Heat exchanger equipped with an interface housing having guide fins

Abstract

The invention relates to a device for heat exchange between two heat transfer fluids, comprising: an outer housing (10) that defines a chamber in which the heat transfer fluids flow; an inlet (20) and an outlet (30) for a first heat transfer fluid in the chamber; an inlet and an outlet for a second heat transfer fluid in the chamber; a heat exchange block (14) in the flow chamber (12). The device further comprises at least one interface box (20) that forms one of the fluid inlets or one of the fluid outlets, said interface box comprising a convex casing (24) that is provided with an inlet / outlet orifice (26) and an interface frame mechanically connected to the outer housing. The box (20) further comprises a plurality of separate guide fins (22a, 22b, 22c, 22b) which extend between the orifice and the interface frame.

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION: HEAT EXCHANGER EQUIPPED WITH AN INTERFACE HOUSING WITH GUIDE FINS

[0003] Technical field of the invention

[0004] The invention relates to a heat exchanger equipped with a fluid flow collector box and / or a fluid flow distribution box comprising fins for guiding this fluid flow. The invention relates in particular to such an exchanger intended for aeronautical use.

[0005] Technological background

[0006] A heat exchanger, particularly one intended to equip an aircraft, is likely to be subjected to significant temperature gradients during its operating cycles. This is particularly the case for a heat exchanger intended to cool high-pressure air taken from an aircraft propulsion engine (better known as bleed air) or from an auxiliary power unit (commonly referred to by the English acronym APU for Auxiliary Power Unit).

[0007] When a heat exchanger begins to be supplied with bleed air, the temperature of the internal elements of the exchanger block (also called "core") increases more quickly than the adjacent elements of the exchanger block and its periphery. This results in temperature gradients causing mechanical stresses that can lead to possible deformation of the exchanger elements (rotation of the closing bars of the exchanger block for example). Such deformations can go as far as causing the rupture of certain elements, materializing by cracks or debrazing of certain brazed parts. These phenomena pose a risk of fluid leaks inside the exchanger, or even to the outside of it.

[0008] In order to reinforce the mechanical strength of the heat exchanger and to facilitate the supply and distribution of fluid (such as air for example) to the heat exchanger, it is common to equip such a heat exchanger with a fluid flow collector box and / or a fluid flow distribution box, both mechanically connected to the exchanger block.

[0009] Throughout the following, the fluid will mainly be designated by the term “air”, it being understood that another fluid, mainly gaseous, can be used within the framework of this invention.

[0010] The distributor box is often supplied with air from a pipe with a circular cross-section. The distributor box delivers the received air to the exchanger block, which generally has a parallelepiped shape and is formed, for example, by a stack of plates forming two by two channels for the circulation of air flows in thermal interaction within the exchanger block. The flow collector box receives the air at the outlet of the exchanger block and delivers it to a pipe which generally has a circular cross-section.

[0011] These changes in geometry (circular pipe to parallelepiped exchanger block and parallelepiped exchanger block to circular pipe) generate, within the collector box and the distribution box, vortices which can impact the air flow.

[0012] That being said, the collector box and the distribution box (hereinafter referred to as interface boxes) are necessary to ensure the passage of air between the pipes and the exchanger block and to ensure mechanical resistance to pressure and stress of the heat exchanger, essential in view of the constraints mentioned above.

[0013] The inventors therefore sought to propose an evolution of the heat exchanger and in particular of the interface boxes to reconcile the collection and distribution of the air flow to the exchanger with the mechanical constraints of the exchanger.

[0014] Objectives of the invention

[0015] The invention aims to provide a heat exchange device which overcomes at least some of the drawbacks of known devices. The invention also aims to provide, in at least one embodiment, such an exchange device which makes it possible to limit pressure losses.

[0016] The invention also aims to provide, in at least one embodiment, such an exchange device which can be obtained from a known exchange device, without significant structural modification.

[0017] The invention also aims to provide, in at least one embodiment, such a device which can exhibit better thermomechanical behavior than known exchange devices.

