Surface heat exchanger including a pressure drop reducer and aircraft nacelle equipped with such a heat exchanger

Abstract

A heat exchanger (20), particularly for an aircraft nacelle, comprising a first skin (21) and a second skin (22) assembled together and a plurality of distribution channels (23) for a hydraulic fluid (F1) disposed between the first skin (21) and the second skin (22), the exchanger further comprising a first hydraulic interface (24) and a second hydraulic interface (25) for said hydraulic fluid. Said heat exchanger (20) further comprises at least one pressure-reducing element (40) extending axially towards the first hydraulic interface (24) or the second hydraulic interface (25), said pressure-reducing element (40) having a generally conical cross-section. Figure for the abbreviation: [Fig 4]

Description

Title of the invention: Surface heat exchanger comprising a pressure drop reducer and aircraft nacelle equipped with such a heat exchanger. Technical field of the invention

[0001] The present invention relates to the field of heat exchangers, in particular the fairings of an aircraft engine, called "nacelle". Prior art

[0002] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0003] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0006] Generally, an aircraft is propelled by one or more propulsion units, each comprising an engine or turbojet housed in a tubular nacelle.

[0007] A nacelle generally comprises a tubular body including an upstream section with an air inlet upstream of the turbojet engine, a midsection configured to surround a turbojet fan, and a downstream section configured to house thrust reversing means and to surround the turbojet combustion chamber. The nacelle generally includes an exhaust nozzle downstream of the downstream section, the outlet of which is located downstream of the turbojet engine.

[0008] Furthermore, the nacelle usually comprises an external structure and a fixed internal structure, known as the "inner fixed structure," abbreviated as "IFS" in English. The fixed internal structure is concentric with the external structure at the downstream section and surrounds the core of the turbojet engine downstream of the fan.

[0009] These external and internal structures define an annular flow channel, called a secondary channel, designed to channel a flow of cold air, called secondary, circulating outside the turbojet.

[0010] The external structure comprises an external fairing defining an external aerodynamic surface and an internal fairing defining an internal aerodynamic surface. The internal and external fairings are connected upstream by a leading edge wall forming an air inlet lip.

[0011] Generally, the turbojet engine comprises a set of blades driven in rotation by a gas generator through a set of transmission means. The nacelle further comprises a lubricant distribution system to ensure proper lubrication and cooling of these transmission means. The lubricant is advantageously oil.

[0012] In order to cool the lubricant, the nacelle generally includes a cooling system comprising at least one heat exchanger. The cooling system is configured to circulate a fluid, for example the lubricant or a coolant, which will cool the lubricant.

[0013] There are air / lubricant heat exchangers that use air drawn from the secondary flow (so-called cold flow) of the nacelle or one of the first stages of the compressor. Drawing and circulating air through the heat exchanger disrupts the airflow and results in additional pressure losses, known as drag, which is undesirable.

[0014] Heat exchangers with fins fixed to one of the walls of the nacelle delimiting the secondary flow are also known. The fluid is cooled by the flow of air in the secondary flow along the fins on the surface of the exchanger.

[0015] Such a solution also generates significant aerodynamic losses, which in turn leads to significant fuel consumption losses.

[0016] Fluid cooling systems comprising a structural surface heat exchanger, i.e., a finless heat exchanger, are also known. forming a generally smooth contact surface with the fluid circulating outside the exchanger, so as to avoid pressure losses caused by the presence of fins.

[0017] In the example illustrated in [Fig.1], a structural surface heat exchanger 10 without fins comprises a first corrugated skin 11 and a second smooth skin 12, assembled to form distribution channels 13 which allow the flow of a fluid F, for example, a heat transfer fluid or a lubricant, from an inlet interface 14 to an outlet interface 15 of fluid.

[0018] The hydraulic inlet interfaces 14 and outlet interfaces 15 are calibrated to distribute an identical flow rate in each distribution channel 13 as best as possible.

[0019] However, these hydraulic interfaces induce significant pressure losses which need to be reduced.

[0020] Current heat exchangers present risks of non-homogeneous distribution of flow rates between the different distribution channels, which degrades their thermal efficiency.

[0021] Indeed, as can be seen in [Fig.1], when the fluid arrives perpendicularly to the smooth skin 12 or aerodynamic skin before feeding the distribution channels 13, the fluid F undergoes a 90° change of direction, generating significant pressure losses.

[0022] In order to maximize the thermo-hydraulic performance of the surface exchanger, the pressure losses must be as low as possible and the flow distribution almost identical from one channel to another.

[0023] These pressure losses must also be minimized in order to limit the size, weight and cost of the circulation pumps to be installed which are required to overcome these pressure losses.

[0024] Regarding surface heat exchangers with rectangular cross-section channels, it is known to reduce the dispersion of flow rates by increasing or decreasing the width of these channels in order to equalize the pressure losses.

