A direct current combustion wind tunnel

Abstract

The application discloses a direct current combustion wind tunnel, wherein a main body of the wind tunnel comprises a power section, a round-to-square transition section, a stable section, a contraction section, a test section and a diffusion section in sequence; a linkage pollution discharge system is arranged in the bottom of the stable section; the linkage pollution discharge system is formed by cooperation of a first leakage hole in an array on a top cover, a second leakage hole on a sealing plate, a fixed frame, a moving frame and an extension rod, and the first leakage hole and the second leakage hole are dislocated in an initial position; the linkage pollution discharge system is hidden in the stable section; one-key triggering of complete sealing in a non-working state and cleaning working conditions is realized; and the problem of influence of stable section cleaning smoke discharge pollution on flow field quality after combustion wind tunnel experiment in the prior art is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of combustion test, in particular to a direct-flow combustion wind tunnel. BACKGROUND

[0002] Large low-speed wind tunnels are the core infrastructure for studying aerodynamics and combustion science. Although the current international mainstream devices (such as the 12.2m x 24.4m low-speed wind tunnel of NASA Ames Research Center) have the potential to carry out combustion experiments, there are still significant limitations in their design.

[0003] The inherent contradiction between the stable section exhaust system and the flow field quality is particularly prominent. The traditional wind tunnel usually opens a fixed exhaust port at the bottom of the stable section to clean the smoke pollution accumulated in the honeycomb and damping net flow regulating components. The top of the exhaust port is protruding and non-hidden. The airflow can be discharged through the exhaust port, which will affect the flow field, increase the pressure drop, destroy the airflow uniformity, change the guide effect of the inner wall of the wind tunnel, cause the turbulence to rise, and cause the experimental data to deviate.

[0004] Therefore, the existing needs are not met, and for this purpose, we propose a direct-flow combustion wind tunnel. SUMMARY

[0005] Therefore, the present application provides a direct-flow combustion wind tunnel to solve the problem of the influence of the stable section cleaning smoke dust exhaust port on the flow field quality in the prior art.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme:

[0007] According to the first aspect of the present application, a direct-flow combustion wind tunnel comprises a wind tunnel main body, which comprises a power section, a round-to-square transition section, a stable section, a contraction section, a test section and a diffusion section in sequence;

[0008] The stable section bottom of the stable section is provided with a linkage exhaust system, and the stable section bottom is composed of a bottom plate, a top cover and a rectangular side frame. The linkage exhaust system comprises:

[0009] The first leakage hole is arranged in an array on the top cover;

[0010] The sealing plate is provided with a second leakage hole corresponding to the first leakage hole, and the sealing plate is slidingly connected in a limiting space at the bottom of the top cover. The first leakage hole and the second leakage hole are misaligned in the initial position;

[0011] The fixed frame is fixedly connected below the top cover;

[0012] The moving frame is connected to the bottom end of both sides of the sealing plate, and the two sides of the moving frame are slidingly connected with the fixed frame;

[0013] The telescopic rod drives the moving frame, one side of the fixed frame is provided with the telescopic rod, and the output end of the telescopic rod is connected with the moving frame.

[0014] The blowdown port is arranged on the bottom plate.

[0015] Further, the power section input end is provided with an outward turning air inlet lip, the inner middle section of the power section is provided with a flow guide cover, and an axial flow fan is arranged in the middle section of the flow guide cover.

[0016] Further, the top end of the bottom plate at the bottom of the stabilizing section is a conical surface, and the blowdown port is arranged at the lowest part of the conical surface.

[0017] Further, the bottom of the top cover is fixedly connected with L-shaped plates, and the L-shaped plates and the top cover form a limiting space.

[0018] Further, a funnel-shaped conical blowdown frame is arranged below the blowdown port, the output end of the conical blowdown frame is connected with a blowdown pipe, the inner wall of the blowdown port is slidably connected with a blowdown port cover plate, and a sealing ring is arranged at the edge of the blowdown port cover plate.

