A device for burning and collecting flying spark particles

Abstract

This invention relates to the field of fire experimental equipment technology, specifically to a device for the combustion and collection of flying fire particles. The device includes a combustion unit, a collection unit, and a vibration recovery unit. The combustion unit provides and drives the flying fire particles. The collection unit settles and collects the flying fire particles generated by the combustion unit. The vibration recovery unit collects the flying fire particles falling from the combustion chamber and returns them to the combustion chamber, where they are then collected in the collection unit. This design utilizes a specific two-dimensional Vitósinski profile equation to design the contraction section, enabling the flying fire particles to focus near their axis while allowing for precise airflow control. Coupled with a multi-mechanism settling chamber, it achieves efficient interception and safe extinguishing of flying fire particles of all sizes, forming a closed-loop experimental study. This provides reliable experimental technical support for research on forest fire prevention mechanisms and optimization of engineering solutions.

Description

Technical Field

[0001] This invention relates to the field of fire test equipment technology, specifically to a device for burning and collecting stray fire particles. Background Technology

[0002] Fire, as a complex disaster phenomenon, is characterized by high destructiveness and uncertainty in both forest ecosystems and urban living environments. In forest ecosystems, flying fire particles are a significant factor initiating forest fires and a key technological bottleneck in my country's forest fire prevention and control, playing a crucial role in predicting and controlling forest fire behavior. The formation of flying fire particles is primarily due to strong stratospheric winds at ground level. The flame plume or convection column from the fire field throws these particles into the air, where they are then propagated over long distances by high-altitude horizontal winds. Additionally, fire cyclones can also carry away flying fire particles, thus generating flying embers. The highly random and unreproducible nature of external fire environments makes quantitative research on the mechanisms of flying fire spread impossible. Therefore, researchers have attempted to establish flying fire particle combustion research equipment in the laboratory to describe the combustion process, size and temperature changes of flying fire particles, as well as their potential transmission distance. These parameters can help researchers better understand the movement patterns of flying fire particles, thereby predicting the spread range and speed of forest fires and providing a scientific basis for firefighting efforts.

[0003] Existing equipment for studying the combustion of flying spark particles has technical limitations when conducting experimental research on these particles: 1. It is designed only for room-temperature micron-sized particles, making it difficult to handle high-temperature, millimeter-sized, and combustible flying spark particles. This not only easily leads to safety hazards such as particle adhesion and equipment ignition, but also causes significant errors in experimental data. 2. At the same time, it lacks a targeted particle focusing design, resulting in significant problems with radial diffusion and escape of particles. Under high-volume conditions, particles easily follow the airflow streamlines and the interception efficiency is insufficient to meet experimental requirements. Summary of the Invention

[0004] To address the technical problem that existing flying spark particles generated by research equipment are prone to diffusion and difficult to collect safely and completely, this invention provides a flying spark particle combustion and collection device.

[0005] This invention employs the following technical solution: a device for burning and collecting flying spark particles, comprising a combustion device, a collection device, and a vibration recovery device. The combustion device includes a combustion chamber and a fan; the combustion chamber provides the flying spark particles, and the fan drives the particles. The collection device includes a settling chamber and a converging section located at the end of the combustion chamber along the airflow direction. The converging section includes an inlet end communicating with the combustion chamber and an outlet end communicating with the settling chamber. The cross-sections of the inlet and outlet ends are geometrically similar, with an area ratio of 2 to 6:1. The wall of the converging section, from the inlet to the outlet, is designed based on the Vitósinski curve, and the maximum angle between the tangent of the converging section wall and the airflow direction ranges from 15 to 20°. The converging section provides a stable flow field, allowing the flying spark particles flowing into the combustion chamber to enter the settling chamber along a straight line near the axis of the converging section. The settling chamber is used to collect and settle the flying spark particles entering from the converging section. The vibration recovery device includes a collection plate and a drive assembly. The collection plate is located at the bottom of the combustion chamber and near the inlet end, and is used to collect flying spark particles that fall from the combustion chamber. The drive assembly is used to drive the collection plate to reciprocate along the vertical direction of the combustion chamber, and when the collection plate moves upward, it blows the flying spark particles collected on the collection plate to the contraction section based on the airflow.

[0006] As a further improvement of the present invention, the cross-sections at both the inlet and outlet ends are circular, elliptical, or regular polygons with rounded corners. When both the inlet and outlet cross-sections are regular polygonal structures with rounded corners, each wall surface of the contraction section is designed using the exact same Wittsinski curve.

[0007] As a further improvement of the present invention, the center point of the cross-section where the inlet end is located is set as the origin of the coordinate system, the flow direction of the airflow is the positive x-axis, the direction perpendicular to the airflow is the y-axis, and the horizontal length of the contraction section along the positive x-axis is L; then the two-dimensional Wittsinski profile equation of the cross-section at any point x along the positive x-axis on the contraction section is as follows: ; In the formula: y(x) is the vertical distance from the center point of the contraction section at the axial position x to the boundary of the section; y0 is the vertical distance from the center point of the contraction section at the inlet end to the boundary of the section; y1 is the vertical distance from the center point of the contraction section at the outlet end to the boundary of the section.

[0008] As a further improvement of the present invention, the settling chamber includes a box body, a water tank, and at least two funnels; the box body is connected to the outlet end, and multiple baffles are provided inside the box body; the multiple baffles are arranged sequentially along the length direction of the box body, and one of two adjacent baffles is fixed to the top of the box body and extends downward, while the other baffle is fixed to the bottom of the box body and extends upward; the two funnels are arranged sequentially along the length direction of the box body and are respectively connected to the box body; the outlet of the funnel is connected to the water tank; the flying sparks blocked by the baffles enter the water tank through the funnel under the action of gravity.

