Field of the invention

[0001] The invention relates to a heat exchanger.

Background

[0002] Existing single-pass heat exchangers (such as a car radiator for example), in which a cooling fluid passes through the heat exchanger from a forward region to a rearward region, suffer from thermal inefficiencies because the fluid to be cooled (e.g. oil) passing through a rearward region of the of the heat exchanger would be cooled less compared to the fluid to be cooled passing through a forward region of the heat exchanger.

[0003] While multi-pass heat exchangers present a solution to the problem in existing single-pass heat exchangers, existing multi-pass heat exchangers suffer from relatively high-pressure drops.

[0004] In this context, there is a need for an improved heat exchanger or to at least provide the public with a useful choice.

Summary of the invention

[0005] According to an aspect of the present invention, there is provided a heat exchanger comprising: a core having: a forward side and a rearward side, wherein a first fluid passes through the core along a first axis from the forward side and exits the core from the rearward side, an inlet side and an outlet side, and a tube arrangement for conveying a second fluid along a second axis that intersects the first axis, the tube arrangement having a first set of tubes with inlets on the inlet side and/or outlets on the outlet side, wherein the inlets and/or outlets of the first set of tubes are arranged substantially along the first axis; wherein each tube of the first set of tubes includes: one or more portions that are located at or toward the forward side of the core; and one or more portions that are located at or toward the rearward side of the core. [0006] The heat exchanger in a preferred embodiment is for a single-pass heat exchanger or a multi-pass heat exchanger. For example, the heat exchanger could be for a dual-pass heat exchanger.

[0007] The first axis is preferably substantially perpendicular to the second axis. In particular, the first axis is about 90° to the second axis. Thereby, in a preferred embodiment, the core has a body with a substantially square profile, the body being defined by the forward side, rearward side, inlet side, and the outlet side. In other examples, the body of the core may have different shapes. For example, the body may have any one of a rectangular profile, a circular profile, a triangular profile, any other geometric profile, or any other non-geometric or freeform profile. By way of further example, the body may be substantially cylindrical, spherical, or other volumetric shape with perpendicular planes or with a curved or freeform surface profile.

[0008] The heat exchanger preferably includes a plurality of sets of tubes, which includes the first set of tubes. The tubes are preferably spaced apart from each other to allow the first fluid to flow therethrough. The tubes are interleaved, interlaced, braided, plaited, or interwoven to form a lattice structure for the core. The inlets and/or outlets of each respective set of tubes may be arranged substantially along the first axis. The plurality of sets of tubes are preferably arranged along the second axis and each tube of each set of tubes includes: one or more portions that are located at or toward the forward side of the core; and one or more portions that are located at or toward the rearward side of the core.

[0009] The inlets of each set of tubes are arranged along a respective axis, and the axis through the inlets of a respective one of the sets of tubes is preferably offset from the axis through the inlets of another one of the sets of tubes. The axes through the inlets may be parallel with each other. Additionally or alternatively, the outlets of each set of tubes are arranged along a respective axis, the axis through the outlets of a respective one of the sets of tubes is preferably offset from the axis through the outlets of another one of the sets of tubes. The axes through the outlets may be parallel with each other.

[0010] Preferably, each tube in the tube arrangement includes: one or more portions that are located at the forward side of the core; and one or more portions that are located at the rearward side of the core.

[0011] The inlets of the, or each respective, set of tubes and the outlets of the, or each respective, set of tubes on the outlet side are arranged substantially along the first axis. Where the tube arrangement includes a plurality of sets of tubes, the inlets and outlets of one set are laterally offset from the inlets and outlets of another set. [0012] Each tube includes one or more sloping or curved portions between the portion located at or near the forward side of the core and the portion located at or near the rearward side of the core.

[0013] Each tube preferably has a substantially sinusoidal profile along the second axis. For example, one or more portions corresponding to peaks of the sinusoidal profile are provided at or near the forward side, while one or more portions corresponding to troughs of the sinusoidal profile are provided at or near the rearward side.

