Combustor Liner

Abstract

The present invention provides a small-hole combustor liner for a gas mitigation system. The combustor liner comprises a hollow body defined by a wall, the wall comprising a plurality of interconnected substantially concentric layers, each layer of the wall comprising a substantially regular openwork mesh, the substantially regular openwork mesh of each layer configured so that it is out of phase with one or more adjacent layers, and the wall comprising sufficient layers arranged such that the wall is optically opaque when viewed externally in any radially inward direction perpendicular to the wall.

Description

[Technical Field]

[0001] The present invention relates to gas reduction system radiant combustors, and more particularly to small-hole combustor liners, methods for designing small-hole combustor liners, and methods for manufacturing small-hole combustor liners. [Background technology]

[0002] Radiation combustors are well known and are typically used, for example, to process exhaust gas streams from manufacturing process tools used in the semiconductor or flat panel display manufacturing industries. During such manufacturing, residual compounds are present in the exhaust gas stream pumped from the processing tool.

[0003] Known radiant combustors use combustion to remove compounds from the exhaust gas stream. Fuel gas is mixed with the exhaust gas stream, and this gas stream mixture is delivered into a combustion chamber laterally surrounded by the outlet surface of a small-hole gas combustor. Fuel gas and air are supplied simultaneously to the small-hole combustor liner to achieve flameless combustion at the outlet surface, and the amount of air passing through the small-hole combustor liner is sufficient not only for supplying fuel gas to the combustor but also for consuming all the combustible material in the mixed gas stream injected into the combustion chamber.

[0004] Typically, perforated combustor liners are made from layup attachments of fibers or polyurethane foams, which may be powder-coated and sintered or unsintered in various ways.

[0005] The inventors have found that known liners have several drawbacks. For example, both fiber-based liners and foam liners are typically formed from sheets, which leads to the presence of seam lines and affects their macro-uniformity. On the other hand, since both the fiber layup and foam formation processes are random or pseudo-random, modifying the properties of combustor liners to this day has relied on operator experience and trial and error. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] European Patent Application Publication No. 1773747 [Overview of the project] [Problems that the invention aims to solve]

[0007] This invention addresses, at least partially, these and other problems of the prior art. [Means for solving the problem]

[0008] In a first aspect, the present invention provides a perforated combustor liner for a gas reduction system. The perforated combustor liner comprises a hollow body defined by a wall. The wall comprises a plurality of interconnected, substantially concentric layers, each layer of the wall comprising a substantially regular perforated mesh. The substantially regular perforated mesh of each layer is configured such that it is phase-shifted with one or more adjacent layers. In addition, the wall comprises a sufficient number of layers arranged such that the wall is optically opaque when viewed from the outside in any radially inward direction perpendicular to the wall.

[0009] In a second aspect, the present invention provides a perforated combustor liner for a gas reduction system, the combustor liner comprising a hollow body defined by walls, the walls comprising a plurality of interconnecting layers, the layers comprising at least one substantially right-handed helical support coupled to at least one substantially left-handed helical support.

[0010] The present invention further provides a method for manufacturing a small-hole combustor liner in the manner described above, preferably by additive manufacturing.

[0011] Advantageously, the perforated combustor liners and manufacturing methods disclosed herein provide a regular structure that mimics the random structure of prior art foam and fiber layup combustor liners, thereby enabling predictable control of combustor characteristics, simplifying optimization, and avoiding the need for trial-and-error experiments associated with known combustor liner designs.

[0012] The result is a structure that can support combustion with a uniform inner surface ignition rate, low back temperature, and minimum thickness. Nearly six fewer layers can achieve an optical blind spot, and three times this amount are needed to provide a sufficiently low back temperature for the optical blind spot. The design objective is considered to be achieving maximum thermal conductivity within the layers while minimizing inter-layer conductivity. Typically, in use, the back temperature (i.e., the temperature of the outermost surface of the wall) will be approximately the ambient temperature (e.g., 22°C). Typically, in use, the inner surface (e.g., the innermost surface of the wall) will be between approximately 800°C and 1000°C. Fuel and air typically flow from the back to the inside for combustion.