[0019] Further, a first spring is arranged between the bottom end of the blowdown port cover plate and the conical blowdown frame, guide frames are slidably connected to the four corners of the blowdown port cover plate, the bottom end of the guide frame is connected with the bottom end of the inner wall of the blowdown port, one side of the top end of the guide frame is fixedly connected with a pulley block, the top end of the blowdown port cover plate is fixedly connected with a pull rope, and the pull rope passes through the pulley block and is fixedly connected with the moving frame after passing through two driven wheels.

[0020] Further, the linkage blowdown system further comprises an elastic plugging assembly, the elastic plugging assembly comprises a series connection frame, the top end of the series connection frame is provided with arrayed plugging blocks, the plugging blocks are slidably connected with the inner wall of the second leakage hole, the two sides of the series connection frame are fixedly connected with fixed plates, the inner side of the fixed plate is slidably connected with the outer wall of the connecting rod at the top of the moving frame, the outer wall of the connecting rod is sleeved with a second spring, and the second spring is located between the fixed plate and the top cover, the bottom two sides of the series connection frame are fixedly connected with first misalignment blocks, the top end of the bottom plate is fixedly connected with a second misalignment block, in the initial state, the oblique edge of the first misalignment block is in contact with and abuts against the roller on the oblique edge of the second misalignment block, so that the second spring is kept compressed, and the plugging blocks are tightly inserted into the second leakage hole to realize sealing.

[0021] Further, the outer side of the plugging block is an arc-shaped sealing surface, the inner wall of the second leakage hole is provided with a matching arc-shaped groove, and the two form a guide sealing structure.

[0022] Further, the stabilizing section is provided with a honeycomb device, a damping net and a static flow section, the honeycomb device is located upstream of the damping net, and the static flow section is located downstream of the damping net.

[0023] Furthermore, the test section is provided with four layers of heat insulation and fireproof protection at the top and bottom, which, from the outside to the inside, include: a support wall, a heat insulation layer, a fireproof layer, and a surface layer.

[0024] The present invention has the following advantages:

[0025] This invention discloses a DC combustion wind tunnel, the main body of which sequentially includes a power section, a round-to-square transition section, a stabilization section, a contraction section, a test section, and a diffusion section. A linked sewage discharge system is installed at the bottom of the stabilization section, utilizing a first leak hole arrayed on the top cover and a second leak hole arrayed on the sealing plate. Initially, the first and second leak holes are misaligned. Furthermore, a fixed frame, a movable frame, and a telescopic rod are used to form a hidden linked sewage discharge system in the stabilization section, achieving complete sealing in non-working conditions and one-button triggering for cleaning operations. This effectively solves the problem in existing technologies where the smoke and dust discharge from the stabilization section after combustion wind tunnel experiments affects the flow field quality. Attached Figure Description

[0026] Figure 1 This is a front view of a DC combustion wind tunnel proposed in this invention;

[0027] Figure 2 for Figure 1 Internal sectional view;

[0028] Figure 3 This is a front view of the bottom of the stable section of a DC combustion wind tunnel proposed in this invention;

[0029] Figure 4 for Figure 3 The exploded schematic main view;

[0030] Figure 5 for Figure 3 The interior view;

[0031] Figure 6 for Figure 4 A schematic diagram of the decomposition process;

[0032] Figure 7 for Figure 6 A bottom view;

[0033] Figure 8 for Figure 4 Enlarged cross-sectional view of the central sewage outlet area;

[0034] Figure 9 This is a sectional view of a tapered sewage discharge frame;

[0035] Figure 10 This is a cross-sectional view of the thermal insulation and fireproof protective layer in the test section;

[0036] Figure 11 This is an exploded view of the structure of the air guide and axial flow fan.

