Electrical energy catalyst heater for fluid treatment systems

Abstract

A heater assembly includes a heater body having a monolithic honeycomb structure including a plurality of intersecting walls. The walls have a thickness and extend in an axial direction forming a plurality of cells of the honeycomb structure extending axially from a first end face to a second end face. A first electrode is connected to the heater body. A second electrode is connected to the heater body. A current-carrying path is defined on the walls between the first electrode and the second electrode. A plurality of openings extend through the thickness of at least some of the walls. Fluid handling systems, fluid handling methods, and methods of manufacturing a heater assembly are also disclosed.

Description

Background Technology

[0001] This application claims priority to U.S. Provisional Application No. 63 / 119029, filed November 30, 2020, pursuant to 35 U.S. SC §119, the contents of which are incorporated herein by reference in their entirety. 1. Technical Field

[0002] This disclosure relates to fluid handling systems (e.g., exhaust gas aftertreatment systems), and more specifically, to heater assemblies that are auxiliary for fluid handling (e.g., electrically powered heaters for catalyst activation in exhaust gas aftertreatment systems). 2. Background Technology

[0004] Some fluid handling systems (e.g., engine exhaust aftertreatment systems) can benefit from additional heat supplied by a supplemental heater. Examples of such systems include electrically heated catalytic converter (EHC) systems, which have an electrically powered heater that can be used to rapidly achieve temperatures sufficient to activate the catalyst materials in the engine's aftertreatment process. Summary of the Invention

[0005] In some embodiments, the heater assembly includes: a heater body comprising a monolithic honeycomb structure including a plurality of intersecting walls, wherein the walls have a thickness and extend axially to form a plurality of channels in the honeycomb structure extending axially from a first end face to a second end face; a first electrode connected to the heater body; a second electrode connected to the heater body, wherein a current-carrying path is defined on a wall between the first electrode and the second electrode; and a plurality of openings extending through the thickness of at least some of the walls.

[0006] In some embodiments, the heater assembly also includes multiple insulating slots, each extending laterally over at least a portion of the heater body and interfering with the current-carrying path.

[0007] In some implementations, the insulating groove is formed by the absence of cross walls along the groove.

[0008] In some embodiments, the opening includes a shape having an upstream side and a downstream side (relative to the gas flow through the heater body), wherein a first lateral dimension of the upstream side is wider than a second lateral dimension of the downstream side.

[0009] In some embodiments, the opening includes a shape in which the flow area in the upstream axial half near the upstream side of the shape is greater than that in the downstream axial half near the downstream side of the shape.

[0010] In some embodiments, the openings each include a shape having a gradually tapering end.

[0011] In some implementations, the tapering end is the downstream side of the shape, relative to the gas flow through the heater body.

[0012] In some implementations, the tapering end is triangular, trapezoidal, semi-circular, or semi-elliptical.

[0013] In some implementations, the shape includes a rectangular portion at the upstream end and a triangular portion at the downstream end.

[0014] In some implementations, the shape is pentagonal.

[0015] In some implementations, the channel has a cross-sectional shape surrounded by multiple mesh portions of the wall, each mesh portion extending between the intersections of the walls.

[0016] In some implementations, the cross-sectional shape of the channel is square.

[0017] In some embodiments, each channel is surrounded by multiple sections of a cross wall, and wherein the heater body includes at least one of the openings in each section of the wall.

[0018] In some embodiments, each channel is surrounded by multiple sections of a cross wall, and the heater body includes multiple openings in at least some sections of the wall surrounding each channel.

[0019] In some implementations, at least some sections include at least two rows in the opening.

[0020] In some implementations, at least some sections include columns of openings spaced apart along the axial direction of the section.

[0021] In some implementations, at least some sections include an array of openings, wherein the array includes multiple rows and multiple columns.

[0022] In some embodiments, at least one subgroup of the channel is surrounded by a plurality of segments of cross walls, wherein each of the plurality of segments of the channel includes at least a first wall segment and a second wall segment, wherein the first wall segment and the second wall segment each include at least one opening, and wherein the at least one opening in the first wall segment is not axially aligned with any opening in the second wall segment.

[0023] In some embodiments, the at least one opening in the first wall segment includes a first set of openings axially spaced apart from each other along the first wall segment, wherein the at least one opening in the second wall segment includes a second set of openings axially spaced apart from each other along the second wall segment, and wherein the first set of openings is axially aligned with respect to the second set of openings.

[0024] In some embodiments, the at least one opening in the first wall segment includes a first set of openings axially spaced apart from each other along the first wall segment, wherein the at least one opening in the second wall segment includes a second set of openings axially spaced apart from each other along the second wall segment, and wherein the first set of openings is axially offset relative to the second set of openings.

[0025] In some embodiments, the cross-sectional shape of the channels in the channel subgroup is rectangular, and the first wall section and the second wall section are arranged opposite to each other.

