Porous combustion medium and porous medium combustor

Abstract

The invention discloses a porous combustion medium and a porous medium combustor, and belongs to the technical field of porous medium combustion, and the porous combustion medium comprises a plate hole corrugated combination body which is provided with a three-dimensional circulation network and is used for mixing gas; the plate hole corrugated combination comprises a plate hole corrugated plate, the section of the plate hole corrugated plate is corrugated, the plate hole corrugated plate is provided with plate hole structures arranged periodically, and gas can pass through the plate hole structures. The plate hole structure comprises a plurality of corrugated flow channels and through holes, and every two adjacent corrugated flow channels are communicated through the through holes. The through holes penetrate through the plate hole corrugated plate in the thickness direction of the plate hole corrugated plate. The inner wall of the corrugated flow channel is provided with a second-stage fluid regulation and control structure used for disturbing flowing gas, and the flow and heat transfer collaborative optimization is achieved, specifically, the regular plate holes and the corrugated flow channel form a low-resistance main circulation network, and the second-stage structure provides fine turbulent flow excitation capacity; cooperative optimization of macroscopic flow resistance and microcosmic heat transfer is achieved, and the comprehensive heat exchange efficiency is high.

Description

Technical Field

[0001] This invention belongs to the field of porous media combustion technology, specifically relating to a porous combustion medium and a porous media burner. Background Technology

[0002] Porous media combustion technology, as a highly efficient and clean advanced combustion method, relies on the large specific surface area and complex pore structure of porous solid materials to achieve thorough mixing of fuel gas and air, flame stability, and high-intensity heat exchange between combustion products and unburned gases. This "super-adiabatic combustion" effect can significantly improve combustion efficiency, broaden the lean-burn limit, and effectively reduce emissions of pollutants such as nitrogen oxides.

[0003] Currently, the most common porous media in industrial applications are mainly foam ceramics and honeycomb ceramics. Foam ceramics (such as alumina and silicon carbide foam) have high porosity (usually >70%) and three-dimensional interconnected open-pore structure, with random and disordered distribution of pores inside. Although this randomness promotes gas turbulence and mixing to a certain extent, it also brings inherent technical defects: (1) large and uncontrollable flow resistance: when gas passes through tortuous and random channels, local eddies and dead zones coexist, resulting in significant overall pressure drop loss; (2) thermal stress concentration and vulnerability: random pore structure is prone to forming stress concentration points at weak points such as pore throats and ligaments. Under severe thermal cycling (thermal shock), cracks are easily generated and propagated, leading to premature cracking and failure of the material, and limited service life; (3) poor performance reproducibility: due to the uncontrollability of its structure, there are differences in key parameters such as pore distribution and specific surface area between different batches or even the same batch of foam ceramics, resulting in unstable burner performance and difficulty in achieving precise design and optimization.

[0004] On the other hand, honeycomb ceramics (such as cordierite) have a regular parallel straight channel structure and low flow resistance. However, their specific surface area is much smaller than that of foam ceramics, and the straight channels are not conducive to lateral mixing and radial heat exchange between gases, which limits further improvement in their heat feedback efficiency and combustion intensity.

[0005] To improve the performance of porous media, researchers have made various attempts. For example, utility model patent CN214327577U discloses a porous ceramic with a multi-layered pore structure, in which the pores of adjacent pore structures are interconnected and the pore size increases sequentially along a predetermined direction.

[0006] However, its simple layered channel design results in poor flow field control, limiting its ability to achieve ultra-high thermal radiation efficiency and extremely low pollutant emissions. Summary of the Invention

[0007] The purpose of this invention is to provide a porous combustion medium and a porous medium burner, which are suitable for industrial heating and combustion devices with stringent requirements for thermal efficiency, emission control, operational stability and service life. This technical solution can provide an efficient, stable, clean and compact combustion solution.

