HEAT EXCHANGER

Abstract

A layer of a heat exchanger includes plurality of flow paths, a first end section comprising a plurality of flow path inlets and a plurality flow path outlets. a second end section comprising a turnaround section, a first morphing section fluidly connect to the first end section, a second morphing section fluidly connected to the second end section; and a central section positioned between and fluidly connected to the first and second morphing sections. The plurality of flow paths extend from the flow path inlets to the flow path outlets via the turnaround section in the second end section. In the first end section and the second end section the flow paths have a first cross section. The central section the flow paths have a second cross section and in the first and second morphing section the cross section of the flow paths morph between first and second cross sections.

Claims

1. A layer for a multilayer heat exchanger, the layer comprising: a plurality of flow paths; a first end section comprising a plurality of flow path inlets and a plurality flow path outlets; a second end section comprising a turnaround section; a first morphing section fluidly connect to the first end section; a second morphing section fluidly connected to the second end section; and a central section positioned between and fluidly connected to the first and second morphing sections; wherein the plurality of flow paths extend from the flow path inlets in the first end section to the flow path outlets at the first end section via the turnaround section at the second end section; wherein in the first end section and the second end section the flow paths have a first cross section; wherein in the central section the flow paths have a second cross section; and wherein in the first and second morphing sections the cross section of the flow paths morphs between first cross section and the second cross section.

2. A layer of a heat exchanger as claimed in claim 1, wherein the first cross section allows for the first and second end sections to fit within an area of a first, relatively small, depth, compared to the second cross section which results in the central section extending across a second, larger depth.

3. A layer of a heat exchanger as claimed in claim 1, wherein the second cross section is arranged such that the flow paths thereof will be interleaved with flow paths of an adjacent layer.

4. A layer of a heat exchanger as claimed in claim 1, wherein the first cross section is rectangular and the second cross section is a diamond shape.

5. A layer of a heat exchanger as claimed in claim 1, wherein the first cross section is rectangular and the second cross section is hexagonal.

6. A layer of the heat exchanger as claimed in claim 1, wherein the cross section of the morphing section is an irregular hexagonal shape.

7. A layer of a heat exchanger as claimed in claim 1, wherein the flow paths have a constant cross-sectional area along their length.

8. A layer of a heat exchanger as claimed in in claim 1, wherein the layer of the heat exchanger is separated into a first side and a second side by a separating wall extending in a longitudinal direction of the layer.

9. A layer of a heat exchanger as claimed in claim 7, wherein the plurality of flow paths may comprise a plurality of outward flow paths and a plurality of return flow paths formed in the first side and second side of the layer respectively.

10. A layer of a heat exchanger as claimed in claim 1, wherein the turnaround section is directly and fluidly connected to all the flow paths within the layer.

11. A layer of a heat exchanger as claimed in claim 9, wherein vanes extend from the plurality of outward flow paths into the turnaround section.

12. A layer of a heat exchanger as claimed in in claim 1, further comprising one or more enclosed flow paths adjacent to the separating wall which do not extend into the turnaround section.

13. A heat exchanger comprising: two or more of the layers as defined in claim 1.

14. The heat exchanger of claim 13, wherein each of two or more layers is rotated by 180 degrees with respect to an adjacent layer.

15. A heat exchanger as claimed in claim 14, wherein the cross-sectional area or cross sectional shape of the plurality of flow paths in one or more layers of the heat exchanger can be different.

16. A method for manufacturing a layer for a multilayer heat exchanger, wherein the layer comprises: a plurality of flow paths; a first end comprising a plurality of flow path inlets and a plurality of flow path outlets; and a second end comprising a turnaround section; wherein the plurality of flow paths extend from the flow path inlets at the first end to the flow path outlets at the first end via the turnaround section at the second end; the method comprising forming a first morphing section adjacent to the first end; forming a second morphing section adjacent to the second end; and forming a central section located between the first and second morphing sections; wherein in the first end the flow paths are formed with a first cross section; wherein in the central section the flow paths are formed with a second cross section; and wherein in the first and second morphing sections the cross section of the flow paths are formed so that they morph between the first cross section and the second cross section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Example embodiments of the invention are described below by way of example only and with reference to the accompanying drawings.

[0058] FIG. 1 shows a core for a diamond channel heat exchanger.

[0059] FIG. 2A shows a schematic of a two-pass heat exchanger.

[0060] FIG. 2B shows a cut-away view of the two-pass heat exchanger as shown in FIG. 2A.

[0061] FIG. 3 shows a cut-away view of a layer of a heat exchanger including morphing sections.

[0062] FIG. 4 shows a series of cross sections of for two layers of a heat exchanger illustrating the changes along the extent of a morphing section.

