickly open valve II6, the pressure P2 in the observation room will rise rapidly, and a certain wind speed V2 will also be obtained. Due to the throttling effect of valve III12 in a partially open state and the supplement of high-pressure air at the inlet, the pressure in the observation room 10 will slowly drop to atmospheric pressure.

[0092] like Figure 7 As shown, taking K = 50 and the initial value of P1 as 0.5MPa as an example, the relationship between P1, P2, and V2 over time is obtained according to the above method. Figure 7 a is the change of velocity over time, Figure 7 b is the change of pressure over time, the horizontal axis is time, and time 0 is the moment when valve Ⅱ6 is opened. P2 will instantly reach about 0.46MPa, and then slowly decrease to 0.1MPa in about 6s. V2 has a high initial value, and then it will decrease rapidly, reaching a stable 11m / s in about 0.5s, and continue until about 3s, and then it will slowly decrease again.

[0093] Assuming that the test needs to collect data when the wind speed is 11m / s and the back pressure is 0.26MPa, it is only necessary to input these two parameters into the PLC controller 28. During the test, the PLC controller 28 will continuously collect analog signals from the hot wire anemometer 27 and the pressure sensor 22. When the valve II6 is opened 2s later, the two collected signals match the manually input target parameters. At this time, a trigger signal will be sent to the synchronous controller 29, and then the optical measurement system 30 will be used for measurement. Typical measurement results under this test condition are as follows: Figure 8 , Fig. 9 and Fig.10 shown. Figure 8 This is the macroscopic structure diagram of the spray under the action of crosswind airflow. It can be seen that the system can effectively obtain the overall development structure of the crosswind spray under specific test conditions, and the crosswind airflow movement has a great influence on the macroscopic development of the spray. Fig. 9This is a test diagram of the microscopic particle size of the spray under the action of crosswind airflow. It can be seen that the system can effectively obtain a clear local microscopic droplet image of the crosswind spray under specific test conditions, as well as the particle size distribution. Fig.10 shown.

[0094] After the crosswind spray measurement system of the present invention is built, P2 and V2 should be calibrated using the above method before testing. During the calibration process, the values ​​of K and P1 are adjusted to obtain different curves of P2 and V2 changing with time. During the formal test, the K value and P1 are flexibly selected according to the calibration curve.

[0095] Example 2

[0096] A testing method for the crosswind spray testing system according to embodiment 1 comprises the following steps:

[0097] Install the fuel injector 19: install the fuel injector adapter 20 on the observation chamber 10, install the fuel injector 19 into the fuel injector adapter 20, connect the trigger signal line of the fuel injector 19 to the synchronous controller 29, and set the trigger time and injection duration;

[0098] Build the optical test system 30: Use the optical test system 30 to observe the interior of the observation chamber 10 through the observation window 23; Install the tracer particle generator into the T-type interface 7;

[0099] Connect the control system: connect the analog signal of the hot wire anemometer 27 and the analog signal of the pressure sensor 22 to the PLC controller 28, the trigger signal of the PLC controller 28 to the synchronous controller 29, and set the wind speed and back pressure in the PLC controller 28;

[0100] Conduct the test: open valve Ⅰ2, close valve Ⅱ6 and valve Ⅲ12, start air compressor 1, wait until the pressure in high-pressure gas storage tank 4 reaches the set pressure, close valve Ⅰ2, open valve Ⅲ12, start the tracer particle generator, quickly and completely open valve Ⅱ6, wait for the system to automatically record data, and after the data recording is completed, close valve Ⅱ6 and turn off the tracer particle generator;

[0101] During the test, always pay attention to the observation window 23. If the observation window 23 is blurred, close valve II 6, fully open valve III 12, and then clean the observation room 10.

[0102] Taking the wind speed of 11m / s, back pressure of 0.26MPa, GDI injector injection pulse width of 2ms, injection pressure of 10MPa, spray development process and velocity field 1.5ms after injection as an example, the test method of the crosswind spray test system is as follows:

[0103] 1 Clean the observation room 10: remove the three window end covers 26 of the observation room 10, remove the observation window 23, clean it with special glass wiping paper, clean the inner wall of the observation room 10 with alcohol, and install it after completion.

[0104] 2 Install the fuel injector 19: Install the fuel injector adapter 20 dedicated to the GDI fuel injector on the upper wall of the observation room 10, and install the GDI fuel injector into the fuel injector adapter 20. The GDI fuel injector trigger signal line is connected to the synchronous controller 29, the trigger time is adjusted to 0, and the injection duration is adjusted to 2ms.

[0105] 3. Build an optical test system 30: Use a high-speed camera to obtain the development process of the spray, connect the high-speed camera trigger signal line to the synchronous controller 29, adjust the trigger time to -100ms, and the sampling duration to 200ms. The sampling frequency can be adjusted according to actual needs. Aim the high-speed camera at the observation window 23 on one side of the observation room 10, the lens is parallel to the side of the observation room 10, and the camera image size covers the entire observation window 23. Use PIV to obtain the spray velocity field, connect the laser and CCD camera signal lines to the synchronous controller 29, single sampling, and adjust the trigger time to 1.5ms. The light sheet generated by the laser is aimed at the center of the observation window 23 at the bottom of the observation room 10, and the light sheet is perpendicular to the lower surface of the observation room 10. Aim the CCD camera at the observation window 23 on the other side, and the camera image size covers the entire observation window 23. Install the tracer particle generator into the T-type interface 7.