[0008] To achieve the above objectives, in a first aspect, the present invention provides a porous combustion medium, comprising a plate-hole corrugated assembly, provided with a three-dimensional flow network for mixing gas, wherein the direction in which the gas passes through the plate-hole corrugated assembly is the mainstream gas direction. The perforated corrugated plate assembly includes a perforated corrugated plate with a corrugated cross section and periodically arranged perforated plate structures, through which gas can pass. The plate perforation structure includes several corrugated flow channels and through holes, which connect two adjacent corrugated flow channels. The through holes are arranged to penetrate the corrugated plate along its thickness direction. A two-stage fluid control structure is provided on the inner wall of the corrugated flow channel to disturb the flowing gas.

[0009] Furthermore, the diameter d1 of the through hole is 2~5mm, and the hole spacing p is 2.5~5 times the diameter.

[0010] Furthermore, the amplitude A of the corrugated channel is between 3 and 10 mm, the wavelength λ is between 3 and 30 mm, the relationship between A and λ satisfies 0.1 ≤ A / λ ≤ 1.0, and the corrugated tooth angle α is between 30° and 150°.

[0011] Furthermore, the plate-hole corrugated assembly has a single continuous gradient structure, in which at least one of the parameters—amplitude A, wavelength λ, and corrugated tooth angle α—gradually decreases along the mainstream gas direction.

[0012] Furthermore, the angle θ formed between the extension direction of the corrugated channel and the mainstream gas direction is ± (15°~75°).

[0013] Furthermore, the height h of the secondary fluid control structure and the hydraulic diameter D of the corrugated channel satisfy the following condition: 0.05 ≤ h / D ≤ 0.25.

[0014] Furthermore, the secondary fluid control structure includes a convex hull structure, which is hemispherical or frustum-shaped with a diameter d = 0.5~2mm and a height h = 0.5~3mm. The convex hull structure is distributed in a staggered or sequential manner along the mainstream gas flow direction.

[0015] Furthermore, the secondary fluid control structure includes a dune structure, which is a streamlined crescent-shaped ridge with a length L = 1~15mm and a height h = 0.5~3mm. The angle between the tangent of the windward curved surface at the apex and the base plane (windward elevation angle) β ≤ 45°, and the angle between the tangent of the leeward curved surface at the apex and the base plane (leeward depression angle) γ ≥ 15°.

[0016] In this technical solution, by precisely controlling the aperture d1 (2~5mm), aperture spacing p (2.5~5 times the aperture), and the amplitude A (3~10mm), wavelength λ (3~30mm), amplitude-to-wavelength ratio A / λ (0.1~1.0), corrugated tooth angle α (30°~150°), and flow direction angle θ (±15°~75°) of the corrugated flow channel, a basic three-dimensional flow network with low flow resistance, high specific surface area, and excellent mechanical strength is formed.

[0017] Furthermore, optional fine flow control is introduced, such as the option to set secondary fluid control structures (e.g., convex hull structures, dune structures, fins) on the inner wall of the corrugated channel. By controlling the ratio of its height to the hydraulic diameter of the channel, h / D (0.05~0.25), micro-disturbances of the fluid near the wall can be achieved, breaking the thermal boundary layer and thus further enhancing heat transfer and mixing when needed.

[0018] Simultaneously achieving a gradient distribution of functions, the plate-hole corrugated assembly can be designed as a single continuous structure, so that at least one of its corrugation parameters (amplitude A, wavelength λ, tooth angle α) changes continuously along the thickness direction of the medium, thereby forming a gradient structure; for example, from the inlet to the outlet, the amplitude A continuously decreases, thereby generating strong disturbance at the inlet end and tending to be gentle at the outlet end to uniform temperature field, perfectly matching the combustion chemical reaction process.

[0019] In a second aspect, the present invention provides a porous medium burner applicable to the porous combustion medium described in the first aspect above, comprising a combustion chamber, wherein the porous combustion medium is located within the combustion chamber, and the combustion medium can be an independent plate-hole corrugated assembly or multiple plate-hole corrugated assemblies arranged sequentially along the gas flow direction. By adjusting the direction of the corrugated flow channels between adjacent plate-hole corrugated assemblies (parallel or intersecting at 5°~90°), secondary guidance and mixing of the fluid can be achieved, further optimizing the combustion effect.