[0026] In some embodiments, the first axial distance between at least a first adjacent pair of axially spaced openings is not equal to the second axial distance between at least a second adjacent pair of axially spaced openings.

[0027] In some implementations, the heater body is arranged in a dish.

[0028] In some embodiments, the fluid handling system includes heater assemblies and ceramic honeycomb bodies in fluid communication with each other from any of the aforementioned segments.

[0029] In some embodiments, the ceramic honeycomb is arranged as a catalyst substrate or a particulate filter.

[0030] In some implementations, the fluid handling system is an exhaust gas aftertreatment system.

[0031] In some embodiments, a method of treating a fluid with any of the fluid handling systems described in the preceding paragraphs includes: applying a voltage potential to the electrodes of a heater assembly to generate heat in the heater body as a result of current flowing through a current-carrying path between the electrodes; heating the airflow with the heat generated by the heater body to increase the temperature of the airflow; and then heating the ceramic honeycomb with the airflow.

[0032] In some embodiments, the ceramic honeycomb includes a catalyst material, and heating the ceramic honeycomb includes igniting the catalyst material to a temperature at which the catalyst material becomes catalytically active.

[0033] In some embodiments, a method of manufacturing a single heater body for a heater assembly includes: forming a plurality of intersecting walls, wherein the walls have a thickness and extend in an axial direction to form a plurality of channels in a honeycomb structure extending axially from a first end face to a second end face; and forming a plurality of openings extending through the thickness of at least some of the walls.

[0034] In some implementations, the method includes connecting a first electrode to a heater body and a second electrode to a heater body, thereby creating a current-carrying path on a cross wall between the first and second electrodes.

[0035] In some embodiments, the method includes forming one or more insulating grooves that extend laterally into the heater body, wherein the insulating grooves interfere with current flow, resulting in a serpentine current-carrying path.

[0036] In some implementations, the cross walls and the plurality of openings are formed simultaneously using an additive manufacturing process.

[0037] In some implementations, additive manufacturing processes include 3D printing.

[0038] It should be understood that the general description above and the detailed description below are merely exemplary, intended to provide a general overview or framework for understanding the nature and characteristics of the claimed subject matter. The accompanying drawings, which are incorporated in and form part of this specification, provide further understanding. The drawings illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles and operation of various embodiments. Attached Figure Description

[0039] Figure 1 This shows the end face of a heater assembly according to one embodiment disclosed herein.

[0040] Figure 2A yes Figure 1 A cross-sectional view of the heater assembly, taken roughly along line 2A-2A, shows multiple openings forming through the cross walls of the heater assembly.

[0041] Figure 2B yes Figure 2A A magnified view of the area shown, revealing one of the openings in more detail.

[0042] Figure 2C The illustration schematically shows a single channel formed by multiple sections of a cross wall of a honeycomb structure for a heater assembly, according to one embodiment disclosed herein.

[0043] Figure 3 The illustration schematically shows a fluid handling system (e.g., an exhaust gas aftertreatment system) including a heater assembly according to one embodiment disclosed herein.

[0044] Figures 4A-4D This document shows alternative shapes for openings in cross walls according to various embodiments disclosed herein.

[0045] Figures 5A-5C This shows patterns of openings arranged in a cross wall according to various embodiments disclosed herein.

[0046] Figures 6A-6BThese are diagrams showing the heating performance of heater assemblies with and without openings in the cross walls, according to various examples described herein. Detailed Implementation

[0047] Reference will now be made in detail to exemplary embodiments illustrated in the accompanying drawings. Wherever possible, the same reference numerals are used throughout the drawings to denote the same or similar components. Components in the drawings are not necessarily to scale; rather, they are highlighted to illustrate the principles of the exemplary embodiments.

[0048] Those skilled in the art, as well as those who utilize and use this disclosure, will make improvements to it. Therefore, it is to be understood that the embodiments shown in the accompanying drawings and described herein are merely illustrative and not intended to limit the scope of this disclosure, which is defined by the appended claims and, in accordance with the principles of patent law, is to include the doctrine of equivalents.

[0049] As used herein, the term “about” means that a quantity, size, formulation, parameter, and other variable and characteristic is not and does not need to be exact, but may be approximate and / or larger or smaller as required, reflecting tolerances, conversion factors, rounding and measurement errors, and other factors known to those skilled in the art. When the term “about” is used to describe a range of values ​​or endpoints, it should be understood that this disclosure also includes the specific values ​​or endpoints referenced.

[0050] The directional terms used in this article, such as up, down, left, right, front, back, top, and bottom, are only for reference to the accompanying drawings and are not intended to indicate absolute orientation.