[0013] The present invention will be further described below with reference to the following figures, which are intended to be non-limiting. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram of a small-pore combustor layer. [Figure 2] This is a schematic diagram of a small-pore combustor layer. [Figure 3] This diagram shows a single left-handed spiral in a small-hole combustor liner. [Figure 4] This diagram shows left-handed and right-handed spirals of a small-hole combustor liner. [Figure 5] This is a diagram showing one layer of the small-hole combustor liner. [Figure 6] This diagram shows the two layers of the small-hole combustor liner. [Figure 7] This is a diagram showing a 10-layer small-perforation combustor liner. [Figure 8]It is a view showing the innermost layer of the small-hole combustor liner. [Figure 9] It is a view showing two layers of a combustor liner having an intermediate spacer layer. [Figure 10] It is a view showing an optically opaque wall of the small-hole combustor liner. [Figure 11] It is a view seen from above the combustor liner wall of FIG. 10. [Figure 12] It is a view showing a combustor liner having an outer perforated foil coating. [Figure 13] It is a view showing a spiral tape used to form the foil coating of FIG. 2. [Figure 14] It is a view showing a truncated conical combustor liner.

Best Mode for Carrying Out the Invention

[0015] The present invention provides a small-hole combustor liner for a gas reduction system. The combustor liner includes a hollow body defined by a wall. The wall includes a plurality of interconnected layers.

[0016] Each layer of the wall defining the hollow body can include a substantially regular perforated mesh. Typically, the mesh will include a plurality of struts and nodes arranged to form a porous mesh. The mesh may be composed of one or more repeating units, and preferably each repeating unit is substantially identical, and preferably each repeating unit includes a plurality of struts and nodes defining one or more pores or voids. Typically, the volume fraction of the voids is relatively large compared to the volume fraction of the repeating unit, and preferably, most of the repeating unit by volume is void.

[0017] Preferably, the perforated combustor liner is optically opaque when viewed from the outside in any radially inward direction perpendicular to the outermost surface of the wall. That is, the wall can have sufficient layers arranged such that there are no linear radially inward paths from the outermost surface of the wall to the innermost surface of the wall that are not obstructed (i.e., intersecting) by at least one support and / or knot forming part of the wall. The perforated mesh has voids or holes that provide linear radially inward paths through the entire thickness of the layer. Therefore, a single layer of the perforated combustor liner wall cannot be both perforated mesh and optically opaque.

[0018] The minimum number of layers required to achieve optical opacity may be influenced by the diameter of the support columns and the phase offset between adjacent layers.

[0019] Preferably, the wall comprises a number of layers greater than the minimum required to achieve optical opacity, preferably at least twice the number of layers required to achieve optical opacity, and more preferably at least three times the number of layers required to achieve optical opacity. Typically, the wall comprises at least three layers, for example, about 3 to about 20 layers, preferably about 4 to about 12 layers, and more preferably about 4 to about 9 layers.

[0020] Advantageously, the 3x optical opacity provides a sufficiently low back temperature (e.g., about ambient temperature) during use.

[0021] The perforated mesh of each layer can be configured such that it is phase-shifted from one or more adjacent layers. That is, the repeating units of adjacent layers are not aligned when viewed radially inward, perpendicular to the outer surface of the layer. Instead, typically, the repeating units of one layer will be circumferentially offset from the repeating units of adjacent layers such that the nodes of adjacent layers are not aligned when viewed radially inward, perpendicular to the outermost layer of the wall.

[0022] Preferably, at least a portion of the corresponding supports of the repeating units in adjacent layers will overlap at least partially but not completely when viewed in a radially inward direction perpendicular to the outermost layer of the wall. The circumferential offset between adjacent layers is sometimes referred to as the interlayer pitch. Typically, the interlayer pitch is about 5% to 30% of the support diameter, with about 10% being an example.

[0023] Preferably, the mesh is substantially continuous around the entire layer. Advantageously, there are considered to be no seams between layers.

[0024] Preferably, the layer comprises at least one substantially right-handed helical support connected to at least one substantially left-handed helical support, preferably a plurality of substantially right-handed helical supports connected to at least one substantially left-handed helical support.

[0025] layer When the system comprises two or three substantially right-handed helical struts connected to two or three or more substantially left-handed helical struts, preferably the right-handed struts are substantially parallel and the left-handed struts are also substantially parallel.

[0026] Preferably, the right-handed supports of each layer are substantially parallel to the right-handed supports of each other layer. Preferably, the left-handed supports of each layer are substantially parallel to the left-handed supports of each other layer.

[0027] Preferably, the right-handed and left-handed helical supports of each layer have substantially the same helical pitch. The helical pitch may be defined as the height of one complete helical turn, measured parallel to the axis of the helix.

