HEAT EXCHANGER FRAME

Abstract

An external frame for a heat exchanger, the external frame being for holding a heat exchanger core; wherein the external frame is a single integrated structure including: inlet and outlet couplings for connection to a first fluid circuit for supply and return of a first fluid to the heat exchanger core; a first tank at a first end of the external frame for fluid communication with a first end of the heat exchanger core; a second tank at a second end of the external frame for fluid communication with a second end of the heat exchanger core; and a gallery extending along the external frame between the first tank and the second tank providing fluid communication between the first tank and the second tank; wherein the external frame is arranged to be sealed to the heat exchanger core so that the first fluid flows from the inlet, through the heat exchanger core and the tanks, and to the outlet.

Claims

1. An external frame for a heat exchanger, the external frame being for holding a heat exchanger core; wherein the external frame is a single integrated structure including: inlet and outlet couplings for connection to a first fluid circuit for supply and return of a first fluid to the heat exchanger core; a first tank at a first end of the external frame for fluid communication with a first end of the heat exchanger core; a second tank at a second end of the external frame for fluid communication with a second end of the heat exchanger core; and a gallery extending along the external frame between the first tank and the second tank providing fluid communication between the first tank and the second tank; wherein the external frame is arranged to be sealed to the heat exchanger core so that the first fluid flows from the inlet, through the heat exchanger core and the tanks, and to the outlet.

2. The external frame as claimed in claim 1, wherein the external frame is arranged to provide a supporting structure for holding the heat exchanger core by encircling the heat exchanger core.

3. The external frame as claimed in claim 1, comprising an upper enclosure formed integrally as a part of the external frame and being for providing sealing along an upper surface of the heat exchanger core and/or a lower enclosure formed integrally as a part of the external frame and being for providing sealing along a lower surface of the heat exchanger core.

4. The external frame as claimed in claim 3, comprising a lower enclosure formed integrally as a part of the external frame and being for providing sealing along a lower surface of the heat exchanger core and wherein the gallery is integrated with the lower enclosure.

5. The external frame as claimed in claim 1, wherein the external frame includes sealing surfaces for forming a seal with the heat exchanger core in order to seal fluid flow paths of the heat exchanger core.

6. The external frame as claimed in claim 1, wherein the external frame is arranged such that the heat exchanger core can be coupled to the external frame via mechanical means

7. The external frame as claimed in claim 1, wherein the external frame includes all parts required to complete the structure of the heat exchanger once the heat exchanger core has been inserted.

8. The external frame as claimed in claim 1, wherein the external frame is provided with appropriate housings or mounting points for heat exchanger components such as valves and/or sensors.

9. The external frame as claimed in claim 1, wherein the external frame is formed using additive manufacturing.

10. The external frame as claimed in claim 1, wherein the external frame includes flow guide sections for joining segments of a multiple segment heat exchanger core such that the heat exchanger can be assembled by inserting multiple such segments.

11. The external frame as claimed in claim 1, wherein the external frame has a curved shape and is arranged to hold a curved heat exchanger core.

12. A heat exchanger comprising: an external frame as claimed in claim 1; and a heat exchanger core fitted within the external frame.

13. The heat exchanger as claimed in claim 12, wherein the heat exchanger is a curved heat exchanger for an air-intake of an aircraft.

14. A method of manufacture of a heat the method comprising: providing an external frame as claimed in claim 1; and inserting a heat exchanger core into the external frame.

15. The method as claimed in claim 14, wherein the structure of the heat exchanger is fully completed by the step of insertion of the heat exchanger core into the external frame.

16. The method as claimed in claim 15, wherein the external frame is provided with appropriate housings or mounting points for heat exchanger components such as valves and/or sensors.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Certain preferred embodiments will now be described by way of example only and with reference to the accompanying drawings, in which

[0025] FIG. 1 is a perspective view of a prior art heat exchanger in exploded view;

[0026] FIG. 2 shows the heat exchanger of FIG. 1 when assembled;

[0027] FIG. 3 shows a first perspective view of a heat exchanger core with an external frame in exploded view;

[0028] FIG. 4 is second perspective view showing another side of the external frame and heat exchanger core of FIG. 3;

[0029] FIG. 5 shows a perspective view of the heat exchanger core of FIGS. 3 and 4 assembled with the external frame to form a heat exchanger; and

[0030] FIG. 6 is second perspective view showing another side of the heat exchanger of FIG. 5.