[0051] Catalytic systems for engine exhaust aftertreatment can achieve temperatures sufficient to activate (i.e., "ignite") the catalyst material through passive heating of the catalyst material by heat from the treated exhaust gas. Alternatively, electrically heated catalyst (EHC) systems use active heating schemes, where the catalyst temperature is increased in part by supplying electrical energy (e.g., directly heating the substrate supporting the catalyst and / or heating a separate heater in fluid communication with the substrate supporting the catalyst). For example, an EHC system may include a heater in fluid communication with the catalyst substrate (e.g., a resistance heater), or the catalyst substrate may include a conductive material and be directly supplied with electrical energy to induce resistance heating of the substrate walls. The electrical energy in an EHC system may also be used for heating types other than resistance heating, such as induction heating.

[0052] In an EHC system, the heaters (specifically, resistance heaters) can be arranged with cross walls of a generally honeycomb pattern, defining an array of channels extending axially between opposite faces of the heaters. The wall material can be conductive, such as metal, conductive ceramic, or composite material, so that the conductive walls are subjected to resistance (joule) heating when current flows through them (e.g., between a pair of electrodes connected to the heater).

[0053] The heater may include a honeycomb structure with cross-walls defining an array of channels extending in an axial (longitudinal) direction. According to embodiments disclosed herein, the heater includes openings that extend laterally through the axially extending surface of the wall. In other words, the openings are traversed through the wall, for example, perpendicular to the axial direction. As described herein, these openings advantageously reduce the mass of the heater, which is useful for reducing the time required for the heater to reach its maximum temperature. Furthermore, by reducing the amount of material in the wall, the openings increase the resistance of the current-carrying path through the wall, which advantageously achieves a reduction in the overall length of the current-carrying path. For example, by increasing the resistance of the wall and thus reducing the required length of the current-carrying path, the wall thickness can be increased and / or fewer, smaller, or shorter laterally extending insulating grooves can be implemented, resulting in an increase in the overall strength of the heater. This increase in strength is particularly advantageous when the heater is used in an EHC system for engine exhaust aftertreatment, as such heaters may need to withstand harsh environments and repeated temperature cycling over many years. Furthermore, the opening, which is roughly transverse to the direction of airflow through the heater (i.e., transverse to the direction of the axis through the heater), advantageously interrupts the airflow through the wall, thereby increasing the interaction between the airflow and the wall, which improves the heat transfer to the airflow.

[0054] See now Figure 1 The heater assembly 10 includes a heater body 12 connected between a pair of electrodes 14. Each electrode 14 may be arranged to include one or more conductive components, such as wires, filaments, rods, plates, or other electrical connectors. Electrodes 14 (or portions thereof) may be connected to the heater body 12 in any suitable manner, for example, integrally formed with crosswalls 16 (monolithic), for example via the same additive manufacturing process, or fixed to or connected to the heater body 12 as separate components. The heater body 12 includes a monolithic (single integrally formed component) honeycomb structure formed by a plurality of crosswalls 16 defining a plurality of channels 18 extending axially through the heater body. The walls 16, formed of a conductive material (e.g., metal or conductive ceramic), are subjected to resistance heating after a voltage is applied to the electrodes 14. Figure 1-3 It includes the x, y, and z axes of the Cartesian coordinate system (if applicable) to help indicate the orientation of these figures and their components relative to each other.

[0055] According to the disclosure herein, heater assembly 10 may be included as part of a fluid handling system (e.g., such as...). Figure 3 This is part of the exhaust gas aftertreatment system 100. In this embodiment, the heater assembly 10 is arranged in fluid communication with a catalyst support body 102 (e.g., a catalyst support substrate for a catalytic converter) within the exhaust gas duct 104. In some embodiments, the body 102 is arranged to include a particulate filter with a plugged honeycomb structure. For example, the body 102 may include a porous ceramic honeycomb structure carrying one or more catalyst materials. As described herein, the heater assembly 10 may be arranged to provide heat to ignite the catalyst material carried on the body 102. The heater assembly 10 may also assist in other processes, such as particulate filter regeneration.

[0056] like Figure 3 As shown, electrode 14 can be connected to energy source 106 to provide the electrical energy required for the operation of heater assembly 10. For example, heater assembly 10 can be arranged to heat airflow 25 (shown as arrows) (e.g., exhaust gas from an internal combustion engine) to a temperature sufficient to ignite as airflow 25 flows through body 102 and heats body 102. In some embodiments, heater assembly 10 is arranged to heat airflow 25 to a temperature of at least 800°C, at least 900°C, or even 1000°C. As a supplement and / or alternative, heater body 12 can be positioned relative to body 102 (e.g., upstream or downstream) to provide radiant heating to body 102.