[0009] As a further improvement of the present invention, the drive assembly includes a housing, a drive member, and at least one connecting rod. The housing is installed at the bottom of the combustion chamber and communicates with the combustion chamber. The receiving plate covers the upper end of the housing. One end of the connecting rod is fixed to the bottom of the receiving plate, and the other end extends into the housing. A spring is sleeved on the outside of the connecting rod, and the two ends of the spring are respectively connected to the connecting rod and the bottom of the housing. The drive member is used to pull the receiving plate downward until the top surface of the receiving plate is flush with the bottom surface of the combustion chamber while compressing the spring. When separated from the receiving plate, the receiving plate is driven upward based on the spring's restoring deformation until the upper end surface of the spring abuts against the housing.

[0010] As a further improvement of the present invention, the driving component includes a second housing, a motor, a cam, and a roller; the second housing is disposed inside the first housing and fixedly installed on the bottom surface of the storage plate; the cam is rotatably installed inside the second housing and contacts the second housing through the roller; the motor is used to drive the cam to rotate, and when the contact point between the cam and the roller switches from the short axis end of the cam to the long axis end of the cam, the second housing drives the shrink plate to move downward; when the contact point between the cam and the roller switches from the long axis end of the cam to the short axis end of the cam, the spring restores its deformation and drives the shrink plate to move upward.

[0011] As a further improvement of the present invention, the box includes a main body and a connecting part. The two ends of the connecting part are respectively connected to the main body and the outlet end. The main body is a cuboid structure, and the connecting part is a variable diameter structure, the diameter of which gradually increases from the outlet end to the main body.

[0012] As a further improvement of the present invention, the funnel is an inverted pyramidal structure, and two funnels are used to form a W-shaped bottom of the box; a vibrator is installed on the side wall of the funnel, which is used to vibrate the flying sparks on the side wall of the funnel so that they enter the water tank through the outlet of the funnel.

[0013] As a further improvement of the present invention, the ratio of the cross-sectional area of ​​the side of the connecting part connected to the main body to the cross-sectional area of ​​the side of the connecting part connected to the outlet end is 10.24:1.

[0014] As a further improvement to the present invention, the length of the box is 150cm~180cm.

[0015] As a further improvement of the present invention, the combustion chamber, storage plate, shrink section and box body are all made of stainless steel, and each of them is equipped with heat-insulating ceramic plate inside.

[0016] As a further improvement of the present invention, the surface of the baffle is coated with a ceramic coating.

[0017] The technical solution provided by this invention has the following beneficial effects: (1) The fire combustion and collection equipment provided in this scheme limits the area of ​​the inlet and outlet sections of the contraction section and the maximum angle between the tangent of the contraction section wall and the airflow direction. This allows the constructed contraction section to be designed specifically for the fire particle collection requirement. It maintains a uniform pressure gradient throughout the entire process by relying on the continuous and smooth curvature characteristics of the contraction section itself, thereby eliminating boundary layer separation and eddy current phenomena in the contraction section from the root and effectively preventing the spread of fire particles. The multi-mechanism settling chamber is then coupled to achieve efficient interception and safe extinguishing of fire particles of all sizes, so that most of the fire particles can enter the settling chamber along the contraction section, ultimately achieving the purpose of collecting the fire particles. This complete set of equipment can form a closed-loop experimental study of the entire process of fire particle flight, providing reliable experimental technical support for forest fire prevention mechanism research, engineering scheme optimization, and early warning model verification.

[0018] (2) The spark combustion and collection equipment provided in this scheme has a vibration and recirculation device designed at the end of the combustion chamber. This device can be used to collect spark particles that fall to the end of the combustion chamber and recirculate them back to the middle of the end of the combustion chamber through vibration. The spark particles located in the middle of the end of the combustion chamber can enter the contraction section under the drive of the airflow and enter the settling chamber along the contraction section, thereby realizing the collection of spark particles that fall to the end of the combustion chamber, improving the collection effect of spark particles, and thus providing more experimental data for the study of spark particles.

[0019] (3) The flying fire combustion and collection equipment provided in this scheme is designed based on the Vitósinski curve in its constriction section, so that the flying fire particles flowing through it have no separation acceleration characteristics. Moreover, a low-turbulence, undisturbed axial flow field can be constructed through the constriction section, which can eliminate the radial diffusion of flying fire particles as much as possible. This allows the flying fire particles to be concentrated in the core area of ​​the axial jet throughout the constriction section, so that the baffle in the settling chamber can achieve blind-zone-free interception, making the theoretical interception efficiency of flying fire particles close to 100%. It can also avoid the risk of adhesion and ablation caused by the contact between high-temperature flying fire particles and the pipe wall, ensuring the complete recovery of flying fire particles and the accuracy of experimental data. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a spark combustion and collection device provided by the present invention.

[0021] Figure 2 This is an enlarged structural schematic diagram of the contraction section in the fire combustion and collection device provided by the present invention.

[0022] Figure 3 This is an enlarged structural schematic diagram of the settling chamber in the fire combustion and collection device provided by the present invention.

[0023] Figure 4 A schematic diagram of the internal structure of the vibration recovery device in the flying fire combustion and collection equipment provided by the present invention.

[0024] Figure 5 This is a schematic diagram of the internal structure of the vibration recovery device in another state of the flying fire combustion and collection equipment provided by the present invention.