DETAILED DESCRIPTION

[0031] An example of a heat exchanger formed using an external frame to hold a heat exchanger core 10 is described below with reference to FIGS. 3 to 6. In this example the heat exchanger and hence the heat exchanger core 10 are curved and the heat exchanger is intended for use with a gas turbine engine. As with the prior art of FIGS. 1 and 2, the curved heat exchanger includes a heat exchanger core 10 which is formed of several heat exchanger segments 12 joined together to form a curved shape. This is fitted within an external frame 28, which is described in more detail below. The curved shape of the core 10 is achieved by joining several cuboid segments 12 with wedge sections 14 so that the cuboid segments 12 extend through part of an arc of a circle. This allows for the heat exchanger to fit within the available space whilst also using relatively conventional technology to form each segment 12 of the heat exchanger core 10. For example, a plate fin or a pin fin arrangement may be used for the segments 12 of the core 10. Within each segment 12, a first fluid flows along the length of the exchanger core 10, i.e. along each segment 12 in sequence, and a second fluid flows across the width of the exchanger core 10, i.e. across each segment 12 in parallel. The first fluid may for example be a liquid used to remove or add heat to the second fluid, which may be a gas such as engine air or exhaust from an engine. The wedge sections 14 that join the cuboid segments 12 together can be wedge shaped fluid guide pieces for passing fluid between the segments 12. Typically the wedge sections 14 are provided with appropriate flow guide features, enclosure bars, and/or separator plates so that the first fluid flows as required between the adjacent segments 12 and the second fluid flows only across the width of the heat exchanger core 10 and in general does not enter the wedge sections 14. The heat exchanger core 10 is adapted compared to that shown in FIGS. 1 and 2 by the addition of sealing flanges 48 for forming seals with sealing surfaces of the external frame 28.

[0032] The external frame 28 encircles the heat exchanger core 10, surrounding the two ends as well as upper and lower surfaces of the core 10. The frame is open along the exposed sides of the core 10 to allow for flow of the second fluid. The external frame 28 consists of first and second tanks 36, 38 at each end of the core 10, an upper enclosure 40 along the top of the core 10, a lower enclosure 42 along the bottom of the core 10, a gallery 44 (not visible in the Figures) integrated with the lower enclosure 42, and a mounting structure 46. The external frame 28 is a single integrated piece which provides all of the first and second tanks 36, 38, the upper enclosure 40, the lower enclosure 42, the gallery 44, and the mounting structure 46. It may be formed in a single piece by additive manufacturing, machining and/or casting. The external frame 28 is shaped and sized to receive the heat exchanger core 10 and to form a seal about the core 10, ideally using only mechanical fixings.

[0033] The external frame 28 serves to complete sealing of the flow paths for the first fluid along the upper and lower surfaces as well as the two ends of the heat exchanger core 10. In particular, the upper enclosure 40 and lower enclosure 42 provide sealing along the upper and lower surfaces of the heat exchanger core 10 respectively, for example at the points where the segments 12 join with the wedge sections 14. The upper enclosure 40 and the lower enclosure 42 are curved and in this case they are formed with a sequence of planar sections so that they correspond to the shape of the heat exchanger core 10 and fit closely with the shape of the heat exchanger core 10. This enables adequate sealing of the fluid paths for the first fluid whilst also restricting the overall size of the heat exchanger so that the external frame 28 does not unduly increase the size of heat exchanger. This is particularly important where the design of the heat exchanger is required to meet certain size and shape restrictions due to its intended use, for example when utilised with an engine such as a gas turbine engine.