[0037] In the figure: 1, power section; 11, air inlet lip; 12, fairing; 13, axial flow fan; 2, round-to-square transition section; 3, stable section; 31, honeycomb; 32, damping net; 33, static flow section; 34, stable section bottom; 301, pollution discharge port; 302, pollution discharge port cover plate; 303, conical pollution discharge frame; 304, pollution discharge pipe; 305, steel pipe; 306, first spring; 307, guide frame; 308, pull rope; 309, pulley block; 4, contraction section; 5, test section; 51, fireproof observation window; 52, hanging cover plate; 501, support wall; 502, heat insulation layer; 503, fireproof layer; 504, surface layer; 505, self-tapping screw; 6, diffusion section; 701, top cover; 702, bottom plate; 703, side frame; 72, first leakage hole; 73, cover plate; 74, second leakage hole; 75, L-shaped plate; 76, moving frame; 77, fixed frame; 78, telescopic rod; 81, plugging block; 811, arc-shaped cover; 812, arc-shaped groove; 82, series frame; 83, fixed plate; 84, second spring; 85, first misalignment block; 86, second misalignment block; 87, roller; 9, conical surface. DETAILED DESCRIPTION

[0038] The following will be described by specific embodiments to illustrate the embodiments of the present application, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. Embodiment one

[0039] Reference Figures 1-2 The direct-flow combustion wind tunnel according to the embodiments of the present application is a large-scale low-speed direct-flow combustion wind tunnel, which comprises a wind tunnel main body; the wind tunnel main body comprises, from left to right, a power section 1, a round-to-square transition section 2, a stable section 3, a contraction section 4, a test section 5, and a diffusion section 6.

[0040] Reference Figure 11 The input end of the power section 1 is provided with an outwardly turned air inlet lip 11, and the inner middle end of the power section 1 is provided with a fairing 12, the two ends of the fairing 12 are fixedly connected with the inner wall of the power section 1 through connecting rods, and the middle part of the fairing 12 is provided with an axial flow fan 13; the power section 1 generates flowing air flow by one or more specially made axial flow fans 13, which blows into the wind tunnel main body; the wind speed in the wind tunnel main body can be controlled to simulate a multi-stage wind speed environment by controlling the axial flow fan 13 through frequency conversion.

[0041] The circular-to-square transition section 2 is a transition section downstream of the power section 1, and is designed by using diffusion method. The input end of the transition section 2 is connected with the output end of the power section 1, and the output end is connected with the input end of the stable section 3.

[0042] The stable section 3 is provided with a rectifying device composed of a honeycomb 31 and a damping net 32. The rectifying device provides the contraction section 4 with uniform inlet airflow with fully attenuated turbulent pulsation.

[0043] The honeycomb 31 in the stable section 3 is usually composed of stacked square, circular or hexagonal slender pipes. The main function of the honeycomb 31 is to guide and divide the airflow vortex, thus facilitating the attenuation of the vortex. At the same time, the friction of the honeycomb 31 to the airflow is also conducive to improving the velocity distribution of the airflow, and to a certain extent, it can also reduce the turbulence of the airflow.

[0044] The damping net 32 is usually installed downstream of the honeycomb 31. The main function of the damping net 32 is to improve the uniformity of the velocity distribution and to reduce the turbulence of the airflow. In order to fully play its role, firstly, the opening rate β of the damping net 32 should be greater than 57%; secondly, when multiple layers of damping nets 32 are used, the distance between the damping nets 32 should be greater than 30 times the width W of the net hole, or greater than 500 times the diameter d of the net wire, so as to fully attenuate the turbulence generated by the upstream layer of net before entering the downstream layer of net.

[0045] A static flow section 33 is arranged downstream of the damping net 32 in the stable section 3. It is necessary to design the static flow section 33 after the damping net 32, so as to fully uniform and stabilize the airflow, and to further fully attenuate the turbulence of the airflow.