[0020] In a preferred embodiment of the present invention, the reaction-sintered silicon carbide has a silicon carbide phase content ≥60 wt%, a residual silicon content ≤40 wt%, and a matrix porosity ≤5 vol; the purified silicon carbide has a silicon carbide phase content ≥95 wt%, a residual silicon content ≤5 wt%, and a matrix porosity <15 vol.

[0021] Compared with the prior art, the beneficial effects of the present invention are: (1) Synergistic optimization of flow and heat transfer: The regular plate holes and corrugated channels form a low-resistance main flow network, while the secondary structure provides a fine turbulence excitation capability, realizing the synergistic optimization of macroscopic flow resistance and microscopic heat transfer, resulting in high overall heat exchange efficiency.

[0022] (2) Highly designable performance: All key geometric parameters (aperture, amplitude, wavelength, tooth angle, secondary structure size, etc.) can be precisely designed and controlled, so that the combustion medium can be "customized" to adapt to specific fuel, load and emission requirements, with excellent performance reproducibility.

[0023] (3) Excellent mechanical and thermal stability: The ordered topological structure avoids stress concentration points of random pores. Combined with high-performance silicon carbide materials, it gives the combustion medium excellent compressive strength and thermal shock resistance, and long service life.

[0024] (4) Flexible configuration and application: The combustion medium can be made into a single whole with a continuous internal gradient, or it can be flexibly combined from multiple plate-hole corrugated assemblies; it can be used alone or arranged crosswise in the burner, providing great flexibility for the design of burners with different power and different uses. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the plate-hole corrugated assembly structure of the present invention; Figure 2 This is a partial structural diagram of the plate-hole corrugated assembly of the present invention; Figure 3 This is a schematic diagram of the perforated corrugated plate structure of the present invention; Figure 4 This is a schematic diagram of the first corrugated shape of the perforated corrugated plate in this invention; Figure 5 This is a schematic diagram of the second corrugated shape of the perforated corrugated plate in this invention; Figure 6 This is a schematic diagram of the third corrugated shape of the perforated corrugated plate in this invention; Figure 7 This is a schematic diagram of the fourth corrugated shape of the perforated corrugated plate in this invention; Figure 8 This is a schematic diagram of the fifth corrugated shape of the perforated corrugated plate in this invention; Figure 9 This is a schematic diagram of the first structure of the secondary fluid control structure in this invention; Figure 10 This is a schematic diagram of the second structure of the secondary fluid control structure in this invention; Figure 11This is a schematic diagram of the third structure of the secondary fluid control structure in this invention; Figure 12 This is a schematic diagram of the porous media burner structure of the present invention; 1-Plate-hole corrugated assembly, 2-Plate-hole corrugated plate, 3-Corrugated flow channel, 4-Through hole, 5-Secondary fluid control structure, 6-Combustion chamber, 7-Gas inlet, 8-Flue gas outlet. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] The porous combustion medium provided by this invention is characterized by its ability to actively control the flow field and temperature field during combustion through a precisely designed geometric structure. The porous combustion medium is integrally formed from reaction-sintered silicon carbide or purified silicon carbide using additive manufacturing techniques (such as DLP photopolymer ceramic 3D printing or photopolymer resin template + slurry impregnation), ensuring both structural precision and material density.

[0029] See Figures 1 to 3 As shown, it mainly includes a plate-hole corrugated assembly 1, on which a three-dimensional flow network is provided. During the process of gas moving from one side of the plate-hole corrugated assembly 1 to the other side, the gas can pass through the three-dimensional flow network. The direction in which the gas passes through the plate-hole corrugated assembly 1 is the mainstream gas direction. When the gas flows along the mainstream direction, it is mixed by the plate-hole corrugated assembly 1.