[0018] Statement of the invention

[0019] To this end, the invention relates to a device for heat exchange between two heat transfer fluids comprising: an external casing delimiting a circulation enclosure for the heat transfer fluids, an inlet for a first heat transfer fluid into the circulation enclosure, an outlet for said first heat transfer fluid outside said circulation enclosure, an inlet for a second heat transfer fluid into the circulation enclosure, an outlet for said second heat transfer fluid outside the circulation enclosure, an exchanger block arranged in the circulation enclosure so as to be in fluid communication with said fluid inlets and outlets to allow the circulation of said first fluid and said second fluid in and through this exchanger block and the transfer of calories between them.

[0020] The device according to the invention is characterized in that it comprises at least one interface box forming one of said fluid inlets or one of said fluid outlets, said interface box comprising a curved casing provided with an orifice adapted to be connected to a supply or distribution pipe for one of the heat transfer fluids, and an interface frame mechanically connected to said external casing, said orifice and said interface frame each extending in a plane perpendicular to a longitudinal axis which defines the main direction of circulation of the fluid flow at the inlet or outlet of the box, said box further comprising a plurality of heat transfer fluid guide fins which each extend between the orifice and said interface frame to ensure continuity of geometry between said pipe and said exchanger block,said fins being furthermore separated from each other so as to form passages between the fins which make it possible to transfer the pressure forces onto the curved casing of the interface box.

[0021] The heat exchange device according to the invention thus makes it possible to limit the pressure losses of the interface box equipped with a plurality of guide fins (i.e. at least two separate guide fins) by improving the flow of fluid through the interface box and by eliminating the sudden variation in geometry inherent in the change in section between the supply or distribution pipe of the box and the interface frame which is mechanically connected to the exchanger block. The guide fins make it possible in particular to eliminate the marginal vortices which can develop due to the break in geometry of the flow of the heat transfer fluid through the box.

[0022] Each guide vane of the plurality of vanes extends between the orifice and the interface frame.

[0023] Furthermore, to the extent that the box as such is not modified compared to the exchangers of the prior art, it can retain its mechanical resistance properties to pressure and stress.

[0024] In addition, the guide fins can contribute to absorbing the mechanical forces to which the boxes are subjected. Where appropriate, it is possible to provide boxes that are thinner than the boxes of the prior art, which then allows for better thermomechanical behavior by reducing thermal inertia.

[0025] The box comprising a plurality of guide fins, i.e. at least two distinct fins, the box can be adapted to the environment in which it is arranged. By way of example and according to one embodiment, the presence of a plurality of fins within the box makes it possible to provide a fin which has a different shape from the other fins, which makes it possible to limit the pressure losses of the box linked to a break in the geometry of the pipe, for example if the box has a bend just before the inlet orifice.

[0026] Furthermore, and according to the invention, the fins are separated from each other so as to form air passages between the fins. These passages make it possible to transfer the pressure forces onto the curved skin of the interface box, which is better suited to withstanding these constraints than the convex fins provided in the box.

[0027] The interface box may be an inlet box in the exchanger, in which case it is generally referred to as a distribution box or distributor. Such a box is supplied by a heat transfer fluid inlet pipe which opens into the box at the orifice, which is then an inlet orifice in the box. The distribution box makes it possible to distribute the heat transfer fluid to the exchanger block, from the inlet orifice. The presence of a plurality of guide fins in such a box forms diverging means for guiding the heat transfer fluid towards the exchanger block.

[0028] An interface box can also be an outlet box of the exchanger, in which case it is generally referred to by the terminology of collector box or manifold. Such a box is supplied by the exchanger block and collects the heat transfer fluid from the exchange matrix to supply a pipe connected to the orifice of the box, which is then an outlet orifice of the box. The collector box therefore allows the heat transfer fluid to be conveyed to the outlet orifice, from the exchanger block. The presence of guide fins in such a box forms convergent guide means of the heat transfer fluid towards the outlet orifice of the box.

[0029] Advantageously and according to the invention, for at least one interface box, said orifice is circular and said interface frame is rectangular with a surface area greater than the surface area of ​​said orifice, and at least one guide fin - preferably each guide fin - extends longitudinally and radially in the space of the curved envelope which is not opposite the orifice.