[0014] A portion of a respective one of the tubes at or near the forward side or rearward side of the core preferably corresponds to an inflection point of the respective tube. Preferably, the respective tube includes a first portion and a second portion each leading to the inflection point of the respective tube from opposite sides, wherein an axis through first portion and an axis through the second portion are laterally offset from each other. The first and second portions may be sloping or curved portions by way of example.

[0015] In an example, the tube arrangement includes a tube that includes one portion at or near the forward side and one portion at or near the rearward side. In another example, the tube arrangement includes a tube that includes more than one portion at or near the forward side. In the same or other example, the tube includes more than one portion at or near the rearward side.

[0016] The core that is preferably a jointless and seamless unitary component. Preferably, each tube of the tube arrangement are continuous and non-interrupted. By way of example, the core is manufactured using an additive manufacturing process or a laser powder bed fusion metal additive manufacturing process.

[0017] Another aspect of the present invention provides a method of manufacturing the heat exchanger previously described above, the method including forming the tube arrangement using an additive manufacturing process.

Brief description of the drawings

[0018] The invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Figure 1A shows a perspective view of a heat exchanger according to an embodiment of the present invention;

Figures IB and 1C show a partial front view and a partial side view respectively of the heat exchanger shown in Figure 1 A; and Figures ID to IF show a perspective view, a partial front view, and a side view respectively of the heat exchanger shown in Figures 1A to 1C with one of the tubes shown in solid lines and the other tubes shown in hidden lines.

Detailed description

[0019] Figures 1A to IF show a heat exchanger 100 according to an embodiment of the present invention. The heat exchanger 100 is a single-pass heat exchanger. The heat exchanger 100 is for transferring thermal energy between a first working fluid and a second working fluid. The first working fluid may be referred to as ‘coolant’. The term ‘fluid’ as used in this specification includes liquid and gaseous materials. By way of example, the heat exchanger may be a car radiator. A first fluid passes through the heat exchanger in a first direction A, while a second fluid passes through the heat exchanger in a second direction B, perpendicular to the first direction. The first fluid is a cooling fluid such as cool air for example, while the second fluid is a fluid to be cooled such as oil for example. In particular, the first axis is about 90° to the second axis.

[0020] The heat exchanger comprises a core 120. The core 120 is a body has a substantially boxshaped geometry or volume. The core 120 has air gaps (or a plenum space or spacing) to allow the first fluid to pass through the core. The core 120 comprises a forward side 122, a rearward side 124, an inlet side 126, and an outlet side 128. The forward side may be an air-inlet side and the rearward side may be an air-outlet side, while the inlet side and the outlet side may be an oil-inlet side and an oil-outlet side respectively. The first fluid passes through the core 120 along the first axis A from the forward side 122 and exits the core from the rearward side 124, through the air gaps or spacing in the core. The forward and rearward sides form front and rear surfaces of the core, while the inlet and outlet sides form upper and lower surfaces of the core.

[0021] In a preferred embodiment, the core has a body with a substantially square profile, the body being defined by the forward side, rearward side, inlet side, and the outlet side. In other examples, the body of the core may have different shapes such as a body with a rectangular profile, a circular profile, a triangular profile, any other geometric profile, or any other non-geometric or freeform profile. By way of further example, the body may be substantially cylindrical, spherical, or other volumetric shape with perpendicular planes or with a curved or freeform surface profile.

[0022] The core 120 further includes a tube arrangement for conveying the second fluid along the second axis B that intersects the first axis. The air gap (or plenum space) surrounds the tubes such that thermal energy can be transferred between the two working fluids. The tube arrangement has a plurality of tubes that are arranged in sets to create air gaps or spacing in the core for the passage of the first fluid therethrough. The tubes of the tube arrangement have inlets arranged on the inlet side and outlets arranged on the outlet side. The inlets and outlets are arranged in an array on the respective inlet and outlet sides.