[0057] The resistance (R) of the heater body 12 depends on the geometric and material parameters of the wall 16 through which the current passes. Therefore, to facilitate obtaining the required resistance, the wall 16 of the heater body 12 can be arranged in a pattern that includes regions containing walls on which no current is carried, thereby setting the length of the current-carrying path 22 between the electrodes 14. For example, as... Figure 1 As shown, the heater body 12 includes a plurality of insulating grooves 20 extending laterally (in the x-direction shown) on the heater body 12. For example, the insulating grooves 20 can be formed without intersecting walls (i.e., without the gaps of intersecting walls 16). Alternatively or supplemented, the grooves 20 can be filled with an electrically insulating material, such as non-conductive ceramic or other materials.

[0058] In this way, slot 20 interferes with the current flow between electrodes 14. That is, slot 20 causes the current to move back and forth laterally (in the x direction shown) to carry the current through current path 22 ( Figure 1(Only a portion is shown) The current flows through the heater body 12 in a serpentine pattern. If the insulating grooves 20 were not present, the current would move substantially in a straight line (the y-direction shown) between the electrodes 14. Therefore, the number, length, and width of the grooves 20 can be selected in this way, and the resistance of the heater body can be set by changing the length of the current-carrying path 22. Figure 1 There are 13 slots 20 that extend laterally from opposite sides into the heater body 12. Any number of slots 20 can be included to determine the total length of the current-carrying path 22.

[0059] Figure 2A This is a cross-sectional view of the heater body 12, taken transversely through and along the central slot 20. Because the cross-section is taken along the length of the slot 20 (where there are no intersecting walls 16), therefore... Figure 2A In the cross-section, the wall 16 and the channel 18 are shown only at the end of the groove 20 (relative to the end of the groove 20). Figure 2A The orientation is towards the left side of the heater body 12. The wall 16 has a thickness 't' (both in the x and y directions, however in...). Figure 2A (The center-oriented view only shows the x-direction). For example... Figure 2A As shown, the heater body 12 has an axial length L (in the z direction) that extends axially between opposite end faces 24a and 24b (which may be collectively referred to herein as "end face 24"). Figure 2A A representative airflow 25 is presented, its direction being axial (z-direction) from the first end face 24a to the second end face 24b, thus the first end face 24a can be regarded as the inlet or upstream end face and the second end face 24b can be regarded as the outlet or downstream end face. Therefore, when the heater assembly 10 is in operation, the axial direction of the heater body 12 corresponds to the direction of the airflow 25, and also corresponds to... Figure 1-3 The z-direction of the coordinate system shown.

[0060] like Figure 2A And such as Figure 2B and 2C As shown in the enlarged view in more detail, the heater body 12 includes an opening 26 in the wall 16. More specifically, the opening 26 is formed in an axially extending surface of the wall 16 (a surface extending in the z-direction, for example having a...). Figure 2A The opening 26 is perforated or penetrates the wall 16 through the thickness t (x and y directions). In other words, the opening 26 extends through the wall 16 in a direction perpendicular to the axial direction (e.g., z direction) (e.g., x or y direction), and thus the direction of the opening 26 is through the wall 16 in a direction perpendicular to the airflow 25 (z direction).

[0061] exist Figure 2AIn this embodiment, some of the outermost channels 18 (near the outer circumference of the heater body 12) do not contain openings 26. More specifically, since current preferentially flows through the shortest feasible path, the outermost channels do not make a significant contribution to heating, so the walls 16 near the outer circumference can remain solid (without openings 26) to increase the strength of the heater body 12 without significantly affecting heating performance.

[0062] Any number of openings 26 can be formed in the wall 16 that defines each channel 18. For example, Figure 2C The schematic representation shows one of a single channel 18, defined in the illustrated embodiment by four grids or segments 28a-28d of wall 16, intersecting at the corners to form a square shape. The provided wall segments 28a-28d are merely examples, and therefore, in any embodiment (shown or not shown), the wall segments may be collectively referred to and / or generally referred to as wall segments 28. In alternative embodiments, the channel 18 may be circular or elliptical (e.g., defined by a single continuous wall segment 28), triangular (e.g., defined by three wall segments 28), hexagonal (e.g., defined by six wall segments 28), octagonal (e.g., defined by eight wall segments 28), or any other shape.

[0063] Regardless of the shape of the channel 18, the wall 16 defines a section of the channel 18 (e.g., Figure 2C Sections 28a-28d can have any number of openings 26 forming through them. For example, in Figure 2A In this design, each wall segment of the channel 18 is defined to have a total of eight openings 26 (two columns and four rows) arranged in a 2x4 array. That is, for each wall segment, Figure 2A The openings 26 are arranged in an array of 4 rows (rows spaced apart sequentially along the axial or z-direction) of 2 openings each. Figure 2C In the middle, each wall section (28a-28d) has a total of 4 openings 26 (2x2 array), Figure 2C The openings 26 are arranged in two rows for each wall section 28a-28d, with two openings in each row. In some embodiments, at least some wall sections 28 have only a single opening 26, or a single row of axially spaced openings 26. In some embodiments, a higher density of openings 26 (number of openings 26 per unit surface area of ​​wall 16) is provided in some regions (e.g., towards the center of the heater body 12), thereby increasing the resistance in those regions and thus increasing the heat generated.