[0030] According to this advantageous variant, the orifice of the box has a circular cross-section to correspond to a pipe supplied or supplying the orifice of the interface box which has a circular cross-section. In addition, the interface frame has a rectangular cross-section to be able to correspond to an exchanger block which has a rectangular cross-section, such as plate exchanger blocks for example. In this case and preferably, at least one guide fin, and preferably each fin, extends longitudinally and radially in the space of the curved casing of the box which is not opposite the orifice. This makes it possible to limit the break in the geometry of the flow of the heat transfer fluid by not obstructing the space opposite the orifice of the box.According to this variant, the guide fin makes it possible to maintain the majority of the heat transfer fluid flow in the central part of the box by preventing the fluid from flowing in the vicinity of the domed part of the interface box.

[0031] Advantageously and according to the invention, for at least one interface box, at least one guide fin - preferably each guide fin - has a convex shape and extends longitudinally and radially from said orifice to said interface frame.

[0032] According to this variant, the convex shape of the guide fin ensures continuity of geometry between the orifice and the interface frame which does not generate any sudden variation in the flow of the fluid in the interface box.

[0033] Advantageously and according to the invention, at least one interface box and said guide fins housed in this interface box are metallic and said fins are welded to the box.

[0034] According to this advantageous variant, the guide fins are metallic and welded into the interface box which is itself metallic. For example, the convex fins can be stamped sheets which are welded into the interface box which is itself formed of stamped sheets.

[0035] Alternatively, the fins can simply be fitted between the interface box and the heat exchanger block. They are then housed in the interface box, but not secured to the box.

[0036] Advantageously and according to the invention, for at least one interface box, at least one guide fin has a shape different from the other fins of the box.

[0037] According to this variant, at least one fin of the plurality of fins has a shape different from the other fins of the box. This makes it possible, for example, to limit the pressure losses of the box linked to a break in the geometry of the pipe connected to said orifice of the box. For example, if the supply pipe of the interface box (in the case where the interface box is an inlet box in the exchanger) has an elbow just before the inlet orifice, a fin of specific geometry (and therefore different from the other fins) makes it possible to guide the air flow towards the exchanger block while limiting the pressure losses despite the strong turbulence generated by the elbow upstream of the box. This specific shape may, for example, consist of a curvature of the convex portion of the fin that is greater or less significant than the other fins of the box.

[0038] Advantageously and according to the invention, at least one guide fin - preferably each guide fin - of at least one interface box carries heat recovery elements which extend into the box so as to improve the thermomechanical behavior of said box.

[0039] According to this advantageous variant, the fins also carry heat recovery elements, formed for example by pins which extend into the heat transfer fluid circulation zone. These heat recovery elements will therefore be able to capture part of the heat from the heat transfer fluid which circulates in the box, which will improve the thermomechanical behavior of the box. In the case of an inlet box, this will in particular make it possible to limit the thermal inertia of the exchanger block arranged downstream of the box.

[0040] Advantageously and according to the invention, at least one interface box comprises four separate guide fins regularly distributed around said longitudinal axis.

[0041] According to this advantageous variant, the fins are regularly distributed around the longitudinal axis and are separated from each other so as to form passages between the fins. These passages make it possible to transfer the pressure forces onto the curved outer skin of the interface box, which is better suited to withstanding these constraints than the convex fins provided in the box.

[0042] Advantageously and according to the invention, the exchanger comprises at least one interface box, called distributor box, forming said inlet of said first heat transfer fluid and at least one interface box, called collector box, forming said outlet of said first heat transfer fluid.

[0043] In this variant, the exchanger includes one interface box as an input box and one interface box as an output box. It is also possible to provide an exchanger with four interface boxes, one for each input and one box for each output. Any combination is possible depending on requirements.

[0044] The invention also relates to a heat exchange device characterized in combination by all or part of the characteristics mentioned above or below.

[0045] List of figures

[0046] Other aims, characteristics and advantages of the invention will appear on reading the following description given solely for non-limiting purposes and which refers to the appended figures in which:

[0047] - [FIG. 1] is a schematic perspective view of a heat exchanger according to one embodiment of the invention,

[0048] - [FIG. 2] is a schematic sectional view of a prior art exchanger whose interface boxes are devoid of heat transfer fluid guide fins,

[0049] - [FIG. 3] is a schematic sectional view of an exchanger according to an embodiment of the invention, the interface boxes of which are equipped with guide fins, [FIG. 4] is a schematic view of an interface box of an exchanger according to an embodiment of the invention.

[0050] Detailed description of an embodiment of the invention

[0051] In the figures, scales and proportions are not strictly respected, for the purposes of illustration and clarity.