[0030] The perforated corrugated plate assembly 1 is composed of several perforated corrugated plates 2, making the perforated corrugated plate 2 the basic unit of this invention. The perforated plate 2 has a periodically arranged perforation structure, including corrugated channels 3. These channels include front and back corrugated channels. The front corrugated channels are located on the front side of the perforated corrugated plate 2, and the back corrugated channels are located on the back side. The front and back corrugated channels are alternately arranged along the length or width of the perforated corrugated plate 2, creating a wavy cross-section. The perforation structure also includes through holes 4, which penetrate the perforated corrugated plate 2 along its thickness direction, connecting the front and back corrugated channels. The diameter d1 of the through holes 4 is designed to be 2-5 mm, and the hole spacing p is 2.5-5 times the diameter. The cross-section of the through holes 4 can be one or more of the following: circular, elliptical, conventional polygonal, or rounded polygonal, to ensure smooth airflow.

[0031] See Figure 3 As shown, there are several corrugated channels 3, which are connected by through holes 4. The amplitude A of the corrugated channel 3 is 3~10mm, the wavelength λ is 3~30mm, and it satisfies the relationship 0.1 ≤ A / λ ≤ 1.0. The corrugated tooth angle α is between 30° and 150°. There is an angle θ between the direction of the corrugated channel 3 and the direction of the mainstream gas flow, which ranges from ±(15°~75°). This design can induce the gas to flow laterally and enhance mixing.

[0032] The corrugated plates 2 with holes mentioned above can be fixed by sintering or mechanical assembly. The direction of the corrugated flow channels 3 between the layers can be consistent or intersecting at a certain angle to further optimize the flow field.

[0033] As a highly efficient optimization method, referencing Figure 2 As shown, a secondary fluid control structure 5 can be optionally provided on the inner wall of the corrugated flow channel 3. Figure 9 The staggered distribution of hemispherical convex hull structures is shown, with diameter d = 0.5~2mm and height h = 0.5~3mm; Figure 10 The structure of the streamlined crescent-shaped sand dune is shown in cross-sectional view. Its length L = 1~15mm, height h = 0.5~3mm, windward elevation angle β≤45°, and leeward depression angle γ≥15°. Figure 11 The structure of the fins is shown, with a height h = 0.5~3mm and a thickness δ = 0.2~1mm. The ratio of the height h of these secondary structures to the hydraulic diameter D of the flow channel satisfies 0.05 ≤ h / D ≤ 0.25, which is designed to generate micro-disturbances in the near-wall fluid, break the thermal boundary layer, and thus enhance heat transfer.

[0034] To achieve better combustion performance, the plate-perforated corrugated assembly 1 can be designed as a single continuous structure. In this case, at least one of its corrugation parameters (amplitude A, wavelength λ, and tooth angle α) changes along the thickness direction of the medium, thereby forming a gradient structure. Preferably, along the mainstream gas flow direction from the inlet to the outlet, the amplitude A continuously decreases, and / or the wavelength λ continuously increases, and / or the corrugated tooth angle α continuously decreases. For example, from the inlet to the outlet, the amplitude A continuously decreases, thereby generating strong disturbances at the inlet to enhance mixing, and becoming gentler at the outlet to homogenize the temperature field.

[0035] As for the second aspect of the present invention, see the following embodiment. Figure 12 As shown, the main application is the porous combustion medium described in the first aspect. In this embodiment, it is applied in a porous medium burner, which includes a combustion chamber 6, a gas inlet 7, and a flue gas outlet 8. The porous combustion medium is located in the combustion chamber 6. The premixed gas inlet 7 and the flue gas outlet 8 are both connected to the combustion chamber 6. The premixed gas enters from the gas inlet 7 and is stably and efficiently combusted in the combustion medium. The flue gas is then discharged from the outlet.

[0036] In this scheme, the aforementioned porous combustion medium can be set as one or more, that is, one or more plate-hole corrugated assembly 1 or multiple plate-hole corrugated assembly 1 are set. When multiple are set, they are arranged sequentially along the gas flow direction. Preferably, the corrugated flow channels 3 of adjacent plate-hole corrugated assembly 1 are parallel to each other or at an intersection angle of 5° to 90°.