[0064] In some embodiments, each wall segment 28 has the same number of openings 26 formed therethrough, while in other embodiments, different wall segments 28 have different numbers of openings 26. For example, in some embodiments, such as... Figure 2A As shown, the wall 16 near the end of the groove 20 (through which current flows in a serpentine pattern that defines the current-carrying path 22) contains fewer openings 26 (e.g., no openings 26) compared to the section of wall 26 aligned with the length of the groove 20.

[0065] In some embodiments, all and / or all openings 26 of each wall section 28 and the entire heater body 12 are of the same size and / or shape. In some embodiments, the openings 26 in different wall sections 28 are of different sizes and / or shapes, for example, determined by different locations within the heater body 12. In some embodiments, wall sections 28 extending in a transverse direction parallel to the slot 20 (e.g., wall sections extending in the x-direction, for example...) Figure 2C The arrangement of the openings 26 in the wall sections 28b and 28d is different from that of the wall sections 28 extending in a transverse direction perpendicular to the groove 20 (e.g., wall sections extending in the y-direction, e.g.) Figure 2C The wall sections 28a and 28c, for example, different sizes, shapes, orientations, patterns, and / or quantities. For example, although Figure 2C Each wall segment 28 is shown to have an opening 26, but in some embodiments, only portions of the wall 16 extending in a direction parallel to the slot 20 (i.e., wall segments 28b and 28d) have openings 26. In some embodiments, some openings 26 in a single wall segment 28 are different in size or shape from other openings 26 in that wall segment 28. In some embodiments, wall segments 28 defining adjacent channels 18 alternately have openings 26 with different numbers, shapes, sizes, patterns, or orientations.

[0066] Figure 1-2C The opening 26 shown has a generally pentagonal (five sides) shape, but can also be other shapes, such as circles, ellipses, rectangles, squares, triangles, and other polygons, including combinations of these shapes. However, as further discussed herein, the inventors have found that shapes that are wider on the downstream side (with a larger lateral dimension, such as in the x or y direction) relative to the direction of the airflow 25 compared to the upstream side provide unexpectedly superior results. For example, as Figure 2A , 2CAs shown in 5A-5C, the heater assembly 10 is oriented relative to the airflow 25 such that the tapering tip of the pentagonal opening 26 points towards the airflow 25. In other words, the tapering tip of the pentagonal opening 26 is aimed in the opposite direction to the direction of the airflow 25 (rotated 180° relative to each other). Furthermore, pentagons or other shapes with tapering ends are particularly suitable for forming monolithic honeycomb structures for additive manufacturing processes (e.g., powder bed fusion or other 3D printing processes) because the tapering shape typically provides a gradually increasing amount of support for each subsequent printed layer during the printing process.

[0067] Figure 2B An exemplary shape of the opening 26 is shown, wherein the opening 26 has a first lateral dimension (e.g., a first width) W1 on its upstream side 30, which is greater than a second lateral dimension (e.g., a second width) W2 on its downstream side 32. In this example, the second dimension W2 is approximately a single point where the gradually decreasing edges of the pentagonal shape converge, but in other embodiments, the second dimension W2 may be larger than a single point (e.g., in a trapezoidal shape, such as...). Figure 4C (As shown in the example).

[0068] As an alternative to measuring the specific lateral dimensions at the axial extremes of the upstream and downstream edges of its shape, in some embodiments, the flow area of ​​the opening 26 in the upstream half of the shape is greater than the flow area in the downstream half of the shape. Alternatively and / or additionally, in some embodiments, the maximum lateral dimension of the opening 26 (e.g., in the x or y direction) is located in the upstream half of the shape, and the shape gradually decreases from this maximum dimension toward the downstream side. For example, in some embodiments, the shape of the opening 26 is curved on the upstream side 30 and then gradually decreases toward the downstream side 32, such as a teardrop shape (see...). Figure 4D (Examples). For example, from Figure 2B It can be seen that, relative to the centerline drawn at the axial midpoint between the upstream side 30 and the downstream side 32, the area of ​​the shape of the opening 26 in the upstream half (axially, from the upstream side 30 to the centerline) is larger than that in the downstream half (axially, from the centerline to the downstream edge 32). Furthermore, the maximum lateral dimension (in...) Figure 2B In the example, this scale (W1) is located in the upstream half of the shape, and then it gradually decreases in the downstream half of the shape.

[0069] Figures 4A-4D Additional shape examples for opening 26 are shown, such as: Figure 4A The arch shape in the middle (circular on the downstream side 32 and rectangular on the upstream side 30), Figure 4B The triangle shape in the middle, Figure 4CThe trapezoidal shape in, and Figure 4D The teardrop shape in the examples. In each of these examples, the largest lateral scale is in the upstream half of the shape, thus the shape has a larger flow area towards the upstream side compared to the downstream side.

