HEAT EXCHANGER COMPRISING AT LEAST ONE PLATE INCLUDING AT LEAST ONE WATER SPRAY CHANNEL, COOLING SYSTEM AND MANUFACTURING METHOD

Abstract

HEAT EXCHANGER COMPRISING AT LEAST ONE PLATE COMPRISING AT LEAST ONE WATER SPRAY CHANNEL, COOLING SYSTEM AND MANUFACTURING METHOD The invention relates to a heat exchanger comprising: a circulation chamber including a first inlet (2) and a first outlet (4) of a first fluid, a second inlet (6) and a second outlet (8) of a second fluid outside the circulation chamber, characterized in that said exchanger comprises a plurality of circulation plates (20, 25) for said first fluid arranged substantially parallel to each other, each space between two plates (20, 25) defining a circulation layer for said second fluid, and each plate (20, 25) comprising: a plurality of conduits (21) configured to allow the circulation of said first fluid between said first inlet (2) and said first outlet (4), at least one water circulation channel (17),featuring at least one inlet (22) and a plurality of spray orifices (26) configured to open upon contact with said second fluid. Figure for the abbreviation: Figure 1,

Description

Title of the invention: HEAT EXCHANGER COMPRISING AT LEAST ONE PLATE COMPRISING AT LEAST ONE WATER SPRAY CHANNEL, COOLING SYSTEM AND MANUFACTURING METHOD Technical field of the invention

[0001] The invention relates to a heat exchanger that can be used in an air-cooling system, for example in an aircraft, railway, or land vehicle. In particular, the invention relates to a heat exchanger comprising at least one plate including at least one water spray channel. Technological background

[0002] Air cooling systems are used in many fields, particularly in aircraft and railways. They can be used to cool a flow of fluid (called a hot fluid) in a liquid or gaseous state.

[0003] For example, we know of cabin environmental control systems, better known by the acronym ECS for the English term "Environmental Control System", designed to provide the cabin (which generally designates any interior space of a vehicle whose air pressure and / or temperature must be controlled, such as a passenger cabin, the cockpit, a cargo hold, etc.) with air at controlled pressure and / or temperature.

[0004] Such a heat exchanger generally comprises a transverse hot circuit and a transverse cold circuit configured to be able to ensure heat exchanges between the airflow conveyed by the hot circuit (also designated hot pass) and the cold airflow conveyed by the cold circuit (also designated cold pass).

[0005] The cooling circuit can, for example, be supplied by an airflow taken from the secondary flow of an aircraft engine, known as fan air, the temperature of which is close to the aircraft's external environment. The cooling circuit can also be supplied by an airflow taken from an aircraft scoop that feeds an air duct, more commonly known as RAM air.

[0006] For example, WO2020 / 178505 is known to designate a heat exchanger for cooling hot primary air with cold secondary air, comprising secondary channels and primary channels, each interposed between two secondary channels, and water circulation channels, each extending adjacent to a secondary channel in said secondary direction in the vicinity of the primary air outlets between a water inlet and a water outlet so as to allow the heating of this water by heat exchange with said primary airflow of said primary channels. The exchanger further comprises hollow micro-perforated water spray bars, each extending adjacent to a primary channel in said primary direction, between a water inlet fluidly connected to at least one water outlet of said water circulation channels and water spray micro-perforations opening towards the secondary air inlets so as to allow evaporation of the heated water sprayed at the inlet of said secondary channels which thus contributes to cooling the secondary airflow at the inlet of the exchanger.

[0007] Such water circulation channels extending in the vicinity of the primary air outlets imply additional constraints related to the sealing of these outlets and impact the primary air pass of the exchanger by their presence. Objectives of the invention

[0008] The invention aims to provide a heat exchanger to overcome these drawbacks.

[0009] The invention also aims to provide a heat exchanger exhibiting excellent efficiency while having a limited mass.

[0010] The invention also aims to provide, in at least one embodiment, a compact heat exchanger that can be used in an air, rail or land vehicle, in particular in a system for cooling a liquid by an airflow.

[0011] The invention also aims to provide, in at least one embodiment, a heat exchanger comprising at least one water spray channel whose integration within said exchanger is optimized.