[0037] In a preferred embodiment of the present invention, the reaction-sintered silicon carbide has a silicon carbide phase content ≥60 wt%, a residual silicon content ≤40 wt%, and a matrix porosity ≤5 vol; the purified silicon carbide has a silicon carbide phase content ≥95 wt%, a residual silicon content ≤5 wt%, and a matrix porosity <15 vol.

[0038] Example 1, see Figure 4 As shown: Structural configuration: The single-layer corrugated shape of the perforated corrugated plate 2 is a smooth triangle with a rounded apex, amplitude A=4.7mm, wavelength λ=7.2mm, A / λ=0.653, tooth angle α=74.9°, and the radius of the rounded corner of the corrugated apex R=1.0mm; circular holes are arranged in a straight line along the flow channel direction in the corrugated flow channel, with a hole diameter d1=2.0mm and a hole spacing p=7.0mm; the corrugated flow channel 3 is arranged at an angle θ of ±45° with the mainstream gas flow direction, and the corrugation parameters remain unchanged along the thickness direction. A hemispherical convex hull structure is provided on the inner wall of the corrugated flow channel 3 as a secondary fluid control structure (5, convex hull diameter d=1.0mm, height h=1.0mm, distributed in a staggered manner along the flow channel, h / D≈0.2).

[0039] Material characteristics: Reaction-bonded silicon carbide is used as the porous combustion medium substrate, with a silicon carbide phase content of 75 wt%, a residual silicon content of 25 wt%, and a matrix porosity of ≤ 0.1%.

[0040] Application Results: Tested under a heat load of 800 kW / m². The convex hull structure enhances the initial disturbance of the flow field and promotes early mixing of the premixed gas. No structural damage occurred after 300 cycles between room temperature and combustion conditions.

[0041] Example 2, see Figure 5 and Figure 9 As shown: Structural configuration: The single-layer corrugated shape of the perforated corrugated plate 2 is a triangular wave with an amplitude A = 5.0 mm, a wavelength λ = 10.0 mm, A / λ = 0.5, and a tooth angle α = 90°. Circular holes arranged in a straight line along the flow channel are provided within the corrugated channel, with a hole diameter d1 = 3.0 mm and a hole spacing p = 8.0 mm. The angle θ between the direction of the corrugated channel 3 and the mainstream gas flow direction is 30°. A hemispherical bulge is added to the inner wall of the corrugated channel 3 as a secondary structure, with a bulge diameter d = 1.0 mm and a height h = 0.5 mm, arranged in a staggered pattern along the flow channel, h / D ≈ 0.1.

[0042] Material characteristics: Reaction-bonded silicon carbide is used as the porous combustion medium substrate, with a silicon carbide phase content of 78 wt%, a residual silicon content of 22 wt%, and a matrix porosity of ≤ 0.1%.

[0043] Application Results: Tested under a heat load of 800 kW / m². Parameter adjustments to the convex hull structure optimized flow field disturbance, resulting in an average burner surface temperature increase of approximately 25°C compared to Example 1. Radiative efficiency increased to 37%, and NOx emissions decreased to 40 mg / Nm³. No structural damage occurred after 300 cycles between room temperature and combustion conditions.

[0044] Example 3, see Figure 6 and Figure 10 As shown: Structural Configuration: The single-layer corrugated shape of the perforated corrugated plate 2 is a smooth trapezoidal corrugated wave with a rounded apex, amplitude A=6.0mm, wavelength λ=12.0mm, A / λ=0.5, tooth angle α=80°, and apex radius R=1.5mm. Rounded square holes are arranged sequentially along the flow direction within the corrugated channel, with a hole diameter r=2.0mm and hole spacing p=10.0mm. The angle θ between the direction of the corrugated channel 3 and the mainstream gas flow direction is 30°. A dune-shaped secondary structure is added to the inner wall of the corrugated channel 3, with a dune length L=8mm, height h=1.2mm, h / D≈0.15, windward elevation angle β=30°, and leeward depression angle γ=20°.

