INTEGRATED HEADERS FOR HEAT EXCHANGERS

Abstract

A plurality of heat exchanger designs with integrated headers are provided. The heat exchanger comprises a heat exchanger matrix with a plurality of flow paths in a first direction wherein the plurality of flow paths are patterned to create a plurality of inputs to the plurality of flow paths on an input surface. The integrated header comprises a primary distribution header and a plurality of distribution header channels that connect to a plurality of feeder tubes that fluidly couple the plurality of distribution header channels with the plurality of matrix inputs such that there is a single feeder tube for each input.

Description

FIELD

The present patent document relates to headers for additively manufactured heat exchangers and in particular headers that are integrated into the additively manufactured design.

BACKGROUND

In recent years, advancements in Additive Manufacturing (AM) have made it a viable option for the production of heat exchangers and heat exchanger components. The use of AM for heat exchangers has opened up new possibilities for heat exchanger geometries. In particular, heat exchangers can now be made with geometries previously not possible to manufacture using traditional methods. Applicant has provided numerous novel heat exchanger designs for AM in U.S. patent application Ser. No. 17/531,681, which is hereby incorporated by reference in its entirety.

A typical fluid-fluid heat exchanger assembly includes a chamber, commonly called a header, which contains porting for connection with the fluid supply and return. The supply and return headers can be separate components or can be combined for heat exchanger matrices with multiple passes. A typical header attaches to the heat exchanger core by welding or mechanical fasteners.

However, when AM is used, in addition to the heat exchanger matrix being designed and built using AM, the headers may also be integrated into the AM design and produced using AM. The production could be simultaneously with the heat exchanger matrix or the matrix and headers could be made separately and joined after the AM process. In addition, headers, which have forms that are hard to manufacture with conventional means, could be manufactured using AM and attached to non-AM cores.

The typical header chamber form is such that expansion/contraction pressure losses are minimized and uniform flow distribution across the core is promoted. Since the fluid wetted area is defined by the perimeter of the core the pressure vessel is relatively large, requiring thick walls or stiffening features to contain the pressure loads for the header walls and the matrix interface which may create undesirable weight.

A tubeplate is the portion of the header that forms the barrier to the secondary fluid at the side of the core matrix and in conventional designs, is part of the header pressure vessel. The tubeplate can experience high pressure loads from the fluid contained within the header and, in some designs, these high-pressure loads can be a design limitation. Flow expansion from the port into the chamber is the main source of header pressure losses. Header forms designed to reduce the expansion impact must be balanced against installation envelope restrictions.

To this end, there is a need in the industry for a more efficient heat exchanger header design that reduces wall pressures and creates a more efficient heat exchanger. There is also a need for heat exchanger headers that work effectively with the more complex geometries of heat exchanger matrices that were created using the AM process.

SUMMARY OF THE EMBODIMENTS

One object of the present patent document is to provide an improved heat exchanger header and/or new heat exchanger system including a header and matrix. In preferred embodiments, a heat exchanger comprises a heat exchanger matrix with a plurality of flow paths in a first direction wherein the plurality of flow paths are patterned to create a plurality of inputs to the plurality of flow paths on an input surface. In most embodiments, the input surface is a two-dimensional plane. However, in some embodiments, the input surface may be a three-dimensional surface such as a curved surface or any other type of surface.

The heat exchanger comprises a header and that header comprises a primary distribution header that spans across the input surface in a second direction. The header further comprises a plurality of distribution header channels that span across the input surface in a third direction perpendicular to the second direction wherein each distribution header channel in the plurality of distribution header channels is in fluid communication with the primary distribution header. The header further comprises a plurality of feeder tubes that fluidly couple and/or form a contiguous volume with the plurality of distribution header channels with the plurality of inputs such that there is a single feeder tube for each input in the heat exchanger matrix.

In some embodiments, each distribution header channel tapers from an interface with the primary distribution header towards a distal end of the distribution header channel.