[0025] However, in the case of surface heat exchangers with semi-circular cross-section channels, the design of the channels does not easily allow modification of the cross-section of said channels.

[0026] There is a need to improve fluid cooling systems, in particular surface heat exchangers. Description of the invention

[0027] The present invention therefore aims to overcome the aforementioned drawbacks.

[0028] The objective of the invention is to reduce the pressure losses inherent in the inlet and / or outlet interfaces of a heat exchanger, to promote a homogeneous distribution of the fluid flow in the distribution channels and thus to improve the heat exchange between respectively a fluid circulating inside and the air circulating outside said heat exchanger.

[0029] The invention relates to a heat exchanger, preferably surface heat exchanger, particularly for aircraft nacelle, comprising a first skin or wall and a second skin or wall assembled together and a plurality of hydraulic fluid distribution channels arranged between the first skin and the second skin.

[0030] The exchanger further comprises a first hydraulic interface, for example an inlet hydraulic interface, and a second hydraulic interface, for example an outlet hydraulic interface.

[0031] Said exchanger further comprises at least one pressure loss reduction element extending axially towards the first hydraulic interface or the second hydraulic interface, said pressure loss reduction element having a generally conical cross-section.

[0032] The pressure loss reduction device is an intermediate part that separates the incoming hydraulic flow into the inlet hydraulic interface and distributes it into each distribution channel of the exchanger.

[0033] In the hydraulic outlet interface, the pressure loss reduction device allows the different hydraulic flows arriving from the distribution channels to be collected homogeneously.

[0034] The particular conical shape of the pressure loss reducer makes it possible to reduce pressure losses without reducing the passage of the hydraulic flow in the associated hydraulic interface.

[0035] Thanks to the invention, the transition of change of plane between the associated hydraulic interface and the second smooth skin of the surface exchanger is softened thanks to the pressure loss reduction element extending towards the associated hydraulic interface.

[0036] Furthermore, the heat exchanges between a fluid circulating in the heat exchanger and the air circulating outside said heat exchanger are optimized, while improving the structural integrity of the heat exchanger and reducing aerodynamic pressure losses.

[0037] Advantageously, the pressure loss reduction element extends axially at least in part into the first hydraulic interface or the second hydraulic interface. This allows for improved fluidity of the transition and therefore a better reduction of pressure losses.

[0038] Preferably, at least one of the first and second hydraulic interfaces forms an angle with the second skin, preferably greater than or equal to 60°, for example equal to 90°.

[0039] Preferably, each of the distribution channels is directly connected to the hydraulic inlet interface and the hydraulic outlet interface.

[0040] The distribution channels extend in a single plane. In other words, no part of the distribution channels protrudes from either of the skins. This allows for a substantially flat heat exchanger.

[0041] For example, each of the distribution channels is directly connected to the first hydraulic interface and to the second hydraulic interface and the distribution channels are regularly distributed around the entire perimeter of the associated hydraulic interface.

[0042] This allows for a larger number of channels and a homogeneous distribution at the input or output regardless of the number of channels. It also limits load losses by directly powering each channel from the input interface.

[0043] By "surface exchanger", we mean a finless exchanger, a smooth exchanger, whose wall or skin which defines the vein forms the heat exchange surface.

[0044] The absence of fins, or other shapes intended to increase the contact area between the flow and the exchanger, makes it possible to avoid any obstruction to the airflow in the duct, and therefore to reduce aerodynamic pressure losses.

[0045] The first skin and the second skin can be, for example, sheets of metal.

[0046] By "sheet metal", we mean a flat steel product, rolled either hot or cold, A sheet metal sheet is therefore made of metallic material, generally with a smooth surface or sometimes with protrusions.

[0047] The distribution channels are configured to extend in a single plane between the first hydraulic interface and the second hydraulic interface.

[0048] By "distributed over the whole perimeter of the hydraulic interface", it is meant that certain channels are connected to one of the hydraulic interfaces by a first end extending in a direction opposite to the other of the hydraulic interfaces.

[0049] The ends are extended by a main part, for example straight, extending towards the other of the hydraulic interfaces to a second end.

[0050] The second end can also extend in a direction opposite to one of the hydraulic interfaces.

[0051] For example, the channels are connected to the hydraulic inlet interface by an inlet end and to the hydraulic outlet interface by an outlet end.

[0052] The input end is, for example, connected to the output end by a main part.

[0053] An inlet end of at least one channel extends in a direction opposite to the hydraulic outlet interface and an outlet end of at least one channel extends in a direction opposite to the hydraulic inlet interface.

[0054] For example, the hydraulic inlet and outlet interfaces have a circular cross-section.

[0055] For example, the hydraulic inlet and outlet interfaces each include an outlet orifice extending along a plane perpendicular to the extension planes of the skins.

[0056] Advantageously, the thickness of each distribution channel is constant over the entire length of the corresponding channel.

