Air valve opening degree regulation and control device and method for tunnel fire limit flow smoke exhaust

Abstract

The invention discloses an air valve opening degree regulation and control device and method for tunnel fire limit flow smoke exhaust, a plurality of smoke exhaust ports are formed in the inner wall of the top of a tunnel body, a plurality of smoke circulation air channels are formed in the tunnel body, and the smoke circulation air channels are located at the tops of the smoke exhaust ports and communicate with the smoke exhaust ports; a plurality of adjusting air valve clamping grooves are formed in the inner walls of the two sides of the flue gas exhaust channel in the middle of the interior of the tunnel main body, the adjusting air valve clamping grooves communicate with the flue gas circulation air channel, and adjusting assemblies used for controlling the opening degree of flue gas adjusting air valves fixedly installed in the adjusting air valve clamping grooves are arranged in the flue gas adjusting air valves; the whole regulation and control device is based on the flue gas limit flow regulation and control theory, flow is accurately distributed according to a negative pressure attenuation equation, a flue gas discharge outlet air valve closest to a fire source is opened, only a necessary air valve is opened, far-end suction redundancy is avoided, and the problems that an existing air valve opening regulation and control theory method is lack, and an air valve device is insufficient in regulation precision and poor in sealing performance are solved.

Description

Technical Field

[0001] This invention belongs to the field of tunnel fire smoke exhaust technology, and particularly relates to a valve opening control device and method for tunnel fire extreme flow smoke exhaust, which is used to improve the smoke exhaust efficiency of the tunnel transverse smoke exhaust system and improve the fire smoke control capability. Background Technology

[0002] While tunnel construction brings immense convenience to transportation, its fire safety issues are becoming increasingly prominent. In the event of a fire in a tunnel, poor smoke extraction and heat dissipation conditions make it difficult to remove high-temperature, toxic fumes, easily causing traffic congestion and serious casualties. Therefore, tunnels require smoke extraction systems. Currently, transverse smoke extraction systems are widely used in practical engineering, using exhaust fans to generate negative pressure and expel smoke from exhaust vents. However, the negative pressure generated by the exhaust fans decreases longitudinally, resulting in differences in negative pressure gradients at different exhaust vent locations. This leads to uneven flow distribution at each exhaust vent, causing insufficient suction at vents near the fire source and excessive air mixing at distant vents, affecting smoke extraction efficiency. Installing dampers at the exhaust vents and utilizing their dynamic opening adjustment function to rationally distribute smoke flow at different exhaust vents is an effective way to ensure more smoke is promptly discharged from exhaust vents near the fire source, achieving efficient smoke extraction.

[0003] Currently, tunnel smoke exhaust valves have several shortcomings in practical applications, and their performance directly affects the smoke extraction effect. Firstly, the lack of a theoretical method for controlling smoke flow makes it impossible to maximize the flow of smoke discharged from the smoke exhaust port near the fire source, hindering the efficient and short-distance exhaust of smoke from the tunnel. Secondly, the valve opening adjustment precision is insufficient, making it difficult to accurately control the smoke exhaust flow according to different stages of fire development and smoke generation, easily leading to untimely or excessive smoke extraction. Thirdly, the valve's sealing performance is poor, easily causing air leakage when not open, resulting in a large decrease in negative pressure in the smoke exhaust channel and insufficient suction at the open smoke exhaust port, affecting the overall efficiency of the smoke extraction system. Furthermore, the lack of an effective limiting mechanism during opening makes it difficult to ensure the stability of the valve's state after adjustment. Fourthly, the transmission logic of existing valve drive mechanisms is relatively simple, often using a single power source to directly drive the valve plate rotation. This easily leads to jamming during adjustment and cannot achieve the orderly action of unlocking before adjustment, further affecting the reliability and stability of valve adjustment.

[0004] Based on the shortcomings of the existing technology, there is an urgent need for a tunnel fire smoke exhaust valve control device and method that can accurately adjust the valve opening according to the needs of efficient smoke exhaust, has good sealing performance, and has automatic sealing and opening functions as well as impurity collection functions. Summary of the Invention

[0005] In view of this, in order to solve the problems of lack of theoretical methods for regulating the opening of existing air valves, insufficient adjustment accuracy of air valve devices, and poor sealing performance, this invention provides an air valve opening regulation device and method for extreme flow smoke exhaust in tunnel fires.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A device for regulating the opening of a damper for smoke exhaust at the limit flow rate in a tunnel fire includes a smoke exhaust channel located in the middle of the tunnel body, multiple smoke exhaust ports on the top inner wall of the tunnel body, multiple smoke airflow ventilation ducts inside the tunnel body, the smoke airflow ventilation ducts being located above the smoke exhaust ports and connected to the smoke exhaust ports, multiple regulating damper slots on both sides of the inner wall of the smoke exhaust channel, the regulating damper slots being connected to the smoke airflow ventilation ducts, a smoke regulating damper being fixedly installed inside the regulating damper slot, and an adjustment component for controlling the opening of the damper being provided inside the smoke regulating damper.

[0008] The adjustment assembly includes a rotating shaft that rotates through the interior of the flue gas regulating damper. A rotating sealing plate is fixedly fitted onto the outer wall of the rotating shaft. Fixed blocks are fixedly installed on the inner walls of both sides of the flue gas regulating damper. The two fixed blocks are centrally symmetrically arranged and located on both sides of the rotating sealing plate. Rubber blocks are fixedly installed at both ends of the rotating sealing plate. Multiple arc-shaped grooves are opened on one side of the rubber blocks. Multiple arc-shaped protrusions are fixedly installed on the inner wall of one side of the fixed blocks. The arc-shaped protrusions cooperate with the arc-shaped grooves. A servo motor is fixedly installed on the top inner wall of the flue gas regulating damper. Half gear II and half gear I are fixedly fitted onto the outer wall of the output shaft of the servo motor. A spur gear I is fixedly fitted onto the outer wall of the rotating shaft. A rack, spur gear I, and half gear I are slidably connected to the bottom inner wall of the flue gas regulating damper. I. All mesh with the rack and pinion. A fixing block is fixedly installed on the bottom inner wall of the flue gas regulating damper. A compression spring is set between one side of the fixing block and one end of the rack. Both ends of the compression spring are fixed to one side of the fixing block and one end of the rack through spring seats. A lead screw is rotatably connected to the inner wall of the flue gas regulating damper through a bearing seat. A spur gear II is fixedly sleeved on the outer wall of the lead screw. The spur gear II meshes with the half gear II. A connecting plate is slidably connected between the inner walls of the two sides of the flue gas regulating damper. Limiting strip plates are fixedly installed on both sides of the top of the connecting plate. Two strip holes II are opened inside the flue gas regulating damper. The top of the limiting strip plate slides through the strip hole II. The side of the limiting strip plate abuts against the side of the rotating sealing plate. The thread of the lead screw passes through the connecting plate.

[0009] A method for regulating the opening degree of a ventilation valve for smoke exhaust at the limit flow rate in a tunnel fire includes the following steps:

[0010] S1. Establish a database of damper opening degree, local resistance coefficient, and flue gas velocity.

[0011] By combining CFD (Computational Fluid Dynamics) simulations and model tests on the influence of smoke exhaust air volume in various tunnel fire scenarios, the smoke velocity and local resistance coefficient of each smoke exhaust port under different valve openings are obtained to form a database for use after a fire occurs, ensuring that the optimal parameters can be quickly retrieved during a fire.