[0028] The right-handed and left-handed spiral supports of a layer may also be offset circumferentially by the intra-layer pitch. Typically, the intra-layer pitch may be the same as or different from the inter-layer pitch.

[0029] In this specification, right-handed or left-handed helices may be referred to as instances. A wall layer may comprise one or more instances, typically two or more instances. Preferably, there are about 6 to about 400 instances, more preferably about 8 to about 120 instances. Reducing the number of instances in a layer increases nodal separation for a given helical pitch and combustor liner circumference. The number of instances is typically higher for combustor liners with relatively high helical pitches (about 100 to 400 instances) and lower for those with relatively low helical pitches (about 6 to about 20 instances). Generally, a higher number of instances per layer results in a lower number of layers required to achieve optical opacity for a given column diameter and layer pitch.

[0030] As discussed, the intra-layer pitch and inter-layer pitch may be substantially the same. Preferably, the intra-layer pitch is about 5% to about 30% of the column diameter, with about 10% being an example.

[0031] Similar to contributing to the number of layers required for optical opacity, greater than zero interlayer and intralayer pitches ensure that helical struts can intersect adjacent helical struts at nodes. That is, the struts overlap at nodes radially with respect to the longitudinal axis of the combustor liner.

[0032] The amount of overlap contributes to both the structural integrity of the wall and its radial thermal conductivity. Therefore, a balance can be struck between these two properties depending on the material selection, the size of the combustor, and its intended use. A radial overlap of approximately 10%, preferably about 5% to 15%, of the column diameter of the combustor liner relative to the longitudinal axis has been found to be particularly advantageous in low-helix-pitch embodiments.

[0033] Conversely, intralayer overlaps of approximately 100% of the column width, for example, greater than approximately 90% or greater than approximately 95%, have also been found to be advantageous, particularly for high-helix-pitch embodiments with a relatively high number of instances per layer.

[0034] For the purposes of this invention, a relatively low helical pitch can be considered to have a pitch angle of approximately X to approximately Y.

[0035] In addition to or instead of this, a relatively high helical pitch can be considered to have a pitch angle greater than Y, preferably from about V to about W.

[0036] As discussed, in embodiments, each layer may comprise a plurality of right-handed substantially helical struts coupled to a plurality of spaced left-handed substantially helical struts. In addition, one or more substantially helical struts in each layer may intersect and be integrally formed with substantially helical struts in adjacent layers. Preferably, each substantially helical strut intersects and is integrally formed with substantially helical struts in adjacent layers.

[0037] In alternative embodiments, one or more radially extending spacers can connect the first layer to adjacent layers. Typically, multiple circumferentially separated radially extending spacers separate the first layer from adjacent layers. These radially extending spacers take the form of intermediate spacing layers that separate each adjacent primary layer of a wall.

[0038] Preferably, the spacers are spaced substantially uniformly around the inner outer surfaces of the two layers and the outer inner surfaces of the two layers and bonded to them. Typically, the spacers separate one layer from an adjacent layer by a radial distance substantially equal to the diameter and / or radial thickness of the spacer. When there are multiple intermediate spacer layers in a small-hole combustor, preferably, the spacers of adjacent intermediate spacer layers are offset circumferentially. The spacers can favorably reduce radial / interlayer heat conduction and / or increase the heat path through the combustor, as is the case when the internode separation is relatively low.

[0039] Radially extending spacers may take the form of barrel slabs, typically longitudinally extending barrel slabs. Typically, longitudinally extending barrel slabs can be substantially straight, but they may equally be spiral or part of a spiral.

[0040] The intermediate spacer layer is typically used in the walls of a small-perforation combustor liner having low nodular separation, for example, less than about 4 mm, preferably about 1 mm to about 4 mm.

[0041] As those skilled in the art will recognize below, the size of the walls of a perforated combustor liner will depend on the intended application, and therefore the present invention is intended not to be limited to any particular wall shape. However, typically, a perforated combustor liner wall will be substantially tubular with a substantially annular cross-section. The radial thickness of the wall is typically relatively small compared to the radius of the tube it provides.

[0042] Typically, the walls of the small-hole combustor liner will have an axial length of 50 mm to about 500 mm, more preferably about 60 mm to about 200 mm, with about 75 mm and about 150 mm being examples.

[0043] The inner diameter of the wall of the small-hole combustor liner may be approximately 50 mm to approximately 250 mm, preferably approximately 100 mm to approximately 200 mm, with approximately 150 mm and approximately 175 mm being examples.