[0057] For example, the distribution channels have an identical cross-section between them.

[0058] Alternatively, different cross-sections could be provided for each of the channels. For example, the longest distribution channels could be provided for having a larger cross-section in order to balance the flow rates between said distribution channels.

[0059] Advantageously, the pressure loss reduction device is a solid of revolution.

[0060] By "solid of revolution", it is understood that each specific zone of the pressure loss reduction device introducing the hydraulic flow into each distribution channel is repeated as many times as there are distribution channels.

[0061] Preferably, the pressure loss reduction element comprises a base directed towards the second skin on the side opposite the associated hydraulic interface and a conical hydraulic flow deflection portion extending from the base to a top and directed towards the associated hydraulic interface, on the side opposite the second skin.

[0062] Without limiting the foregoing, the apex is located at the center of the associated hydraulic interface.

[0063] The portion of the hydraulic flow deflection extends, for example, at least in part into the associated hydraulic interface.

[0064] Advantageously, the base of the pressure loss reduction element has a shape that is homothetic or similar to the associated hydraulic interface, for example circular, oval, etc...

[0065] In all cases, it is important not to restrict the hydraulic flow passage section between the cylindrical inlet of the associated interface and the passage at the right of the hydraulic flow deflection part.

[0066] The circular shape of the base of the pressure loss reduction element allows for stress-free fixing in the associated hydraulic interface.

[0067] According to one embodiment, the hydraulic flow deflection part of the pressure loss reduction device comprises a smooth external surface.

[0068] According to another embodiment, the hydraulic flow deflection portion of the pressure loss reduction device comprises an external surface comprising a plurality of concave facets, with curved or uncurved faces, said concave facets extending from the base to the apex and connected to said apex.

[0069] Each concave facet is preferably located opposite an associated distribution channel.

[0070] Thus, the concave facets make it possible to guide the flow in each distribution channel or to help each incident hydraulic flow to exit with the smallest pressure loss.

[0071] According to another embodiment, the hydraulic flow deflection portion of the pressure loss reduction element comprises an external surface including a plurality of protrusions regularly distributed around the periphery of the cone and a plurality of grooves or recesses regularly distributed around the periphery of the cone alternately with the protrusions, each protrusion extending from the base to the apex and being connected to said apex. Each groove preferably forms a flow path located opposite an associated distribution channel.

[0072] Said grooves allow the flow to be guided in each distribution channel or help each incident hydraulic flow to exit with the smallest pressure loss.

[0073] By "outgrowth" is meant an extruded elongated surface.

[0074] The outgrowths have, for example, a curved face.

[0075] Alternatively, it could be provided that the outgrowths have a non-curved face.

[0076] Alternatively, the pressure loss reduction device could also be provided for as a solid of revolution of general conical shape formed by vertical triangular plates to separate the incident flow or direct the incoming flow.

[0077] According to one embodiment, the pressure loss reduction device is integrated directly into the second skin or the associated hydraulic interface.

[0078] By "integrated directly", it is understood that the pressure loss reduction element is integral with the second skin or associated intermediate hydraulic interface without an intermediate element, by any non-removable means of fixing such as welding, gluing, brazing, riveting or any removable means of fixing such as screwing, or made of material with the second skin or associated intermediate hydraulic interface.

[0079] According to one embodiment, the heat exchanger comprises a plate fixed to the second skin and provided with studs arranged between the second and first skins, so as to ensure the attachment of said interfaces to the first and second skins by means of fastening means cooperating with said studs. The pressure loss reduction element is preferably integrated directly into the plate.

[0080] By "integrated directly", it is meant that the pressure loss reduction element is integral with the plate without an intermediate element, by any non-removable means of fixing such as welding, gluing, brazing, riveting or any removable means of fixing such as screwing, or even made of material with the plate.

[0081] The load paths can thus be optimized in order to reduce the total mass and the margins of mechanical stresses according to the different cases of mechanical stresses, such as hydraulic loads and aerodynamic and mechanical loads.

[0082] According to one embodiment, each of the first and second skins is flat.

[0083] Alternatively, each of the first and second skins is curved to ensure aerodynamic continuity with the rest of the nacelle.

[0084] Advantageously, the exchanger comprises a plurality of spacers or spacers arranged between the first skin and the second skin, two adjacent spacers delimiting a distribution channel.

[0085] For example, the first skin and the second skin are joined together by an assembly zone, for example by welding or brazing, at the level of the spacer members, said assembly zone extending from the first skin to the second skin.

[0086] According to one embodiment, the first skin comprises a plurality of undulations, the distribution channels being delimited each by an undulation of the first corrugated skin and the second skin.

[0087] For example, each distribution channel has a semi-circular cross-section.

[0088] Generally, the first skin has a thickness between 0.6mm and 3mm and the second skin has a thickness between 0.6mm and 4mm.