[0070] Although Figure 2A and 3 In one embodiment, the openings 26 in each row are generally aligned and equally spaced along the axial direction, but the openings 26 can be arranged in other patterns, for example, relative to... Figures 5A-5C As shown. More specifically, Figures 5A-5C Showing two different walls of the same channel 18, for example Figure 2C The walls 28b and 28d are arranged opposite each other (two other wall segments interconnected between walls 28b and 28d are not shown). However, the pattern of the opening 26 described herein is not limited to oppositely arranged walls, and thus the pattern described herein can be applied to any two or more sets of different wall segments, such as different wall segments of the same channel or different channels. Furthermore, as an alternative to different wall segments, the pattern described herein can also be applied to openings 26 in different columns within the same wall segment 28 (e.g., Figure 2C (Axially adjacent pairs of openings in each wall segment).

[0071] therefore, Figure 5A The display has similar Figure 2A and 3 In one embodiment of the pattern, the openings 26 in each wall are axially aligned. For example, this can be determined relative to a reference line shown at a common location on each opening 26. Figure 5A The alignment of opening 26 in the middle. That is to say, Figures 5A-5C Each opening 26 in the diagram is shown as a pentagonal shape, serving as a combination of a rectangular base and gradually decreasing triangle apexes, with each rectangular base displaying a center line. (See also...) Figure 5A As shown, the openings 26 are axially aligned, so that the center lines of the shapes of the openings 26 are collinear. Furthermore, in Figure 5A In this context, openings 26 are axially spaced uniformly along wall segments 28. For example, in... Figure 5A In the middle, the axial distance between the leftmost and middle opening 26 and between the middle and rightmost opening 26 are the same, so both of these distances are represented as having an axial distance d1.

[0072] Figure 5B In the illustrated embodiment, the openings 26 in the different wall sections 28 of the channel 18 (e.g., wall sections 28b and 28d defining oppositely arranged rectangular or square channels) are axially staggered. For example, in Figure 5BIn the wall section 28b, the opening 26 is axially misaligned or axially intersecting with the opening 26 in the wall section 28d, such as... Figure 5B The centerlines are not collinear. Instead, each opening 26 in wall segment 28d is spaced axially by a distance d2 from the opening 26 in wall segment 28b. However, similar to Figure 5A , Figure 5B In the embodiment, the openings 26 in each wall segment 28 are spaced apart by a consistent axial distance d1 relative to each other.

[0073] Figure 5C Another embodiment is shown, wherein the axial spacing between axially adjacent openings 26 varies along the length of the wall segment 28. For example, Figure 5C This example illustrates a first pair of axially adjacent openings 26 spaced by a first axial distance d3, and a second pair of axially adjacent openings 26 spaced by a second axial distance d4, different from d3. Although the axial spacing between adjacent openings 26 varies, it is similar to... Figure 5A The openings 5A in the two wall sections 28b and 28d are axially aligned, and the center lines of the shape of the opening 26 are collinear. In some embodiments, arrangements are... Figure 5B and 5C The combination of implementations, wherein the spacing between axially adjacent openings 26 in each wall segment is varied, and wherein the openings 26 in different wall segments 28 are axially misaligned with each other (i.e., the openings 26 in the first wall segment of the channel are axially misaligned or axially staggered relative to the openings in the second wall segment of the channel).

[0074] As relative to Figure 5B As discussed, arranging the openings 26 in a staggered pattern can also help increase flow mixing. For example, staggered or axially offset openings 26 result in uneven pressure due to wall friction, because relative to aligned holes ( Figure 5A In terms of ), hole 26 is deviated ( Figure 5B As a supplement or alternative, varying axial spacing can be arranged. Figure 5C This can alter the flow mixing. For example, the pattern of the openings 26 arrangement can result in a lower density of openings 26 in the upstream portion of the heater body 12 near the upstream or inlet end face 24a (fewer openings 26 per unit surface area of ​​the wall 16, and / or relative to the flow mixing). Figure 5C In this case, the distance d3 is longer than the distance d4, thus providing a higher flow cross-sectional area for the current in the upstream portion of the heater body 12, thereby enabling slightly higher power. In this way, heat transfer efficiency can be further improved and the maximum temperature can be further reduced due to the increased heat transfer to the airflow.

