Large combustion wind tunnel for test

Abstract

The invention discloses a large combustion wind tunnel for test, and relates to the technical field of wind tunnel test, and the large combustion wind tunnel comprises a heater, the left side of the heater is provided with a transition section, the left side of the transition section is provided with a supersonic nozzle, the left side of the supersonic nozzle is provided with a test section body, and the left side of the test section body is provided with a super-expansion section. An ejector is arranged on the left side wall of the super-expansion section, a silencing tower is arranged on the left side of the ejector, a first connecting pipe is arranged between the ejector and the silencing tower, and a test section inlet is formed in the right side wall of the test section body. The high-frequency dynamic pressure sensor, the hot-wire anemometer, the temperature measurement sensor, the high-speed camera and the thermal infrared imager are matched with one another, so that multi-dimensional real-time monitoring of flow field parameters and flame behaviors in a test section is realized, and accurate data support is provided for active control of a flow field.

Description

Technical Field

[0001] This invention relates to the field of wind tunnel testing technology, specifically to a large-scale combustion wind tunnel for testing. Background Technology

[0002] Forest fires have been a constant presence on Earth since the emergence of forests. Globally, an average of over 200,000 forest fires occur annually, burning more than 1‰ of the world's total forest area. In China, an average of over 10,000 forest fires occur annually, burning hundreds of thousands to millions of hectares of forest, approximately 5-8‰ of the country's total forest area. Forest fires not only kill and damage trees, directly reducing forest area, but also severely damage forest structure and the forest environment, leading to an imbalance in forest ecosystems, decreased forest biomass, reduced productivity, a decline in beneficial animals and birds, and even causing injury or death to humans and livestock. Real-world environments are not stable but complex, characterized by varying wind fields. The leakage, diffusion, and combustion of combustible materials, as well as flame spread, may exhibit unique patterns due to wind conditions, differing from those under stable environments. Under wind conditions, the leakage and diffusion area of ​​hazardous sources, safe distances, fire spread range, and smoke concentration migration are all significantly affected. Single emergency rescue and response plans cannot meet the demands of complex and ever-changing wind field environments. Therefore, establishing a wind tunnel experimental platform capable of simulating forest fire combustion under different wind field conditions is crucial for conducting fundamental research on the transition from underground fires to deflagration under sudden fire wind pressure conditions, as well as research on fire suppression techniques under complex wind field conditions. The development of this combustion wind tunnel experimental platform is of great significance to both basic science and practical firefighting.

[0003] A search revealed a Chinese patent with publication number CN113494987A, which discloses a combustion wind tunnel. It includes: a gas collection section, a power section, a vibration isolation ring, a diffusion section, a damping net, a stabilization section, a contraction section, and a test section. The power section contains a fairing, and the stabilization section contains several layers of damping nets. The test section of this invention includes a shell, a heat insulation layer, a heat insulation coating, an ignition slot, a combustion bed, a refractory brick layer, and a barrier net. This invention, by constructing a forest fire combustion wind tunnel experimental platform, focuses on measuring the characteristics of forest fire behavior and combustion parameters under simulated different fire environments. This allows for a deeper understanding of fire dynamics, revealing the laws and mechanisms of forest fire spread, constructing forest fire spread models, and determining various technical parameters for fire suppression. This is beneficial for conducting research on fire monitoring, early warning, and emergency decision-making technologies, providing technical support for forest fire prevention and control. However, existing technologies cannot effectively address the bidirectional coupling effect between the fire source and the flow field, leading to distorted experimental data. Specifically, this manifests as: the inability to monitor and compensate for the thermal buoyancy effect and pressure field interference caused by combustion in real time, resulting in the disruption of flow field homogeneity; and a lack of proactive control over flow field distortion during flame propagation, causing significant deviations between observed flame behavior characteristics and actual fire conditions.

[0004] Therefore, based on the above-mentioned search and combined with existing technologies, a large-scale combustion wind tunnel for testing is proposed to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a large-scale combustion wind tunnel for testing, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A large combustion wind tunnel for testing includes: a heater; a transition section is provided on the left side of the heater; a supersonic nozzle is provided on the left side of the transition section; a test section body is provided on the left side of the supersonic nozzle; an overexpansion section is provided on the left side of the test section body; an ejector is provided on the left side wall of the overexpansion section; a silencer is provided on the left side of the ejector; a connecting pipe is provided between the ejector and the silencer; a test section inlet is provided on the right side wall of the test section body; and a test section outlet is provided on the left side wall of the test section body; an observation window is provided on the front side wall of the test section body; and a monitoring mechanism and an adjustment mechanism are provided on the test section body.