[0089] The first skin and / or the second skin is made of aluminum or an aluminum alloy. This improves the lightness, formability of the skins, and heat exchange.

[0090] According to a second aspect, the invention relates to a turbomachine nacelle comprising an external structure and an internal structure defining an annular secondary flow channel, said nacelle comprising a housing for a turbomachine, which, together with the internal structure, defines an annular primary flow channel. The nacelle comprises at least one heat exchanger as described above, fixed either in the external structure, on the side of the secondary flow channel or on the external side of said external structure, or in the internal structure or internal fairing, on the side of the secondary flow channel.

[0091] When the exchanger is fixed in the internal fairing, the second skin of the heat exchanger is in contact with the airflow circulating in the secondary vein.

[0092] When the exchanger is fixed in the internal structure of the nacelle, the second skin of the heat exchanger is in contact with the airflow circulating in the secondary vein.

[0093] Alternatively, it could be provided that when the exchanger is fixed in the external structure of the nacelle, the second skin of the heat exchanger can be in contact with the outside airflow.

[0094] Thus, the heat exchanger can be used to cool a fluid from the secondary flow or from outside air. Brief description of the drawings

[0095] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the indexed drawings in which:

[0096] [Fig.l], is a schematic view of a cross-sectional view of a structural surface heat exchanger according to the prior art;

[0097] [Fig.2] is a schematic view of a surface heat exchanger according to an embodiment of the invention;

[0098] [Fig.3] is a partial cross-sectional detail view of the exchanger according to the invention along section III-III of [Fig.2];

[0099] [Fig.4] is a partial cross-sectional detail view of the exchanger according to the invention along section IV-IV of [Fig.2];

[0100] [Fig.5] is a perspective view of a pressure loss reducer of the exchanger of the [Fig.4];

[0101] [Fig.6] is a perspective view of a pressure loss reducer according to a second embodiment of the invention;

[0102] [Fig.7] is a perspective view of a pressure loss reducer according to a third embodiment of the invention;

[0103] [Fig.8] is a partial cross-sectional view of a surface heat exchanger according to another embodiment of the invention;

[0104] [Fig.9A], [Fig.9B] are views of a surface heat exchanger according to another embodiment of the invention;

[0105] [Fig. 10] is a partial cross-sectional view of a surface heat exchanger according to another embodiment of the invention; and

[0106] [Fig. 11] is a schematic view of a nacelle equipped with a heat exchanger according to one of the embodiments of the invention.

[0107] Detailed description of at least one embodiment

[0108] In the following description, the terms "upstream" and "downstream" are defined with respect to the direction of airflow in the turbomachine. The terms "internal" and "external" are defined with respect to the longitudinal axis of the turbomachine, the internal term defining an element closer to said axis than an external element.

[0109] With reference to the example illustrated in Figures 2 to 4, a heat exchanger 20 comprises a first skin 21, for example a sheet, and a second skin 22, for example a sheet.

[0110] The first skin 21 comprises a plurality of undulations 21a, for example, made by forming said first skin 21 and the second skin 22 is here flat.

[0111] The exchanger 20 comprises a plurality of distribution channels 23 delimited each by a corrugation 21a of the first corrugated skin 21 and the second smooth skin 22.

[0112] Each distribution channel 23 has a semi-circular cross-section. Alternatively, the cross-section could be provided to have any general shape.

[0113] As illustrated, the distribution channels 23 have a cross-section of identical size between them.

[0114] Alternatively, different sized sections could be provided between each of the channels.

[0115] For example, it could be provided that the longest distribution channels have a larger cross-section in order to balance the flow rates between said distribution channels.

[0116] The distribution channels 23 are connected, here, directly respectively to a first hydraulic interface 24, for example an inlet hydraulic interface, and a second hydraulic interface 25, for example an outlet hydraulic interface.

[0117] In the present description, the inlet and outlet are defined with respect to the normal flow direction of the cooling fluid in the exchanger.

[0118] As illustrated in [Fig. 2], the inlet ends 23a of the distribution channels 23 are uniformly, i.e. regularly, distributed on the entire perimeter of the hydraulic inlet interface 24 and the outlet ends 23b of the distribution channels 23 are distributed uniformly over the entire perimeter of the hydraulic outlet interface 25.

[0119] By "distributed over the whole perimeter", it is understood that an inlet end 23a of at least one channel 23 extends in a direction opposite to the hydraulic outlet interface 25 and that an outlet end 23b of at least one channel 23 extends in a direction opposite to the hydraulic inlet interface 24.

[0120] The inlet ends 23a of the channels 23 and the outlet ends 23b of the channels 23 have a curved shape.

[0121] The inlet ends 23a and the outlet ends 23b of the channels 23 are connected to each other by a main part 23c, here straight.