[0046] The input end of the contraction section 4 is connected with the output end of the stable section 3, and the output end of the contraction section 4 is connected with the input end of the test section 5. The cross-sectional area of the contraction section 4 decreases from the input end to the output end. The function of the contraction section 4 is to uniformly accelerate the airflow to reach the required flow rate of the test section 5.

[0047] The input end of the test section 5 is connected with the output end of the contraction section 4, and the output end of the test section 5 is connected with the input end of the diffusion section 6. The boundary layer thickness of the wall surface along the closed test section 5 in the airflow direction is gradually increased. This makes the streamwise cross section of the closed test section 5 gradually decrease, so that a negative static pressure gradient is generated along the axial direction of the closed test section 5, so that the test model is subjected to an additional resistance which does not exist in atmospheric flight. The fireproof observation window 51 is arranged on the side wall of the test section 5, and the hoistable cover plate 52 is arranged on the top.

[0048] The input end of the diffusion section 6 is connected with the output end of the test section 5, and the opening area of the input end to the output end of the diffusion section 6 gradually increases; the main function is to gradually restore the kinetic energy of the airflow to pressure energy, thereby reducing the energy loss of the airflow in each section downstream of the diffusion section 6; the design points of the diffusion section 6 are to avoid flow separation and to reduce the pressure loss as much as possible, and the design parameters mainly include the equivalent diffusion angle and the area ratio; experiments show that the diffusion angle should be less than 7°, and when the diffusion angle is less than 7°, if the area ratio is too large or the inlet velocity profile is uneven, there is also a risk of separation.

[0049] In use: place the combustion experiment in the test section 5; observe the internal situation through the fireproof observation window 51; the airflow enters from the external environment through the outwardly flared horn-shaped air inlet lip 11, is pressed into the circular-to-square transition section 2 by starting the axial flow fan 13, and in this process, the kinetic energy is gradually converted into pressure energy, reducing energy loss; the airflow then enters the core flow regulating cabin-stabilization section 3; in turn, the airflow is divided into large-scale vortices and the flow direction deviation angle is corrected by the honeycomb device 31 in the stabilization section 3; the double-layer stainless steel damping net 32 further homogenizes the velocity distribution and attenuates the turbulence level to the experimental requirements; the static flow section 33 makes the airflow fully smooth, and finally forms a low disturbance and high uniformity flow field.

[0050] The airflow after flow regulation is accelerated by the contraction section 4: the inlet curvature is steep and the outlet curvature is gentle, avoiding boundary layer separation while outputting parallel and uniform flow, directly reaching the core test section 5; the 0.25° micro-expansion angle of the side wall of the test section 5 actively offsets the static pressure gradient caused by the thickening of the boundary layer, restoring the real wind field environment; the staff controls the combustion experiment through the fireproof observation window 51, and captures key data such as fire spread and plume characteristics under wind speed conditions; the airflow carrying combustion products finally enters the diffusion section 6, and the diffusion angle of the diffusion section 6 is less than 7°, and the kinetic energy is converted into pressure energy again to release slowly; the frequency conversion control system accurately adjusts the speed of the axial flow fan 13 throughout the process, realizing stepless simulation of wind speed. Example Two

[0051] Basically the same as example one, since the heat is mainly concentrated in the test section 5 hole body during the ignition experiment, a heat insulation and fireproof protective layer is added on the top and bottom of the test section 5 hole body; further, refer to Figure 10, the heat insulation and fireproof protective layer is provided with four layers of structures; from outside to inside, the first layer is a support wall 501, the material of which is a plate of a large steel plant superior to Q235B containing Q235B, the plate is 8 mm thick, cooperates with longitudinal rib strips with a spacing of 600-800 mm and a height of 150 mm and a thickness of 10 mm, to ensure the strength of the wind tunnel body. The second layer is a heat insulation layer 502, which is made of 20 mm high-aluminum silicate aluminum fiber plate with a high temperature resistance of above 1250℃. The third layer is a fireproof layer 503 made of calcium silicate plate; the calcium silicate plate has excellent high temperature resistance, and the temperature can be above 1050℃, and will not easily appear problems such as softening, deformation and melting under short-term high temperature of above 1500℃, thereby stably protecting the internal structure of the wind tunnel experiment. The fourth layer is a surface layer 504 made of 3 mm thick stainless steel plate, which is used to ensure the smoothness. Self-tapping nails 505 are used to penetrate the upper three layers of structures and the support wall 501 of the first layer to be connected, the gaps are filled with fire-resistant mortar and polished smooth with sandpaper.