[0044] Typically, the aspect ratio (i.e., the ratio of the inner diameter of the wall to its height) is about 5:1 to about 1:5, such as about 3:1 to about 1:3. Aspect ratios greater than 1:1 are preferred, such as about 1:1 to about 1:5 or preferably about 2:3 to about 1:3.

[0045] The radial thickness of the wall of the perforated combustor liner is preferably 1 to about 10 mm, and preferably about 2 mm to about 6 mm.

[0046] While we do not wish to be bound by theory, the number of helical turns completed by each substantially helical support in each layer will be determined by its helical pitch and the aspect ratio of the perforated combustor liner. For example, a relatively low-pitch helix can perform a relatively high number of helical turns for a given length of combustor liner, while a relatively high-pitch helix will perform a lower number of helical turns for the same length of combustor.

[0047] A small-perforated combustor liner may be provided in which each of the substantially right-handed and substantially left-handed helical struts in each layer completes more than one complete helical winding. Alternatively, each substantially helical strut may complete a portion of the helical winding, preferably one or fewer helical windings.

[0048] Referring to Figures 1 and 2, which show the unfolded layers laid flat for the purpose of understanding, here is the case: H = height HP = Helical Pitch <°=Pitch angle=Tan- 1 (HP / C) C = circumference = π.D D=diameter C / I = Circumference ÷ Number of Instances I = Instance (of the LH or RH helix in the layer) NS=nodule separation=(C 2 +HP 2 ) 0.5 / (2xI) n = starting angle, and ((360 / instance) / (offset-1) = 0, n, 2n, 3n, etc. is used for calculation.

[0049] Table 1 shows, as a non-limiting example, how adjusting various parameters of the combustor liner, including inner diameter, height, wire diameter, in-layer pitch, instance, layer, and inter-layer pitch, facilitates control of nodule separation, density, and wire size. Note, for example, that nodule separation can be significantly increased or decreased without a similar effect on the volumetric density of the combustor liner. TIFF0007853963000001.tif142157 * ((360 / instance) / (offset-1) starting angle calculated as n, 2n, 3n, etc.) ** To achieve blind spots, arbitrary parameters based on wire thickness and wire separation

[0050] Therefore, those skilled in the art can adjust the characteristics of the combustor liner in a predictable manner to address the problems identified in known small-hole combustors.

[0051] Preferably, the porous combustor liner wall has a volume density of about 65% to about 90%, more preferably about 70% to about 85%. This can be calculated by comparing the calculated mass of the porous structure with that of a solid cylinder of the same nominal dimensions.

[0052] We now move to Figure 3, which shows a left-handed, substantially spiral support (1). The spiral (1) has a height (H) of 75 mm and a spiral pitch of 25 mm. That is, the illustrated spiral (1) has three spiral turns. The diameter of the support is 0.3 mm.

[0053] Figure 4 shows a right-handed spiral support (2) coupled to a left-handed spiral support (1) in Figure 2 to form a pair of spiral instances (3). The right-handed spiral (2) is substantially identical to the left-handed spiral (1), except for their palmarity. The in-layer offset is 0.27 mm so that when the spiral supports overlap substantially, they do so by about 10% of their diameter. Preferably, the substantially spiral supports of the instance pair intersect at one end in an end-to-end, face-to-face configuration. In the embodiment shown in Figure 3, both ends of the spiral supports forming the instance pair intersect at end-to-end, face-to-face configuration.

[0054] While not mandatory, preferably, every helical support in a layer begins with a knot (13) and / or ends with a knot (14), and preferably, every helical support in any layer of the wall begins with a knot and / or ends with a knot. Such a configuration can facilitate manufacturing and / or improve structural robustness.

[0055] Figure 5 shows a layer comprising 12 instance pairs (24 helical instances) according to Figure 3. This layer is the innermost layer of the wall. The inner diameter (D) of the wall is 75 mm. All helical columns have a nearly circular cross-section. All helical columns have substantially the same diameter (e.g., 0.3 mm).

[0056] Figure 6 shows the first layer (4) of Figure 5 surrounded by a second layer (5). In the illustrated embodiment, the second layer (5) has the same number of instances as the innermost layer (4). Typically, each layer has the same number of instances, but the number of instances can be similarly increased or decreased in the radially outward direction.