[0122] In the embodiment illustrated in [Fig. 2], the heat exchanger 20 comprises a first anteroposterior axis of symmetry SI-SI passing through the inlet interface 24 and the outlet interface 25 and a transverse axis of symmetry S2-S2 perpendicular to the SI-SL axis. The distribution channels 23 are arranged symmetrically with respect to the SI-SL axis of symmetry.

[0123] The concavity of the inlet ends 23a and outlet ends 23b of the channels 23 is directed towards the center of the exchanger 20 formed by the intersection of the two axes of symmetry SI-SI and S2-S2.

[0124] Alternatively, it remains possible that the exchanger does not have an axis of symmetry.

[0125] The distribution channels 23 are arranged in the same plane not extending outward from the skins 21, 22. Thus, the channels do not create additional bulk in the overall thickness of the exchanger.

[0126] By "thickness" we mean the dimension in the direction along the axis ZZ perpendicular to the longitudinal extension axis of the exchanger and to the transverse axis of the exchanger.

[0127] The longitudinal axis is parallel to the axis Sl-Sl and the transverse axis is parallel to the axis S2-S2.

[0128] In the example illustrated in [Fig.2], and in no way limitingly, the hydraulic interfaces 24, 25 are aligned along the first axis of symmetry Sl-Sl.

[0129] Alternatively, the hydraulic interfaces 24, 25 could be provided for to be aligned along another axis, for example a transverse axis.

[0130] In general, the invention is not limited to the shape of the distribution channels, which are configured to extend along the longitudinal direction between the hydraulic inlet interface 24 and the hydraulic outlet interface 25.

[0131] The first and second skins 21, 22 are joined by a welding or brazing zone 26, 27, visible in [Fig. 3], on either side of the corrugation 21a of the first corrugated skin 21. Said welding or brazing zone 26, 27 extends from the first corrugated skin 21 to the second skin 22.

[0132] The exchanger 20 is a heat exchanger between a first hydraulic fluid Fl and air F2. The hydraulic fluid Fl is intended to circulate in the channels 23 and the air is intended to circulate in contact with the second smooth skin 22.

[0133] Generally, the first skin 21 has a thickness between 0.6mm and 3mm and the second skin 22 has a thickness between 0.6mm and 4mm.

[0134] The first skin 21 and / or the second skin 22 is made of aluminum or an aluminum alloy. This improves the lightness, heat exchange, and formability of the skins.

[0135] The exchanger 20 is, for example, sealed up to 1 Obars.

[0136] As illustrated in [Fig.2], and by no means limiting the use of the term, the exchanger 20 comprises eight distribution channels 23.

[0137] Alternatively, the heat exchanger 20 could include a different number of distribution channels 23, for example greater than or equal to three, or greater than or equal to four.

[0138] As illustrated in [Fig.4], the hydraulic interface, here the inlet hydraulic interface 24 is orthogonal to the second skin 22, said to be smooth.

[0139] In general, the invention finds a particularly advantageous application for at least one of the hydraulic interfaces forming respectively an angle with the second skin 22, said to be smooth, preferably greater than 60°, for example equal to 90°.

[0140] In the illustrated example, each hydraulic interface 24, 25 forms respectively an angle equal to 90° with the second skin 22, known as the smooth skin of the exchanger.

[0141] The [Fig.4] is a partial cross-sectional view of the connection of an input interface 24 or output interface 25 to the first skin 21 and the second skin 22, according to the invention.

[0142] As illustrated in [Fig.4], the input interface 24, and similarly the output interface 25, have an extension axis Y coincident here with the vertical axis ZZ.

[0143] However, it could be envisaged that the input interface 24 and / or the output interface 25 are understood along an extension axis Y forming a non-zero angle with the vertical axis ZZ, see secant to the vertical axis ZZ-.

[0144] With reference to the example illustrated in figures 4 and 5, the heat exchanger 20 includes a plate 30 fixed to the second skin 22, preferably by welding with beads 30a.

[0145] The plate 30 comprises a plurality of studs 31 projecting axially along an axis perpendicular ZZ to the extension plane of the exchanger 20.

[0146] The studs 31 are arranged between the second skin 22 and the first skin 21 and between the corrugations 21a of the first skin 21. The studs 31 here have a cylindrical cross-section.

[0147] The connection between the plate 30, the first skin 21 and the corresponding hydraulic interface 24, 25 is made with screws 32 each comprising a head 33 and a threaded rod 34.

[0148] The threaded rods 34 pass through a base 24a of the corresponding hydraulic interface 24, 25 and the first skin 21 and cooperate with corresponding (unreferenced) threads provided on the studs 31, so as to clamp the base 24a, 25a and the first skin 21 between the heads of the screws 32 and the studs 31.

[0149] The flow of the hydraulic fluid F is schematically represented by the arrows connecting a hydraulic interface 24 and distribution channels 23. The direction of flow naturally depends on the type of interface. Thus, the flow direction is from an inlet interface 24 to distribution channels 23 and from distribution channels 23 to an outlet interface 25.