[0007] Preferably, the monitoring mechanism includes two sets of sensor array assemblies, which are respectively fixedly installed in the inner wall of the test section body and located on one side of the test section inlet and outlet. The sensor array assembly includes: a connecting plate, which is fixedly installed in the inner wall of the test section body. A high-frequency dynamic pressure sensor is fixedly installed on the bottom surface of the connecting plate, and a hot-wire anemometer and a temperature measurement sensor are fixedly installed on two adjacent surfaces of the connecting plate, respectively.

[0008] Preferably, the monitoring mechanism further includes: a mounting plate, which is fixedly installed on the front side wall of the test section body, a high-speed camera is fixedly installed on the top surface of the mounting plate, and an infrared thermal imager is fixedly installed on the right side wall of the high-speed camera.

[0009] Preferably, the adjustment mechanism includes: an adjustable damping net, which is fixedly installed in the inner wall of the test section body and located on the left side of the test section entrance; a connecting groove is provided on the top surface of the test section body; a connecting box is fixedly installed on the inner wall of the connecting groove; and a connecting pipe two is provided between the connecting box and the connecting pipe one.

[0010] Preferably, the adjustment mechanism further includes: a fixing block, wherein two fixing blocks are provided and are respectively fixedly installed on the top surface inside the test section body, a rotating column is rotatably connected between the two fixing blocks, a guide vane is fixedly installed on the outer surface of the rotating column, and an opening is provided on the top surface of the connecting box.

[0011] Preferably, the adjustment mechanism further includes: a sealing plate, which is rotatably connected to the inner wall of the opening via a rotary bearing; a connecting rod is provided between the guide vane and the sealing plate; and the adjustment mechanism further includes a drive assembly supplementary assembly.

[0012] Preferably, the drive assembly includes: a drive motor, which is fixedly mounted on the side wall of one of the fixed blocks, a protective shell is fixedly mounted on the side wall of one of the fixed blocks, the drive motor is located in the protective shell, the output shaft of the drive motor is connected to the side wall of the rotating column, and a wind baffle is fixedly mounted between the two fixed blocks.

[0013] Preferably, the supplementary component includes: a cooler, which is fixedly installed on the rear side wall of the test section body, and a connecting pipe three is provided on the bottom surface of the cooler, with the other end of the connecting pipe three extending into the interior of the test section body.

[0014] Preferably, a central controller is fixedly installed on the rear side wall of the test section body, located on one side of the cooler.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, by incorporating a monitoring mechanism and a central controller, a high-frequency dynamic pressure sensor, a hot-wire anemometer, a temperature measurement sensor, a high-speed camera, and an infrared thermal imager work together to achieve comprehensive real-time monitoring of pressure fluctuations, flow velocity distribution, temperature field changes, and flame morphology characteristics within the test section. Specifically, the high-frequency dynamic pressure sensor captures pressure fluctuations with a millisecond-level response speed, the hot-wire anemometer accurately measures local flow velocity and turbulence intensity, the temperature measurement sensor array constructs a three-dimensional temperature field distribution, the high-speed camera records the dynamic development process of the flame, and the infrared thermal imager provides visualized temperature field data. This monitoring data is fused and processed in real-time by the central controller, constructing a complete flow field and flame coupling database, providing precise data support for subsequent active flow field control, and significantly improving the reliability and accuracy of experimental data. 2. In this invention, by incorporating an adjustment mechanism, the adjustable damping mesh, guide vanes, drive motor, connecting box, and cooler work in concert to achieve multi-level active compensation for thermal buoyancy effects and pressure field interference. The adjustable damping mesh adjusts the inlet velocity distribution in real time by changing the mesh density; the guide vanes, under the precise control of the drive motor, deflect at an angle to effectively guide local airflow; the connecting box, in conjunction with the ejector system, promptly discharges the hot airflow from the top; and the cooler replenishes cooling gas at the bottom of the three-way test section through the connecting pipe. These components form a complete closed-loop control system under the unified scheduling of the central controller, which can adjust the working state of each actuator in real time based on monitoring data, effectively suppressing the thermal buoyancy effect and pressure field interference caused by combustion, ensuring the stability and uniformity of the flow field within the test section, and creating an ideal testing environment for conducting precise combustion experiments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the front structure of the test section of the present invention; Figure 3 This is a schematic diagram of the test section and the disassembled connecting box structure of the present invention; Figure 4 This is a schematic diagram of the rear structure of the test section of the present invention; Figure 5 This is a schematic diagram of the internal structure of the test section of the present invention; Figure 6 This is a schematic diagram of the internal structure of the test section of the present invention viewed from below; Figure 7 This is a schematic diagram of a partial exploded structure of the adjusting mechanism of the present invention; Figure 8 This is a schematic diagram of the exploding structure of the communicating box of the present invention; Figure 9 This is a schematic diagram of the overall structure of the sensor array assembly of the present invention.