[0057] The interlayer pitch between the first and second layers is 0.27 mm. The intralayer offset is 0.27 mm. Therefore, when the supports of adjacent layers form a knot, the adjacent layers overlap by approximately 10% of their diameters.

[0058] As can be seen by providing a second layer (4) offset from the innermost layer, the optical transparency of the combustor liner can be reduced. That is, when viewed in the radially inward direction, there is a reduction in the area of ​​the outer layer from which a direct and unobstructed path to the longitudinal axis of the combustor liner exists.

[0059] As previously discussed, preferably, the perforated combustor liner has a layer sufficient to be optically opaque. Advantageously, this means there are no direct radial paths from the outer surface of the combustor liner to the inner surface of the combustor liner, which could lead to localized overheating.

[0060] Figure 7 shows a perforated combustor liner wall (6) comprising the layers shown in Figures 5 and 6, constructed up to 10 concentric layers. This combustor liner wall is optically opaque in any radially inward direction perpendicular to the outer surface of the wall.

[0061] Preferably, the perforated combustor liner comprises at least three times the minimum number of layers required to achieve optical opacity for a selected layer configuration, each of which is referred to herein individually as an opacity group. The minimum number of layers required to achieve optical opacity can be calculated using finite element analysis. The wall may comprise about 9 to about 25 layers.

[0062] Advantageously, as can be seen, the small-perforation combustor liner does not have seams because each layer is substantially uniform and continuous. The absence of seams improves the macro-uniformity of the combustor liner and therefore its performance. In embodiments, the combustor liner can be substantially isotropic in the transverse direction.

[0063] Figure 8 shows the innermost layer (7) from a small-hole combustor with an alternative configuration.

[0064] As shown in the figure, layer (7) comprises multiple left-handed (8) and right-handed (9) helical struts. In this example, the overlap of the helical struts within the layer is substantially 100%. That is, the helical struts pass linearly through each other at each node (16). The height of the small-hole combustor liner is again 75 mm, but the helical pitch is 250 mm so that each helical strut completes a helical turn of 0.3 mm. The helical struts have a diameter of 0.3 mm. There are 120 instances in the layer. This can be considered a relatively steep-angle (high-pitch) structure. Such a structure may be advantageous because it can be more easily additively manufactured.

[0065] Similar to previous embodiments, the substantially spiral supports intersect at one end in an end-to-end and face-to-face configuration.

[0066] Preferably, every helical column in a layer begins and / or ends with a knot (15), and preferably, every helical column in any layer of the wall begins and / or ends with a knot. Such a configuration can facilitate manufacturing and / or improve mechanical strength and structural robustness.

[0067] As can be seen from Figures and Table 1, the separation of the nodes provided by this type of arrangement can be substantially smaller than that in the arrangements shown in Figures 1 to 7.

[0068] The smaller the node spacing, the higher the thermal conductivity can be.

[0069] The illustrated watermark mesh has repeating units with diamond unit cells. As can be seen in Figures 8 and 9, the illustrated repeating units within a layer are substantially identical. Similarly, the repeating units in each layer are substantially identical to those in adjacent layers.

[0070] In this embodiment, the adjacent layer can be formed directly on the outer surface of the inner layer.

[0071] Alternatively, as shown in Figure 9, radially adjacent layers (10, 11) can be joined to each other using one or more radially extending spacers (12). In the illustrated embodiment, the radially extending spacers (12) are in the form of one or more longitudinally extending barrel slabs (12). The illustrated barrel slabs are substantially linear.

[0072] The circumferential separation (CS) of the radially extending spacer (12) is equal to or greater than the nodal separation (NS) of the layer, preferably greater than the nodal separation (NS) of the layer, and preferably at least twice as much as the nodal separation (NS) of the layer.

[0073] In embodiments, radially extending spacers (12) can be considered as intermediate spacer layers separating the primary layers (10, 11) of the wall (i.e., layers formed substantially from helical supports). Preferably, each intermediate spacer layer (12) may comprise longitudinal supports of about 10 to about 50, preferably about 20 to about 30, with 24 being an example. Preferably, the longitudinally extending barrels of the spacer layer are substantially uniformly separated circumferentially (i.e., uniformly spaced around the circumference of the layer to which the spacer layer is attached).

[0074] Preferably, the barrel planks extending in the longitudinal direction have circumferential spacing of about 5 to about 20 mm, with 10 mm being an example. The diameter of the barrel planks may be substantially larger or smaller than the diameter of the spiral supports, but preferably substantially the same.