[0150] As illustrated in [Fig.4], the heat exchanger 20 further includes a pressure loss reduction element 40 extending axially here partly into the inlet hydraulic interface 24.

[0151] It could be envisaged that the heat exchanger 20 further comprises a second pressure loss reduction element 40 extending axially partly into the hydraulic outlet interface 25.

[0152] Generally, the heat exchanger 20 includes at least one pressure loss reduction element 40 extending axially towards the associated hydraulic interface 24, 25.

[0153] The pressure loss reduction element 40 is an intermediate part which separates the hydraulic flow entering the hydraulic inlet interface 24 and distributes it into each distribution channel 23 of the exchanger 20. In the hydraulic outlet interface 25, the pressure loss reduction element 40 allows the different hydraulic flows arriving from the distribution channels 23 to be collected in a homogeneous manner.

[0154] As illustrated, the pressure loss reduction device 40 is of revolution, that is to say that each specific zone introducing the hydraulic flow into each distribution channel 23 is repeated as many times as there are channels 23.

[0155] The pressure loss reduction element 40 has a shape adapted to the number of channels 23 to be supplied.

[0156] The pressure loss reduction element 40 comprises a base 41, here circular, directed towards the second skin 22 on the side opposite the associated hydraulic interface 24, 25, and a conical hydraulic flow deflection portion 42 extending from base 41 towards a vertex S and directed towards the associated hydraulic interface 24, 25, on the opposite side to the second skin 22.

[0157] As illustrated and in no way limiting, the vertex S is located at the center of the associated hydraulic interface 24, 25.

[0158] The hydraulic flow deflection part 42 extends here at least in part into the associated hydraulic interface 24, 25.

[0159] Generally, the base 41 of the pressure loss reduction element 40 has a shape homothetic or similar to the associated hydraulic interface and may be circular, oval, etc...

[0160] The circular shape of the base 41 of the pressure loss reduction element 40 allows for stress-free fixing in the associated hydraulic interface 24, 25.

[0161] In geometry, a "solid of revolution" is generated by a closed plane surface rotating around an axis located in the same plane as it and having no points in common with it or only points of its boundary.

[0162] A cone is a ruled surface defined by a straight line, called the generatrix, passing through a fixed point S called the vertex and a variable point describing a curve, called the directrix. In the right circular cone, the directrix is ​​a circle with center O, visible in [Fig. 4], located in a plane perpendicular to SO. This cone is called a right circular cone because it can be generated simply by rotating the generatrix around a vertical axis of rotation SZ passing through the vertex S.

[0163] The particular conical shape of the pressure loss reducer 40 makes it possible to reduce pressure losses without reducing the passage of the hydraulic flow F inlet or outlet.

[0164] In the embodiment illustrated in figures 4 and 5, the pressure loss reduction element 40 is integrated directly into the plate 30.

[0165] By "integrated directly", it is meant that the pressure loss reduction element 40 is integral with the plate 30 without an intermediate element, by any non-removable means of fixing such as welding, gluing, brazing, riveting or any removable means of fixing such as screwing, or even made of material with the plate 30.

[0166] The load paths can thus be optimized in order to reduce the total mass and the margins of mechanical stresses according to the different cases of mechanical stresses, such as hydraulic loads and aerodynamic and mechanical loads.

[0167] In this embodiment, the external surface 42a of the conical hydraulic flow deflection part 42 is smooth.

[0168] In the embodiment illustrated in [Fig. 6], in which the same elements bear the same reference numerals, the external surface 42a of the deviation part 42 of the Conical hydraulic flow includes a plurality of concave facets 42b, here, with curved face.

[0169] Alternatively, the external surface 42a of the conical hydraulic flow deflection part 42 could be provided that it comprises a plurality of concave facets 42b with a non-curved face.

[0170] The concave facets 42b extend from the base 41 to the vertex S and are connected to said vertex S.

[0171] The concave facets 42b are intended to be located opposite an associated distribution channel 23 and allow the flow to be guided in each distribution channel 23 or help each incident hydraulic flow to exit with the smallest pressure loss.

[0172] In the embodiment illustrated in [Fig.7], in which the same elements bear the same references, the external surface 42a of the conical hydraulic flow deflection part 42 comprises a plurality of protrusions 42c regularly distributed around the periphery of the cone and a plurality of grooves 42d or recesses regularly distributed around the periphery of the cone in an alternating manner with the protrusions 42c.

[0173] By "outgrowth" is meant an extruded elongated surface.

[0174] Each outgrowth 42c extends from the base 41 to the apex S and is connected to said apex S.

[0175] The protrusions 42c here present a curved face.

[0176] Alternatively, it could be provided that the outgrowths 42c have a non-curved face.