[0025] The following are marked in the diagram: 11. Combustion chamber; 12. Fan; 21. Contraction section; 211. Inlet end; 212. Outlet end; 221. Box body; 222. Water tank; 223. Funnel; 224. Baffle; 225. Main body; 226. Connecting part; 227. Vibrator; 3. Vibration recovery device; 31. Storage plate; 321. Shell one; 322. Connecting rod; 323. Spring; 324. Shell two; 325. Cam; 326. Roller. Detailed Implementation

[0026] The present invention will now be further described in conjunction with specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0027] In the description of this invention, it should be noted that directional terms such as "center," "lateral," "longitudinal," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific scope of protection of this invention. The terms "first," "second," etc., in the specification and claims of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "comprising" and "having," and any variations thereof, in the specification and claims of this invention, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0028] This embodiment provides a device for burning and collecting stray particles, such as... Figure 1 and Figure 2As shown, it includes a combustion device, a collection device, and a vibration recovery device. The combustion device includes a combustion chamber 11 and a fan 12. The combustion chamber 11 has an open structure at both ends. The fan 12 is located on the left side of the combustion chamber 11, and the collection device is connected to the right side of the combustion chamber 11. The combustion chamber 11 is used to simulate the flying embers generated by the burning of pine forests in forest fires. The fan 12 is used to provide wind energy to the combustion chamber 11 and drive the flying embers generated by the combustion chamber 11. This scheme can simulate the entire flight process of flying embers generated by the burning of pine needles or pine wood in forest fires by designing the combustion device. This scheme does not improve the combustion device. Its specific structure can be simulated by existing technology through wind tunnel tests to simulate the natural flight of flying embers. The collection device includes a contraction section 21 and a settling chamber. The contraction section 21 is a hollow structure with an inlet end 211 and an outlet end 212. The inlet end 211 is connected to the right side of the combustion chamber 11, and the outlet end 212 is connected to the settling chamber. The converging section 21 provides a stable flow field, allowing the flying spark particles flowing into the combustion chamber 11 to enter the settling chamber along a straight line near the axis of the converging section 21. The settling chamber is used to collect and settle the flying spark particles entering from the converging section 21. A vibration recovery device is located on the right side of the combustion chamber 11, near the inlet end 211. This device collects flying spark particles that fall to the end of the combustion chamber 11 and returns them to the middle of the end of the combustion chamber 11 through vibration. The flying spark particles located in the middle of the end of the combustion chamber 11 are driven by the airflow to enter the converging section 21 and then along it into the settling chamber, thus achieving the collection of flying spark particles that fall to the end of the combustion chamber 11, improving the collection efficiency, and providing more experimental data for the study of flying spark particles.

[0029] The cross-sections at the inlet end 211 and the outlet end 212 are geometrically similar, and the cross-sectional area of ​​the contraction section 21 gradually increases from the inlet end 211 to the outlet end 212. All these cross-sections are vertical. Furthermore, the area ratio of the inlet end 211 to the outlet end 212 in this design can be designed to be 2~6:1. The wall surface of the contraction section 21 from the inlet end 211 to the outlet end 212 is designed based on the Vitosinski curve. The maximum angle (i.e., the maximum contraction angle) between the tangent of the wall surface of the contraction section 21 and the airflow direction ranges from 15° to 20°. This scheme limits the area of ​​the cross-sections at the inlet end 211 and outlet end 212 of the contraction section 21, and also limits the maximum angle between the tangent of the wall of the contraction section 21 and the airflow direction. This ensures that the contraction section 21 is designed specifically for the collection of flying spark particles. It maintains a uniform pressure gradient throughout the entire process due to the continuous and smooth curvature of the contraction section 21, fundamentally preventing boundary layer separation and eddy currents. This effectively avoids the diffusion of flying spark particles, allowing most of them to enter the settling chamber along the contraction section 21, ultimately achieving the goal of collecting them. Specifically, by limiting the maximum contraction angle of the contraction section 21 to the range of 15°~20°, this scheme balances the flow field quality and structural compactness of the contraction section 21. This results in a flow velocity uniformity of over 95% and a turbulence intensity of less than 1% for the flying spark particles flowing through the contraction section 21 at the outlet end 212, providing a stable flow field environment for the stable transport of flying spark particles. Furthermore, by limiting the area ratio of the cross-section of the inlet end 211 to the cross-section of the outlet end 212 to 2~6:1, the airflow entering the contraction section 21 can be smoothly accelerated. Under the action of the airflow in the contraction section 21, the Stokes number Stk of the flying fire particles in the contraction section 21 can jump to 10-50, which far exceeds the existing inertial collision critical criterion of Stokes number Stk>1 for flying fire particles. This completely solves the core problem of flying fire particles escaping by following the streamline due to insufficient airflow acceleration in the existing technology, and provides the core physical premise for the interception of flying fire particles. Meanwhile, the contraction section 21 of this scheme is designed based on the Vitósinski curve, ensuring that the flying spark particles flowing through it do not separate and accelerate. Furthermore, the contraction section 21 constructs a low-turbulence, undisturbed axial flow field, which minimizes the radial diffusion of flying spark particles. This allows the flying spark particles to concentrate entirely within the axial jet core region of the contraction section 21, enabling the baffle 224 in the settling chamber to achieve blind-zone-free interception. This results in a theoretical interception efficiency of nearly 100% for flying spark particles and avoids the risks of adhesion and ablation caused by high-temperature flying spark particles contacting the pipe wall, ensuring the complete recovery of flying spark particles and the accuracy of experimental data. It also precisely controls the flow field at the outlet end 212, preventing strong turbulence in the settling chamber from causing secondary entrainment of already settled particles. Combined with the expansion and deceleration of the settling chamber, this achieves rapid gravity settling of disabled particles.