[0012] S2. Determine the exhaust air volume and damper opening sequence.

[0013] Based on monitoring data from fire temperature sensors, smoke concentration sensors, and wind speed sensors, the maximum heat release rate of the fire source in the actual fire scenario is predicted, and the required smoke exhaust air volume is calculated. Based on the fire location and smoke diffusion, the opening sequence of the exhaust valve under the extreme flow control mode is preliminarily determined to achieve rapid response.

[0014] S3. Determine the limit flow rate and damper opening for each flue gas emission outlet.

[0015] Based on the theory of limit flow control, the maximum volumetric flow rate and the remaining volumetric flow rate of each flue gas emission outlet are determined, and the database is called to determine the opening degree of each damper.

[0016] S4. Dynamically Adjustable Air Valve Opening and Closing Sequence

[0017] The control unit adjusts the opening degree and opening / closing sequence of the dampers in real time based on the calculation results to ensure efficient exhaust of flue gas.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. The damper opening control device for tunnel fire smoke exhaust at maximum flow rate disclosed in this invention uses a servo motor to drive half-gear I and half-gear II to rotate, achieving an orderly action of first lowering and unlocking the limiting strip plate and then driving the rotating sealing plate to rotate. This allows for flexible adjustment of the damper opening based on the actual smoke volume, ensuring the smoke exhaust flow rate is within a reasonable range and avoiding problems such as untimely smoke exhaust or fire spread due to improper opening. Simultaneously, the compression spring provides buffering during adjustment, reducing wear on transmission components and improving the smoothness of the adjustment process. Furthermore, the rubber blocks at both ends of the rotating sealing plate cooperate with the fixed stops, and the arc-shaped grooves and arc-shaped protrusions abut against each other, forming a multi-layer sealing structure. This enhances the sealing performance of the damper in the closed state, preventing smoke leakage from the closed damper and ensuring the overall smoke exhaust efficiency of the system. In addition, the upward movement of the limiting strip plate limits the rotating sealing plate, further ensuring the sealing stability of the closed portion of the rotating sealing plate.

[0020] 2. The smoke valve opening control device for extreme flow smoke exhaust in tunnel fires disclosed in this invention uses a servo motor-driven linkage structure for the smoke regulating valve, which can achieve precise control of the valve opening, accurately control the smoke flow angle and flow area, reduce the turning resistance loss when the smoke flows from the tunnel to the smoke exhaust channel, and improve the smoke flow rate; the smoke exhaust volume can be dynamically adjusted according to parameters such as the fire source location and heat release rate; whether it is a car fire, a medium-sized bus fire, or a heavy truck fire, the optimal smoke exhaust effect can be achieved through parameter adjustment, solving the problem of poor adaptability of existing fixed valves or simple adjustment methods.

[0021] 3. The damper opening control device for tunnel fire smoke exhaust at extreme flow rates disclosed in this invention features an inclined design on the inner wall of the bottom of the smoke exhaust channel. Combined with the ash discharge hole, ash discharge channel, and dust collection box, after a fire, the sealing block can be retracted by activating an electric push rod, allowing filtered impurities and dust to slide down the inclined surface into the dust collection box for collection. This structure eliminates the need for manual entry into the smoke exhaust channel for cleaning, reducing the labor intensity and danger of cleaning work. It also prevents blockage of the smoke exhaust channel due to impurity accumulation, ensuring the long-term stable operation of the smoke exhaust system. A servo motor simultaneously drives half-gear I and half-gear II, achieving the movement of the limiting strip plate and rotating sealing plate through the cooperation of the gear and rack screw. The transmission path is clear, reducing the number of transmission components and lowering the probability of failure. A fixed stop limits the rotation range of the rotating sealing plate, preventing excessive rotation and component damage, further extending the device's service life.

[0022] 4. The damper opening control device for tunnel fire smoke exhaust at extreme flow rates disclosed in this invention features a detachable filter screen on one side of the mounting frame, facilitating regular disassembly, cleaning, or replacement to ensure filtration efficiency. The dust collection box is placed through a rectangular hole, and the side door facilitates the removal and cleaning of collected impurities, reducing maintenance costs. The temperature sensor monitors the temperature within the smoke exhaust channel in real time, providing data for damper opening adjustment and enhancing the intelligence level of the smoke exhaust system.

[0023] 5. The method for regulating the opening of dampers in tunnel fire smoke exhaust at extreme flow rates disclosed in this invention achieves a significant improvement in smoke exhaust efficiency and a comprehensive enhancement of system adaptability by dynamically adjusting the damper opening. Regarding efficiency improvement, based on the theory of "extreme flow rate regulation of smoke," the system precisely allocates flow according to the negative pressure attenuation equation, opening the damper at the smoke exhaust port closest to the fire source, and only opening necessary dampers to avoid redundant suction at distant locations; the synchronous opening adjustment of the valve plates guides the smoke flow parallel into the smoke exhaust channel, reducing turning resistance losses; data from the embodiments show that the extreme flow rate mode reduces the amount of smoke near the fire source, effectively curbing the long-distance spread of smoke and the risk of settling.

[0024] 6. The method for regulating the opening degree of the damper for smoke exhaust at the limit flow rate in tunnel fires disclosed in this invention has the following advantages in terms of adaptability: a multi-sensor network (fire temperature sensor, smoke concentration sensor, wind speed sensor) collects data in real time and supports dynamic switching of regulation modes (limit flow rate, uniform flow rate, etc.) using PID or fuzzy control algorithms, ensuring robustness under different fire scenarios; the different opening degree configurations of single-pressure and dual-pressure smoke exhaust in the embodiments verify the stability of the system in variable environments. These effects work together to make the device efficient, economical, and reliable in complex tunnel environments.

[0025] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0027] Figure 1 This is a three-dimensional structural schematic diagram of the damper opening control device for tunnel fire smoke exhaust at extreme flow rates according to the present invention.

[0028] Figure 2 This is a schematic diagram of the installation of the flue gas regulating damper in the flue gas discharge channel in this invention;

[0029] Figure 3 This is a three-dimensional sectional view of the main tunnel section in this invention;

[0030] Figure 4 This is an assembly diagram of the mounting frame and the tunnel body in this invention;

[0031] Figure 5 This is an assembly diagram of the filter screen and mounting frame in this invention;

[0032] Figure 6 This is a three-dimensional view of the flue gas regulating valve in this invention;

[0033] Figure 7 This is a three-dimensional sectional view of the flue gas regulating valve in this invention;

[0034] Figure 8 This is an assembly diagram of the rotating sealing plate and the fixed stop block in this invention;

[0035] Figure 9 This is a schematic diagram of horizontal smoke exhaust according to an embodiment of the present invention;

[0036] Figure 10(a) is a comparison chart of the smoke exhaust efficiency of different damper control modes under single-pressure smoke exhaust according to the present invention. Figure 10 (b) is a comparison diagram of the amount of flue gas in the tunnel under different valve control modes under single-pressure flue gas exhaust according to the present invention;

[0037] Figure 11 (a) is a comparison chart of the smoke exhaust efficiency of different damper control modes under dual-pressure smoke exhaust according to the present invention. Figure 11 (b) is a comparison diagram of the amount of smoke in the tunnel under different air valve control modes under the dual-pressure smoke exhaust of the present invention.