In some embodiments, the cross section of each distribution header channel is shaped in a teardrop. The tear drop shape enables AM manufacture in a particular build orientation and is not a functional feature of the header. To this end, the teardrop shape may have different orientations in different embodiments. In some of those embodiments, the points of each teardrop are all oriented in the second direction parallel to the primary header longitudinal axis.

In some embodiments, the plurality of distribution header channels comprises at least two layers stacked in the first direction. In embodiments with multiple layers of distribution header channels, some embodiments have a first layer of distribution header channels that are offset in the second direction from a second layer of distribution header channels. This allows for a greater packing density of distribution header channels.

In order to increase structural rigidity and keep weight to a minimum, some embodiments of the heat exchanger comprise a plurality of fins run in the second direction wherein a fin mechanically couples each feeder tube to a distribution header channel. The fins or ribs may also be used for AM build support as well as some level of structural support.

In some embodiments, a wall gap separates the input surface from the header.

In yet other embodiments, each distribution header channel has more than one feeder tube extending to the input surface along a single plane in the second direction.

In still yet other embodiments, each distribution header channel spans more than one input along the second direction. In some embodiments, like those that span more than one input, a cross-section of each distribution header channel is shaped like a “D”. In embodiments with a “D” shaped cross-section a tubeplate may separate the input surface from the header. The tubeplate forms the flat side of the “D” shaped cross-section.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a top-down view of a first embodiment of a heat exchanger with an integrated header that was manufactured using AM;

FIG. 2 illustrates a cutaway isometric view of the heat exchanger with a header of FIG. 1;

FIG. 3 illustrates a top-down view of a second embodiment of a heat exchanger with an integrated header that was manufactured using AM;

FIG. 4 illustrates an isometric view of the heat exchanger with a header of FIG. 3;

FIG. 5 illustrates an isometric view of a third embodiment of a heat exchanger with an integrated header that was manufactured using AM;

FIG. 6 illustrates a cutaway isometric view of the heat exchanger with a header of FIG. 5.

FIG. 7 illustrates isometric view of an embodiment of a heat exchanger design with an integrated header accordingly to the teachings herein

FIG. 8 illustrates a cross sectional view of the heat exchanger of FIG. 7 to illustrate the transfer tubes connecting to the distributors.

DETAILED DESCRIPTION OF THE DRAWINGS

A novel header has been designed comprising multiple small pressure vessels which do not transmit pressure loads into the heat exchanger core matrix structure or its bounding walls. The primary application of the novel integrated header is for a heat exchanger whereby a liquid passes through the header ports, the secondary fluid may be a liquid or a gas. However, other applications are possible. The invention is conceived for an additively manufactured application but is not exclusive to this method of manufacture.

FIG. 1 illustrates a top-down view of a heat exchanger 10 with a header 12 that was manufactured using AM. In the embodiment shown in FIG. 1, the header 12 is made up of a primary header channel 14 and distribution header channels 16 that extend away from the primary header channel 14 on opposing sides of the primary header channel 14. Although in the embodiment shown in FIG. 1, the distribution header channels 16 extend away from the primary header channel 14 on opposing sides like fingers of a hand, in other embodiments, other configurations may be used. For example, the distribution header channels 16 may extend away from the primary header channel 14 like the spokes of a bicycle wheel. In yet other embodiments, other configurations are possible.

FIG. 2 illustrates a cutaway isometric view of the heat exchanger 10 with a header 12 of FIG. 1. Both the integrated header 12 and the heat exchanger core/matrix 18 may be seen in FIG. 2. As may be seen by looking at both FIG. 1 and FIG. 2, the distribution header channels 16 are not limited to a single plane. Instead, the primary header channel 14 has a depth into the header 12 towards the heat exchanger matrix 18 and an additional row of distribution header channels 16 are located below the top-level distribution header channels 16. Although in the embodiment shown in FIGS. 1 and 2, only two layers, or planes, of distribution header channels 16 are used, in other embodiments, 3, 4, 5, 6 or more layers of distribution header channels 16 may exist. In some embodiments, only a single layer of distribution header channel 16 is needed.