[0052] Working principle: The heat insulation and fireproof protective layer of the four-layer composite fire-resistant structure; the support wall 501 made of Q235B steel + the heat insulation layer 502 made of high-aluminum silicate aluminum fiber plate + the fireproof layer 503 made of calcium silicate plate + the surface layer 504 made of stainless steel plate resist flame erosion of greater than or equal to 1000℃, maintain the flow field quality of the high-smooth inner wall, prevent flame and high temperature conduction, and delay the spread of fire; form a fireproof protective layer.

[0053] The advantages are as follows: ①Significant heat preservation and insulation effect: the structure has a low thermal conductivity, which can reduce heat conduction and loss, and has good heat preservation effect; this not only helps to maintain the high temperature environment inside the test section 5 of the wind tunnel, but also helps the wind tunnel to achieve energy saving and cost reduction; ②High strength and good toughness: the construction effect ensures that the test section 5 has high strength and toughness, which ensures that the test section 5 is not easily deformed in a high temperature environment, thereby ensuring the stability and usability of the test section 5 of the wind tunnel; ③Maintain structural stability: this structure helps to maintain the structural stability of the test section 5 due to its high temperature resistance, reduces the risk of damage caused by high temperature, and prolongs the service life of the overall structure of the test section 5; ④And various structural materials have the following advantages: they are all green and environmentally friendly materials without toxic substances; the surface of the surface layer 504 stainless steel plate is smooth and has high smoothness, which can reduce the flow resistance of the flow field to ensure the quality of the flow field airflow; the material has stable performance, is anti-aging and anti-seismic, has good durability, is mildew-resistant and antibacterial; the structural material is non-combustible A1-level homogeneous material with a smoke toxicity index of zero.

[0054] The DC combustion wind tunnel disclosed in the embodiment of the present application solves the experimental limitations caused by the insufficient refractoriness of the traditional wind tunnel by means of the integrated design of the four-layer composite refractory structure (support wall + heat insulation layer + fireproof layer + high-smooth surface layer) of the test section, which can resist the flame erosion of greater than or equal to 1000 DEG C while maintaining the flow field quality. The smooth inner wall of the surface layer of stainless steel effectively reduces the flow resistance, and the 0.25 DEG micro-expansion angle of the test section actively offsets the static pressure gradient caused by the thickening of the boundary layer, so that the wind tunnel has both the safety of high-temperature combustion experiment and the real flow field restoration ability, and significantly improves the capture accuracy of key data such as fire spread and plume characteristics. Embodiment three

[0055] The same as embodiment one, and further, referring to Figure 9 The stable section 3 is composed of a stable section top plate, a stable section side plate and a stable section bottom 34, the bottom surface of the stable section bottom 34 is provided with a blowdown port 301, the blowdown port 301 is provided below with a funnel-shaped conical blowdown frame 303, the output end of the conical blowdown frame 303 is connected with a blowdown pipe 304, the inner wall of the blowdown port 301 is slidingly connected with a blowdown port cover plate 302, the blowdown port cover plate 302 is fixedly connected with the inner wall of the blowdown port 301 by means of flat head screws, and a sealing ring is arranged at the edge of the blowdown port cover plate 302 to ensure the sealing property in the normal working state.