[0038] In the diagram: 1. Tunnel main body; 2. Side door panel; 4. Flue gas regulating damper; 5. Flue gas exhaust channel; 6. Dust collection box; 7. Ash discharge hole; 8. Strip hole I; 9. Ash discharge channel; 10. Rectangular hole; 11. Regulating damper slot; 12. Flue gas ventilation duct; 13. Flue gas exhaust port; 15. Mounting frame; 18. Electric push rod; 19. Sliding block; 20. Sealing block; 22. Filter screen; 23. Smoke exhaust fan; 24. Temperature sensor; 25. Rotating sealing plate; 26. Limiting strip plate; 27. Strip hole II; 28. Connecting plate; 29. ​​Fixing block; 30. Compression spring; 31. Spur gear I; 32. Half gear I; 33. Half gear II; 34. Spur gear II; 35. Rack; 36. Lead screw; 37. Servo motor; 38. Rotating shaft; 39. Fixing block; 40. Rubber block; 41. Arc groove; 42. Arc protrusion. Detailed Implementation

[0039] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0040] like Figure 1-2 The damper opening control device for the tunnel fire limit flow smoke exhaust shown is integrally assembled inside the tunnel body 1. Specifically, a smoke exhaust channel 5 is opened in the middle of the tunnel body 1, and multiple smoke exhaust ports 13 are machined on the top inner wall of the tunnel body 1. The smoke exhaust ports 13 are evenly distributed along the length of the tunnel body 1. Figure 3As shown, multiple flue gas ventilation ducts 12 are machined inside the tunnel body 1 at the top position corresponding to the flue gas emission port 13. The flue gas ventilation ducts 12 correspond one-to-one with the flue gas emission port 13 and are connected to each other, so as to introduce flue gas from inside the tunnel body 1 into the flue gas ventilation ducts 12. Multiple regulating valve slots 11 are machined on both sides of the inner wall of the flue gas discharge channel 5. The regulating valve slots 11 correspond one-to-one with the flue gas ventilation ducts 12 and are connected to each other. Flue gas regulating valves 4 are fixedly installed inside the regulating valve slots 11. The flue gas regulating valves 4 are used to control the opening and closing between the flue gas ventilation ducts 12 and the flue gas discharge channel 5. The flue gas regulating valves 4 are equipped with adjustment components for controlling the valve opening.

[0041] like Figure 7 As shown, the adjustment assembly includes a rotating shaft 38 that rotates through the inside of the smoke regulating damper 4. A rotating sealing plate 25 is fixedly fitted onto the outer wall of the rotating shaft 38. The rotating sealing plate 25 is made of high-temperature resistant stainless steel, which can adapt to the high-temperature environment in a fire scenario. Fixed blocks 39 are fixedly installed on the inner walls of both sides of the smoke regulating damper 4. The two fixed blocks 39 are centrally symmetrically arranged and located on both sides of the rotating sealing plate 25. Rubber blocks 40 are fixedly installed at both ends of the rotating sealing plate 25. The rubber blocks 40 are made of fluororubber, which has excellent high-temperature resistance and sealing performance. Figure 8 As shown, multiple arc-shaped grooves 41 are machined on one side of the rubber block 40, and multiple arc-shaped protrusions 42 are fixedly installed on the inner wall of one side of the fixed stop block 39. The arc-shaped protrusions 42 and the arc-shaped grooves 41 work together to enhance the sealing effect between the rotating sealing plate 25 and the fixed stop block 39. In order to realize the driving and limiting of the rotating sealing plate 25, a servo motor 37 is fixedly installed on the top inner wall of the flue gas regulating damper 4. Half gear II 33 and half gear I 32 are fixedly sleeved on the outer wall of the output shaft of the servo motor 37, and a spur gear I 31 is fixedly sleeved on the outer wall of the rotating shaft 38. A rack 35 is slidably connected to the bottom inner wall of the flue gas regulating damper 4. Both the spur gear I 31 and the half gear I 32 mesh with the rack 35. A fixing block 29 is fixedly installed on the bottom inner wall of the flue gas regulating damper 4. A distance is set between one side of the fixing block 29 and one end of the rack 35. There is a common compression spring 30. Both ends of the compression spring 30 are fixed to one side of the fixed block 29 and one end of the rack 35 through spring seats. The inner wall of the flue gas regulating valve 4 is rotatably connected to the lead screw 36 through the bearing seat. The outer wall of the lead screw 36 is fixedly sleeved with a spur gear II 34. The spur gear II 34 meshes with the half gear II 33. The same connecting plate 28 is slidably connected between the inner walls of the two sides of the flue gas regulating valve 4. The two sides of the connecting plate 28 are fixedly installed with sliders. The inner walls of the two sides of the flue gas regulating valve 4 are provided with sliding grooves. The sliders and sliding grooves are slidably connected.

[0042] like Figure 6As shown, limiting strip plates 26 are fixedly installed on both sides of the top of the connecting plate 28. Two strip holes II 27 are machined inside the flue gas regulating valve 4. The top of the limiting strip plate 26 slides through the strip hole II 27, and the side of the limiting strip plate 26 abuts against the side of the rotating sealing plate 25. The screw rod 36 is threaded through the connecting plate 28. During the opening process of the flue gas regulating valve 4, the servo motor 37 is started. The output shaft of the servo motor 37 drives the half gear I 32 and half gear II 33 to rotate. At this time, half gear I 32 is not in contact with the rack 35. Half gear II 33 first drives the spur gear II 34 to rotate, which in turn drives the screw rod 36 to rotate. The screw rod 36 drives the connecting plate 28 to move downwards, and the connecting plate 28 drives the limiting strip plate 26 to move downwards out of the strip hole II 27, thus unlocking the rotating sealing plate 25. Subsequently, half gear II 33 disengages from the spur gear II 34, and half gear I 32 begins to contact the rack 35. Half gear I 32 drives the rack 35 to move laterally. When the rack 35 moves, it drives the spur gear I 31 to rotate and compresses the spring 30. The spur gear I 31 drives the rotating shaft 38 to rotate, and the rotating shaft 38 drives the rotating sealing plate 25 to rotate. This changes the opening of the air valve according to the actual situation. The mutual contact between the arc groove 41 and the arc protrusion 42 can achieve multi-layer sealing. After the adjustment is completed, the servo motor 37 reverses, the compression spring 30 resets and drives the rack 35 to move back. The half gear II 33 meshes with the spur gear II 34 again, driving the connecting plate 28 to move upward. The limiting strip plate 26 moves upward to limit the rotating sealing plate 25 and ensure the sealing of the other unopened parts of the rotating sealing plate 25.

[0043] A dust collection assembly is installed on one side of the bottom of the flue gas exhaust channel 5. A mounting frame 15 is fixedly installed at one end of the flue gas exhaust channel 5, and a smoke exhaust fan 23 is fixedly installed inside the mounting frame 15. A fire temperature sensor 24, a smoke concentration sensor, and a wind speed sensor are installed in the main passageway within the tunnel body 1 to provide data for adjusting the opening of the air valve; such as Figure 5 As shown, a filter screen 22 is detachably connected to one side of the mounting frame 15 by multiple screws. The filter screen 22 is made of stainless steel wire mesh, which has good high temperature resistance and filtration performance, and can initially intercept large particulate impurities in flue gas.