[0030] The theoretical formula for the inertial collision separation theory (Stokes Number) is as follows: ; In the formula: τ p U0 is the relaxation time of the spark particles, which is proportional to the mass of the spark particles; D is the airflow velocity. c The characteristic dimension is Dc. Physically, it is defined as the characteristic spatial scale at which the flow field undergoes significant distortion when airflow intercepts an obstacle; it is also the critical length at which particles need to respond to changes in the flow field. The size of Dc is not fixed but varies depending on different operating conditions. In multiple collisions, it represents the baffle size in the first collision and the vertical clearance in subsequent collisions.

[0031] Specifically, the Stk collision theory explains why particles do not follow the fluid flow but instead impact the baffles due to horizontal inertia. Because the low-turbulence axisymmetric jet output from the Vitósinski contraction section has a constant-velocity core region that is 4-6 times the outlet hydraulic diameter, much larger than the distance of the first baffle, the first collision is certain to occur. After the collision, the gas flows along the upper and lower ends of the first baffle, and some particles follow this flow. The collision theory primarily explains whether subsequent particle collisions involve inertial impaction.

[0032] Solution for the overall velocity of the box after the collision: low-speed flow, Mach number less than 0.3, incompressible constant-length flow, Q constant. , where 0.625 and 0.64 are the areas, and 0.9 is the flow area correction coefficient η introduced to account for the blocking effect of the internal baffle.

[0033] Taking the most unfavorable operating conditions: minimum particle size of 1 mm, minimum density of 300 kg / m³, minimum average flow velocity in the settling chamber of 2 m / s, and aerodynamic viscosity... Then the calculation yields: Particle relaxation time: ; .

[0034] It satisfies the requirement of being greater than 1. For the s-baffle group, D c Vertical clearance = internal net height of the enclosure - vertical extension height of a single baffle (this value can be 30cm). Settlement velocity formula: .

[0035] For 1mm small-diameter flying sparks: take Substituting into the terminal settlement velocity formula, we get v ts ≈3.1 m / s. For 5 mm medium-sized flying particles: substituting the same parameters, we get vts ≈6.9 m / s. For 10 mm large-diameter flying sparks: substituting the same parameters, we get v ts ≈9.8m / s, all greater than 2.2m / s.

[0036] Therefore, the design logic is as follows: when Stk>1, the flying fire particles cannot follow the airflow and will directly collide with the airflow.

[0037] The cross-sections of the inlet end 211 and the outlet end 212 of the contraction section 21 can both be circular, elliptical, or regular polygons with rounded corners. When both the inlet end 211 and the outlet end 212 are regular polygons with rounded corners, each wall of the contraction section 21 is designed using the exact same Wittsinski curve. In this scheme, to match the outlet of the combustion chamber 11 at the front end, the cross-sections of the inlet end 211 and the outlet end 212 can preferably be designed as squares with rounded corners. Taking the example that both the inlet end 211 and the outlet end 212 are squares with rounded corners, the center point of the cross-section of the inlet end 211 is set as the origin of the coordinate system, the airflow direction is the positive x-axis, the direction perpendicular to the airflow is the y-axis, and the horizontal length of the contraction section 21 along the positive x-axis is L. Where x=0 corresponds to the cross-section at the inlet end 211 of the contraction segment 21; and x=L corresponds to the cross-section at the outlet end 212 of the contraction segment 21; the range of x is 0≤x≤L. The two-dimensional Wittsinski profile equation for the cross-section at any point x along the positive x-axis on the contraction segment 21 is as follows: ; In the formula: x is the lateral coordinate of any point on the contraction section 21 to the center point of the inlet end 211 of the contraction section 21; y(x) is the half-width of the cross section of the contraction section 21 at the axial position x; y0 is the half-width of the cross section at the inlet end 211 of the contraction section 21; y1 is the half-width of the cross section at the outlet end 212 of the contraction section 21. Based on the above standardized analytical two-dimensional Vitósinski profile, the contraction section 21 of this scheme can be constructed. When using a square with rounded corners to construct the contraction section 21, the two-dimensional Vitósinski profile used in the width and height directions is exactly the same, which can ensure the symmetry of the bidirectional flow effect. The contraction section 21 of this scheme is constructed by using a standardized analytical profile, which is convenient for precise processing. The bidirectional symmetrical design can reduce manufacturing costs and can compress the axial length of the device while ensuring performance, adapting to the laboratory installation space and fully taking into account the core performance of the device and its engineering feasibility. In addition, the curve equation y(x) of the contraction section 21 ensures that the airflow has no separation and low turbulence before entering the settling chamber. This means that all particles are concentrated in a high-speed jet beam centered on the axis, rather than scattered at the edges. This allows the baffle 224 in the settling chamber to theoretically achieve an interception efficiency close to 100%.

[0038] Wherein, the contraction angle β(x) is the angle between the tangent of the profile of the contraction segment 21 and the airflow axis (i.e., the x-axis), and its absolute value is the effective contraction angle. The mathematical expression for the contraction angle β(x) is: ; In the formula: dy / dx is the first derivative of the profile equation y(x) with respect to x, which represents the slope of the profile.

[0039] By taking the derivative of the two-dimensional Wittsinski profile equation and performing extreme value analysis, it can be found that the contraction segment 21 constructed by this scheme has the following inherent characteristics: the maximum slope of its profile (i.e., the corresponding maximum contraction angle) always appears at x≈0.2L, which is about 20% of the axial length from the inlet end 211.