[0017] In the diagram: 1. Heater; 2. Transition section; 3. Supersonic nozzle; 4. Test section body; 5. Overexpansion section; 6. Ejector; 7. Silencer tower; 8. Connecting pipe one; 9. Test section inlet; 10. Test section outlet; 11. Observation window; 12. Connecting plate; 13. High-frequency dynamic pressure sensor; 14. Hot-wire anemometer; 15. Temperature measurement sensor; 16. High-speed camera; 17. Infrared thermal imager; 18. Adjustable damping mesh; 19. Connecting slot; 20. Connecting box; 21. Connecting pipe two; 22. Fixing block; 23. Rotating column; 24. Guide vane; 25. Connecting rod; 26. Opening; 27. Rotary bearing; 28. Sealing plate; 29. ​​Drive motor; 30. Protective shell; 31. Wind baffle; 32. Cooler; 33. Connecting pipe three; 34. Central controller; 35. Mounting plate. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In one typical implementation of this application, please refer to Figures 1-9As shown, a large combustion wind tunnel for testing includes: a heater 1, a transition section 2 on the left side of the heater 1, a supersonic nozzle 3 on the left side of the transition section 2, a test section body 4 on the left side of the supersonic nozzle 3, an overexpansion section 5 on the left side of the test section body 4, an ejector 6 on the left side wall of the overexpansion section 5, a silencer tower 7 on the left side of the ejector 6, and a connecting pipe 8 between the ejector 6 and the silencer tower 7. Heater 1 employs a ternary combustion method, precisely controlling the flow ratio of air, hydrogen, and oxygen to generate a high-temperature, high-pressure mixed gas, ensuring that the molar fraction of oxygen in the mixed gas after the chemical reaction is 21% to simulate a real environment. The transition section 2, connected to the inlet, is equipped with a large-angle conical diffuser with an internal metal mesh, used to initially rectify the turbulent airflow output from heater 1, preventing airflow separation and ensuring uniform airflow diffusion. The supersonic nozzle 3, with a specific profile design, obtains a supersonic airflow at a set Mach number by isentropically accelerating the test airflow. The test section body 4 is the core testing area of ​​the entire wind tunnel. The main function of the super-expansion section 5 in the wind tunnel is to minimize the pressure of the airflow after the test section, thereby improving the efficiency of the blowing test. The ejector 6 uses compressed air as the ejector medium, discharging the gas downstream of the super-expansion section 5 through a two-stage annular ejector. Its function is twofold: firstly, to create a near-vacuum low pressure downstream of the super-expansion section 5, ensuring the high pressure ratio necessary for the formation of hypersonic flow; secondly, to act as a compressor, increasing the total pressure of the main airflow in the wind tunnel, making it higher than atmospheric pressure, thus allowing it to be smoothly discharged into the atmosphere. The silencer tower 7 is used to reduce the noise generated during the exhaust process, ensuring that the environmental noise meets national standards, and to discharge the exhaust gas (mainly composed of nitrogen, oxygen, and water vapor) into the atmosphere.

[0020] The test section body 4 has a test section inlet 9 on the right side wall and a test section outlet 10 on the left side wall; an observation window 11 is located on the front side wall of the test section body 4; a monitoring mechanism and an adjustment mechanism are provided on the test section body 4.

[0021] The monitoring mechanism includes two sets of sensor array components. The two sets of sensor array components are fixedly installed in the inner wall of the test section body 4 and located on one side of the test section inlet 9 and the test section outlet 10. The sensor array components include: a connecting plate 12, which is fixedly installed in the inner wall of the test section body 4. A high-frequency dynamic pressure sensor 13 is fixedly installed on the bottom surface of the connecting plate 12. A hot wire anemometer 14 and a temperature measurement sensor 15 are fixedly installed on two adjacent surfaces of the connecting plate 12, respectively. These sensors are distributed in an array and can monitor the pressure distribution, flow velocity field and temperature field in the test section in real time.