[0012] The invention also aims to provide, in at least one embodiment, a method for manufacturing a heat exchanger whose implementation is facilitated and reliable. Description of the invention

[0013] To this end, the invention relates to a heat exchanger comprising:

[0014] a circulation enclosure comprising a first inlet of a first fluid into the circulation enclosure and a first outlet of said first fluid out of the circulation enclosure,

[0015] a second inlet of a second fluid into the circulation chamber and a second outlet of said second fluid out of the circulation chamber,

[0016] characterized in that said exchanger comprises a plurality of plates, called circulation plates of said first fluid, each plate comprising:

[0017] a plurality of conduits configured to allow the circulation of said first fluid between said first inlet and said first outlet,

[0018] at least one channel, referred to as the water circulation channel, having at least one inlet and a plurality of spray orifices configured to be able to open upon contact with said second fluid,

[0019] and in that said circulation plates of said first fluid are arranged substantially parallel to each other, each space between two plates defining a circulation layer of said second fluid.

[0020] Thus, according to the invention, the integration of such water circulation channels within a heat exchanger is not only facilitated but also significantly increases the efficiency, and therefore the cooling performance, of the heat exchanger. The invention further improves the reliability of the heat exchanger by reducing—or even eliminating—the risks of leaks due to the presence of such water circulation channels. Moreover, since the plates incorporate conduits for the circulation of the first fluid and a water circulation channel, the water circulating in the water circulation channel is heated by conduction within the plate containing the first fluid, when the first fluid has a temperature higher than that of the water introduced into the water circulation channel.This also improves the cooling performance of the heat exchanger.

[0021] The water that can be sprayed through said orifices within a flow of said second fluid allows it to absorb heat by evaporating and thus lower the air temperature. This effect therefore amplifies the cooling efficiency of the second fluid.

[0022] The circulation plates of said first fluid are therefore arranged without being in contact with each other, two plates adjacent to each other leaving a free space allowing the passage of said second fluid, so as to form an alternation of so-called "cold" layers and so-called "hot" layers.

[0023] Each conduit delimits at least in part a circulation channel of said first fluid within such a circulation plate.

[0024] Advantageously and according to the invention, each circulation plate of said first fluid is formed of a single piece, that is to say of a single unit integrating said conduits and said water circulation channel.

[0025] Advantageously and according to the invention, each water circulation channel extends longitudinally at least in part substantially parallel to said conduits of said circulation plate of said first fluid.

[0026] Said spray orifices can be configured to allow water to be sprayed at the inlet of said second fluid, i.e. outside the spaces between the circulation plates of the first fluid but, for example, inside a inlet box of the second fluid of the exchanger. Alternatively or in combination, the spray orifices can also be configured to allow water to be sprayed directly between the spaces between the circulation plates of the first fluid, for example substantially in the center of the circulation layer of the second fluid or between the center and the inlet of the second fluid within said circulation layer of said second fluid concerned.

[0027] Thus, advantageously and according to the invention, at least one circulation plate of said first fluid comprises at least one water circulation channel having a plurality of spray orifices configured to open in the vicinity of said second inlet of said second fluid. Advantageously and according to the invention, at least one circulation plate of said first fluid comprises at least one water circulation channel having a plurality of spray orifices configured to open within a circulation layer of said second fluid.

[0028] It is of course possible to provide circulation layers for said second fluid in which no water is sprayed. The presence of spray orifices, and therefore of a water circulation channel, is not essential within each circulation layer of said first fluid.

[0029] Advantageously and according to the invention, each conduit of said circulation plates of said first fluid of a heat exchanger according to the invention is adapted to allow the passage of a fluid in the liquid state or in the gaseous state.

[0030] Advantageously and according to the invention, each circulation layer of said second fluid of a heat exchanger according to the invention is adapted to allow the passage of a fluid in the gaseous state.

[0031] The first fluid can, for example, refer to a liquid to be cooled (hot liquid) and the second fluid can refer to a gas, in particular air, having a temperature lower than that of the first fluid (so-called cold or fresh air).

[0032] Furthermore, flow guides (or fins) can be arranged in each circulation layer of said second fluid, between said circulation plates of said first fluid. Advantageously, and according to the invention, each circulation layer of said second fluid comprises at least one flow guide having a corrugated shape. Such a flow guide can take various forms and be, for example, in the form of a corrugated sheet, a corrugated strip, or even zigzag fins. Advantageously, and according to the invention, each flow guide of a circulation layer of said second fluid is disposed in contact with at least one circulation plate of said first fluid.

[0033] The circulation of each of the said first and second fluids can take various forms, including cross-flow or counter-flow (single or multiple passes). A heat exchanger according to the invention can, by for example, it can be configured to allow a U-shaped circuit of said first fluid or any more complex circuit.