As may be appreciated, in the embodiment shown in FIGS. 1 and 2, the location of the distribution header channels 16 in the X-Y plane (from the perspective of the top view in FIG. 1, where the Z direction is into and out of the heat exchanger matrix or into and out of the page in FIG. 1) may be staggered between planes in the Z direction such that the packing density of the distribution header channels 16 may be increased. In FIGS. 1 and 2, the distribution header channels 16 are spaced apart in the Y direction along the primary header channel 14. The rows in the Z direction are offset from each other to allow a better packing density of distribution header channels 16.

In the embodiment shown in FIGS. 1 and 2, the distribution header channels 16 are tapered as they extend away from the primary header channel 14. To this end, the area of the cross-section of the distribution header channels 16 decreases as they extend away from the primary header channel 14 to their distal tips. As may be appreciated, a lower volume of flow needs to be supported as the distance from the primary header channel 14 increases. To this end, tapering the distribution header channels 16 may be done to minimize header mass and pressure loads without impact to performance.

In addition to tapering, the distribution header channels 16 may also have a unique cross-sectional shape. In the embodiment shown in FIGS. 1 and 2, the cross-section of the distribution header channels 16 is teardrop shaped. In other embodiments, other cross-sectional shapes may be used for the distribution header channels 16.

In the embodiment shown in FIGS. 1 and 2, the teardrop cross-section is oriented where the points of the teardrops are all aligned and pointing along a length of the primary header channel 14, or parallel with the interface surface between the header 12 and the matrix 18. In other embodiments, other cross-sectional shapes and other orientation may be used.

As may be appreciated from FIGS. 1 and 2, the distribution header channels 16 are laid out in two layers in the z-direction, i.e. two layers at different depths from the heat exchanger matrix 18. Accordingly, the primary header channel 14, has a depth that spans both layers of distribution header channels 16 to facilitate the interfaces between all layers of the distribution header channels 16. In the embodiment shown in FIGS. 1 and 2, the depth of the primary header channel 14 spans the depth of the header 12.

As may be seen in FIG. 2, each distribution header channels 16 has a plurality of tubes 20 that connect the distribution header channels 16 to the heat exchanger core/matrix 18. In the embodiment shown in FIG. 1, each tube 20 is small. In this case, each tube 20 has a diameter approximately equal to the diameter of a channel that it feeds in the heat exchanger core 18. In other embodiments each feeder tube 20 has a diameter smaller than the matrix channel it feeds. To be clear, the feeder tubes 20 do not need to have a diameter that matches the channel it feeds in the core. In some embodiments, each feeder tube has a diameter half or less the diameter of the matrix channel it feeds. In contrast, the distribution header channels 16 have a diameter that is 2, 3, 4, 5, 10 or 20 times the diameter of a channel in the heat exchange core 18. To this end, the tubes 20 are much smaller than the distribution header channels 16.

In the embodiment shown in FIGS. 1 and 2, each individual matrix channel in the heat exchanger core 18 has its own dedicated tube 20 that feeds it from a distribution header channel 16. To this end, each distribution header channels 16 has a plurality of individual tubes 20 all aligned in a row and extending down the length of the distribution header channels 16 to a matrix channel of the heat exchanger matrix 18. The distribution header channels 16 are numbered and placed above the heat exchanger core 18 such that each channel in the heat exchanger core 18 gets its own dedicated feeder tube 20 from a distribution header channels 16.

As may further be appreciated from the embodiment in FIGS. 1 and 2, each feeder tube 20 is a straight tube from the distribution header channel 16 to the channel of the heat exchanger matrix it supplies.