[0052] Identical, similar or analogous elements are designated by the same references in all figures.

[0053] Figure 1 schematically illustrates in perspective a heat exchanger according to an embodiment of the invention comprising an external casing 10 delimiting an enclosure 12 for circulating heat transfer fluids. The enclosure 12 is visible in particular in Figure 3. The heat transfer fluids can be of any type. It can for example be a flow of hot air, for example taken from a propulsion engine of an aircraft, and a flow of cold air, taken for example from outside the aircraft, by a dedicated scoop.

[0054] The heat exchanger further comprises an interface box 20 forming an inlet of the first heat transfer fluid (for example a flow of hot air) into the circulation enclosure and an interface box 30 forming an outlet of the first heat transfer fluid outside the circulation enclosure.

[0055] The exchanger also comprises an interface box 40 forming an inlet of the second heat transfer fluid (for example a flow of cold air) into the circulation enclosure and an outlet of the second heat transfer fluid outside the circulation enclosure. The outlet is not visible in the perspective view of FIG. 1 being arranged on the hidden face of the perspective.

[0056] According to other embodiments, the exchanger may comprise a single interface box to form a fluid inlet or outlet. Any configuration is possible without compromising the principle of the invention. The structure of the interface box will be described later in connection with Figures 3 and 4.

[0057] The exchanger also comprises a parallelepiped exchanger block 14 arranged in the circulation enclosure 12. This exchanger block 14 is in fluid communication with the fluid inlets and outlets and ensures heat exchanges between the two fluids. This exchanger block is for example formed of a stack of parallel plates 16 which alternately delimit circulation channels for the first heat transfer fluid and the second heat transfer fluid. Thus, heat exchanges can occur between the two fluids, inside the enclosure 12 by conduction of the plates delimiting the different channels.

[0058] Figure 4 schematically illustrates the interface box 20 which forms a fluid inlet into the enclosure 12. It should however be noted that according to one embodiment, the other interface boxes (if the exchanger comprises several interface boxes as in Figure 1) may comprise a structure identical to the interface box 20 represented by Figure 4.

[0059] As shown in Figures 3 and 4, the interface box 20 comprises a domed casing 24 provided with a circular orifice 26 mechanically and fluidically connected to a heat transfer fluid supply pipe 18, cylindrical with a circular cross section. The interface box 20 also comprises an interface frame 28 mechanically connected to the external casing 10 and fluidically connected to the exchanger block 14. In other words, the interface box 20 makes it possible to receive the heat transfer fluid via the orifice 26 and convey it to the interface frame 28 to supply the exchanger block 14 of the exchanger.

[0060] Of course, such an interface box can also form the fluid outlet and thus be intended to receive fluid via the interface frame, from the exchanger block 14, and convey this fluid to the orifice 26, which is then an outlet orifice, fluidically and mechanically connected to a fluid distribution pipe.

[0061] The interface box 20 according to the embodiment of FIG. 4 further comprises a plurality of fins 22a, 22b, 22c, 22d for guiding the heat transfer fluid. Each fin 22a, 22b, 22c, 22d extends between the orifice 26 and the interface frame 28 to ensure continuity of geometry between the pipe 18 and the exchanger block 14.

[0062] As shown in Figure 4, the fins are regularly distributed around an axis, called the longitudinal axis L, which corresponds to the main direction of flow of the fluid through the interface box.

[0063] The guide fins are separated from each other so as to form passages 30, 31 between them. These air passages make it possible to transfer the pressure forces onto the curved casing 24 of the interface box.

[0064] The fins have, according to the embodiment of the figures, a convex shape and extend longitudinally and radially in the space delimited by the curved envelope 24.

[0065] The fins 22a, 22b, 22c, 22d are for example formed from stamped sheets and welded inside the interface box.

[0066] The guide fins 22a, 22b, 22c, 22d make it possible to eliminate marginal vortices which can develop due to the break in the geometry of the flow of the heat transfer fluid through the box.

[0067] Figure 2 schematically illustrates the flow of air through an exchanger whose interface box 20' forming an inlet box and interface box 30' forming an outlet box are each devoid of guide fins and Figure 3 schematically illustrates the flow of air through an exchanger according to an embodiment of the invention whose interface boxes 20 and 30 are each provided with guide fins.