[0034] The first tank 36 is positioned at a first end of the external frame 28 and forms a seal against the sealing flanges 48 of the end most segment 12. The first tank 36 includes inlet and outlet ports 47 for the first fluid. At the opposite end of the external frame 28 is the second tank 38 which similarly forms a seal against the sealing flanges 48 of the opposing end most segment 12. In this exemplary embodiment, the heat exchanger is arranged such that the first fluid enters via an inlet 47 of the first tank 36, flows along a first section of the heat exchanger core 10, for example a lower half of the core 10, and then enters the second tank 38 where the flow is turned to return along a second section of the heat exchanger core 10, for example an upper half of the core 10, and back to the first tank 36 where it can exit via an outlet 47 of the first tank 36. It will be appreciated that the flow can be in either direction and so the inlet and outlet ports 47 are in some ways interchangeable. Their location and the direction of flow can be adjusted based on the available space and any other restrictions on the plumbing to the heat exchanger. Alternatively, the external frame 28 may be adapted for use with a single-pass heat exchanger arrangement, or other multiple pass heat exchanger arrangements, with the first and second tanks 36, 38 being modified accordingly.

[0035] The gallery 44 is integrated with the lower enclosure 42, and allows for diversion of flow between the first tank 36 and the second tank 38, for example when it is desired to circulate the first fluid without flow through heat exchanger core 10 and/or when there is a blockage preventing flow through the heat exchanger core 10. Since the gallery 44 is integrated with the lower enclosure 42 it corresponds closely to the shape of the heat exchanger core 10 and fits closely to the core 10. The integrated gallery 44 forms a flow path which runs along the entire length of the heat exchanger core 10 between the first and second tanks 36, 38. As there is no need to form a weld bead along the length of the integrated gallery 44 as with the prior art gallery 24 shown in FIG. 1 then the integrated gallery 44 can be formed with a much more consistent cross-section for the flow path within the integrated gallery 44, and problems from impingement of weld beads into the flow path are avoided.

[0036] In relation to the flow path for the second fluid across the segments 12 of the heat exchanger core 10, a mounting structure 46 is provided for mounting the external frame 28 to other parts, such as an interface with the engine, so that flow of the second fluid can be guided into the heat exchanger core 10 and through each of the segments 12. This flow path is otherwise similar to that of the prior art, since the structure of the heat exchanger core 10 that guides the second fluid is not changed compared to the prior art.

[0037] FIGS. 5 and 6 show the heat exchanger core 10 and external frame of FIGS. 2 and 4 assembled together to form the heat exchanger that is ready to be mounted at its point of use. It will be appreciated that the assembly of the core sections 12 into a curved shape along with the external frame 28 results in a compact arrangement that can be designed to fit with a specific shape and size corresponding to the available space, which in this example is a curved region around an engine such as a gas turbine engine.

[0038] In another embodiment, the external frame 28 may additionally include the wedge sections 14 for separating the segments 12 of the heat exchanger core 10. In this way, the wedge sections are formed integrally with the external frame such that the external frame is a single integrated piece which provides all of the first and second tanks 36, 38, the upper enclosure 40, the lower enclosure 42, the gallery 44, the mounting structure 46 and the wedge sections 14. The external frame 28 may be formed in a single piece by additive manufacturing, machining and/or casting.

[0039] The heat exchanger may be assembled by inserting individual segments 12 into the external frame. The wedge sections 14 of the external frame 28 can be wedge shaped fluid guide pieces and thus pass fluid between the individual segments 12 to complete the flow paths through the heat exchanger core 10. Typically, the wedge sections 14 are provided with appropriate flow guide features, enclosure bars, and/or separator plates so that the first fluid flows as required between the adjacent segments 12 and the second fluid flows only across the width of the heat exchanger core 10 and in general does not enter the wedge sections 14. The individual segments 12 may include sealing flanges 48 for sealing against the sealing surfaces of the external frame 28, for example the sealing surfaces of the first and second tanks 36, 38 and/or the wedge sections 14.

[0040] Advantageously, this embodiment allows for individual installation and/or replacement of the segments 12 of the heat exchanger core 10. For example, if a segment 12 were to become damaged or otherwise required replacing then it could be removed from the external frame 28 without having to remove the other segments 12 that form the heat exchanger core 10. Similarly, the replacement or repaired section 12 could be inserted in the external frame 28, forming a seal with the sealing surfaces of the external frame 28 to seal the fluid flowpaths of the heat exchanger core 10.