[0044] like Figure 4As shown, the collection assembly includes an ash discharge hole 7 located on one side of the bottom of the flue gas discharge channel 5. A connected ash discharge channel 9 is machined at the bottom of the ash discharge hole 7, and a rectangular hole 10 is machined at the bottom of the ash discharge channel 9. A dust collection box 6 is placed inside the rectangular hole 10. Side door panels 2 are hinged to both sides of the rectangular hole 10, which can shield the rectangular hole 10 and reduce flue gas leakage. A connected strip-shaped hole I8 is machined on the top inner wall of the ash discharge hole 7. An electric push rod 18 is fixedly installed on one side of the inner wall of the strip-shaped hole I8. A slider 19 is slidably connected to the inner wall of the strip-shaped hole I8. A sealing block 20 is fixedly installed at the bottom of the slider 19, sealing the ash discharge hole 7. The piston rod of the electric push rod 18 is fixedly connected to one side of the slider 19. The bottom inner wall of the flue gas discharge channel 5 is inclined, which can guide dust to slide down towards the ash discharge hole 7. During fire smoke extraction, the sealing block 20 keeps the ash discharge hole 7 sealed to prevent smoke from escaping. After the fire, the electric push rod 18 is activated. The piston rod of the electric push rod 18 drives the slider 19 and the sealing block 20 to retract. The sealing block 20 no longer seals the ash discharge hole 7. At this time, the filtered impurities and dust slide down the bottom slope of the smoke discharge channel 5 and enter the interior of the ash discharge channel 9. They are then sent to the interior of the dust collection box 6 for collection. After collection, the dust collection box 6 can be removed for cleaning by opening the side door panel 2. This device requires regular maintenance, including: regularly checking and cleaning the smoke and dust impurities in the sealing cavity and the dustproof and heat-insulating sleeve; regularly applying grease to the transmission components such as the lead screw 36, guide rod, and rack 35 to ensure smooth transmission; regularly checking the wear of the rubber block 40 and the sealing cavity seals, and replacing them in time if they are aged or damaged; and regularly cleaning the filter screen 22 and the dust collection box 6 to ensure smoke extraction and dust collection effects.

[0045] When a fire occurs at a certain location inside the tunnel body 1, the smoke cannot be discharged quickly. At this time, the corresponding smoke regulating valve 4 is opened, and the smoke exhaust fan 23 is started. The smoke exhaust fan 23 draws the smoke into the smoke exhaust channel 5. The smoke enters the smoke flow ventilation duct 12 through the smoke exhaust port 13, and then enters the regulating valve slot 11 through the smoke flow ventilation duct 12, and finally enters the smoke exhaust channel 5. Due to the negative pressure generated by the start of the smoke exhaust fan 23, the smoke can be discharged smoothly through one end of the smoke exhaust channel 5, and is initially filtered by the filter screen 22. After the fire is over, the smoke exhaust fan 23 is turned off.

[0046] This device also includes a PLC controller, which is electrically connected to the servo motor 37, electric push rod 18, exhaust fan 23, temperature sensor 24, smoke concentration sensor, and wind speed sensor. The PLC controller has a pre-stored database of damper opening, local resistance coefficient, and flue gas velocity. It can receive real-time temperature signals from the temperature sensor 24 and control the start, stop, and forward / reverse rotation of the servo motor 37 according to a preset program to adjust the damper opening, control the extension and retraction of the electric push rod 18 to open and close the ash discharge hole 7, and control the start and stop of the exhaust fan 23 to adjust the smoke exhaust intensity, thus achieving coordinated operation of all components.

[0047] A sealing strip is provided between the limiting strip plate 26 and the strip hole II 27 to prevent smoke and dust from entering the transmission gap.

[0048] The working principle of the smoke exhaust valve opening control device for the tunnel fire limit flow is as follows: If a fire occurs at a certain location inside the tunnel body 1 and the smoke cannot be discharged quickly, the corresponding smoke regulating valve 4 can be opened and the smoke exhaust fan 23 can be started. The smoke exhaust fan 23 draws the smoke into the smoke exhaust channel 5. The smoke enters the smoke flow ventilation duct 12 through the smoke exhaust port 13, then enters the regulating valve slot 11 through the smoke flow ventilation duct 12, and finally enters the smoke exhaust channel 5. After preliminary filtration by the filter screen 22, it is discharged through one end of the smoke exhaust channel 5.

[0049] As the exhaust fan 23 starts, it helps to expel the smoke. After the fire, the electric push rod 18 can be activated. The piston rod of the electric push rod 18 drives the slider 19 and the sealing block 20 to retract. The sealing block 20 no longer blocks the ash discharge hole 7. At this time, the filtered impurities and dust slide down the bottom slope of the smoke discharge channel 5 and enter the interior of the ash discharge channel 9, and are sent to the interior of the dust collection box 6 for collection. During the opening of the smoke regulating valve 4, the servo motor 37 is activated. The output shaft of the servo motor 37 drives the half gear I 32 and half gear II 33 to rotate. At this time, half gear I 32 is not in contact with the rack 35. Half gear II 33 first drives the spur gear II 34 to rotate. The spur gear II 34 drives the rack 35 to rotate. The rack 35 drives the lead screw 36 to rotate. The lead screw 36 drives the connecting plate 28 to move downwards, and the connecting plate 28 drives the limiting strip plate 26 to move downwards into the interior of the strip hole II 27. The half gear II 33 disengages from the spur gear II 34, and the half gear I 32 begins to contact the rack 35. The half gear I 32 drives the rack 35 to move laterally, and the rack 35 drives the spur gear I 31 to rotate and squeezes the compression spring 30. The spur gear I 31 drives the rotating shaft 38 to rotate, and the rotating shaft 38 drives the rotating sealing plate 25 to rotate. Thus, the opening degree of the air valve can be changed according to the actual situation. The mutual contact between the arc groove 41 and the arc protrusion 42 achieves multi-layer sealing. Furthermore, by moving the limiting strip plate 26 upwards, the rotating sealing plate 25 can be limited to ensure the sealing of the other unopened parts of the rotating sealing plate 25.

[0050] The method for regulating the opening of the damper based on the limit flow smoke exhaust device in this tunnel fire includes the following steps:

[0051] S1. Establish a database of damper opening degree, local resistance coefficient, and flue gas velocity.

[0052] By combining CFD (Computational Fluid Dynamics) simulations and model tests on the influence of smoke exhaust air volume in various tunnel fire scenarios, the smoke velocity and local resistance coefficient of each smoke exhaust port under different valve openings are obtained to form a database for use after a fire occurs.

[0053] Specifically, the steps include the following:

[0054] S11, CFD Simulation Settings and Parametric Modeling

[0055] A three-dimensional geometric model of the tunnel smoke exhaust system was established using professional CFD software, including the main passage, smoke exhaust channel 5, smoke exhaust outlet 13, and smoke regulating valve 4. The model needs to take into account the actual dimensions and set boundary conditions, such as the heat release rate of the fire source, ambient temperature and wind speed, and combustion materials. Temperature sensor 24, smoke concentration sensor, and wind speed sensor are installed in the main passage.

