Heat exchanger comprising at least one plate that comprises at least one water spray channel, a cooling system, and a manufacturing method thereof

Abstract

The invention relates to a heat exchanger comprising: a flow enclosure that comprises a first inlet (2) and a first outlet (4) for a first fluid, a second inlet (6) and a second outlet (8) for a second fluid outside the flow enclosure, characterised in that the exchanger comprises a plurality of plates (20, 25) for the flow of the first fluid that are arranged substantially parallel to one another, wherein each space between two plates (20, 25) defines a layer for the flow of the second fluid, and wherein each plate (20, 25) comprises: - a plurality of ducts (21) configured to allow the first fluid to flow between the first inlet (2) and the first outlet (4), wherein at least one water flow channel (17), has at least one inlet (22) and a plurality of spray apertures (26), which are configured to be able to open and make contact with the second fluid.

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION: HEAT EXCHANGER COMPRISING AT LEAST ONE PLATE COMPRISING AT LEAST ONE WATER SPRAY CHANNEL, COOLING SYSTEM AND MANUFACTURING METHOD

[0003] Technical field of the invention

[0004] The invention relates to a heat exchanger suitable for use in an air cooling system, for example in an air, rail or land vehicle. In particular, the invention relates to a heat exchanger comprising at least one plate comprising at least one water spray channel.

[0005] Technological background

[0006] Air cooling systems are used in many fields, including aircraft and rail vehicles. They can be used to cool a flow of fluid (called hot fluid) in liquid or gaseous state.

[0007] For example, we know about cabin environmental control systems, better known by the acronym ECS for the English term "Environmental Control System", intended 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 hold, etc.) with air at controlled pressure and / or temperature.

[0008] Such a heat exchanger generally comprises a transverse hot circuit and a cold circuit configured to be able to ensure thermal exchanges between the air flow carried by the hot circuit (also called hot pass) and the cold air flow carried by the cold circuit (also called cold pass).

[0009] The cold circuit can, for example, be supplied by an air flow taken from the secondary flow of an aircraft engine, known as fan air, whose temperature is close to the aircraft's external environment. The cold circuit can also be supplied by an air flow taken from a scoop of the aircraft which feeds an air channel, better known as RAM air.

[0010] For example, WO2020 / 178505 discloses an 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 exchanges with said primary air flow 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 fluidically 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 air flow at the inlet of the exchanger.

[0011] Such water circulation channels extending in the vicinity of the primary air outlets involve additional constraints linked to their sealing and impact the primary air flow of the exchanger by their presence.

[0012] Objectives of the invention

[0013] The invention aims to provide a heat exchanger making it possible to overcome these drawbacks.

[0014] The invention also aims to provide a heat exchanger having excellent efficiency while having limited mass.

[0015] The invention also aims to provide, in at least one embodiment, a compact heat exchanger which can be used in an air, rail or land vehicle, in particular in a system for cooling a liquid by an air flow.

[0016] 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.

[0017] The invention also aims to provide, in at least one embodiment, a method for manufacturing a heat exchanger whose implementation is facilitated and reliable.

[0018] Statement of the invention

[0019] To this end, the invention relates to a heat exchanger comprising: a circulation chamber comprising a first inlet for a first fluid into the circulation chamber and a first outlet for said first fluid outside the circulation chamber, a second inlet for a second fluid into the circulation chamber and a second outlet for said second fluid outside the circulation chamber, characterized in that said exchanger comprises a plurality of plates, called circulation plates for said first fluid, each plate comprising: a plurality of conduits configured to allow the circulation of said first fluid between said first inlet and said first outlet, 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,and in that said circulation plates for said first fluid are arranged substantially parallel to each other, each space between two plates defining a circulation layer for said second fluid.,

[0020] Thus and according to the invention, the integration of such water circulation channels within a heat exchanger is not only facilitated but also makes it possible to significantly increase 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 breaking the seal thereof linked to the presence of such water circulation channels. In addition, said plates integrating conduits for the circulation of said first fluid and a water circulation channel, this allows the water circulating in said water circulation channel to be heated by conduction within said circulation plate of said first fluid, when the first fluid is a fluid whose temperature is higher than the temperature of the water introduced into the water circulation channel.This also helps improve the cooling performance of the heat exchanger.