In almost all conceivable configurations, a header comprised only of the distribution header channels 16 and the feeder tubes 20 would be structurally very unstable. In the embodiments described herein, fins or support ribs 22 are incorporated to add structural rigidity. Alternatively, if weight permits, then the distribution headers and feeder tubes may be encased within solid material. Because the ribs are present primarily to aid the AM build, a header may be designed without them if the build orientation permits or there are advances in AM technology.

In the embodiment shown in FIGS. 1 and 2, for each row of feeder tubes 20, a continuous fin 22 runs along the Y-direction of the heat exchanger from top to bottom, i.e. parallel with the primary header channel 14. There is a separate fin 22 for each row of feeder tubes 20, one fin 22 per heat exchanger core lattice row, such that each feeder tube 20 is structurally connected to a distribution header channel 16 by a fin 22. In other embodiments, more or less rows of fins 22 may be used. The fins 22 tie all the feeder tubes 20 and all the distribution header channels 16 together to create a light weight structurally rigid design.

In addition to, or in conjunction with the ribs 22, the additive manufacturing design flexibility may be exploited to vary distributor wall thickness with localised thickening to support high stress regions and thinning or other mass reducing methodologies, including but not limited to, lattice patterns in other regions.

The embodiment shown in FIGS. 1 and 2 has a wall 24 that spans the entire surface area between the header 12 and the heat exchanger core 18. The wall 24 is present to provide a boundary for the secondary flow through the heat exchange matrix 18. The header 12 is not within the second fluid path. The design contains a shield to form the boundary of the secondary fluid path in the core. This is not under pressure loads from the primary fluid. The transfer tubes pass 20 through this wall 24 as they join with the core flow path.

FIG. 3 illustrates a top-down view of a second embodiment of a heat exchanger 30 with an integrated header 12 that was manufactured using AM. As may be appreciated from FIG. 3, there are fewer distribution header channels 16 in the heat exchanger header embodiment 30 shown in FIG. 3 than in the heat exchanger header embodiment 10 shown in FIGS. 1 and 2. Moreover, in the integrated header 12 shown in embodiment 30, the distribution header channels 16 are all in a single plane.

FIG. 4 illustrates an isometric view of the heat exchanger 30 with the header 12 of FIG. 3. One main difference between the heat exchanger 10 shown in FIGS. 1 and 2 and the heat exchanger 30 shown in FIGS. 3 and 4 is the number of feeder tubes 20 per distribution header channels 16 in a plane. In the embodiment shown in FIGS. 1 and 2, a single feeder tube 20 exists between the header 12 and the matrix 18 for each distribution header channel 16 in any one plane. The heat exchanger 10 has a single feeder tube 20 for each lattice row of the heat exchanger matrix 18. In the embodiment shown in FIGS. 3 and 4, three feeder tubes 20 are used per distribution header channels 16 in any one vertical plane. To this end, three lattice rows in the heat exchanger matrix 18 are connected to a single distribution header channel 16 in one plane. In the embodiment shown in FIGS. 3 and 4, the feeder tubes 20 are curved to branch out to the lattice rows of the matrix 18.

FIG. 5 illustrates an isometric view of a third embodiment of a heat exchanger 40 with an integrated header 12 that was manufactured using AM. FIG. 6 illustrates a cutaway isometric view of the heat exchanger with a header of FIG. 5. As may be appreciated from FIGS. 5 and 6, the heat exchanger 40 has a primary distribution header 14 and a plurality of distribution header channels 16. In the embodiment shown in FIGS. 5 and 6, each distribution header channel 16 is designed to span multiple heat exchanger matrix channels in the Y-direction. In the embodiment shown in FIGS. 5 and 6, each distribution header channel 16 spans three heat exchanger matrix channels in the Y-direction such that three rows of feeder tubes 20 are covered by each distribution header channel 16. In other embodiments, each distribution header channel 16 may cover 2 or 4 or 5 or more heat exchanger matrix channels in the Y-direction.