[0056] To the opening degree θ of the air valve i Discretization is performed within the range of 0 to π / 2 radians (with intervals of 0.1 radians) to simulate the flue gas velocity v at each emission port under different opening degrees. se,i and local drag coefficient ζ sd,i The simulation needs to incorporate turbulence models (such as the k-ε model) and energy conservation equations to accurately capture the flue gas flow characteristics;

[0057] The output includes the pressure distribution, velocity field, and local drag coefficient at each flue gas emission outlet;

[0058] S12, Model Experiment Verification and Data Calibration

[0059] A scaled-down tunnel model was built in the laboratory, and the flue gas velocity and drag coefficient were measured under different valve openings using a hot-wire anemometer and pressure sensor. The test fire source was simulated using a standard burner to ensure consistency with the CFD simulation conditions.

[0060] Data calibration: Compare the experimental results with CFD simulation data, and correct the simulation model through error analysis (e.g., relative error <5%) to improve the reliability of the database.

[0061] S13, Database Construction and Structured Storage

[0062] A relational database is used, and the table fields include the valve opening degree θ. iLocation of flue gas outlet i, flue gas velocity v se,i and v sd,i Local drag coefficient ζ se,i and ζ sd,i And corresponding fire scenario parameters (heat release rate of fire source) Q Ambient temperature T a Ambient wind speed v a The database is integrated into the control unit, supporting real-time queries.

[0063] S2. Determine the exhaust air volume and damper opening sequence.

[0064] Based on monitoring data from fire temperature sensor 24, smoke concentration sensor, wind speed sensor, etc., the maximum heat release rate of the fire source in the actual fire scenario is predicted, and the required smoke exhaust air volume is calculated; based on the fire location and smoke diffusion, the opening sequence of the exhaust valve under the extreme flow control mode is preliminarily determined.

[0065] Specifically, the steps include the following:

[0066] S21, Multi-sensor data acquisition and fusion

[0067] Fire temperature sensors 24, smoke concentration sensors, and wind speed sensors are deployed in the main passageway. These sensors are distributed in an array to cover the potential fire source area, with a sampling frequency of ≥1Hz to ensure real-time performance. Kalman filtering algorithm is used to remove noise, and multi-sensor data is fused to improve the accuracy of fire source location.

[0068] S22. Fire source parameter prediction and smoke exhaust volume calculation

[0069] The maximum heat release rate of the fire source is predicted by using empirical models or machine learning algorithms (such as regression models based on historical data) combined with real-time sensor data to estimate the heat release rate; the minimum required smoke exhaust volume is calculated based on the cross-sectional area of ​​the smoke exhaust channel and the smoke control requirements.

[0070] S23. Preliminary determination of the valve opening sequence

[0071] Based on the "limited flow control mode," the damper at the nearest flue gas emission outlet to the fire source is opened first, and then the flow extends downstream sequentially. The sequence decision considers both the flue gas release rate and the diffusion rate. The sequence is not fixed but is fine-tuned based on the real-time flue gas inventory and can be further optimized through the control unit.

[0072] S3. Determine the limit flow rate and damper opening for each flue gas emission outlet.

[0073] Based on the theory of limit flow control, the maximum volumetric flow rate and the remaining volumetric flow rate of each flue gas emission outlet are determined, and the database is called to determine the opening degree of each damper.

[0074] Specifically, the principle of S31 and limit flow control is as follows:

[0075] Ideally, all smoke from a tunnel fire should be exhausted from the exhaust vent closest to the fire source. However, in actual engineering projects, the randomness of the fire source location makes long-distance smoke spread unavoidable. To improve the overall efficiency of the smoke exhaust system, a damper intervention mechanism is used to allow as much smoke as possible to be exhausted from the exhaust vent closest to the fire source. Any remaining smoke is then exhausted from the next set of exhaust vents, and so on. Based on this flow distribution principle, this is called the "smoke limit flow control" mode under damper action. This mode dynamically controls the mass flow rate of smoke exhausted from each exhaust vent by adjusting the exhaust fan's airflow and the damper opening based on the amount of smoke remaining in the section between each exhaust vent. In this case, we have:

[0076] (1)

[0077] The above formula shows that the mass flow rate m of the flue gas to be discharged from the i-th group of flue gas emission outlets se,i Equal to the residual flue gas mass flow rate m at the (i-1)th group of flue gas emission outlets s,i-1 .

[0078] Converting mass flow rate to volumetric flow rate for calculation, the required flue gas volumetric flow rate V at the i-th flue gas emission outlet is then calculated. se,i and the residual flue gas volume flow rate V at the flue gas emission outlet of the (i-1)th group s,i-1 The following relationship must be satisfied:

[0079] (2)

[0080] If the remaining flue gas volume flow rate V at the flue gas emission outlet of the (i-1)th group is s,i-1 The volumetric flow rate V of the flue gas to be discharged from the i-th group of flue gas emission outlets se,i If the above formula is satisfied, then all the flue gas in the flue gas emission outlet section will be discharged. Conversely, if the actual flue gas mass flow rate of the i-th group of flue gas emission outlets does not meet the requirements, the flue gas still needs to be discharged to the next group of flue gas emission outlets. Where ρ s,i-1 and T s,i-1 Let ρ be the density and temperature of the remaining flue gas at the (i-1)th group of flue gas emission outlets, respectively. se,i and T se,i and represent the density and temperature of the flue gas emitted from the i-th group of flue gas emission outlets, respectively.

[0081] In the above-mentioned flue gas limit flow control mode, the volumetric flow rate V of the flue gas discharged from each flue gas emission port se,i The exhaust air volume V of the exhaust fan can be used as a reference. f and the opening degree θ of the flue gas exhaust valve i Solving for parameters such as the number of times to open (n), i.e.:

[0082] (3)

[0083] S32. The method for determining the opening degree of the flue gas exhaust valve is as follows: For the volumetric flow rate V of the flue gas discharged from each flue gas exhaust port... se,i Angle θ with air valve i Based on the relationship between the opening direction of the damper and the direction of the smoke flow, we have:

[0084] (4)

[0085] In the formula: a is the length of the flue gas emission outlet; h is the height of the damper.

[0086] For the volumetric flow rate V of the flue gas discharged from each flue gas outlet se,i With the exhaust air volume V of the exhaust fan f Based on the relationship between the negative pressure attenuation law along the longitudinal length of the flue gas discharge channel and fluid mechanics theory, we have:

[0087] (5)

[0088] In the formula: P x P represents the negative pressure at position x within the flue gas exhaust channel. f For negative pressure of the smoke exhaust fan; λ sd ζ is the friction coefficient along the flue gas exhaust channel; l D is the local resistance coefficient of the flue gas exhaust passage per unit length; sd ρ is the equivalent diameter of the flue gas exhaust channel. s v represents the density of the flue gas within the flue gas exhaust channel. f The smoke velocity at the exhaust fan.

[0089] Among them, the local resistance coefficient ζ of the flue gas exhaust passage per unit length l Local resistance coefficient ζ of flue gas emission outlet passage sd,i The local resistance coefficient of the flue gas emission outlet passage is related to the velocity ratio and the valve opening degree, that is:

[0090] (6)

[0091] ,

[0092] Therefore, by solving the simultaneous equations, we can obtain the opening degree θ of any damper. i The lower smoke flow velocity v se,i for:

[0093] (7)

[0094] At this point, it is only necessary to determine the opening degree θ of different air valves.i Resistance coefficient ζ per unit length of flue gas exhaust channel l The value of (which can be obtained through fluid dynamics simulation and model tests to obtain pressure and flue gas velocity under different valve openings, and calculated according to the energy conservation equation) can be used to solve for the valve opening under a given flue gas discharge volume flow rate.