[0034] Advantageously, and according to the invention, the conduits of each circulation plate of said first fluid are configured to allow the circulation of said first fluid between said first inlet and said first outlet in a direction substantially orthogonal to a principal direction of circulation of said second fluid in each circulation layer of said second fluid. According to this aspect of the invention, the heat exchangers thus formed are cross-pass. Advantageously, and according to the invention, the conduits of each circulation plate of said first fluid are U-shaped.

[0035] Nothing prevents the conduits from being configured to allow the circulation of said first fluid in a direction substantially parallel to a principal direction of circulation of said second fluid in each circulation layer of said second fluid. According to this aspect of the invention, the heat exchangers thus formed are co-current or counter-current.

[0036] Nothing prevents us from providing that each circulation plate of said first fluid also includes conduits configured to allow the circulation of a third fluid, distinct from said first fluid.

[0037] The invention also relates to a cooling system comprising a heat exchanger according to the invention.

[0038] The invention also relates to an air conditioning system comprising a heat exchanger according to the invention. An air conditioning system for a cabin of a transport vehicle, such as for example an aircraft, includes in particular a device for drawing compressed air from at least one compressor of an aircraft engine (a propulsion engine or an auxiliary engine of the aircraft).

[0039] Such a known air conditioning system also includes an air cycle turbomachine comprising at least one compressor and one turbine mechanically coupled to each other, the compressor comprising an air inlet connected to a compressed air intake device and an air outlet, and the turbine comprising an air inlet and an air outlet connected to said cabin, in order to supply it with air at controlled pressure and temperature.

[0040] The compressor of the air cycle turbomachine can be directly supplied with ambient air taken from outside the aircraft, the compression of the air being ensured directly by the compressor of the air cycle turbomachine.

[0041] Such an air conditioning system generally also includes at least one heat exchanger, referred to as the main cooling exchanger, arranged in a dynamic air circulation duct taken from outside the aircraft, between the air outlet of said compressor and the air inlet of said turbine, said exchanger main comprising a primary circuit supplied by a hot air stream from said compressor, and a secondary circuit supplied by said dynamic air forming a cold air stream intended to cool said hot air stream.

[0042] Thus, advantageously and according to the invention, said air conditioning system includes a main cooling exchanger and is configured such that said first fluid is from a hot air stream from a compressor of a dynamic air circulation channel taken from outside an aircraft.

[0043] The water introduced into said water circulation channel may originate from the condensation of water from water-laden air originating from the cathode outlet of a fuel cell such as a hydrogen fuel cell, based on the redox reaction between dihydrogen and dioxygen. Thus, advantageously and according to the invention, said cooling system comprises a fluid conduit configured to connect a fuel cell and the inlet of said water circulation channel to at least one circulation plate of the first fluid of said heat exchanger.

[0044] A heat exchanger according to the invention comprises a container adapted to hold water intended to be introduced into each water circulation channel. Thus, advantageously and according to the invention, said heat exchanger further comprises a container in fluid communication with the inlet of said water circulation channel of at least one circulation plate of the first fluid.

[0045] The invention also relates to a method for manufacturing such a heat exchanger. The invention therefore also relates to a method for manufacturing a heat exchanger, said heat exchanger comprising:

[0046] - a circulation chamber comprising a first inlet of a first fluid within the circulation area and a first exit of said first fluid outside the circulation area,

[0047] - a second inlet of a second fluid into the circulation chamber and a second outlet of said second fluid outside the circulation area,

[0048] in which a plurality of plates, called circulation plates of said first fluid, are arranged substantially parallel to each other, each space between two circulation plates of said first fluid defining a circulation layer of said second fluid and each circulation plate of said first fluid comprising:

[0049] - a plurality of conduits configured to allow the circulation of said first fluid between said first inlet and said first outlet,

[0050] - at least one channel, called a water circulation channel, having at least one inlet and a plurality of spray orifices configured to be able to open upon contact with said second fluid.

[0051] The invention also relates to a heat exchanger, a method for manufacturing such a heat exchanger, a cooling system and an aircraft characterized in combination by all or part of the characteristics mentioned above or below. List of figures

[0052] Other objects, features and advantages of the invention will become apparent from the following description, given by way of non-limiting example only, and which refers to the accompanying figures in which:

[0053] [Fig-1] is a schematic perspective view of a heat exchanger according to a first embodiment of the invention,

[0054] [Fig.2] is a schematic view of a detail of the exchanger of [Fig.1],

[0055] [Fig.3] is a schematic perspective view of a portion of a heat exchanger heat according to a second embodiment of the invention,

[0056] [Fig.4] a schematic perspective view of only part of a heat exchanger according to the second embodiment of the invention.