[0056] In order to facilitate the removal of the blowdown port cover plate 302, a steel pipe 305 is fixedly connected to the middle end of the bottom of the blowdown port cover plate 302, a first spring 306 is installed at the bottom end of the inner wall of the conical blowdown frame 303, the top end of the first spring 306 is in contact with the bottom end of the blowdown port cover plate 302, and the first spring 306 is a thrust spring.

[0057] Working principle: when it is necessary to clean the inner wall of the wind tunnel main body, the honeycomb 31 and the damping net 32, the flat head bolt for fixing the blowdown port cover plate 302 is loosened, the blowdown port cover plate 302 is lifted by the first spring 306, the blowdown port cover plate 302 is removed, and the blowdown port 301 is leaked.

[0058] By means of the hidden blowdown port 301, the blowdown port 301 will not affect the flow field, increase the pressure drop, destroy the airflow uniformity, change the guiding effect of the inner wall of the wind tunnel, cause the turbulence degree to rise, and cause the experimental data to deviate. Embodiment four

[0059] The same as embodiment three, except that the flat head bolt, the first spring 306 and the blowdown port cover plate 302 are not installed, and further, referring to Figures 3-8 The stable section 3 is composed of a stable section top plate, a stable section side plate and a stable section bottom 34, the stable section bottom 34 is composed of a bottom plate 702, a top cover 701 and a rectangular side frame 703.

[0060] The top cover 701 has an array of first drainage holes 72; the top of the bottom plate 702 has an irregular conical surface 9, and the bottom of the conical surface 9 has a drain outlet 301.

[0061] Working principle: When it is necessary to clean the inner wall of the wind tunnel body, honeycomb unit 31, and damping net 32, the flushing wastewater seeps into the bottom 34 of the stable section through the first leakage hole 72, and gathers at the drain outlet 301 through the irregular conical surface 9 opened at the top of the bottom plate 702, and is discharged through the drain outlet 301. Example 5

[0062] Similar to Example 4, the first leak hole 72 in the above scheme is not sealed, resulting in air leakage and affecting the flow field. To further address this issue, refer to... Figures 3-8 The top cover 701 has L-shaped plates 75 fixedly connected to both sides of its bottom end. The top cover 701 and the L-shaped plates 75 on both sides form a limiting space. A sealing plate 73 is slidably connected to the inner wall of the space. A second leakage hole 74 is opened on the sealing plate 73. In the initial state, the first leakage hole 72 and the second leakage hole 74 are misaligned with each other.

[0063] Movable frames 76 are fixedly connected to both sides of the bottom end of the sealing plate 73, and fixed frames 77 are fixedly connected to the bottom end of the top cover 701. The two sides of the movable frames 76 are slidably connected to the fixed frames 77. A telescopic rod 78 is fixedly installed on one side of the fixed frame 77, and the output end of the telescopic rod 78 is fixedly connected to the movable frame 76.

[0064] Working principle: When it is necessary to clean the inner wall of the wind tunnel body, the honeycomb unit 31, and the damping net 32, the telescopic rod 78 is controlled to pull the moving frame 76 to move. The moving frame 76 drives the sealing plate 73 to move, so that the first leakage hole 72 corresponds to the second leakage hole 74. The flushing sewage seeps into the bottom 34 of the stable section through the first leakage hole 72 and the second leakage hole 74, and is collected at the drain outlet 301 through the irregular conical surface 9 opened at the top of the bottom plate 702, and discharged through the drain outlet 301. Example 6

[0065] Basically the same as in Example 5, but further: Refer to Figures 3-8 A drain cover 302 is slidably connected to the inner wall of the drain outlet 301; a first spring 306, which is a tension spring, is installed between the bottom center of the drain cover 302 and the conical drain frame 303; sliding holes are provided at the four corners of the drain cover 302, and guide frames 307 are slidably connected to the inner walls of the sliding holes; the bottom end of the guide frame 307 is fixedly connected to the bottom end of the inner wall of the drain outlet 301; a pulley group 309 is fixedly installed on one side of the top of the guide frame 307, and a pull rope 308 is fixedly installed at the top center of the drain cover 302; the pull rope 308 passes through the pulley group 309 as... Figure 8 The device passes through two driven wheels and is then fixedly connected to the movable frame 76.