In the embodiment shown in FIGS. 5 and 6, the feeder tubes are all straight tubes between the distribution header channel 16 and the heat exchanger matrix 18. The tubes 20 are incorporated into a tube plate 42. The tube plate 42 is a flat plate with all the feeder tubes 20 passing through that is effectively the interface between the header 12 and the heat exchanger matrix 18. To this end, each distribution header channel 16 is “D” shaped and the tubeplate 42 forms the straight section of the D.

FIG. 7 illustrates isometric view of an embodiment of a heat exchanger design 50 with an integrated header accordingly to the teachings herein. As may be appreciated from FIG. 7, in this embodiment, a header 12 has been added on two opposing sides of the heat exchanger matrix 18, one for ingress of the fluid and one for egress of the fluid. In the embodiment shown in FIG. 7, the primary header channel 14, a.k.a. the central manifold, runs vertically with distribution header channels 16 branching out horizontally from opposing sides of the primary header 14. The primary header channel 14 is fed by ingress port 21 matched to a fluid egress port on the opposite header. There are eight distribution header channels 16 on each side of the primary header channel 14 and the two headers create 32 total distribution header channels, 16 per side of the matrix 18.

Each of the distribution header channels 16 further split into numerous transfer tubes 20 to deliver the fluid into the heat exchanger core 18. This is of application to a heat exchange matrix 18 comprising discrete channels or one formed from parallel layers or having a complex regular (e.g. triply periodic minimal surfaces) or irregular form.

FIG. 8 illustrates a cross sectional view of the heat exchanger 50 of FIG. 7 to illustrate the transfer tubes 20 connecting to the distributors 16.

In some embodiments, the distributors 16 may be profiled to enhance the uniformity of fluid distribution into the heat exchanger core 18. This profiling may take the form of varying flow gallery cross-sectional area or devices and forms which facilitate flow distribution with minimal disturbances. Further profiling of the manifold 14, distributors 16 and transfer tubes 20 may be required to facilitate the additive manufacturing process depending on build orientation.

The transfer tubes 20 and their coupling to the core 18 may be arranged to enhance the equalization of fluid distribution into the heat exchanger core 18.

The header 12 may contain one port 21 for fluid supply, and a corresponding header 12 on the other side of the heat exchange core 18 contain one port for fluid return (not shown); or a single header 12 may contain both ports, each communicating with a manifold 14, and a corresponding turning header be integrated on the other side of the heat exchanger core 18. The location of porting on the manifold 14 may be arranged to suit the installation of the heat exchanger 50.

The novel header pressure vessel 12 is de-coupled from the core 18, such that there is very little transfer of stress loads to the core 18 when fluid pressure is applied within the header. Instead of one large pressure vessel, the fluid is contained within smaller volumes, resulting in lower wall stresses, allowing for low-mass designs of optimized wall thicknesses.

In preferred embodiments, the headers are built as one piece with the heat exchanger core, thus reducing part count and weight required for mechanical joining features such as bolted flanges.

For large format heat exchangers comprising multiple core sections, the integrated headers may be built onto each core section and ported such that the cores are interfaced to make an array.

The integrated header could be thermally active to increase heat exchange.

In some embodiments, further functions are integrated into the header design which include, but are not limited to, control valve housings, fluid bypass porting, instrumentation, bleed & test ports and mounting interfaces.

For applications where the fluid pressure loss is critical and apportioning of the budget between the loss within headers and core must be defined early within the design process, the novel header offers advantages. The pressure loss can be readily calculated since the header form is defined, and no iteration of its size is required. The design does not have large expansion losses but the pressure loss within the manifold and distributors is analyzed. The central manifold 14 and the openings into the distributors 16 have relatively large diameters to minimize pressure losses due to turning flow.