[0177] The grooves 42d form flow paths intended to be located opposite an associated distribution channel 23 and allow the flow to be guided in each distribution channel 23 or help each incident hydraulic flow to exit with the smallest pressure loss.

[0178] Alternatively, the pressure loss reduction device 40 could also be provided for as a solid of revolution of general conical shape formed by vertical triangular plates to separate the incident flow or direct the incoming flow.

[0179] In the embodiment illustrated in [Fig.8], in which the same elements bear the same references, the pressure loss reduction element 40 is integrated directly into the second smooth skin 22.

[0180] By "integrated directly", it is meant that the pressure loss reduction element 40 is integral with the second skin 22 without an intermediate element, by any non-removable means of fixing such as welding, gluing, brazing, riveting or any removable means of fixing such as screwing, or even made of material with the second skin 22.

[0181] In the example illustrated in [Fig.8], the pressure loss reduction element 40 has a conical shape with a smooth external surface 42a.

[0182] Alternatively, any form of the pressure loss reduction device 40 could be provided as described with reference to Figures 6 and 7.

[0183] In the embodiment illustrated in figures 9A, 9B and 10, in which the same elements bear the same references, the pressure loss reduction element 40 is integrated directly into the associated hydraulic interface 24, 25.

[0184] By "integrated directly", it is meant that the pressure loss reduction element 40 is integral with the associated hydraulic interface 24, 25 without an intermediate element, by any non-removable means of fixing such as welding, gluing, brazing, riveting or any removable means of fixing such as screwing, in the example of [Fig. 10] or even made of material with the associated hydraulic interface 24, 25, in the example visible in Figures 9A and 9B.

[0185] In the example illustrated in Figures 9A and 9B, the pressure loss reduction element 40 comprising a conical hydraulic flow deflection part 42 having an external surface 42a of generally conical shape includes a plurality of protrusions 42c regularly distributed around the periphery of the cone and a plurality of grooves 42d or recesses regularly distributed around the periphery of the cone in an alternating manner with the protrusions 42c.

[0186] Each outgrowth 42c extends, here, from the base 41 to the apex S and is connected to said apex S.

[0187] The protrusions 42c here present a curved face.

[0188] Alternatively, it could be provided that the outgrowths 42c have a non-curved face.

[0189] Alternatively, any form of the pressure loss reduction device 40 could be provided as described with reference to Figures 5 and 6.

[0190] The heat exchangers 20 described above are advantageously intended to equip a nacelle 60 of a turbomachine 50 or aircraft engine visible in [Fig.11].

[0191] Figure 11 shows a very schematic axial section of a turbomachine 50, with a general longitudinal axis X-X', for example of a twin-spool turbojet type comprising a fan 51, coupled to a gas turbine engine comprising a low-pressure compressor 52, a high-pressure compressor 53, an annular combustion chamber 54, a high-pressure turbine 55 and a low-pressure turbine 56.

[0192] The rotors of the high-pressure compressor and the high-pressure turbine are connected by a high-pressure (HP) shaft (not shown) and together form a high-pressure body. The rotors of the low-pressure compressor and the low-pressure turbine are connected by a low-pressure (LP) shaft (not shown) and together form a low-pressure body. The HP and LP shafts extend along a longitudinal axis X-X' of the turbomachine 50.

[0193] The blower shaft is rotationally linked to the BP shaft directly or indirectly.

[0194] It should be noted that the invention is not limited to such a turbomachine structure and could apply to a turbomachine of a different structure, for example to a turbomachine of the turbofan type with a double-flow turbojet, in which the low-pressure compressor acts as a blower.

[0195] The nacelle 60 of the turbomachine includes a housing 61 for the turbomachine 50 and has a tubular structure comprising an external fairing 62 defining an external aerodynamic surface and an internal fairing 63 defining an internal aerodynamic surface for flow through the turbomachine 50 and in particular the fan 51.

[0196] The external and internal fairings 62, 63 are connected upstream by an air inlet lip wall 64 forming a leading edge of the nacelle 60.

[0197] The external and internal fairings 62, 63 delimit an external structure usually comprising a fixed part and a movable part (not shown), such as, for example, thrust reversing means.

[0198] The nacelle 60 further comprises an internal fixed structure 65, known as the "inner fixed structure," abbreviated as "IFS" in Anglo-Saxon terms. The internal fixed structure 65 is concentric with the external structure at a downstream section and surrounds the core of the turbojet 50 downstream of the fan 51.

[0199] These external and internal structures define an annular flow channel, called the secondary flow VS, designed to channel a flow of cold air, called secondary, circulating outside the turbomachine 50.

[0200] Downstream of the blower 51, the main airflow FPP is separated by the fixed internal structure 65 of the nacelle, which here acts as a separating element, into a primary airflow FP and a secondary airflow FS.