[0022] The monitoring mechanism also includes: a mounting plate 35, which is fixedly installed on the front side wall of the test section body 4. A high-speed camera 16 is fixedly installed on the top surface of the mounting plate 35, and an infrared thermal imager 17 is fixedly installed on the right side wall of the high-speed camera 16. The high-speed camera 16 records the shape changes and spread behavior of the flame through the observation window 11, and the infrared thermal imager 17 is used to capture the temperature distribution and thermal radiation characteristics.

[0023] The adjustment mechanism includes: an adjustable damping mesh 18, which is fixedly installed in the inner wall of the test section body 4 and located on the left side of the test section inlet 9. The inlet flow velocity distribution is adjusted by changing the mesh density; a connecting groove 19 is opened on the top surface of the test section body 4, and a connecting box 20 is fixedly installed on the inner wall of the connecting groove 19. A connecting pipe 21 is provided between the connecting box 20 and the connecting pipe 8, and the connecting box 20 is connected to the connecting pipe 8 through the connecting pipe 21.

[0024] The adjustment mechanism also includes: a fixing block 22, two fixing blocks 22 are provided, which are fixedly installed on the top surface inside the test section body 4 respectively, and a rotating column 23 is rotatably connected between the two fixing blocks 22. A guide plate 24 is fixedly installed on the outer surface of the rotating column 23, and an opening 26 is opened on the top surface of the connecting box 20.

[0025] The adjustment mechanism also includes: a sealing plate 28, which is rotatably connected to the inner wall of the opening 26 via a rotary bearing 27; a connecting rod 25 is provided between the guide vane 24 and the sealing plate 28 to form a linkage mechanism; when the guide vane 24 deflects, it drives the sealing plate 28 to rotate via the connecting rod 25, thereby changing the opening degree of the opening 26; the adjustment mechanism also includes a drive assembly and a supplementary assembly.

[0026] The drive assembly includes: a drive motor 29, which is fixedly mounted on the side wall of one of the fixed blocks 22. A protective shell 30 is fixedly mounted on the side wall of one of the fixed blocks 22. The drive motor 29 is located in the protective shell 30. The output shaft of the drive motor 29 is connected to the side wall of the rotating column 23 and can drive the guide vane 24 to deflect at a specific angle. A baffle plate 31 is fixedly mounted between the two fixed blocks 22.

[0027] The supplementary components include: a cooler 32, which is fixedly installed on the rear side wall of the test section body 4. A connecting pipe 33 is provided on the bottom surface of the cooler 32, and the other end of the connecting pipe 33 extends into the interior of the test section body 4 for supplying cooling gas into the test section.

[0028] The rear side wall of the test section body 4 is fixedly mounted with a central controller 34 on one side of the cooler 32. The central controller 34 is electrically connected to all sensors, drive motors 29 and cooler 32 to form a closed-loop control system. It is used to receive real-time data from the sensor array, analyze the flow field state through built-in algorithms, and automatically drive the corresponding actuators to perform compensation control when flow field distortion is detected.

[0029] Working principle: During operation, at the start of the test, the high-temperature gas generated by heater 1 is initially rectified by transition section 2 and then accelerated by supersonic nozzle 3 to form a supersonic airflow, which enters the test section body 4. During the combustion test within the test section, the monitoring mechanism collects flow field data in real time: high-frequency dynamic pressure sensor 13 monitors pressure fluctuations and pressure gradients; hot-wire anemometer 14 measures flow velocity and turbulence intensity; temperature sensor 15 monitors temperature distribution; and high-speed camera 16 and infrared thermal imager 17 record flame behavior through observation window 11. When the central controller 34 detects flow field distortion through sensor data, it activates a corresponding compensation mechanism: when thermal buoyancy causes the airflow to rise, the central controller 34 controls drive motor 29 to drive guide vane 24 to deflect, and simultaneously drives sealing plate 28 to rotate via connecting rod 25, opening opening 26 of connecting box 20. The hot airflow at the top of the test section is discharged through connecting box 20 under the suction of ejector 6, while cooler 32 replenishes cold air to the bottom of the test section through connecting pipe 33, effectively balancing the buoyancy effect. When pressure field interference is detected causing local pressure anomalies, the central controller 34 controls the corresponding drive motor 29 to adjust the deflection angle of the guide vanes 24 according to the pressure distribution, thereby guiding the airflow and eliminating unnecessary pressure gradients and flow separation. When poor flow field uniformity is detected, the central controller 34 adjusts the mesh density of the adjustable damping mesh 18 to improve the inlet velocity distribution. The entire control process forms a closed-loop feedback, with the central controller 34 dynamically adjusting each actuator based on real-time monitoring data to ensure the flow field remains stable within the test section. After the test, the airflow is depressurized in the super-expansion section 5 and discharged into the silencer tower 7 through the ejector 6 and connecting pipe 8, where it is discharged into the atmosphere after noise reduction treatment.