[0057] Detailed description of an embodiment of the invention

[0058] In the figures, the scales and proportions are not strictly respected for the purposes of illustration and clarity.

[0059] Identical, similar or analogous elements are designated by the same references in all figures.

[0060] Figures 1 and 2 illustrate a first embodiment of a heat exchanger 1 according to the invention. Figures 3 and 4 illustrate a second embodiment of a heat exchanger according to the invention.

[0061] The heat exchanger 1 comprises a plurality of plates 20, 25 for circulating a first fluid between a first inlet 2 of the first fluid into a circulation chamber and a first outlet 4 of the first fluid out of the circulation chamber. The plates 20, 25 for circulating the first fluid are arranged substantially parallel to each other and between two external plates 40, 42 which are themselves also arranged substantially parallel to the circulation plates 20, 25.

[0062] Each plate 20, 25 for circulating the first fluid incorporates a plurality of conduits 21 configured to allow the circulation of the first fluid between the first inlet 2 and said first outlet 4. In the embodiment shown, the conduits of each plate 20, 25 for circulating the first fluid are configured to allow a U-shaped circuit of the first fluid within each plate 20, 25. It can be seen in [Fig. 1] that the heat exchanger 1 comprises a first fluid inlet box 50 including a first fluid inlet port 60, two first fluid direction change boxes 54, 56 (corresponding to the base of the U of the U-shaped circuit) and a box 52 for the outlet of the first fluid including a mouth 62 for the outlet of the first fluid.

[0063] Each plate 20 of circulation of the first fluid of the first embodiment of a heat exchanger 1 according to the invention further integrates a water circulation channel 17 having an inlet 22 and a plurality of spray orifices 26 configured to be able to open in contact with the second fluid, at the level of a second inlet 6 of a second fluid.

[0064] In the first embodiment shown, the outlets of the water circulation channels 17 are closed by a plate 29 adjoining the box 54. Nothing prevents the provision of any other device allowing these ends of the water circulation channels 17 to be closed in addition to or in replacement of such a plate 29.

[0065] In the embodiment shown, each water circulation channel 17 has a plurality of spray orifices 26. This number of orifices is variable and can be adjusted according to different parameters of the heat exchanger. For example, it is possible to provide a distance of between 10 mm and 800 mm between each neighboring orifice of the same water spray channel of a plate 20.

[0066] The space between two adjacent (immediately adjacent but not in contact with each other) circulation plates 20, 25 of the first fluid defines a circulation layer of the second fluid between the second inlet 6 and a second outlet 8 of the heat exchanger. Each circulation layer of the second fluid is closed on the side of the first inlet 2 of the first fluid, the first outlet 4 of the first fluid, and the boxes 54, 56 for changing the direction of the first fluid by closing bars 36 which also serve to space each circulation plate 20 of the first fluid from an adjacent circulation plate 20.

[0067] Fins 30 can be arranged in each circulation layer of the second fluid, i.e. here in what is also called the cold pass of the exchanger.

[0068] In the embodiment illustrated in Figures 1 and 2, the heat exchanger 1 comprises four circulation plates 20 of the first fluid and five circulation layers of the second fluid, two end circulation layers being formed respectively between the circulation plate 20 closest to the outer plate 40 and the outer plate 40, and on the other hand, between the circulation plate 20 closest to the outer plate 42 and the outer plate 42.

[0069] Figures 3 and 4 illustrate a second embodiment of a heat exchanger according to the invention, identical to the first embodiment described above, except that each circulation plate 25 comprises, in addition to a water circulation channel 18 having orifices 27 opening at the level of the second inlet 6 of the second fluid, a water circulation channel 19 disposed substantially at the center of the conduits 21, whose spray orifices 28 open into a circulation layer of the second fluid (and not at the inlet of the second fluid's circulation layers). This enhances the effect of water spraying into the second fluid and thus the cooling efficiency of the first fluid.

[0070] Each water circulation channel 17, 18, 19 is configured to allow the introduction of water (or a mixture of water and air) with a pressure of approximately 0.3 MPa. The fluid capable of circulating within each water circulation channel 17, 18, 19 can therefore be water only (i.e., 100% by volume) or, in the embodiments exemplified in Figures 1 to 4, a fluid comprising at least 4% water by volume, in particular at least 8% water by volume (volume proportion of water relative to the total volume of the mixture at the inlet of the water circulation channel), such that the water can exit the spray orifices 26, 27, 28 preferably in the form of a mist (or fine water droplets).