[0023] The tubes of the tube arrangement have portions in the forward side and portions in the rearward side to minimize the thermal bias suffered by existing single-pass heat exchangers. A forward tube in the tube arrangement would be arranged or constructed towards the rearward side (and possibly back towards the forward side), while a rearward tube in the tube arrangement would be arranged or constructed towards the forward side (and possible back towards the rearward side). The tubes can cycle once, partially, or several times depending on the heat exchange requirements.

[0024] Adjacent tube portions in the core 120 are provided with a plurality of spaced apart ribs (or fins). The ribs are provided along the length of the tube and provide reinforcement to the tubes. The ribs act as a scaffold to hold the tubes in place during an additive manufacturing process and allows for the core to be additively manufactured without compromising the structural integrity of the tubes particularly for larger tube lengths.

[0025] The tube arrangement includes a plurality of sets of tubes. The tubes are interleaved, interlaced, braided, plaited, or interwoven to form lattice structure for the core 120. The inlets and outlets of each respective set of tubes are arranged on the respective inlet and outlet sides of the core substantially along the first axis. The inlets and outlets of one set are laterally offset from the inlets and outlets of another set. The inlets of each set of tubes are arranged along a respective axis, and the axis through the inlets of a respective one of the sets of tubes is preferably offset from the axis through the inlets of another one of the sets of tubes. The axes through the inlets is parallel with each other and is parallel with the first axis. Similarly, the outlets of each set of tubes are arranged along a respective axis, the axis through the outlets of a respective one of the sets of tubes is preferably offset from the axis through the outlets of another one of the sets of tubes. The axes through the outlets is parallel with each other and is parallel with the first axis.

[0026] Each tube of each set of tubes includes one or more portions that are located at the forward side of the core; and one or more portions that are located at the rearward side of the core. The portion(s) of the tube at the forward side of the core are longitudinally offset, along the second axis, from the portion(s) of the tube at the rearward side of the core. Each tube has, or approximates, a helical profile or a substantially sinusoidal profile along the second axis. For example, one or more portions corresponding to peaks of the sinusoidal profile are provided at or near the forward side, while one or more portions corresponding to troughs of the sinusoidal profile are provided at or near the rearward side. A portion of a respective one of the tubes at or near the forward side or rearward side of the core preferably corresponds to an inflection point (i.e. a peak or trough) of the respective tube. The respective tube includes a first portion and a second portion each leading to the inflection point of the respective tube from opposite sides, wherein an axis through first portion and an axis through the second portion are laterally offset from each other. The first and second portions are sloping or curved portions. That is, a transition of the tube from a portion of the tube on the forward side to the portion of the tube on the rearward side is sloping or curved.

[0027] Each tube may have one or more portions at the forward side and one or more portions at the rearward side, depending on the heat exchange requirements and size of the core. For example, each tube may have one portion at the forward side and one portion at the rearward side. In another example, each tube may have a plurality of portions at the forward side and a plurality of portions at the rearward side. In yet another example, each tube may have one portion at one of the forward side or rearward side and a plurality of portions at the other one of the forward side or rearward side.

[0028] The tube arrangement with each tube having a portion at or near the forward side and a portion at or near the rearward side according to preferred embodiments of the present invention have the following advantages: (1) improved thermal efficiency when compared to a straight tube design, (2) reduced thermal gradient/bias across heat exchanger core, (3) boundary layer disruption, and (4) a smaller footprint compared to straight tube design, without compromising the thermal performance.

[0029] The core with the tube arrangement is formed as a monolithic structure. There is no requirement for a separate assembly of end tanks and manifolds and accordingly the potential failure modes of welded or bolted joints are avoided. The core is manufactured using a manufacturing process that creates a jointless and seamless unitary component. In other words, the heat exchanger components are continuous and non-interrupted. By way of example, the core is manufactured using an additive manufacturing process. In a preferred embodiment, the core is formed using a laser powder bed fusion metal additive manufacturing process.

[0030] While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

[0031] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavor to which this specification relates.

[0032] Throughout this specification and the claims which follow, unless the context requires otherwise, the word ‘comprise’, and variations such as ‘comprises’ and ‘comprising’, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.