[0106] 4 Connect the control system: connect the analog signal of the hot wire anemometer 27 and the analog signal of the pressure sensor 22 to the PLC controller 28, and connect the trigger signal of the logic controller 28 to the synchronization controller 29. Enter the wind speed 11m / s and the back pressure 0.26MPa in the input panel of the logic controller 28.

[0107] 5. Conduct the test: open valve Ⅰ2, close valve Ⅱ6 and valve Ⅲ12. Start the air compressor 1, and when the pressure in the high-pressure gas storage tank 4 reaches 0.5MPa, close valve Ⅰ2. Open valve Ⅲ12, with an opening of 50%. Start the tracer particle generator, quickly and completely open valve Ⅱ6, and wait for the system to automatically record data. After the data recording is completed, close valve Ⅱ6 and turn off the tracer particle generator.

[0108] 6 Repeat step 5 and repeat the test multiple times under the same working condition. During the test, always pay attention to the observation window 23. If the observation window 23 is blurred, close valve II 6, fully open valve III 12, and then clean the observation room 10.

[0109] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0110] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A crosswind spray test system, characterized in that: It comprises an air compressor (1), a high-pressure air storage tank (4), a uniform airflow generating device (8), an optical testing module (9) and an observation room (10); The air compressor (1) is connected to a high-pressure air storage tank (4) via an air inlet pipe (3); the high-pressure air storage tank (4) is connected to an air inlet end of a uniform airflow generating device (8) via a connecting pipe (5); the air inlet end of the observation chamber (10) is connected to an air outlet end of the uniform airflow generating device (8); the air outlet end of the observation chamber (10) is connected to an exhaust pipe (11); the optical test module (9) is connected to the observation chamber (10); The uniform airflow generating device (8) comprises a diffusion section, a rectifying section and a contracting section which are connected in sequence; a plurality of uniformly arranged guide vanes (15) are provided in the diffusion section; a plurality of screens (16) are provided in the front section of the rectifying section, and the size of the screen holes (16) decreases from the front to the back; The upper part of the observation chamber (10) is provided with an injector adapter (20), a hot wire wind speed probe (21) and a pressure sensor (22); The observation chamber (10) is provided with a step at the injector adapter (20), and the injector adapter (20) is connected to the observation chamber housing (18); an injector (19) is provided on the injector adapter (20), and the injector (19) nozzle extends into the observation chamber (10), and the injection direction of the spray generated by the injector (19) is perpendicular to the upper surface of the observation chamber (10); the hot wire wind speed probe (21) is located at the central position of the observation chamber (10) and is used to detect the wind speed in the observation chamber (10); The pressure sensor (22) is in communication with the interior of the observation chamber housing (18), and the pressure sensor (22) is used to detect the pressure in the observation chamber (10); The inner surface of the uniform airflow generating device (8) is polished; The air inlet pipe (3) is provided with a valve I (2), the connecting pipe (5) is provided with a valve II (6), and the exhaust pipe (11) is provided with a valve III (12); The connecting pipe (5) is also provided with a T-shaped interface (7); the tracer particle generator is connected to the T-shaped interface (7); The observation chamber (10) is provided with window steps (25) on both sides and the bottom, and an observation window (23) is provided on the window steps (25); and a window end cover (26) is provided on the observation window (23); A sealing groove is provided on the contact surface between the window step (25) and the observation window (23), and a rubber ring is provided in the sealing groove; a polytetrafluoroethylene gasket is provided between the window end cover (26) and the observation window (23); The optical testing module (9) comprises a hot wire anemometer (27), a PLC controller (28), a synchronous controller (29) and an optical measurement system (30); The hot wire anemometer (27) is connected to the hot wire anemometer probe (21); the PLC controller (28) is respectively connected to the hot wire anemometer (27), the pressure sensor (22) and the synchronous controller (29); the synchronous controller (29) is respectively connected to the injector (19), the PLC controller (28) and the optical measurement system (30).

2. The crosswind spray test system according to claim 1, characterized in that: The contraction curve satisfies the formula: ； Where: y is the distance from the profile curve to the central x-axis, is the maximum cross-sectional half length, is the minimum cross-sectional half length, L c is the length of the contraction section.

3. A method for testing a crosswind spray test system according to any one of claims 1 to 2, characterized in that: The steps include: Install the fuel injector (19): install the fuel injector adapter (20) on the observation room (10), install the fuel injector (19) into the fuel injector adapter (20), connect the trigger signal line of the fuel injector (19) to the synchronous controller (29), and set the trigger time and injection duration; Building an optical test system (30): using the optical test system (30) to observe the interior of the observation chamber (10) through the observation window (23); installing a tracer particle generator into the T-type interface (7); Connecting the control system: connecting the analog signal of the hot wire anemometer (27) and the analog signal of the pressure sensor (22) to the PLC controller (28), connecting the trigger signal of the PLC controller (28) to the synchronization controller (29), and setting the wind speed and back pressure in the PLC controller (28); Conduct the test: open valve I (2), close valve II (6) and valve III (12), start the air compressor (1), wait until the pressure in the high-pressure gas storage tank (4) reaches the set pressure, close valve I (2), open valve III (12), start the tracer particle generator, quickly and completely open valve II (6), wait for the system to automatically record data, and after the data recording is completed, close valve II (6) and turn off the tracer particle generator; During the test, always pay attention to the observation window (23). If the observation window (23) is blurred, close valve II (6), fully open valve III (12), and then clean the observation room (10).

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