[0068] Figure 2 shows the presence of significant vortices in the 20' inlet interface box and residual vortices in the 30' outlet interface box.

[0069] In Figure 3, the inlet 20 and outlet 30 interface boxes are equipped with guide fins, which make it possible to guide the air flow between the inlet orifice with a circular cross-section and the parallelepiped exchanger block. The fins thus make it possible to guide the air flow by eliminating the sudden variation in geometry inherent in the change in section between the supply or distribution pipe of the box and the interface frame which is mechanically connected to the exchanger block.

[0070] According to an embodiment not shown in the figures, at least one guide fin further carries heat recovery elements which extend into the box so as to improve the thermomechanical behavior of the box. These heat recovery elements are for example pins carried by the fin which extend into the fluid flow. These pins thus make it possible to capture part of the calories of the fluid circulating in the interface box in contact with the fins. A heat exchange device can be used for various applications, and in particular, but not exclusively, for an air conditioning system of a transport vehicle such as an aircraft.

Claims

CLAIMS 1. Device for heat exchange between two heat transfer fluids comprising: an external casing (10) delimiting an enclosure (12) for circulation of the heat transfer fluids, an inlet (20) for a first heat transfer fluid in the circulation enclosure, an outlet (30) of said first heat transfer fluid outside said circulation enclosure, an inlet (40) for a second heat transfer fluid in the circulation enclosure, an outlet of said second heat transfer fluid outside the circulation enclosure, an exchanger block (14) arranged in the circulation enclosure (12) so as to be in fluid communication with said fluid inlets and outlets to allow the circulation of said first fluid and said second fluid in and through this exchanger block and the transfer of calories between them, characterized in that it comprises at least one interface box (20, 30) forming one of said fluid inlets or one of said fluid outlets,said interface box (20) comprising a curved casing (24) provided with an orifice (26) adapted to be connected to a supply line (18) or distribution line for one of the heat transfer fluids, and an interface frame (28) mechanically connected to said external casing (10), said orifice (26) and said interface frame (28) each extending in a plane perpendicular to a longitudinal axis (L) which defines the main direction of circulation of the fluid flow entering or leaving the box, said box (20) further comprising a plurality of fins (22a, 22b, 22c, 22d) for guiding the heat transfer fluid which each extend between said orifice (26) and said interface frame (28) to ensure continuity of geometry between said line (18) and said exchanger block (14), said fins being furthermore disjointed, to each other so as to form passages between the fins which allow the pressure forces to be transferred to said curved casing of the interface box.

2. Device according to claim 1, characterized in that for at least one interface box (20), said orifice (26) is circular and said interface frame (28) is rectangular with a surface area greater than the surface area of ​​said orifice, and in that at least one guide fin (22a, 22b, 22c, 22d) - preferably each guide fin - extends longitudinally and radially in the space of the curved envelope (24) which is not opposite the orifice (26).

3. Device according to one of claims 1 or 2, characterized in that for at least one interface box (20), at least one guide fin - preferably each guide fin - has a convex shape and extends longitudinally and radially from said orifice (26) to said interface frame (28).

4. Device according to one of claims 1 to 3, characterized in that at least one interface box (20) and said guide fins (22a, 22b, 22c, 22d) housed in this interface box are metallic and in that said fins are welded to the box.

5. Device according to one of claims 1 to 4, characterized in that for at least one interface box (20), at least one guide fin (22a, 22b, 22c, 22d) has a different shape from the other guide fins.

6. Device according to one of claims 1 to 5, characterized in that at least one guide fin (22a, 22d, 22c, 22d) - preferably each guide fin - of at least one interface box (20) carries heat recovery elements which extend into the box so as to improve the thermomechanical behavior of said box.

7. Device according to one of claims 1 to 6, characterized in that at least one interface box comprises guide fins (22a, 22b, 22c, 22d) regularly distributed around said longitudinal axis.

8. Device according to one of claims 1 to 7, characterized in that at least one interface box (20) comprises four guide fins (22a, 22b, 22c, 22d). regularly distributed around said longitudinal axis.

9. Device according to one of claims 1 to 8, characterized in that it comprises at least one interface box (20), called distributor box, forming said inlet of said first heat transfer fluid and at least one interface box (30), called collector box, forming said outlet of said first heat transfer fluid.

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