[0040] Furthermore, this scheme also studies the characteristics of the contraction section 21 constructed when the maximum contraction angle is >25° and the contraction section 21 constructed when the maximum contraction angle is <10°. The contraction section 21 constructed when the maximum contraction angle is >25° exhibits the following characteristics: due to the rapid change in the slope of the profile of this contraction section 21, an adverse pressure gradient occurs in the airflow inside the contraction section 21, leading to boundary layer separation, the generation of eddies in the flow field, and a sharp increase in the turbulence intensity. This causes the flying particles flowing through the contraction section 21 to diffuse radially, failing to concentrate in its axial jet core region. The contraction section 21 constructed when the maximum contraction angle is <10° exhibits the following characteristics: the axial length of this contraction section 21 is too long, resulting in an excessive volume. Simultaneously, its boundary layer thickness increases, reducing the proportion of flying particles entering the contraction section 21 in the flow field core region. Therefore, by limiting the maximum contraction angle range to 10°~25°, this scheme can maximize the balance between flow field quality and volume, thereby providing a stable flow field environment for the stable transport of flying particles.

[0041] This scheme also studies the range of the area ratio between the cross-section of the inlet end 211 and the cross-section of the outlet end 212. When the area ratio between the cross-section of the inlet end 211 and the cross-section of the outlet end 212 is less than 2, the airflow acceleration provided by the constructed contraction section 21 is insufficient, resulting in a limited increase in the Stokes number Stk of the flying particles in the contraction section 21, which cannot break through the inertial collision critical criterion of Stk>1. This causes most of the flying particles to escape by following the airflow streamline, resulting in low collection efficiency of flying particles. When the area ratio between the cross-section of the inlet end 211 and the cross-section of the outlet end 212 is greater than 6, the flying particles in the contraction section 21 are prone to boundary layer separation. To avoid this phenomenon, the axial length of the contraction section 21 needs to be significantly increased, which will cause the volume of the contraction section 21 to exceed the standard. At the same time, the flow velocity at the outlet end 212 is also very high, causing the flying particles entering the settling chamber through the outlet end 212 to form strong turbulence in the settling chamber, which is not conducive to the settling and capture of flying particles in the settling chamber. Therefore, in this scheme, the ratio of the cross-sectional area of ​​the inlet end 211 to the cross-sectional area of ​​the outlet end 212 can be set to 2~6:1, which significantly increases the Stk value of the flying fire particles (usually reaching the order of 10-50), thereby avoiding the radial diffusion phenomenon of flying fire particles.

[0042] Please refer to Figure 1 and Figure 3The settling chamber may include a housing 221, a water tank 222, and two funnels 223. The housing 221 may include a main body 225 and a connecting part 226. One end of the connecting part 226 is connected to the outlet end 212, and the other end is connected to the main body 225. The main body 225 may be a cuboid structure, and the connecting part 226 is a variable-diameter structure along the airflow direction, with its diameter gradually increasing from the outlet end 212 to the main body 225. By designing this expanded-capacity housing 221, the expanded-capacity housing 221 can effectively decelerate the incoming flying particles and provide space for their settling, meeting the needs of flying particles of various sizes. Multiple baffles 224 are provided inside the housing 221; the multiple baffles 224 are arranged sequentially along the length of the housing 224, and one of every two adjacent baffles 224 is fixed to the top of the housing 221 and extends downwards, while the other baffle 224 is fixed to the bottom of the housing 221 and extends upwards. The vertical length of baffle 224 is greater than half the width of the box 221, so that the vertical projection of baffle 224 can cover the entire box 221, thereby effectively blocking and intercepting flying particles entering the box 221. This design ensures that all flying particles entering the box 221 fall into the funnel 223 below, effectively collecting them. Two funnels 223 are arranged sequentially along the length of the box 221 and connected to it. The mass of flying particles collected by the funnel 223 closer to the outlet 212 is less than or equal to the mass of flying particles collected by the funnel 223 farther from the outlet 212, thus forming a two-stage settling zone. The outlet of the funnel 223 connects to the water tank 222, and the flying particles blocked by baffle 224 pass through the funnel 223 and enter the water tank 222 under gravity. A water seal is used to isolate the chamber 221 from the outside world, thereby ensuring the stability of the airflow inside the chamber 221. At the same time, the water tank 222 can extinguish the fire nucleus of the flying fire particles, thus enabling the safe collection of the flying fire particles.

[0043] In the actual design process, in order to effectively reduce the airflow velocity (i.e., the velocity of the flying spark particles) entering the settling chamber and accommodate the baffle 224, the cross-sectional area of ​​the main body 225 of the box 221 can be designed to be 10.24 times the cross-sectional area of ​​the inlet end 211. The length of the box 221 can be designed to be 150cm~180cm, preferably 160cm, to ensure that the flow field inside the box 221 can be fully expanded and that the flying spark particles can have a sufficient horizontal stopping distance inside the box 221.

[0044] Multiple baffles 224 can be used, and these baffles 224 can be arranged alternately up and down along the vertical direction of the housing 221. When using baffles 224 arranged alternately up and down, the total area of ​​the projected baffles 224 in the airflow direction must be greater than the area of ​​the outlet end 212 to ensure that the baffles 224 can effectively collect the incoming flying particles as much as possible. In addition, the baffles 224 arranged alternately up and down can force the airflow in the housing 221 to form an "S" shaped flow path. This allows large-diameter flying particles to be intercepted by the first baffle, while medium-diameter and small-diameter flying particles gradually settle after entering the S-shaped flow path, thereby achieving further separation of medium-diameter flying particles.