[0095] S33. Determination of the limit flow rate and damper opening at each flue gas emission outlet.

[0096] ① For the volumetric flow rate V of the flue gas discharged from the first group of flue gas emission outlets se,1 The value should be equal to the maximum volumetric flow rate that can be achieved at this flue gas emission outlet; this is the problem of finding the maximum value.

[0097] make ,So The extreme values ​​are determined by differentiation.

[0098] (8)

[0099] make If in If there are multiple solutions within the range, perform the following steps:

[0100] a. Verify and obtain the solution Both sides The positive or negative sign of a property is determined by its left neighbor. And the right neighbor When that is, it is the maximum possible value.

[0101] b. Verify endpoint values: when , ;when , .

[0102] c. Compare the obtained function value with the endpoint values. ,but This represents the maximum flow rate of the first group of flue gas emission outlets, and vice versa.

[0103] Therefore, the volumetric flow rate V of the flue gas discharged from the first group of flue gas outlets under the limit flow mode control can be obtained. se,1 And the corresponding damper opening θ1.

[0104] ② For the volumetric flow rate V of the flue gas discharged from the second group of flue gas emission outlets se,2 The remaining flow rate of flue gas that has passed through the first set of flue gas emission outlets but has not yet been discharged from the tunnel should be considered. Therefore:

[0105] (9)

[0106] In the formula: Vse It is the total volumetric flow rate of the flue gas generated by the fire source; V ρ,12 The volumetric flow rate of the smoked gas caused by the density difference due to temperature decay between the first and second group of flue gas emission outlets.

[0107] In this case, it is still necessary to determine the maximum volumetric flow rate of the second group of flue gas emission outlets. Therefore, the maximum volumetric flow rate V of the second group is obtained by the extreme value method. se,2，max and the corresponding damper opening θ 2，max However, it is necessary to determine whether all the remaining smoke can be discharged.

[0108] a. When V se,2 >V se,2，max If the maximum volumetric flow rate of the second group of flue gas emission outlets is still insufficient to discharge all the remaining flue gas, the downstream third group of flue gas emission outlets needs to continue discharging flue gas. The maximum volumetric flow rate V of the second group should be used. se,2，max The corresponding damper opening θ 2，max .

[0109] b. When V se,2 ≤V se,2，max At that time, the second group of flue gas emission outlets is sufficient to discharge all the remaining flue gas, so the remaining volumetric flow rate V of the second group should be taken. se,2 The corresponding damper opening θ2.

[0110] ③ For the third group of flue gas emission outlets, the control method is the same as for the second group, based on the remaining flow rate. The remaining groups follow the same principle. When the preceding flue gas emission outlet can effectively discharge all flue gas, the following flue gas emission outlets should be closed to reduce exhaust energy loss.

[0111] S4. Dynamically Adjustable Air Valve Opening and Closing Sequence

[0112] The control unit adjusts the opening degree and opening and closing sequence of the damper in real time according to the calculation results to ensure efficient exhaust of flue gas. The damper adjustment process can be optimized by using PID control algorithm or fuzzy control algorithm to improve the response speed.

[0113] Specifically, the steps include the following:

[0114] S41, Control Unit Architecture and Real-Time Data Processing

[0115] The control unit employs a PLC embedded system, processing a data stream once per second, including valve opening feedback, flue gas flow rate, and pressure readings; it integrates a database query module to compare the target flue gas velocity V in real time. se,i Based on the actual value, generate adjustment instructions;

[0116] S42, Control Algorithm Optimization

[0117] The damper adjustment process is optimized by using PID control algorithm or fuzzy control algorithm. The control unit supports mode switching. PID is used to ensure stability during low fire and fuzzy control is switched to enhance adaptability during high fire.

[0118] S43, Control Unit Architecture and Real-Time Data Processing

[0119] Monitor the flue gas volume at each emission outlet. If the i-th group of emission outlets cannot handle the remaining flow, automatically open the (i+1)-th group of dampers; otherwise, close the downstream dampers to reduce energy loss. Include over-limit protection, such as damper opening limits and motor overload detection, to ensure system reliability.

[0120] Single-pressure smoke extraction relies on a single exhaust fan located at the end of the smoke exhaust channel. The negative pressure generated by the fan draws in smoke by attenuating it longitudinally along the exhaust channel. The exhaust valve control depends on a single negative pressure source, with the negative pressure gradient decreasing from the fan location towards the heat source. Dual-pressure smoke extraction uses two fans working in tandem, one upstream and one downstream of the exhaust channel, creating bidirectional negative pressure suction. Structurally, this requires an additional upstream fan and matching valve, increasing system complexity, but it reduces the negative pressure attenuation distance. Flow balance is achieved through bidirectional negative pressure coordination. The combined action of the upstream and downstream fans reduces negative pressure fluctuations within the exhaust channel, resulting in a more uniform flow distribution at each exhaust port.

[0121] Single-pressure smoke extraction is suitable for shorter tunnels or scenarios with relatively fixed fire sources, and it has lower costs but poor control and fault tolerance. Dual-pressure smoke extraction is more suitable for long tunnels, complex environments with multiple fire source risks, or large gradient changes, and enhances the system's robustness through bidirectional negative pressure.

[0122] Figure 9 This is a schematic diagram of transverse smoke exhaust in an embodiment. Taking a heat release rate of 50MW from the fire source as an example, the opening degree of the air valve at each flue gas emission outlet under the limit flow control is calculated, and the smoke exhaust efficiency and the amount of flue gas in the tunnel are compared under single-pressure and dual-pressure smoke exhaust modes with no air valve, equal opening, uniform flow and limit flow modes to verify its performance.

[0123] Smoke exhaust operating condition table under damper opening control

[0124]

[0125] Figure 10 , Figure 11 The results show that the baseline smoke exhaust efficiency under single-pressure and dual-pressure valveless conditions is 74.9% and 88.5%, respectively. The extreme smoke flow control mode can improve the total smoke exhaust efficiency by about 9% and 6%, respectively, and reduce the amount of smoke within 130m of the fire source by about 48% and 13%, respectively.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A damper opening control device for extreme flow smoke exhaust in tunnel fires, characterized in that, This includes a flue gas exhaust channel (5) located in the middle of the tunnel body (1), multiple flue gas exhaust ports (13) connected to the flue gas exhaust channel (5) and located at the top of the tunnel body (1), and multiple regulating valve slots (11) evenly distributed on the inner wall of the flue gas exhaust channel (5). A flue gas regulating valve (4) is fixedly installed inside the regulating valve slot (11), and an adjustment component for controlling the valve opening is provided inside the flue gas regulating valve (4). The adjustment component includes a rotating component that passes through the flue gas... The regulating damper (4) has a rotating shaft (38) inside. The outer wall of the rotating shaft (38) is fixedly fitted with a rotating sealing plate (25). The top inner wall of the flue gas regulating damper (4) is fixedly installed with a servo motor (37). The outer wall of the output shaft of the servo motor (37) is fixedly fitted with a half gear II (33) and a half gear I (32). The outer wall of the rotating shaft (38) is fixedly fitted with a spur gear I (31). The bottom inner wall of the flue gas regulating damper (4) is slidably connected with a rack (35), a spur gear I (31) and a half gear I (32). 32) All mesh with the rack (35). A fixing block (29) is fixedly installed on the bottom inner wall of the flue gas regulating valve (4). The same compression spring (30) is set between the fixing block (29) and the rack (35). Both ends of the compression spring (30) are fixed to one side of the fixing block (29) and one end of the rack (35) through spring seats. The inner wall of the flue gas regulating valve (4) is rotatably connected to the lead screw (36) through the bearing seat. The outer wall of the lead screw (36) is fixedly sleeved with a spur gear II (34). The spur gear II (34) 4) It meshes with half gear II (33). The same connecting plate (28) is slidably connected between the inner walls of the two sides of the flue gas regulating valve (4). Limiting strip plates (26) are fixedly installed on both sides of the top of the connecting plate (28). Two strip holes II (27) are opened inside the flue gas regulating valve (4). The top of the limiting strip plate (26) slides through the strip hole II (27). The side of the limiting strip plate (26) abuts against the side of the rotating sealing plate (25). The screw (36) threaded through the connecting plate (28).