[0075] The influence of opening 26 and its shape and orientation was studied. In the first study, modeling was used to first determine approximately based on the relationship with... Figure 1 and 2A The resistance and corresponding power output of a first heater assembly (“Embodiment 1”) with a given geometry formed by the honeycomb design but without openings 26 in any of the cross walls are then determined. The resistance and output power from the first heater assembly (“Embodiment 1”) are then used as target parameters. Next, a corresponding geometry for a second heater assembly (“Embodiment 2”) capable of achieving the same resistance and output power parameters is determined, wherein the second heater assembly has eight openings 26 per wall segment along the length of the insulating groove (e.g., ...). Figure 1 and 2A (As shown and described). Therefore, the dimensions of the heater assembly in Example 2 are set to match the power output of Example 1. The heater bodies in Examples 1 and 2 are modeled using Inconel 625, respectively. Table 1 summarizes the target parameters, corresponding heater geometries, and other performance variables obtained for these two modeled heaters (represented as Examples 1 and 2). Table 1: Geometries with and without openings that can achieve target properties and obtained heater performance parameters.

[0076]

[0077]

[0078] As summarized in Table 1, the heater body of Example 1 (heater assembly without opening 26) is modeled with a pore density of approximately 361 channels per square inch (cpsi) and a wall thickness of approximately 8 mils (similar to...). Figure 2A The wall thickness (t), 17 laterally extending insulating grooves (similar to) Figure 1 The slot 20), and an axial length of 0.21 inches (similar to...). Figure 2A The axial length L). The mass of the heater body in Example 1 is approximately 60g.

[0079] When a potential of 48V is applied to the electrodes (corresponding to a resistance of approximately 0.385 ohms), the design of Embodiment 1 delivers approximately 6kW of power. These parameters are used as target values ​​to determine the geometry of Embodiment 2, which includes an opening 26 in its wall 16 and is capable of achieving these target parameters. As described herein, including the opening 26 increases the resistance of the heater while all other parameters remain constant. Therefore, in Embodiment 2, the axial length of the heater body of Embodiment 2 is stretched relative to this dimension in the heater body of Embodiment 1 (see...). Figure 2AThe target resistance and output power parameters are achieved by using the axial length L of the heater body. It should be noted that, alternatively, dimensions other than the axial length in Embodiment 2 can be increased, for example, the wall thickness of the heater body (e.g., ...). Figure 2A The wall thickness t) is used to achieve the same heater resistance as in Example 1. Furthermore, since the inclusion of opening 26 reduces the cross-sectional area of ​​the current-carrying path, the number of insulating grooves (see [reference]) can be increased. Figure 1 The number of insulating grooves 20 was reduced from 17 in Example 1 to only 13 in Example 2. Table 1 also summarizes that, despite the increase in the axial length of the heater body in Example 2, the thermal mass was reduced from 60g in Example 1 to approximately 54g in Example 2, while still achieving the target resistance and output power parameters.

[0080] The decrease in thermal mass is directly related to the faster heating time of the heater assembly in Example 2, as shown by the time constant values ​​in Table 1. The time constant is calculated in seconds (s) and is the thermal mass (mCp) divided by the product of the heat transfer efficiency (THC) and the total surface area (TSA). The thermal mass is the product of mass (m) and heat capacity (Cp). Generally speaking, a smaller time constant (as calculated in Table 1) indicates more energy transfer for heating the airflow, resulting in faster airflow heating.

[0081] As summarized in Table 1, the heat transfer efficiency of the heater assembly of Example 2 was found to be significantly increased compared to Example 1, i.e., as a result of better flow mixing achieved by opening 26. The heat transfer efficiency can be determined by multiplying the heat transfer coefficient (HTC) by the total surface area (TSA) of wall 16 (i.e., HTC*TSA). The improved heat transfer efficiency of Example 2 is achieved at least in part because opening 26 disrupts the formation of boundary layers in the airflow through orifices 18 and / or slots 20, and increases flow mixing between adjacent orifices 18 and slots 20 (flow from any given orifice 18 and / or slot 20 can flow through opening 26 into one or more adjacent orifices 18 and / or slots 20). The presence of opening 26 also facilitates the redistribution of flow leaving slot 20, resulting in up to 70% (by mass) of airflow passing through the channel in Example 2, compared to only 54% in Example 1.

[0082] Figure 6A and 6B The display shows a heating comparison (temperature versus time) between the temperature of the heater body and the temperature of the airflow (e.g., airflow 25). Figures 6A-6BAs shown, the heater assembly of Embodiment 2 achieves the combined advantages of faster heater body heating (e.g., due to lower thermal mass) and airflow heating (e.g., due to excellent heat transfer between the heater and the airflow). Furthermore, to prevent damage due to overheating, a target value of 1000°C is set as the maximum temperature for the heater, and the heater assembly of Embodiment 2 achieves this at least in part due to its improved heat transfer efficiency (flow mixing). In contrast, the heater assembly of Embodiment 1 heats both the heater body and the airflow more slowly, and exceeds the target maximum temperature because it is relatively inefficient in transferring heat to the airflow.

[0083] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the claimed subject matter. Therefore, the claimed subject matter is not limited except for the appended claims and their equivalents.