[0045] The funnel 223 has an inverted pyramidal structure, and two funnels 223 form a W-shaped bottom. The inverted pyramidal design allows sparkling particles blocked by the baffle 224 to quickly enter the water tank 222 along the funnel 223, preventing them from remaining inside. A vibrator 227 is installed on the side wall of the funnel 223 to vibrate the sparkling particles on the side wall, allowing them to enter the water tank 222 through the funnel 223's outlet. The vibrator 227 further prevents sparkling particles from adhering to the inner wall of the funnel 223, improving the collection efficiency. The vibrator can be a pneumatic or electric hammer. It periodically taps the outer wall of the funnel 223, preventing sparkling particles from accumulating and clogging the funnel 223.

[0046] Please refer to Figure 1 , Figure 4 and Figure 5 The vibration recovery device may include a collection plate 31 and a drive assembly. The collection plate 31 is disposed at the bottom of the combustion chamber 11 and near the inlet end 211. The collection plate 31 is used to collect flying spark particles that fall into the combustion chamber 11. The drive assembly is used to drive the collection plate 31 to reciprocate along the vertical direction of the combustion chamber 11, and when the collection plate 31 moves upward, it blows the flying spark particles collected on the collection plate 31 to the contraction section 21 based on wind energy.

[0047] Please refer to Figure 4 and Figure 5The drive assembly may include a housing 321, a drive component, and at least one connecting rod 322. The housing 321 has an opening at its upper end and is fixed to the bottom of the combustion chamber 11 and communicates with the combustion chamber 11. A limiting plate is provided on the side of the housing 321 facing the combustion chamber 11, and the limiting plate extends into the housing 321 from its side wall. A receiving plate 31 covers the upper end of the housing 321, and the edge of the receiving plate 31 can be connected to the bottom of the combustion chamber 11 by a flexible seal, such as Teflon or a thin film. This seal can both isolate the housing 321 and the combustion chamber 11 through the receiving plate 31 and the flexible seal to ensure stable airflow within the combustion chamber 11, and allow the receiving plate 31 to move vertically. One end of the connecting rod 322 is fixed to the bottom of the receiving plate 31, and the other end extends into the housing 321. The connecting rod 322 is offset from the limiting plate so that the connecting rod 322 can move up and down in the vertical direction. A spring 323 is sleeved on the outside of the connecting rod 322. One end of the spring 323 is fixed to the bottom of the housing 321, and the other end is fixed to the bottom of the connecting rod 322. The spring 323 is always under compression inside the housing 321. When the receiving plate 31 is stationary, the spring 323 abuts against the limiting plate based on its elastic potential energy. The driving component is used to pull the receiving plate 31 downward until the top surface of the receiving plate 31 is flush with the bottom surface of the combustion chamber 11, while compressing the spring 323. At this time, the receiving plate 31 can be used to collect the flying fire particles that fall into the combustion chamber 11. When the drive unit separates from the receiving plate 31, the receiving plate 31 is driven to move upward by the spring 323 restoring its deformation until the upper end face of the spring 323 abuts against the limiting plate. At this time, the speed of the shrink plate drops to zero under the cooperation of the spring 323 and the limiting plate. The flying fire particles collected on the shrink plate move upward under the action of a large upward speed and inertia, and enter the shrink section 21 and the settling chamber in sequence under the action of airflow. Then, they fall under the action of the baffle 224 in the settling chamber, thus realizing the collection of flying fire particles.

[0048] Please refer to Figure 4 and Figure 5The driving components may include a second housing 324, a motor, a cam 325, and a roller 326. The second housing 324 is disposed within the first housing 321 and fixedly mounted on the bottom surface of the storage plate 31. The cam 325 is rotatably mounted within the second housing 324 and contacts the second housing 324 via the roller 326. The motor drives the cam 325 to rotate. When the contact point between the cam 325 and the roller 326 switches from the short shaft end of the cam 325 to the long shaft end, the cam 325 generates a downward thrust on the second housing 324, causing the second housing 324 to move the storage plate 31 downwards, further compressing the spring 323. When the contact point between the motor-driven cam 325 and the roller 326 switches from the long shaft end to the short shaft end of the cam 325, the cam 325 exerts no downward thrust on the housing 324. Under the elastic force of the spring 323, it will drive the collecting plate 31 to move upward until the spring 323 abuts against the limiting plate. At this time, the speed of the shrinking plate drops to zero under the cooperation of the spring 323 and the limiting plate. The flying fire particles collected on the shrinking plate move upward under the action of a large upward speed and inertia, and enter the shrinking section 21 and the settling chamber in sequence under the action of airflow. Then, they fall under the action of the baffle 224 in the settling chamber, thus realizing the collection of flying fire particles.

[0049] In this design, there can be multiple connecting rods 322, which can be symmetrically arranged at the bottom of the collecting plate 31. Each connecting rod 322 is provided with a spring 323 below it. The cooperation of multiple sets of connecting rods 322 and springs 323 can effectively support the collecting plate 31. At the same time, when the springs 323 rebound, they can provide more power to the collecting plate 31, so that the flying fire particles collected on the collecting plate 31 can be rebounded higher and re-enter the collecting section for collection.