[0063] FIG. 5A shows a heat exchanger, or a part of a heat exchanger, comprising six layers.

[0064] FIG. 5B shows the layers of FIG. 5A with a cut through a morphing section.

[0065] FIG. 5C shows the six layers of FIG. 5A with a cut through a central section.

[0066] FIG. 5D shows the layers of FIG. 5A with a cut through a first end section.

DETAILED DESCRIPTION

[0067] FIG. 1 shows a core for a diamond channel heat exchanger 1 comprising a plurality of layers 5. The heat exchanger 1 is a single pass counter flow heat exchanger. Each layer 5 comprises a plurality of flow paths 5 wherein the primary fluid 7 and the secondary fluid 8 flow in alternating layers and in opposite directions.

[0068] Each side of the heat exchanger 1 comprises the inlet for one of the primary fluid 7 or secondary fluid 8 and the outlet for the other.

[0069] FIGS. 2A and 2B show a two pass heat exchanger. The main section 14 of the heat exchanger comprises multiple layers, where each layer contains either the primary fluid 7 or the secondary fluid 8.

[0070] As the heat exchanger 10 incorporates two-pass flow, the primary fluid inlet 11a and the primary fluid outlet 11b are on one side of the heat exchanger 10 and the secondary flow inlet 12a and the secondary flow outlet 12b are on the other side of the heat exchanger 10.

[0071] FIG. 2B shows a cut-away view showing a single layer of the heat exchanger 10 with an integrated turnaround section so that the primary fluid inlet 11a and outlet 11b are located on the same side of the heat exchanger.

[0072] FIG. 3 shows a layer 20 of a heat exchanger incorporating both diamond channels and rectangular channels within its flow paths. The layer 20 comprises a first end 22 with a first morphing section 24 directly and fluidly connected to the first end 22. A central section 26 is adjacent to and directly connected to the first morphing section 24 and a second morphing section 28. The second morphing section 28 is directly and fluidly connected to a second end 30 which comprises a turnaround section 42.

[0073] The layer 20 of the heat exchanger is separated into a first side 48 and a second side 50 by a separating wall 36. The layer 20 of the heat exchanger comprises a plurality of flow paths 38, 39 where the flow paths on the first side 48 are the outward flow paths 38 and the flow paths on the second side 50 are the return flow paths 39. The separating wall 36 thus separates the outward flow paths 38 and the return flow paths 39.

[0074] In the example of FIG. 3 the inlets 32 and outward flow paths 38 are on the first side 48 and the outlets 34 and return flow paths 39 are on the second side 50, however it will be appreciated that the inlets 32 and outward flow paths 38 can be on the second side 50 and the outlets 34 and the return flow paths 39 can be on the first side 48.

[0075] The outward flow paths 38 extend from the inlets 32 through the first morphing section 24, the central section 26 and the second morphing section 28 into the second end 30. At the second end 30 the plurality of flow paths 38 are directly and fluidly connected to and open out into the turnaround section 42.

[0076] The turnaround section 42 is also directly and fluidly connected to the plurality of return flow paths 39, which then extend through the second morphing section 28, the central section 26, first morphing section 24 and the plurality of outlets 34.

[0077] In addition to the plurality of flow paths 38, 39 that open into the tank within the turnaround section 42 there are also one or more enclosed flow paths 40 closest to the separating wall 36. FIG. 3 shows three enclosed flow paths 40, however there may be only one enclosed flow path 40 or alternatively there could be more than three.

[0078] The enclosed flow paths 40 do not extend into the turnaround section 42 in the second end 30. Instead the enclosed flow paths 40 turn individually and the flow path side wall 46 constrains the fluid within the flow path at the turning point.

[0079] The enclosed flow paths 40 ensure that sufficient fluid is present in all the flow paths 38, 39, 40 within the layer.

[0080] Some of the flow paths 38, 39 further comprise vanes 44, which extend from the end of the flow path section within the second morphing section into the turnaround section 42. In FIG. 3 the vanes extend from the outward flow path 38 and encourage the flow to change direction towards the inlets of the return flow paths 39.

[0081] FIG. 4 shows the change in cross section of the flow paths 38, 39 between the first and second end 22, 30 and the central section 26 through the morphing sections. As seen in the progression between the diamond channel shape in the top image and the rectangular channel shape at the bottom, the cross sections of the flow paths 38, 39 change gradually between a first cross section 52 at the first end 22 to a second cross section 54.

[0082] In the example of FIG. 4 the first cross section 52 at the first end 22 and the second end 30 are rectangular. In the first and second morphing sections 24, 28 the cross section gradually changes in a linear manner in incremental steps while maintaining a constant cross-sectional area.