[0066] Working principle: when the inner wall of the wind tunnel main body, honeycomb 31, and damping net 32 need to be cleaned, control the telescopic rod 78 to pull the moving frame 76 to move, drive the sealing plate 73 to move through the moving frame 76, so that the first leak hole 72 corresponds to the second leak hole 74; at the same time, the moving frame 76 pulls the sewage outlet cover plate 302 to rise along the guide frame 307 through the pull rope 308, and opens the sewage outlet 301; the sewage for flushing seeps into the bottom of the stable section 34 through the first leak hole 72 and the second leak hole 74, is gathered to the sewage outlet 301 through the irregular conical surface 9 opened at the top of the bottom plate 702, and is discharged through the sewage outlet 301. Example seven

[0067] The same as example six, and further, referring to Figures 3-8 A direct-flow combustion wind tunnel further comprises a series frame 82, the top end of the series frame 82 is provided with an array of blocking blocks 81, the blocking blocks 81 are in sliding connection with the inner wall of the second leak hole 74; the two sides of the series frame 82 are fixedly connected with fixed plates 83, the inner side of the fixed plate 83 is in sliding connection with the outer wall of the connecting rod at the top of the moving frame 76, the outer wall of the connecting rod is sleeved with a second spring 84, the second spring 84 is located between the fixed plate 83 and the top cover 701, the second spring 84 is a thrust spring in the initial state; the outer side of the blocking block 81 is provided with an arc-shaped sealing surface 811, the inner wall bottom of the second leak hole 74 is provided with an arc-shaped groove 812, the arc-shaped groove 812 corresponds to the arc-shaped sealing surface 811, and the two cooperate to play a guiding and auxiliary sealing role.

[0068] The bottom of the series frame 82 is fixedly connected with first misalignment blocks 85 on both sides, and the top of the bottom plate 702 is fixedly provided with second misalignment blocks 86; in the initial state, the inclined edge of the first misalignment block 85 is in contact with and abuts against the roller 87 on the inclined edge of the second misalignment block 86, so that the second spring 84 is kept compressed, the blocking block 81 is tightly inserted into the second leak hole 74 to realize sealing, the inclined edge of the first misalignment block 85 corresponds to the inclined edge of the second misalignment block 86, and the roller 87 is rotatably connected in an array on the inclined edge of the second misalignment block 86; the outer wall of the roller 87 is in contact with the inclined edge of the first misalignment block 85.

[0069] Working principle: in the initial state, the blocking block 81 is in butt joint with the inner wall of the second leak hole 74; the first leak hole 72 is misaligned with the second leak hole 74, the sealing plate 73 closes the first leak hole 72, the inclined edge of the first misalignment block 85 abuts against the roller of the second misalignment block 86, the second spring 84 is compressed to make the blocking block 81 sealingly inserted into the second leak hole 74; the sewage outlet cover plate 302 closes the sewage outlet 301 under the action of the weight or spring force.

[0070] In use: when the inner wall of the wind tunnel main body, honeycomb 31, and damping net 32 need to be cleaned, control the telescopic rod 78 to pull the moving frame 76 to move.

[0071] The sealing plate 73 is moved by the moving frame 76, so that the first leak hole 72 is aligned with the second leak hole 74.

[0072] The moving frame 76 moves to drive the first staggered block 85 to move synchronously, and the oblique edge of the first staggered block 85 slides along the roller 87 on the oblique edge of the second staggered block 86; at this time, under the action of the pushing force of the second spring 84, the series frame 82 is pushed to move downward along the connecting rod of the moving frame 76 together with the fixed plate 83 and the sealing block 81, so as to drive the sealing block 81 to pull out from the second leak hole 74.