[0050] The operation process of the vibration recovery device is described in three stages: (1) Energy storage and descent stage: The motor drives the cam 325 to rotate. When the long shaft end of the cam 325 rotates to the bottom, the cam 325 will press the roller 326 and the housing 324 to move downward; the housing 324 will drive the shrink plate to overcome the resistance of the spring 323 and slowly sink downward. At this time, the flying fire particles on the receiving plate 31 will slowly descend with the receiving plate 31 and remain stationary, such as Figure 4As shown. In this process, the energy conversion is as follows: the spring 323 is further compressed, and the mechanical energy of the motor is converted into the elastic potential energy of the spring 323. (2) Triggering and acceleration stage: When the long shaft end of the cam 325 rotates from the bottom upward, the downward pressure of the cam 325 on the roller 326 is released. At this time, the elastic potential energy accumulated by the spring 323 will be released instantly, and the spring 323 will push the receiving plate 31 to move upward with a large acceleration; the flying fire particles on the receiving plate 31 will also obtain a great upward vertical speed under the support of the receiving plate 31. (3) Emergency stop and projectile stage: When the spring 323 abuts against the limiting plate, the receiving plate 31 will stop moving under the action of the spring 323 and the limiting plate, and the flying fire particles on the receiving plate 31 will move upward under inertia, and enter the contraction section 21 and the settling chamber in sequence under the action of the airflow, such as Figure 5 As shown.

[0051] In this design, the combustion chamber 11, the storage plate 31, the retraction section 21, and the housing 221 can all be made of high-temperature resistant stainless steel, and each is equipped with a heat-insulating ceramic plate inside to facilitate the study of the flight process of high-temperature, combustible flying particles and their subsequent collection. The surface of the baffle 224 can be sprayed with an anti-adhesion ceramic coating to prevent high-temperature flying particles from adhering to the baffle 224.

[0052] In summary, this scheme designs the contraction section 21 using a specific two-dimensional Vitósinski profile equation, enabling the contraction section 21 to focus fire particles near its axis while also allowing for precise airflow control. Furthermore, the coupling of a multi-mechanism settling chamber achieves efficient interception and safe extinguishing of fire particles of all sizes, forming a closed-loop experimental capability that provides reliable experimental technical support for forest fire prevention mechanism research, engineering scheme optimization, and early warning model verification.

[0053] The following describes the specific dimensions of the contraction section 21 and the settling chamber: The inlet end 211 of the contraction section 21 is set as a square with rounded corners, its side length is 50cm, the particle size of the flying particles is 1-10mm, and the density is 300-500kg / m³. 3 The area ratio of the inlet end 211 cross-section to the outlet end 212 cross-section of the contraction section 21 is 4. Therefore, the area of ​​the outlet end 212 cross-section of the contraction section 21 is 625 cm². 2With a side length of 25cm, the velocity at the exit end of the contraction section is approximately four times that at the inlet end, which greatly enhances the inertia of the flying spark particles. To effectively reduce the airflow velocity and accommodate the baffle 224, the cross-sectional dimensions of the main body 225 of the housing 221 can be designed to be 80*80cm, and the length can be designed to be 150-180cm. The position of the baffle 224 inside the housing 221 can be designed to be approximately 35cm from the inlet end, and the dimensions of the baffle 224 can be designed to be 50cm wide and 50cm high to ensure it can cover the jet core area of ​​the contraction section 21. The theoretical basis for the design of the baffle 224's dimensions is to ensure that most of the flying spark particles in the contraction section 21 can completely impact the baffle 224, while sufficient space needs to be left around the housing 221 for airflow dispersion.

[0054] After impacting baffle 224 and losing kinetic energy, the flying fire particles will fall into funnel 223 under the influence of gravity. The principle is as follows: For a fire nucleus with a particle size of 5mm, according to the formula: , In the formula: g is the acceleration due to gravity, d p ρ represents the particle size of the flying spark particles; p The density of the airborne particles in the settling chamber; ρ g To reduce indoor air density; C d is the particle drag coefficient of the flying fire particles, and its value can be 0.45.

[0055] Since the above calculation formula is the conventional formula for calculating the settling velocity of flying spark particles, the final settling velocity v can be obtained based on the specific parameters of the flying spark particles in this scheme. ts ≈6m / s.

[0056] With an expanded-volume structure, if the inlet flow velocity is 20 m / s, the average flow velocity inside the settling chamber will be approximately 2.2 m / s. Since the dominant force in the vertical direction for the flying particles is gravity and v... ts =6m / s is greater than 2.2m / s, so the flying particles in the settling chamber can fall quickly into the funnel 223 below, instead of being carried out of the outlet of the box 221 by the airflow.

[0057] The basic principles, main features, and advantages of this invention have been described above. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made without departing from the spirit and scope of the invention, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection claimed by this invention is defined by the appended claims and their equivalents.

Claims

1. A device for burning and collecting stray particles, characterized in that, It includes: The combustion device includes a combustion chamber (11) and a blower (12), wherein the combustion chamber (11) is used to provide flying fire particles and the blower (12) is used to drive the flying fire particles to fly. The collection device includes a settling chamber and a converging section (21) located at the end of the combustion chamber (11) along the airflow direction. The converging section (21) includes an inlet end (211) communicating with the combustion chamber (11) and an outlet end (212) communicating with the settling chamber. The cross-sections of the inlet end (211) and the outlet end (212) are geometrically similar and have an area ratio of 2 to 6:

1. The wall of the converging section (21) from the inlet end (211) to the outlet end (212) is designed based on the Vitosinski curve, and the maximum angle between the tangent of the wall of the converging section (21) and the airflow direction is 15 to 20°. The converging section (21) is used to provide a stable flow field so that the flying spark particles flowing into the combustion chamber (11) can enter the settling chamber along a straight line close to the axis of the converging section (21). The settling chamber is used to collect the flying spark particles entering the converging section (21). The vibration recovery device (3) includes a collection plate (31) and a drive assembly. The collection plate (31) is located at the bottom of the combustion chamber (11) and near the inlet end (211). The collection plate (31) is used to collect the flying fire particles that fall from the combustion chamber (11). The drive assembly is used to drive the collection plate (31) to reciprocate along the vertical direction of the combustion chamber (11), and blow the flying fire particles collected on the collection plate (31) to the contraction section (21) based on the airflow when the collection plate (31) moves upward.