2. The damper opening control device for tunnel fire smoke exhaust at maximum flow rate as described in claim 1, characterized in that, The flue gas regulating valve (4) has fixed blocks (39) fixedly installed on both sides of the inner wall. The two fixed blocks (39) are centrally symmetrical and located on both sides of the rotating sealing plate (25). Rubber blocks (40) are fixedly installed at both ends of the rotating sealing plate (25). Multiple arc grooves (41) are opened on one side of the rubber block (40). Multiple arc protrusions (42) are fixedly installed on one side of the inner wall of the fixed block (39). The arc protrusions (42) and the arc grooves (41) are used in conjunction.

3. The damper opening control device for tunnel fire smoke exhaust at maximum flow rate as described in claim 1, characterized in that, A dust collection assembly is provided on one side of the bottom of the flue gas discharge channel (5). The collection assembly includes a dust discharge hole (7) opened on one side of the bottom of the flue gas discharge channel (5). A connected dust discharge channel (9) is opened at the bottom of the dust discharge hole (7). A rectangular hole (10) is opened at the bottom of the dust discharge channel (9). A dust collection box (6) is placed inside the rectangular hole (10). Side door panels (2) are hinged on both sides of the rectangular hole (10). A connected strip hole I (8) is opened on the inner wall of the top of the dust discharge hole (7). An electric push rod (18) is fixedly installed on one side of the inner wall of the strip hole I (8). A slider (19) is slidably connected to the inner wall of the strip hole I (8). A sealing block (20) is fixedly installed at the bottom of the slider (19). The sealing block (20) seals the dust discharge hole (7). The piston rod of the electric push rod (18) is fixedly connected to one side of the slider (19). The bottom inner wall of the flue gas discharge channel (5) is inclined.

4. The damper opening control device for tunnel fire smoke exhaust at maximum flow rate as described in claim 1, characterized in that, The flue gas exhaust channel (5) is fixedly installed with a mounting frame (15) at one end. A smoke exhaust fan (23) is fixedly installed inside the mounting frame (15). A filter screen (22) is detachably connected to one side of the mounting frame (15) by multiple screws.

5. A method for regulating the opening of a damper based on the damper opening regulation device for tunnel fire smoke exhaust at the limit flow rate according to claim 1, characterized in that, Includes the following steps: S1. Establish a database of damper opening degree, local resistance coefficient, and flue gas velocity. By combining CFD (Computational Fluid Dynamics) simulations and model tests on the influence of smoke exhaust air volume in various tunnel fire scenarios, the smoke velocity and local resistance coefficient of each smoke exhaust port under different valve openings are obtained to form a database for use after a fire occurs, ensuring that the optimal parameters can be quickly retrieved during a fire. S2. Determine the exhaust air volume and damper opening sequence. Based on the monitoring data from the fire temperature sensor (24), smoke concentration sensor, and wind speed sensor, the maximum heat release rate of the fire source in the actual fire scenario is predicted, and the required smoke exhaust air volume is calculated. Based on the fire location and smoke diffusion, the opening sequence of the exhaust valve under the extreme flow control mode is initially determined to achieve rapid response. S3. Determine the limit flow rate and damper opening for each flue gas emission outlet. Based on the theory of limit flow control, the maximum volumetric flow rate and the remaining volumetric flow rate of each flue gas emission outlet are determined, and the database is called to determine the opening degree of each damper. S4. Dynamically Adjustable Air Valve Opening and Closing Sequence The control unit adjusts the opening degree and opening / closing sequence of the dampers in real time based on the calculation results to ensure efficient exhaust of flue gas.

6. The method for regulating the opening degree of the ventilation valve for smoke exhaust at the limit flow rate in a tunnel fire as described in claim 5, characterized in that, Step S1 specifically includes the following steps: S11, CFD Simulation Settings and Parametric Modeling A three-dimensional geometric model of the tunnel smoke exhaust system was established using CFD software, including the main passageway, smoke exhaust channel (5), smoke exhaust outlet (13), and smoke regulating damper (4); the damper opening θ was adjusted. i Discretization was performed in the range of 0 to π / 2 radians (with an interval of 0.1 radians) to simulate the flue gas velocity and local drag coefficient of each flue gas outlet under different opening degrees; S12, Model Experiment Verification and Data Calibration A scaled-down tunnel model was built in the laboratory, and the flue gas velocity and drag coefficient under different valve openings were measured using a hot-wire anemometer and pressure sensor. The test ignition source was simulated using a standard burner to ensure consistency with the CFD simulation conditions. The test results were compared with the CFD simulation data, and the simulation model was corrected through error analysis to improve the reliability of the database. S13, Database Construction and Structured Storage A relational database is used, and the table fields include the valve opening degree θ. i Location of flue gas outlet i, flue gas velocity v se,i and v sd,i Local drag coefficient ζ se,i and ζ sd,i And corresponding fire scenario parameters (heat release rate of fire source) Q Ambient temperature T a Ambient wind speed v a The database is integrated into the control unit, supporting real-time queries.

7. The method for regulating the opening degree of the ventilation valve for smoke exhaust at the limit flow rate in a tunnel fire as described in claim 5, characterized in that, Step S2 specifically includes the following steps: S21, Multi-sensor data acquisition and fusion Fire temperature sensors (24), smoke concentration sensors, and wind speed sensors are installed in the main passageway. The sensors are distributed in an array to cover the possible fire source area. The sampling frequency is ≥1Hz to ensure real-time performance. Kalman filtering algorithm is used to remove noise and multi-sensor data is fused to improve the accuracy of fire source location. S22. Fire source parameter prediction and smoke exhaust volume calculation The maximum heat release rate of an ignition source is predicted by using empirical models or machine learning algorithms combined with real-time sensor data to estimate the heat release rate. Calculate the minimum required exhaust air volume based on the cross-sectional area of ​​the flue gas exhaust channel and the flue gas control requirements. S23. Preliminary determination of the valve opening sequence Based on the "limit flow control mode", the valve of the nearest flue gas emission outlet to the fire source is opened first, and then the flow extends downstream in sequence; the sequential decision takes into account the amount of flue gas released and the diffusion rate.