Claims

1. A heat exchanger comprising: a heat exchanger matrix with a plurality of flow paths in a first direction wherein the plurality of flow paths are patterned to create a plurality of inputs to the plurality of flow paths on an input surface;a header comprising: a primary distribution header that spans across the input surface in a second direction;a plurality of distribution header channels that span across the input surface in a third direction perpendicular to the second direction wherein each distribution header channel in the plurality of distribution header channels is in fluid communication with the primary distribution header; anda plurality of feeder tubes that fluidly couple the plurality of distribution header channels with the plurality of inputs such that there is a single feeder tube for each input.

2. The heat exchanger of claim 1, wherein each distribution header channel tapers from an interface with the primary distribution header towards a distal end of the distribution header channel.

3. The heat exchanger of claim 1, wherein the cross section of each distribution header channel is shaped in a teardrop.

4. The heat exchanger of claim 1, wherein the plurality of distribution header channels comprises at least two layers stacked in the first direction.

5. The heat exchanger of claim 4, where a first layer of distribution header channels is offset in the second direction from a second layer of distribution header channels.

6. The heat exchanger of claim 5, wherein a plurality of fins run in the second direction and a fin mechanically couples each feeder tube to a distribution header channel.

7. The heat exchanger of claim 1, wherein a wall gap separates the input surface from the header.

8. The heat exchanger of claim 3, wherein a point of the teardrop are all oriented in the second direction.

9. The heat exchanger of claim 1, wherein each distribution header channel has more than one feeder tube extending to the input surface along a single plane in the second direction.

10. The heat exchanger of claim 1, wherein each distribution header channel spans more than one input along the second direction.

11. The heat exchanger of claim 10, wherein a cross-section of each distribution header channel is shaped like a “D”.

12. The heat exchanger of claim 11, wherein a tubeplate separates the input surface from the header and the tubeplate forms a flat side of the “D” shaped cross-section.

13. A heat exchanger comprising: a heat exchanger matrix with a plurality of flow paths in a first direction wherein the plurality of flow paths are patterned to create a plurality of inputs to the plurality of flow paths on an input surface;a header comprising: a primary distribution header that spans across the input surface in a second direction;a plurality of distribution header channels that span across the input surface in a third direction perpendicular to the second direction and taper as they extend away in the third direction towards their distal end wherein each distribution header channel in the plurality of distribution header channels is in fluid communication with the primary distribution header; anda plurality of feeder tubes that fluidly couple the plurality of distribution header channels with the plurality of inputs such that there is a single feeder tube for each input.

14. The heat exchanger of claim 13, wherein the cross section of each distribution header channel is shaped in a teardrop.

15. The heat exchanger of claim 13, wherein the plurality of distribution header channels comprises at least two layers stacked in the first direction.

16. The heat exchanger of claim 15, wherein a first layer of distribution header channels is offset in the second direction from a second layer of distribution header channels.

17. The heat exchanger of claim 16, wherein a plurality of fins run in the second direction and a fin mechanically couples each feeder tube to a distribution header channel.

18. The heat exchanger of claim 13, wherein a wall gap separates the input surface from the header.

19. The heat exchanger of claim 14, wherein a point of the teardrop are all oriented in the second direction.

20. A heat exchanger comprising: a heat exchanger matrix with a plurality of flow paths in a first direction wherein the plurality of flow paths are patterned to create a plurality of inputs to the plurality of flow paths on an input surface;a header comprising: a primary distribution header that spans across the input surface in a second direction;a plurality of distribution header channels that span across the input surface in a third direction perpendicular to the second direction and taper as they extend away in the third direction towards their distal end wherein each distribution header channel in the plurality of distribution header channels is in fluid communication with the primary distribution header and wherein the plurality of distribution header channels comprises at least two layers stacked in the first direction and wherein a first layer of distribution header channels is offset in the second direction from a second layer of distribution header channels; anda plurality of feeder tubes that fluidly couple the plurality of distribution header channels with the plurality of inputs such that there is a single feeder tube for each input.