[0021] The water that can be sprayed through said orifices within a flow of said second fluid makes it possible to absorb heat by evaporating and thus to lower the air temperature. This effect therefore makes it possible to amplify 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 providing 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 at least partially delimits a circulation channel for said first fluid within such a circulation plate.

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

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

[0026] Said spray orifices may 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 an inlet box of the second fluid of the exchanger. Alternatively or in combination, the spray orifices may 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 for said first fluid comprises at least one water circulation channel having a plurality of spray orifices configured to be able to open in the vicinity of said second inlet for said second fluid. Advantageously and according to the invention, at least one circulation plate for said first fluid comprises at least one water circulation channel having a plurality of spray orifices configured to be able to open within a circulation layer for said second fluid.

[0028] It is of course possible to provide circulation layers of said second fluid in which water is not 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 may, for example, designate a liquid to be cooled (“hot” liquid) and the second fluid may designate 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) may 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 may take various forms and may be in the form, for example, 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 arranged in contact with at least one circulation plate of said first fluid.

[0033] The circulation of each of said first and second fluids can take different forms, including those known as cross-flow or counter-flow (single or multiple passes). A heat exchanger according to the invention can, for example, 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 main circulation direction 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 configured in a U.

[0035] Nothing also prevents the provision of the conduits being configured to allow the circulation of said first fluid in a direction substantially parallel to a main 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 also prevents providing that each circulation plate of said first fluid further comprises 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, comprises in particular a device for taking compressed air from at least one compressor of an engine of the aircraft (a propulsion engine or an auxiliary engine of the aircraft).

[0039] Such a known air conditioning system also comprises 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 sampling device and an air outlet, and the turbine comprising an air inlet and an air outlet connected to said cabin, in order to be able to supply it with air at controlled pressure and temperature.

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

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

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

[0043] The water introduced into said water circulation channel may come from the condensation of water from water-laden air coming from an outlet of the cathode of a fuel cell such as a hydrogen cell, based on the redox reaction between dihydrogen and dioxygen. Thus, advantageously and according to the invention, said cooling system comprises a fluid pipe configured to be able to connect a fuel cell and the inlet of said water circulation channel of 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 be able to contain 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: a circulation chamber comprising a first inlet for a first fluid into the circulation chamber and a first outlet for said first fluid outside the circulation chamber, a second inlet for a second fluid into the circulation chamber and a second outlet for said second fluid outside the circulation chamber, in which a plurality of plates, called circulation plates for 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: a plurality of conduits configured to allow the circulation of said first fluid between said first inlet and said first outlet, at least one channel, called 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.,

[0046] The invention also relates to a heat exchanger, a method of manufacturing such a heat exchanger, a cooling system and an aircraft characterized in combination by all or part of the features mentioned above or below.

[0047] List of figures

[0048] 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:

[0049] [Fig. 1] is a schematic perspective view of a heat exchanger according to a first embodiment of the invention,

[0050] [Fig. 2] is a schematic view of a detail of the exchanger of Figure 1, [Fig. 3] is a schematic perspective view of a portion of a heat exchanger according to a second embodiment of the invention,

[0051] [Fig. 4] a schematic perspective view of only part of a heat exchanger according to the second embodiment of the invention.

[0052] Detailed description of an embodiment of the invention

[0053] In the figures, scales and proportions are not strictly respected, for the purposes of illustration and clarity.

[0054] Identical, similar or analogous elements are designated by the same references in all figures.

[0055] 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.

[0056] 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 in a circulation enclosure and a first outlet 4 of the first fluid outside the circulation enclosure. The plates 20, 25 for circulating the first fluid are arranged substantially parallel to each other and between two external plates 40, 42 themselves also arranged substantially parallel to the circulation plates 20, 25.