[0075] Advantageously, by providing radially extending spacers, the interlayer thermal conductivity of the wall can be significantly reduced, and / or the adjustable properties of the porous combustor liner can be further increased, and / or the structural integrity of the wall can be improved.

[0076] As shown in Figures 9 and 11, the adjacent layers (10,11) are phase-shifted, so the nodes (17,18)(19,20) of the adjacent layers are offset. That is, the nodes of one layer do not overlap with the nodes of an adjacent layer. Preferably, as shown, the nodes of the next outer layer are positioned to be approximately radially aligned with the centroid of an unobstructed path (gap) to the center of the combustor liner, starting from the innermost layer and passing through all those layers in its radially inward direction. Typically, this arrangement will be repeated from the innermost layer of the wall until optical opacity is provided. Thereafter, the same arrangement can be repeated through any further group of opacities positioned in its radially outward direction.

[0077] As will be seen below, the number of layers required to achieve optical opacity will substantially depend on the thickness (diameter) of the helical supports, the number of instances per layer, the shape and number of radially extending spacers, and the diameter of the walls. Preferably, about four or five layers are required to achieve optical opacity.

[0078] Preferably, the substantially spiral support has a substantially circular cross-section. Preferably, the substantially spiral support has a diameter of about 0.1 mm to about 1 mm, more preferably about 0.2 mm to about 0.7 mm, with 0.3 mm being an example.

[0079] Preferably, the wall comprises at least three times the minimum number of layers required to achieve optical opacity (i.e., at least three opacity groups). Figure 10 shows an optically opaque wall (23) according to this embodiment.

[0080] Increasing the number of opacity groups increases the heat path from the outermost surface of the combustor liner wall to the innermost surface of the combustor liner wall. Preferably, each opacity group repeats the interlayer offset pattern used to provide the same opacity as its radially inward opacity group.

[0081] Advantageously, such arrangements have been found to provide desirable heat transfer characteristics equivalent to those of known combustor liners.

[0082] Preferably, when present, radially extending spacers in adjacent intermediate spacer layers, particularly longitudinally extending barrel plates (21, 22), can also be offset circumferentially. Such arrangements are shown in Figures 8 and 11. Advantageously, this also increases the heat path and / or reduces thermal conductivity through the walls.

[0083] While the perforated combustor liners shown are all substantially cylindrical tubes, it will be acknowledged that combustor liners according to the present invention can take the form of other hollow bodies, such as the hollow truncated conical combustor liner shown in Figure 14. Those skilled in the art will recognize that the shape of the helical path and repeating units of the struts may vary throughout and / or between layers to accommodate non-cylindrical hollow bodies.

[0084] The inventors have also found that by using struts with a uniform circular cross-section to form a truncated cone combustor, a higher porosity can be obtained at the blunt end of the tapered section, which is particularly noticeable in structures with a large aspect ratio. This can be addressed by varying the cross-section of the struts from one end to the other. For example, smaller diameter helical struts can be used at the narrow end of the truncated cone combustor liner and larger diameter struts at its wider end, or more preferably, helical struts with an elliptical cross-section whose cross-section changes can be used, or even more preferably, inclined elliptical cross-section struts can be used at the larger end if the inclination angle matches the tapering angle.

[0085] In addition to or instead of this, the small-hole combustor line may further comprise one or more flow dispersion elements, preferably in the form of a pair of counter-rotating spiral ribbons (26, 27), as shown in Figure 13.

[0086] Typically, the spiral pitch and ribbon shape are selected so that a chosen number of instances of the circular pattern give control over the open area.

[0087] As shown in FIG. 12, the small hole combustor liner described herein can further include a perforated sheet (24) coupled to the outermost layer (upstream) of the wall, the perforated sheet defining the outer surface of the small hole combustor liner. Preferably, the openings (25) of the sheet are substantially aligned with the voids at the outermost layer of the wall. The perforated sheet (24) can be formed integrally with or later coupled to the rest of the combustor liner. In addition or alternatively, the perforated foil can be formed from a circular pattern of counter-rotating ribbons such as those shown in FIG. 13.

[0088] Preferably, the flow dispersion element has an open area of about 5% (e.g., the area of the openings) and / or a pore size (e.g., the opening size) between 0.75 mm such as 0.8 mm 2 to 1 mm 2 such as 0.8 mm 2 to 1 mm.