[0201] The primary airflow FP travels through an internal passage or primary vein VP as it enters the low-pressure compressor 52, for example at inlet guide vanes 57 or "inlet guide vanes", acronym IGV in Anglo-Saxon terms.

[0202] The secondary airflow FS travels through an external annular passage or secondary vein VS, for example towards outlet guide vanes 58 or "outlet guide vanes", acronym OGV in Anglo-Saxon terms, and then towards the outlet of the turbomachine.

[0203] The nacelle 60 is equipped with a heat exchanger 20, fixed here in the internal structure 63 of said nacelle 60. Thus, the second skin 22 of the heat exchanger 20 configured to perform heat exchange is in contact with the airflow circulating in the secondary vein VS.

[0204] Alternatively, the heat exchanger 20 could be fixed in the internal structure 65 of the nacelle 60.

[0205] According to another variant, the heat exchanger 20 can be fixed in the external fairing 62 of the nacelle 60 with the second skin 22 of the heat exchanger 20 in contact with the outside air.

[0206] According to yet another variant, the heat exchanger 20 could be fixed in the internal structure 65, with the second skin 22 of the heat exchanger 20 in contact with the airflow circulating in the secondary vein VS.

[0207] The cooling air circulates through the exchanger, in particular the second skin 22, known as the smooth skin, where it recovers part of the thermal energy from the heat transfer fluid.

[0208] Thanks to the invention, the transition of change of plane between the hydraulic interface and the second smooth skin 22 of the surface exchanger 20 is softened thanks to the pressure loss reduction element 40 extending in the associated hydraulic interface 24, 25.

[0209] Furthermore, the heat exchanges between a fluid circulating in the heat exchanger 20 and the air circulating outside said heat exchanger are optimized, while improving the structural integrity of the heat exchanger and reducing aerodynamic pressure losses.

Claims

Demands

1. Heat exchanger (20), particularly for an aircraft nacelle, comprising a first skin (21) and a second skin (22) assembled together and a plurality of distribution channels (23) for a fluid (Fl) disposed between the first skin (21) and the second skin (22), the exchanger further comprising a first hydraulic interface (24) and a second hydraulic interface (25) for said fluid, characterized in that said exchanger (20) further comprises at least one pressure loss reduction element (40) extending axially towards the first hydraulic interface (24) or the second hydraulic interface (25), said pressure loss reduction element (40) having a generally conical cross-section and in that the pressure loss reduction element (40) comprises a base (41) directed towards the second skin (22) on the side opposite the associated hydraulic interface (24,25) and a conical hydraulic flow deflection portion (42) extending from the base (41) to a vertex (S) and directed towards the associated hydraulic interface (24, 25), on the side opposite the second skin (22).

2. Exchanger (20) according to claim 1, wherein the pressure loss reduction element (40) extends axially at least partly into the first hydraulic interface (24) or the second hydraulic interface (25).

3. Exchanger (20) according to claim 1 or 2, wherein at least one of the first and second interfaces (24, 25) forms an angle with the second skin (22), preferably greater than or equal to 60°.

4. Exchanger (20) according to any one of the preceding claims, wherein the base (41) of the pressure loss reduction element (40) has a shape homothetic to the associated hydraulic interface (24, 25).

5. Exchanger (20) according to any one of the preceding claims, wherein the hydraulic flow deflection part (42) of the pressure loss reduction device (40) comprises a smooth external surface (42a).

6. Heat exchanger (20) according to any one of the preceding claims, wherein the hydraulic flow diversion portion (42) of the pressure loss reduction device (40) includes an external surface (42a) comprising a plurality of concave facets (42b), said concave facets (42b) extending from the base (41) to the apex (S) and connected to said apex (S) and in which each concave facet (42b) is located opposite an associated distribution channel (23).

7. Heat exchanger (20) according to any one of the preceding claims, wherein the pressure loss reduction element (40) is integrated directly into the second skin (22) or the associated hydraulic interface (24, 25).

8. Exchanger (20) according to any one of claims 1 to 6, comprising a plate (30) fixed to the second skin (22) and provided with studs (31) arranged between the second and first skin (21, 22), so as to ensure the fixing of said hydraulic interfaces (24, 25) to the first (21) and second (22) skins by means of fixing means (32) cooperating with said studs (31) and in which the pressure loss reduction element (40) is integrated directly into the plate (30).

9. Turbomachine nacelle (60) comprising an external structure (62, 63) and an internal structure (65) delimiting an annular secondary flow channel (VS), said nacelle (60) comprising a housing for a turbomachine (50), which delimiting with the internal structure (65) an annular primary flow channel (VP), the nacelle (60) comprising at least one heat exchanger (20) according to any one of the preceding claims fixed either in the external structure (62, 63), on the side of the secondary flow channel (VS) or on the external side of said external structure (62, 63), or in the internal structure (65), on the side of the secondary flow channel (VS).

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