[0045] Material characteristics: Pure silicon carbide is used as the porous combustion medium substrate, with a silicon carbide phase content of 96 wt%, a residual silicon content of <5 wt%, and a matrix porosity of ≤12%.

[0046] Application Results: Tested under a heat load of 800 kW / m². The dune structure effectively optimized the flow field distribution and avoided localized high temperatures. Radiation efficiency reached 38%, and NOx emissions were significantly reduced to 38 mg / Nm³. No structural damage occurred after 300 cycles between room temperature and combustion conditions.

[0047] Example 4, see Figure 7 and Figure 11 As shown: Structural configuration: The single-layer corrugated shape of the perforated corrugated plate 2 is a sinusoidal wave with amplitude A=4.0mm, wavelength λ=8.0mm, and A / λ=0.5. Elliptical holes are arranged sequentially along the flow direction within the corrugated channel, with major axis d1=2.5mm, minor axis d2=2.0mm, and hole spacing p=9mm. The angle θ between the direction of the corrugated channel 3 and the mainstream gas flow direction is 60°. Straight rib fins are added to the inner wall of the corrugated channel 3 as a secondary structure, with fin height h=1.0mm, thickness δ=0.3mm, and h / D≈0.12.

[0048] Material characteristics: Reaction-bonded silicon carbide is used as the porous combustion medium substrate, with a silicon carbide phase content of 80 wt%, a residual silicon content of 20 wt%, and a matrix porosity of ≤ 0.5%.

[0049] Application Results: Tested under a heat load of 800 kW / m². The fins significantly increase the heat exchange area and enhance thermal conductivity. The radiative efficiency reaches 39%, and NOx emissions are 36 mg / Nm³. No structural damage occurred after 300 cycles between room temperature and combustion conditions.

[0050] Example 5, see Figure 4 , Figure 9 and Figure 10 As shown: Structural configuration: The single-layer corrugated shape of the perforated corrugated plate 2 is a smooth triangular shape with rounded apex, amplitude A=5.5mm, wavelength λ=11.0mm, A / λ=0.5, tooth angle α=80°, and corrugated apex radius R=1.2mm; circular holes are arranged in a straight line along the flow direction within the corrugated channel, with a hole diameter d1=3.6mm and a hole spacing p=9mm; the corrugated channel 3 is arranged alternately with an angle θ of ±45° with the mainstream gas flow direction. On the inner wall of the corrugated channel 3, a convex hull structure is set in the inlet section area, and a sand dune is set in the outlet section area, forming a composite two-stage structure.

[0051] Material characteristics: Pure silicon carbide is used as the porous combustion medium substrate, with a silicon carbide phase content of 98 wt%, a residual silicon content of <2 wt%, and a matrix porosity of 11.2%.

[0052] Application Results: Tested under a heat load of 800 kW / m². This design enhances mixing at the inlet and optimizes flow at the outlet. The overall radiative efficiency reaches 39%, and NOx emissions are reduced to 35 mg / Nm³. No structural damage occurred after 200 cycles between room temperature and combustion conditions.

[0053] Example 6: Structural Configuration: The plate-hole corrugated assembly 1 is a single continuous body. The corrugation shape is a smooth triangular wave with rounded apex. Along the main gas flow direction, the amplitude A changes from 8.0 mm at the inlet to 4 mm at the outlet; the wavelength λ changes from 8.0 mm at the inlet to 4 mm at the outlet; the tooth angle α = 90°; the radius of the corrugated apex fillet R = 1.0 mm; the orifice diameter d1 changes from 4.0 mm at the inlet to 2.0 mm at the outlet; the angle θ between the direction of the corrugated channel 3 and the main gas flow direction is 45°. To match the functional requirements of gradient changes, a hemispherical bulge is added to the inner wall of the corrugated channel 3 in the inlet region (where the amplitude is larger), with a bulge diameter d = 1.2 mm and a height h = 0.6 mm; straight rib fins are added in the outlet region (where the amplitude is smaller), with a fin height h = 0.8 mm and a thickness δ = 0.3 mm. The h / D ratios of both secondary structures satisfy 0.05 ≤ h / D ≤ 0.25.