8. The method for regulating the opening degree of the ventilation valve for smoke exhaust at the limit flow rate in a tunnel fire as described in claim 5, characterized in that, Step S3 specifically includes the following steps: S31. Determine the principle of limit flow control Smoke gas is preferentially discharged from the smoke exhaust port closest to the heat source, and the remaining smoke gas is discharged from the next set of smoke exhaust ports, and so on. This flow distribution principle is called the "smoke gas limit flow control" mode under the action of the damper, that is: （1） The above formula shows that the mass flow rate m of the flue gas to be discharged from the i-th group of flue gas emission outlets se,i Equal to the residual flue gas mass flow rate m at the (i-1)th group of flue gas emission outlets s,i-1 ; Converting mass flow rate to volumetric flow rate for calculation, the required flue gas volumetric flow rate V at the i-th flue gas emission outlet is then calculated. se,i and the residual flue gas volume flow rate V at the flue gas emission outlet of the (i-1)th group s,i-1 The following relationship must be satisfied: （2） If the remaining flue gas volume flow rate V at the flue gas emission outlet of the (i-1)th group is s,i-1 The volumetric flow rate V of the flue gas to be discharged from the i-th group of flue gas emission outlets se,i If the above formula is satisfied, then all the flue gas in the flue gas emission outlet section will be discharged; conversely, if the actual flue gas mass flow rate of the i-th group of flue gas emission outlets does not meet the requirements, the flue gas still needs to be discharged to the next group of flue gas emission outlets; where ρ s,i-1 and T s,i-1 Let ρ be the density and temperature of the remaining flue gas at the (i-1)th group of flue gas emission outlets, respectively. se,i and T se,i These are the density and temperature of the flue gas discharged from the i-th group of flue gas emission outlets, respectively. In formula (2) of the flue gas limit flow control mode, the volumetric flow rate V of the flue gas discharged from each flue gas outlet is... se,i The exhaust air volume V of the exhaust fan can be used as a reference. f and the opening degree θ of the flue gas exhaust valve i Solving for parameters such as the number of times to open (n), i.e.: （3） S32, Solve for the opening degree of the flue gas exhaust valve. For the volumetric flow rate V of the flue gas discharged from each flue gas outlet se,i Angle θ with air valve i Based on the relationship between the opening direction of the damper and the direction of the smoke flow, we have: （4） In the formula: a is the length of the flue gas emission port; h is the height of the damper; For the volumetric flow rate V of the flue gas discharged from each flue gas outlet se,i With the exhaust air volume V of the exhaust fan f Based on the relationship between the negative pressure attenuation law along the longitudinal length of the flue gas discharge channel and fluid mechanics theory, we have: （5） In the formula: P x The negative pressure at position x in the flue gas exhaust channel; P f For negative pressure of the smoke exhaust fan; λ sd ζ is the friction coefficient along the flue gas exhaust channel; l D is the local resistance coefficient of the flue gas exhaust passage per unit length; sd ρ is the equivalent diameter of the flue gas exhaust channel. s v represents the density of the flue gas within the flue gas exhaust channel. f The smoke velocity at the exhaust fan; Among them, the local resistance coefficient ζ of the flue gas exhaust passage per unit length l Local resistance coefficient ζ of flue gas emission outlet passage sd,i The local resistance coefficient of the flue gas emission outlet passage is related to the velocity ratio and the valve opening degree, that is: （6） ， Therefore, by solving the simultaneous equations, we can obtain the opening degree θ of any damper. i The lower smoke flow velocity v se,i for: （7） Therefore, the opening degree θ of different air valves is determined. i Resistance coefficient ζ per unit length of flue gas exhaust channel l By taking the value of , the opening degree of the damper under a given flue gas volume flow rate at the flue gas outlet can be determined; S33. Determination of the limit flow rate and damper opening at each flue gas emission outlet. S331, For the flue gas volume flow rate V discharged from the first group of flue gas emission outlets se,1 The value should be equal to the maximum volumetric flow rate that this flue gas outlet can achieve; this is a problem of finding the maximum value. S332, For the flue gas volume flow rate V discharged from the second group of flue gas emission outlets se,2 The remaining flow rate of flue gas in the tunnel that has passed through the first set of flue gas emission outlets but has not yet been discharged from the tunnel should be considered. S333. For the third group of flue gas emission outlets, the control method is the same as that for the second group, based on the remaining flow rate. The remaining groups are controlled in the same way. When the front flue gas emission outlet can effectively discharge all the flue gas, the rear flue gas emission outlet should be closed to reduce the energy loss of the flue gas.

9. The method for regulating the opening degree of the ventilation valve for smoke exhaust at the limit flow rate in a tunnel fire as described in claim 5, characterized in that, Step S331 specifically involves: Let ,So The maximum and minimum values ​​are determined by differentiation. （8） make If in If there are multiple solutions within the range, perform the following steps: a. Verify and obtain the solution Both sides The positive or negative sign of a property is determined by its left neighbor. And the right neighbor When that time, it represents the maximum possible value; b. Verify endpoint values: when , ;when , ; c. Compare the obtained function value with the endpoint values. ,but This represents the maximum flow rate of the first group of flue gas emission outlets, and vice versa; Therefore, the volumetric flow rate V of the flue gas discharged from the first group of flue gas outlets under the limit flow mode control is obtained. se,1 And the corresponding damper opening θ1; Step S332 is as follows: （9） In the formula: V se It is the total volumetric flow rate of the flue gas generated by the fire source; V ρ,12 The volumetric flow rate of the smoked gas caused by the density difference due to temperature decay between the first and second group of flue gas emission outlets. In this case, it is still necessary to determine the maximum volumetric flow rate of the second group of flue gas emission outlets. Therefore, the maximum volumetric flow rate V of the second group is obtained by the extreme value method. se,2，max and the corresponding damper opening θ 2，max However, it is necessary to determine whether all the remaining smoke can be discharged. a. When V se,2 >V se,2，max If the maximum volumetric flow rate of the second group of flue gas emission outlets is still insufficient to discharge all the remaining flue gas, the downstream third group of flue gas emission outlets needs to continue discharging flue gas. Therefore, the maximum volumetric flow rate V of the second group should be used. se,2，max The corresponding damper opening θ 2，max ; b. When V se,2 ≤V se,2，max At that time, the second group of flue gas emission outlets is sufficient to discharge all the remaining flue gas, so the remaining volumetric flow rate V of the second group should be taken. se,2 The corresponding damper opening θ2.

10. The method for regulating the opening degree of the ventilation valve for smoke exhaust at the limit flow rate in a tunnel fire as described in claim 5, characterized in that, Step S4 specifically includes the following steps: S41, Control Unit Architecture and Real-Time Data Processing The control unit employs a PLC embedded system, processing a data stream once per second, including valve opening feedback, flue gas flow rate, and pressure readings; it integrates a database query module to compare the target volumetric flow rate V in real time. se,i Based on the actual value, generate adjustment instructions; S42, Control Algorithm Optimization The damper adjustment process is optimized by using PID control algorithm or fuzzy control algorithm. The control unit supports mode switching. PID is used to ensure stability during low fire and fuzzy control is switched to enhance adaptability during high fire. S43, Control Unit Architecture and Real-Time Data Processing Monitor the flue gas volume at each flue gas emission outlet. If the i-th group of flue gas emission outlets cannot handle the remaining flow, automatically open the (i+1)-th group of dampers; otherwise, close the downstream dampers to reduce energy loss.

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