[0073] At the same time, the moving frame 76 pulls the blow-off port cover plate 302 to rise along the guide frame 307 through the pull rope 308, so as to open the blow-off port 301; the flushed sewage seeps into the bottom part 34 of the stable section through the first leak hole 72 and the second leak hole 74, is gathered to the blow-off port 301 through the irregular conical surface 9 opened at the top end of the bottom plate 702, and is discharged through the blow-off port 301.

[0074] In the above embodiment of the present application, the stable section hidden linkage blow-off system realizes complete sealing in a non-working state and one-key triggering in a cleaning condition through the cooperative action of the elastic sealing assembly (sealing block / staggered block / spring) and the linkage mechanism (pull rope / telescopic rod); in the initial state, the sealing block is tightly inserted into the second leak hole, and the staggered block abuts against the structure to ensure zero air leakage; after starting cleaning, the telescopic rod synchronously completes the three actions of leak hole alignment, sealing block unsealing and blow-off port opening through single operation, and the sewage is quickly gathered and discharged through the conical surface; the design completely eliminates the interference of the traditional blow-off port on the airflow, and ensures that the rectifier (honeycomb / damping net) maintains low turbulence and high uniformity of the inflow condition for a long time.

[0075] In the above embodiment of the present application, the direct-flow combustion wind tunnel forms deep coupling of aerodynamics-structure-control through stepless air regulation of the variable-frequency axial-flow fan in the power section, multi-stage rectification (honeycomb vortex guide+damping net uniform speed+static flow section attenuation) in the stable section and low-loss expansion in the diffusion section; the outward turning type air inlet lip and the flow guide cover optimize the inflow efficiency, the special combustion section avoids additional resistance through micro-expansion angle design; the linkage blow-off system reduces the maintenance downtime, and the four-layer heat insulation structure reduces the heat conduction loss; finally, while realizing high-precision simulation of the wind speed, the comprehensive operation energy consumption is significantly reduced, thereby providing a sustainable and efficient platform for large-scale combustion experiments.

Claims

1. A direct current combustion wind tunnel comprising a wind tunnel body, characterized in that, The wind tunnel body comprises, in sequence, a power section, a round-to-square transition section, a stable section, a contraction section, a test section and a diffusion section. The stable section bottom is internally provided with a linkage sewage discharge system, and the stable section bottom is composed of a bottom plate, a top cover and a rectangular side frame. The first leakage hole is arranged in an array on the top cover. The sealing plate is slidably connected to a limiting space at the bottom of the top cover. The fixed frame is fixedly connected to the bottom of the top cover. The moving frame is slidably connected to the two sides of the fixed frame. The telescopic rod is arranged on one side of the fixed frame. The sewage discharge opening is arranged on the bottom plate. The conical sewage discharge frame is arranged below the sewage discharge opening. The first spring is arranged between the bottom end of the sewage discharge opening cover plate and the conical sewage discharge frame. The linkage sewage discharge system further comprises an elastic sealing assembly, which comprises a series connection frame.

2. A direct-flow combustion tunnel according to claim 1, characterized in that The power section is provided with an outwardly turned air inlet lip at the input end.

3. A direct current combustion tunnel as defined in claim 1, wherein The middle section of the interior of the power section is provided with a flow guide cover.

4. A direct current combustion tunnel as defined in claim 1, wherein The middle section of the interior of the power section is provided with a flow guide cover.

5. A direct current combustion tunnel as defined in claim 1, wherein The middle section of the interior of the power section is provided with a flow guide cover.

6. A direct current combustion tunnel as defined in claim 1, wherein The middle section of the interior of the power section is provided with a flow guide cover.

7. A direct current combustion tunnel as defined in claim 1, wherein The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with a flow guide cover. The middle section of the interior of the power section is provided with

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