[0054] Material characteristics: Reaction-bonded silicon carbide is used as the porous combustion medium substrate, with a silicon carbide phase content of 75 wt%, a residual silicon content of 25 wt%, and a matrix porosity of ≤ 0.1%.

[0055] Application Results: Tested under a heat load of 800 kW / m², the gradient structure perfectly matched the combustion process. The convex hull at the inlet section enhanced mixing, while the fins at the outlet section optimized heat transfer and temperature field uniformity, achieving extremely high temperature uniformity. Radiation efficiency reached 40%, and NOx emissions were further reduced to 33 mg / Nm³. No structural damage occurred after 500 cycles between room temperature and combustion conditions, demonstrating optimal thermal shock reliability.

[0056] Example 7, see Figure 8 As shown: Structural configuration: The single-layer corrugated shape of the perforated corrugated plate 2 is trapezoidal, with an amplitude A = 8.0 mm, a wavelength λ = 12.0 mm, A / λ = 0.667, and a tooth angle α = 120°. Rounded hexagonal holes are arranged in a straight line along the flow path within the corrugated channel. The diameter of the inscribed circle in each hole is d1 = 2.0 mm, the radius of the rounded corner is 0.3 mm, and the hole spacing is p = 10.0 mm. The angle θ between the direction of the corrugated channel 3 and the mainstream gas flow direction is 60°. A streamlined crescent-shaped sand dune is added to the inner wall of the corrugated channel 3 as a secondary fluid control structure 5. The dune length L = 10 mm, the height h = 1.5 mm, h / D ≈ 0.18, the windward elevation angle β = 35°, and the leeward depression angle γ = 22°.

[0057] Material characteristics: Pure silicon carbide is used as the porous combustion medium substrate, with a silicon carbide phase content of 97 wt%, a residual silicon content of <3 wt%, and a matrix porosity of ≤8%.

[0058] Application Results: Tested under a heat load of 800 kW / m². The streamlined dune structure with large angles and amplitudes further optimizes the gas flow field at high velocities, reduces eddy resistance, and enhances mass transfer near the wall. The radiation efficiency is 32%, and stable combustion is maintained even at higher loads of 1200 kW / m², with NOx emissions of 38 mg / Nm³. No structural damage occurred after 300 cycles between room temperature and combustion conditions. This design focuses on high-load conditions; although the radiation efficiency is slightly lower, it achieves low flow resistance and high stability. Comparative Example 1: Structural configuration: Randomly open-cell silicon carbide foam prepared by the traditional replication foam method, with an average pore size of about 2 mm and a porosity of 80%.

[0059] Material characteristics: It adopts reaction sintered silicon carbide with a silicon carbide phase content of 70 wt%, a residual silicon content of 30 wt%, and a matrix porosity of ≤ 0.1%.

[0060] Application Results: Tested under a heat load of 800 kW / m². Combustion stability was poor, the flame was prone to floating, and surface temperature non-uniformity exceeded ±100℃. Radiation efficiency was only 30%, and NOx emissions were as high as 55 mg / Nm³. Macroscopic cracks appeared after 80 cycles between room temperature and combustion conditions.

[0061] Comparative Example 2: Structural configuration: A simple sinusoidal corrugated plate is used, with a four-section structure without through holes. The amplitude A = 5mm and the wavelength λ = 10mm. There is no secondary control structure.

[0062] Material characteristics: It adopts reaction sintered silicon carbide with a silicon carbide phase content of 75 wt%, a residual silicon content of 25 wt%, and a matrix porosity of ≤ 0.1%.

[0063] Application results: Tested under a heat load of 800 kW / m². High flow resistance, uneven combustion, and noticeable localized high-temperature zones were observed. The radiation efficiency was 32%, and NOx emissions were 57 mg / Nm³. Microcracks appeared at the ripple peaks after 160 cycles between room temperature and combustion conditions.