2. The flying spark particle combustion and collection device as described in claim 1, characterized in that, The cross-sections of the inlet end (211) and the outlet end (212) are both circular, elliptical, or regular polygons with rounded corners. When the cross-sections of the inlet end (211) and the outlet end (212) are both regular polygons with rounded corners, each wall of the contraction section (21) is designed using the exact same Wittsinski curve.

3. The flying spark particle combustion and collection device as described in claim 1, characterized in that, Let the center point of the cross section where the inlet end (211) is located be the origin of the coordinate system, the direction of airflow be the positive x-axis, the direction perpendicular to the airflow be the y-axis, and the horizontal length of the contraction section (21) along the positive x-axis be L; then the two-dimensional Wittsinski profile equation of the cross section at any point x along the positive x-axis on the contraction section (21) is as follows: ； In the formula: y(x) is the vertical distance from the center point of the section where the contraction section (21) is located at the axial position x to the boundary of the section; y0 is the vertical distance from the center point of the section where the contraction section (21) is located at the inlet end (211) to the boundary of the section; y1 is the vertical distance from the center point of the section where the contraction section (21) is located at the outlet end (212) to the boundary of the section.

4. The device for burning and collecting flying spark particles as described in claim 1, characterized in that, The settling chamber includes a box (221), a water tank (222), and at least two funnels (223); the box (221) is connected to the outlet end (212), and the box (221) is provided with multiple baffles (224); the multiple baffles (224) are arranged sequentially along the length of the box, and one of two adjacent baffles (224) is fixed to the top of the box (221) and extends downward, and the other baffle (224) is fixed to the bottom of the box (221) and extends upward; the two funnels (223) are arranged sequentially along the length of the box (221) and are respectively connected to the box (221); the outlet of the funnel (223) is connected to the water tank (222); the flying particles blocked by the baffles (224) enter the water tank (222) through the funnel (223) under the action of gravity.

5. The device for burning and collecting flying spark particles as described in claim 1, characterized in that, The drive assembly includes a housing (321), a drive component, and at least one connecting rod (322). The housing is installed at the bottom of the combustion chamber (11) and communicates with the combustion chamber (11). The receiving plate (31) covers the upper end of the housing (321). One end of the connecting rod (322) is fixed to the bottom of the receiving plate (31), and the other end extends into the housing (321). A spring (323) is fitted on the outside of the connecting rod (322). The two ends are respectively connected to the connecting rod (322) and the bottom of the housing (321); the driving member is used to pull the storage plate (31) downward until the top surface of the storage plate (31) is flush with the bottom surface of the combustion chamber (11) and compress the spring (323); and when separated from the storage plate (31), the storage plate (31) is driven to move upward until the upper end surface of the spring (323) abuts against the housing (321) based on the spring (323) restoring its deformation.

6. The flying spark particle combustion and collection device as described in claim 5, characterized in that, The driving component includes a second housing (324), a motor, a cam (325), and a roller (326). The second housing (324) is disposed inside the first housing (321) and fixedly installed on the bottom surface of the storage plate (31). The cam (325) is rotatably installed inside the second housing (324) and contacts the second housing (324) through the roller (326). The motor is used to drive the cam (325) to rotate. When the contact point between the cam (325) and the roller (326) switches from the short shaft end of the cam (325) to the long shaft end of the cam (325), the shrink plate is driven to move downward through the second housing (324). When the contact point between the cam (325) and the roller (326) switches from the long shaft end of the cam (325) to the short shaft end of the cam (325), the shrink plate is driven to move upward through the spring (323) to restore its deformation.

7. The flying spark particle combustion and collection device as described in claim 4, characterized in that, The box (221) includes a main body (225) and a connecting part (226). The two ends of the connecting part (226) are connected to the main body (225) and the outlet end (212) respectively. The main body (225) is a cuboid structure, and the connecting part (226) is a variable diameter structure, whose diameter gradually increases from the outlet end (212) to the main body (225).

8. The device for burning and collecting flying spark particles as described in claim 4, characterized in that, The funnel (223) has an inverted pyramidal structure, and the two funnels (223) are used to form a W-shaped bottom of the box. A vibrator (227) is installed on the side wall of the funnel (223) to vibrate the flying sparks on the side wall of the funnel (223) so that they enter the water tank (222) through the outlet of the funnel (223).

9. The device for burning and collecting flying spark particles as described in claim 7, characterized in that, The ratio of the cross-sectional area of ​​the side of the connecting part (226) connected to the main body (225) to the cross-sectional area of ​​the side of the connecting part (226) connected to the outlet end (212) is 10.24:1; And / or, the length of the box (221) is 150cm~180cm.

10. The device for burning and collecting flying spark particles as described in claim 4, characterized in that, The combustion chamber (11), the storage plate (31), the shrink section (21) and the box body (221) are all made of stainless steel and are equipped with heat-insulating ceramic plates inside. And / or, the surface of the baffle (224) is coated with a ceramic coating.

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