[0089] Preferably, the flow dispersion element, such as the ribbon and / or the perforated sheet, is preferably a metal comprising a high temperature oxidation resistant alloy preferably selected from the group consisting of metals or alloys, preferably iron-chromium-ytterbium alloys, Inconel® 600 and 718, 314 stainless steel, and iron-chromium-aluminum alloys.

[0090] Preferably, the small hole combustor liner is a single unitary structure. Preferably, it is made of a single material, preferably a metallic material.

[0091] Preferably, the small hole combustor liner is preferably additively manufactured using a powder bed fusion technique. Preferably, the build direction is parallel to the longitudinal axis of the small hole combustor liner.

[0092] Alternatively, the combustor liner can be formed from a molten wire.

[0093] Preferably, the combustor liner is made of metal. Preferably, the combustor liner is made of metal or alloy, preferably a high-temperature oxidation-resistant alloy preferably selected from the group consisting of iron-chromium-yttrium alloy, Inconel 600 and 718, and 314 stainless steel, and iron-chromium-aluminum alloy.

[0094] The combustor liner of the present invention may preferably be fitted to a radiant combustor in a gas reduction system for inward-ignition flameless combustion. The present invention also provides a gas reduction system comprising a small-hole combustor according to the embodiments and aspects disclosed of the present invention. The small-hole combustor liner according to the present invention may be installed during the manufacture of the radiant combustor or replaced in a previously used radiant combustor. Suitable radiant combustors are described in EP1773747A and / or sold by Edwards Vacuum (RTM) under the trade name Atlas (RTM).

[0095] To avoid any ambiguity, any features of any aspect or embodiment listed herein can be combined with one another.

[0096] It will be acknowledged that various modifications can be made to the embodiments shown without departing from the spirit and scope of the invention as defined by the attached claims when interpreted under patent law.

[0097] Reference number 1 Left-handed spiral support 2 Right-handed spiral support 3 spiral instance pairs 4. Innermost layer 5. The second layer 6. Small-hole combustor liner wall 7. Innermost layer 8 Left-handed spiral 9 Right-handed spiral 10 Inner layer 11 Outer layer 12. Barrel planks extending in the longitudinal direction 13 Nodules 14 Nodules 15 Nodules 16 Nodules 17 Nodules 18 Nodules 19 Nodules 20 nodules 21. Barrel planks extending in the longitudinal direction 22. Barrel planks extending in the longitudinal direction 23 Wall 24 Perforated Sheets 25 Aperture 26 Spiral Ribbon 27 Spiral Ribbon 28 Truncated cone small hole combustor liner

Claims

1. A small-pore combustor liner for a gas abatement system, It comprises a hollow body defined by walls having multiple interconnected concentric layers, Each layer of the aforementioned wall is provided with a regular perforated mesh, The regular perforated mesh in each layer is configured such that it is phase-shifted from one or more adjacent layers. The wall comprises a sufficient layer arranged such that the wall is optically opaque when viewed from the outside in any radially inward direction perpendicular to the wall. The aforementioned wall has 3 to 20 layers, The layer comprises at least one right-handed spiral support connected to at least one left-handed spiral support, and each spiral support completes less than one spiral turn. One or more spacers in the form of barrel boards extending radially and longitudinally connect the first layer to an adjacent layer. Small-hole combustion chamber liner.

2. The wall comprises more layers than required to achieve optical opacity. The small-hole combustor liner according to claim 1.

3. The wall comprises at least twice the number of layers required to achieve optical opacity. The small-hole combustor liner according to claim 1.

4. The wall comprises at least three times the number of layers required to achieve optical opacity. The small-hole combustor liner according to claim 1.

5. The aforementioned wall comprises 4 to 9 layers. A small-perforated combustion liner according to any one of claims 1 to 4.

6. The aforementioned multiple interconnected layers are arranged in a concentric pattern. A small-perforated combustor liner according to any one of claims 1 to 5.

7. The hollow body is tubular or truncated cone-shaped. A small-perforated combustion liner according to any one of claims 1 to 6.

8. The outermost layer of the wall is bonded to a perforated sheet that defines the outer surface of the small-perforated combustor liner. The perforations in the perforated sheet are aligned with the opening in the outermost layer of the wall. A small-perforated combustor liner according to any one of claims 1 to 7.

9. A small-hole combustor liner according to any one of claims 1 to 8, A small-perforated combustor liner characterized by being manufactured using powder bed melting.

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