[0071] The spray orifices 26, 27, 28 of each water circulation channel 22, 23, 24 have, for example, a hydraulic diameter (or equivalent diameter) of approximately 0.60 mm to 1 mm. Furthermore, each conduit 21 has a hydraulic diameter between 1.5 mm and 2 mm.

[0072] Each plate 20, 25 of circulation of the first fluid can for example be prepared by brazing portions of tubes intended to form the conduits 21 in contact with a slotted flow guide in each of which is predisposed such a portion of tube, at least one tube provided with orifices 26, 27, 28 being predisposed in a desired way, so as to obtain plates 20, 25 according to the invention.

[0073] The solid area of ​​each plate 20, 25 separating each water circulation channel 22, 23, 24 from the circulation channel 17 or 18 ensures separation of the latter from the conduits 21.

[0074] The heat exchanger can be installed within an air conditioning system but also in other applications besides cooling high-temperature air, such as air taken from an aircraft propulsion engine. In particular, it can be used to equip an air conditioning system in a railway vehicle.

Claims

Demands

1. Heat exchanger (1) comprising: • a circulation chamber including a first inlet (2) of a first fluid into the circulation chamber and a first outlet (4) of said first fluid out of the circulation chamber, • a second inlet (6) of a second fluid into the circulation chamber and a second outlet (8) of said second fluid out of the circulation chamber, characterized in that said exchanger comprises a plurality of plates, referred to as circulation plates (20, 25) of said first fluid, each plate (20, 25) comprising: • a plurality of conduits (21) configured to permit the circulation of said first fluid between said first inlet (2) and said first outlet (4), • at least one water circulation channel, referred to as water circulation channel (17, 18, 19), having at least one inlet (22, 23, 24) and a plurality of orifices (26, 27,28) spray nozzles configured to be able to open upon contact with said second fluid, and in that: - said circulation plates (20, 25) of said first fluid are arranged substantially parallel to each other, each space between two plates (20, 25) defining a circulation layer of said second fluid, - each circulation plate (20, 25) of said first fluid is formed of a single piece integrating said conduits (21) and said water circulation channel (17, 18, 19).

2. Heat exchanger according to claim 1, characterized in that, in each plate (20, 25) of circulation of said first fluid, each channel (17, 18, 19) of water circulation extends longitudinally at least in part substantially parallel to said conduits (21) of said plate (20, 25) of circulation of said first fluid.

3. Heat exchanger according to claim 1 or 2, characterized in that at least one circulation plate (20) of said first fluid comprises at least one circulation channel (17) water having a plurality of spray orifices (26, 27) in the vicinity of said second inlet (6) of said second fluid.

4. Heat exchanger according to any one of claims 1 to 3, characterized in that at least one circulation plate (25) of said first fluid comprises at least one water circulation channel (19) having a plurality of spray orifices (28) configured to be able to open into a circulation layer of said second fluid.

5. Cooling system comprising a heat exchanger according to any one of claims 1 to 4.

6. Cooling system according to claim 5, characterized in that it comprises a fluid conduit configured to be able to connect a fuel cell and the inlet of said water circulation channel (17, 18, 19) of at least one plate (20, 25) of circulation of the first fluid of said heat exchanger.

7. A method for manufacturing a heat exchanger (1), said heat exchanger comprising: • a circulation chamber comprising a first inlet (2) of a first fluid into the circulation chamber and a first outlet (4) of said first fluid out of the circulation chamber, • a second inlet (6) of a second fluid into the circulation chamber and a second outlet (8) of said second fluid out of the circulation chamber, in which a plurality of plates, called circulation plates (20, 25) of said first fluid, are arranged substantially parallel to each other, each space between two circulation plates (20, 25) of said first fluid defining a circulation layer of said second fluid and each plate (20,25) circulation of said first fluid comprising: • a plurality of conduits (21) configured to permit the circulation of said first fluid between said first inlet (2) and said first outlet (4), • at least one channel, referred to as the water circulation channel (17, 18, 19), having at least one inlet (22, 23, 24) and one, plurality of spray orifices (26, 27, 28) configured to be able to open upon contact with said second fluid, each plate (20, 25) of circulation of said first fluid being formed of a single piece integrating said conduits (21) and said water circulation channel (17, 18, 19).

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