Claims

1. A heater assembly comprising: The heater body includes a monolithic honeycomb structure comprising multiple cross-walls, wherein the multiple cross-walls have a thickness and extend in an axial direction to form multiple channels of the honeycomb structure extending axially from a first end face to a second end face. The first electrode is connected to the heater body; A second electrode connected to the heater body, wherein a current-carrying path is defined on a plurality of cross walls between the first electrode and the second electrode; and Multiple openings extending through at least some of the thickness of multiple intersecting walls, each opening being defined by a shape having an upstream side and a downstream side; For each of the multiple openings: (i) The first lateral dimension measured at the downstream axial extreme on the downstream side is wider than the second lateral dimension measured at the upstream axial extreme on the upstream side, or (ii) The total flow area of ​​the downstream axial half of the shape is greater than that of the entire upstream axial half of the shape, or (iii) The maximum lateral dimension of the shape is located in the downstream axial half of the shape, and all lateral dimensions in the upstream axial half are smaller than the maximum lateral dimension, or (iv) Combinations of (i)-(iii) above.

2. The heater assembly as claimed in claim 1, further comprising a plurality of insulating grooves, each extending laterally over at least a portion of the heater body and interfering with the current-carrying path.

3. The heater assembly as described in claim 1, wherein, Each of the multiple channels has a square cross-sectional shape.

4. The heater assembly as described in claim 1, wherein, Each of the plurality of channels is surrounded by a plurality of sections of a plurality of cross walls, and wherein the heater body includes a plurality of openings in at least some of the sections of the plurality of cross walls surrounding each of the plurality of channels.

5. The heater assembly as described in claim 4, wherein, At least some of the multiple segments include at least two rows of the multiple openings.

6. The heater assembly as described in claim 4, wherein, At least some of the multiple segments include columns of multiple openings spaced apart along the axial direction of the at least some segments.

7. The heater assembly as described in claim 4, wherein, At least some of the multiple segments include an array of multiple openings, wherein the array includes multiple rows and multiple columns.

8. The heater assembly as claimed in claim 1, wherein, At least one subgroup of multiple channels is surrounded by multiple sections of multiple intersecting walls, wherein each of the multiple channels comprises at least a first wall section and a second wall section, wherein the first wall section and the second wall section each comprise at least one of multiple openings, and wherein the at least one opening in the first wall section is not axially aligned with any of the at least one opening in the second wall section.

9. The heater assembly as claimed in claim 8, wherein, The at least one opening in the first wall segment includes a first set of openings axially spaced apart from each other along the first wall segment, wherein the at least one opening in the second wall segment includes a second set of openings axially spaced apart from each other along the second wall segment, and wherein the first set of openings is axially aligned with respect to the second set of openings.

10. The heater assembly as claimed in claim 8, wherein, The at least one opening in the first wall segment includes a first set of openings axially spaced apart from each other along the first wall segment, wherein the at least one opening in the second wall segment includes a second set of openings axially spaced apart from each other along the second wall segment, and wherein the first set of openings is axially offset relative to the second set of openings.

11. The heater assembly as claimed in claim 8, wherein, The cross-sectional shape of multiple channels in the channel group is rectangular, and the first wall section and the second wall section are arranged opposite to each other.

12. The heater assembly as claimed in claim 1, wherein, The first axial distance between at least a first adjacent pair of axially spaced openings is not equal to the second axial distance between at least a second adjacent pair of axially spaced openings.

13. A fluid handling system comprising a heater assembly and a ceramic honeycomb as described in claim 1, which are in fluid communication with each other.

14. The fluid handling system of claim 13, wherein, Ceramic honeycomb structures are arranged as catalyst substrates or particulate filters.

15. A method for treating a fluid using the fluid processing system of claim 13, comprising: A voltage potential is applied to the first and second electrodes of the heater assembly, and heat is generated in the heater body as a result of current flowing through the current-carrying path between the first and second electrodes. The airflow is heated by the heat generated by the heater body to increase its temperature; and then the airflow is used to heat the ceramic honeycomb.

16. A method for manufacturing a single-unit heater body for a heater assembly, the method comprising: Multiple intersecting walls are formed, wherein the multiple intersecting walls have a thickness and extend axially to form multiple channels of a honeycomb structure extending axially from a first end face to a second end face; and Multiple openings of at least some thickness extending through multiple intersecting walls are formed, each opening being defined by a shape having an upstream side and a downstream side; For each of the multiple openings: (i) The first lateral dimension measured at the downstream axial extreme on the downstream side is wider than the second lateral dimension measured at the upstream axial extreme on the upstream side, or (ii) The total flow area of ​​the downstream axial half of the shape is greater than that of the entire upstream axial half of the shape, or (iii) The maximum lateral dimension of the shape is located in the downstream axial half of the shape, and all lateral dimensions in the upstream axial half are smaller than the maximum lateral dimension, or (iv) Combinations of (i)-(iii) above.

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