[0064] Examples and Summary of Comparative Results Example Radiation efficiency (%) NOx emissions (mg / Nm³) Thermal shock cycles (times) Features Description Example 1 33 42 300+ Convex hull structure Example 2 37 40 300+ Convex hull structure Example 3 38 38 300+ dune structure Example 4 39 36 300+ Fin structure Example 5 39 35 200+ Hybrid structure Example 6 40 33 500+ Gradient structure Example 7 32 38 300+ High-parameter design Comparative Example 1 30 55 80 Random Bubble Comparative Example 2 32 57 160 Simple ripples As can be seen from the above embodiments and comparative examples, the present invention, by introducing a regular, designable plate-hole corrugated structure, supplemented by an optional secondary fluid control structure and a continuous gradient design, can actively and precisely control the combustion process. While maintaining low flow resistance, it significantly improves the radiant efficiency and thermal stability of the burner and effectively reduces pollutant emissions. The radiant efficiency of all embodiments is higher than that of the comparative examples, demonstrating the significant progress of the present invention.

[0065] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A porous combustion medium, characterized in that, The plate-hole corrugated combination (1) is provided with a three-dimensional flow network for mixing gas, and the direction of the gas passing through the plate-hole corrugated combination (1) is the main flow direction of the gas. The plate-hole corrugated combination (1) comprises: The plate-hole corrugated plate (2) is corrugated in cross section and is provided with a periodic plate-hole structure through which the gas can pass. The plate-hole structure comprises: A plurality of corrugated flow channels (3) and through holes (4) are provided to communicate adjacent two corrugated flow channels (3). The through hole (4) penetrates the plate-hole corrugated plate (2) along the thickness direction. During the flow of the gas in the corrugated flow channel (3), the gas can pass through the through hole (4). The aperture d1 of the through hole (4) is 2-5 mm, and the hole spacing p is 2.5-5 times the aperture.

2. The porous combustion medium of claim 1, wherein, The angle θ between the extension direction of the corrugated flow channel (3) and the main flow direction of the gas is ± (15°-75°).

3. The porous combustion medium of claim 1, wherein, The wave amplitude A of the corrugated flow channel (3) is 3-10 mm, the wavelength λ is 3-30 mm, the relationship between A and λ satisfies 0.1 ≤ A / λ ≤ 1.0, and the tooth profile angle α is 30°-150°.

4. The porous combustion medium of claim 1, wherein, The plate-hole corrugated combination (1) has a single continuous gradient structure, at least one of the wave amplitude A, the wavelength λ and the tooth profile angle α gradually decreases along the main flow direction of the gas.

5. The porous combustion medium of claim 1, wherein, The plate-hole corrugated combination (1) is a plurality of plate-hole corrugated combinations (1) arranged in sequence along the main flow direction of the gas, and the directions of the corrugated flow channels (3) of adjacent plate-hole corrugated combinations (1) are parallel to each other or intersected at an angle of 5°-90°.

6. The porous combustion medium of claim 1, wherein, The inner wall of the corrugated flow channel (3) is provided with a secondary fluid regulating structure (5) for disturbing the flowing gas.

7. The porous combustion medium of claim 1, wherein, The secondary fluid regulating structure (5) comprises a convex structure which is semispherical or frustum-shaped, the diameter d=0.5-2 mm, and the height h=0.5-3 mm, and the convex structures are staggered or in line along the gas flow direction.

8. The porous combustion medium of claim 7, wherein, The secondary fluid regulating structure (5) comprises a dune structure which is a streamline crescent-shaped protrusion, the length L=1-15 mm, and the height h=0.5-3 mm, the angle (windward side elevation angle) β between the tangent line of the windward side curve at the vertex and the base plane is ≤ 45°, and the angle (leeward side depression angle) γ between the tangent line of the leeward side curve at the vertex and the base plane is ≥ 15°.

9. The porous combustion medium of claim 7, wherein, The combustion chamber (6) is provided with the porous combustion medium.

10. A porous media burner using the porous combustion media as claimed in any one of claims 1 to 9, characterized in that, ​

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