[0030] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A large combustion wind tunnel for testing, characterized in that: include: Heater (1), a transition section (2) is provided on the left side of the heater (1), a supersonic nozzle (3) is provided on the left side of the transition section (2), a test section body (4) is provided on the left side of the supersonic nozzle (3), an overexpansion section (5) is provided on the left side of the test section body (4), an ejector (6) is provided on the left side wall of the overexpansion section (5), a silencer tower (7) is provided on the left side of the ejector (6), a connecting pipe (8) is provided between the ejector (6) and the silencer tower (7), a test section inlet (9) is provided on the right side wall of the test section body (4), and a test section outlet (10) is provided on the left side wall of the test section body (4). An observation window (11) is provided on the front side wall of the test section body (4); The test section body (4) is equipped with a monitoring mechanism and an adjustment mechanism.

2. A large combustion wind tunnel for testing according to claim 1, characterized in that: The monitoring mechanism includes two sets of sensor array assemblies, which are fixedly installed in the inner wall of the test section body (4) and located on one side of the test section inlet (9) and test section outlet (10). The sensor array assemblies include: A connecting plate (12) is fixedly installed in the inner wall of the test section body (4). A high-frequency dynamic pressure sensor (13) is fixedly installed on the bottom surface of the connecting plate (12). A hot wire anemometer (14) and a temperature measurement sensor (15) are fixedly installed on two adjacent surfaces of the connecting plate (12).

3. A large combustion wind tunnel for testing according to claim 2, characterized in that: Monitoring agencies also include: Mounting plate (35), which is fixedly mounted on the front side wall of the test section body (4), a high-speed camera (16) is fixedly mounted on the top surface of the mounting plate (35), and an infrared thermal imager (17) is fixedly mounted on the right side wall of the high-speed camera (16).

4. A large combustion wind tunnel for testing according to claim 1, characterized in that: The regulating mechanism includes: An adjustable damping net (18) is fixedly installed in the inner wall of the test section body (4) and located on the left side of the test section entrance (9). A connecting groove (19) is provided on the top surface of the test section body (4). A connecting box (20) is fixedly installed on the inner wall of the connecting groove (19). A connecting pipe (21) is provided between the connecting box (20) and the connecting pipe one (8).

5. A large combustion wind tunnel for testing according to claim 4, characterized in that: The regulating mechanism also includes: There are two fixed blocks (22), which are fixedly installed on the top surface inside the test section body (4). A rotating column (23) is rotatably connected between the two fixed blocks (22). A guide plate (24) is fixedly installed on the outer surface of the rotating column (23). An opening (26) is opened on the top surface of the connecting box (20).

6. A large combustion wind tunnel for testing according to claim 5, characterized in that: The regulating mechanism also includes: The sealing plate (28) is rotatably connected to the inner wall of the opening (26) via a rotary bearing (27). A connecting rod (25) is provided between the guide vane (24) and the sealing plate (28). The adjustment mechanism also includes a drive component supplementary component.

7. A large combustion wind tunnel for testing according to claim 6, characterized in that: The driver components include: A drive motor (29) is fixedly mounted on the side wall of one of the fixed blocks (22), and a protective shell (30) is fixedly mounted on the side wall of one of the fixed blocks (22). The drive motor (29) is located in the protective shell (30). The output shaft of the drive motor (29) is connected to the side wall of the rotating column (23). A wind baffle (31) is fixedly mounted between the two fixed blocks (22).

8. A large combustion wind tunnel for testing according to claim 6, characterized in that: The supplementary components include: The cooler (32) is fixedly installed on the rear side wall of the test section body (4). The bottom surface of the cooler (32) is provided with a connecting pipe (33), and the other end of the connecting pipe (33) extends into the interior of the test section body (4).

9. A large combustion wind tunnel for testing according to claim 1, characterized in that: The central controller (34) is fixedly installed on the rear side wall of the test section body (4) on one side of the cooler (32).

Images