[0083] In the morphing section of FIG. 4, the cross section forms a series of irregular hexagons transitioning from rectangular to diamond. The cross section of the flow path comprises a first pair of sides 51 and a second pair of sides 52. In the morphing section of the flow path, each of the second pair of sides 52 split into two sections of equal length with an apex/bottom in the middle forming an obtuse angle so that the cross section of the flow path is an irregular hexagon.

[0084] Along the length of the morphing section the length of each of the first pair of sides gradually decreases, while each side remains equal. As the length of the first pair of sides decreases the angle of the apex/bottom in each of the second pair of sides 52 decreases and the length of each section of the second pair of sides 52 increases.

[0085] Along the length of the morphing section the length of each of the first pair of sides gradually decreases to zero and the angle of the apex/bottom gradually decreases to be a right-angle so that the cross section morphs from hexagonal to a diamond cross section.

[0086] In the central section 26, where the majority of the heat transfer is taking place, the second cross section 54 is a diamond cross section. It will be appreciated that second cross section 54 can have other shapes, for example hexagonal. An advantage of a diamond cross section for the main core of the heat exchanger is that every surface of the flow path channel acts as a primary heat transfer surface.

[0087] As can be seen in FIG. 3 the flow paths 38, 39 in the central section 26 are of equal length, however the enclosed flow paths 40 decrease in length so that the enclosed flow paths 40 closest to the separating wall 36 are shorter than the enclosed flow paths 40 further from the wall. It will be appreciated that the flow paths 38, 39 in the central section 26 can also be of different lengths.

[0088] In order to account for different lengths of the flow paths 38, 39 within the central section 26, the first end section 22, the first morphing section 24, the second morphing section 28 or the second end section 30 can be of different lengths within each flow path. For example in FIG. 3 the enclosed flow paths are shorter in length and hence the first end section 22 comprising the first, rectangular, cross section 52 extends further along each of the enclosed flow paths.

[0089] Additionally, due to the way the enclosed flow paths 40 are formed, the side wall 46 constraining the will get gradually further from the second end turnaround section 42 for the enclosed flow paths 40 closest to the separating wall 36.

[0090] FIGS. 5A-5D show a heat exchanger 60 formed of multiple adjacent layers 20. Each alternating later is rotated by 180 degrees so that the first end section 22 of one layer is in between and in contact with the turnaround section 42 of the second end section 30 of the adjacent layers. The central sections, with the flow paths having the second cross section, have flow paths interleaved together. FIGS. 5A-5D shows a heat exchanger 60 comprising six layers 20, or a part of a heat exchanger that can have more than six layers. It will be appreciated that any number of the layers 20 can be placed together.

[0091] FIG. 5A shows the complete six layer heat exchanger 60 showing the inlets of the outward section of the flow path 38 and the outlets 34 of the return flow paths 34 separated by the separating wall 36.

[0092] The flow paths of the central section 26 are shorter closer to the separating wall 36. These flow paths are the enclosed flow paths 40 as shown on FIG. 3. At the second end 30 the enclosed flow paths 40 do not extend to the turnaround section 42 and in the first end 22 the section of the enclosed flow paths 40 with the first cross section 52 extends further along the flow path. The length that the first cross section 52 extends along the enclosed flow path 40 is equivalent to the distance between the end of the enclosed flow path 40 and the turnaround section 42. This allows the layer to be rotated by 180 degrees and overlaid.

[0093] FIG. 5B shows the six layers 20 with a cut-away showing the first and second morphing sections 24, 28. The cross section of the flow paths 38, 39 are in the morphing stage between the first cross section 52 and 54, but with the same cross-sectional area.

[0094] As discussed previously, in the enclosed flow paths 40, the section with the first cross section 52 extends for longer than in the other flow paths 38, 39. Hence, in FIG. 5B at the point of the cut-away the flow paths 38, 39 have a morphed cross section, while the enclosed flow paths 40 have the first cross section 52.

[0095] FIG. 5C shows another view of the six layers 20 showing only the central section 26, the second morphing section 28 and the second end section 30 with the turnaround section 42. The cutaway shows all the flow paths 39, 39, 40 having the second cross section 54, in this case a diamond cross section.

[0096] FIG. 5D shows another view of the six layers with a cut-away in the first end section 22 and second end section 30 of the layers 20. The cut-away section shows the inlets 31 and outlets 34 of the first end 22 of the layers 20, and the turnaround section 42 of the second end 30 of the alternating layers.

[0097] In use the arrangement of the alternating layers 20 rotated by 180 degrees allows for two-pass flow with the primary and secondary fluid travelling in opposite directions. It also allows for counter flow between the flow in the inlet 32 and outlet 34 travelling in the Y direction and the flow in the turnaround section 42 of the adjacent layers travelling in the perpendicular X direction.