[0057] 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 box 50 for inlet of the first fluid comprising a mouth 60 for inlet of the first fluid, two boxes 54, 56 for changing direction of the first fluid (corresponding to the base of the U of the U-shaped circuit) and a box 52 for outlet of the first fluid comprising a mouth 62 for outlet of the first fluid.Each plate 20 for circulating the first fluid of the first embodiment of a heat exchanger 1 according to the invention further incorporates a water circulation channel 17 having an inlet 22 and a plurality of spray orifices 26 configured to be able to open upon contact with the second fluid, at the level of a second inlet 6 of a second fluid.

[0058] 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 making it possible to close these ends of the water circulation channels 17 in addition to or as a replacement for such a plate 29.

[0059] 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. It is for example 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.

[0060] The space between two adjacent first fluid circulation plates 20, 25 (immediately adjacent but not in contact with each other) defines a second fluid circulation layer between the second inlet 6 and a second outlet 8 of the heat exchanger. Each second fluid circulation layer is closed on the side of the first first fluid inlet 2, the first first fluid outlet 4 and the first fluid direction change boxes 54, 56 by closing bars 36 also serving to space each first fluid circulation plate 20 from a neighboring circulation plate 20.

[0061] 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.

[0062] In the embodiment illustrated in Figures 1 and 2, the heat exchanger 1 comprises four plates 20 for circulating the first fluid and five layers for circulating the second fluid, two end circulation layers being respectively formed 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.

[0063] Figures 3 and 4 illustrate a second embodiment of a heat exchanger according to the invention identical to the first previous embodiment except that each circulation plate 25 comprises, in addition to a water circulation channel 18 having orifices 27 opening at the second inlet 6 of the second fluid, a water circulation channel 19 arranged substantially in the center of the conduits 21 and whose spray orifices 28 therefore open into a circulation layer of the second fluid (and not at the inlet of the second fluid of the circulation layers of the second fluid). This makes it possible to reinforce the effect of the water spray in the second fluid and therefore the cooling efficiency of the first fluid.

[0064] Each water circulation channel 17, 18, 19 is configured to allow the introduction of water (or a mixture of water and air) having a pressure of the order of 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 FIGS. 1 to 4 a fluid comprising at least 4% by volume of water, in particular at least 8% by volume of water (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).

[0065] The spray orifices 26, 27, 28 of each water circulation channel 22, 23, 24 have, for example, a hydraulic diameter (or equivalent diameter) of the order of 0.60 mm to 1 mm. Furthermore, each conduit 21 has a hydraulic diameter of between 1.5 mm and 2 mm.

[0066] Each plate 20, 25 for 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 crenellated flow guide in each of which such a portion of tube is predisposed, at least one tube provided with orifices 26, 27, 28 being predisposed in a desired manner, so as to obtain plates 20, 25 according to the invention. The solid zone of each plate 20, 25 separating each water circulation channel 22, 23, 24 from the circulation channel 17 or 18 makes it possible to ensure separation of the latter from the conduits 21.

[0067] The heat exchanger can be installed within an air conditioning system but also in applications other than cooling high-temperature air, taken for example from an aircraft propulsion engine. It can notably be fitted to an air conditioning system of a railway vehicle.

Claims

CLAIMS 1. Heat exchanger (1) comprising: - a circulation enclosure comprising a first inlet (2) for a first fluid into the circulation enclosure and a first outlet (4) for said first fluid outside the circulation enclosure, - a second inlet (6) for a second fluid in the circulation enclosure and a second outlet (8) for said second fluid outside the circulation enclosure, characterized in that said exchanger comprises a plurality of plates, called plates (20, 25) for circulation of said first fluid, 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 channel, called water circulation channel (17, 18, 19), having at least one inlet (22, 23, 24) and a plurality of spray orifices (26, 27, 28) configured to be able to open upon contact with said second fluid, and in that: - said plates (20, 25) for circulating said first fluid are arranged substantially parallel to each other, each space between two plates (20, 25) defining a layer for circulating said second fluid, - each plate (20, 25) for circulating said first fluid is formed from 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) for circulation of said first fluid, each channel (17, 18, 19) for circulation of water extends longitudinally at least partly substantially parallel to said conduits (21) of said plate (20, 25) for circulation of said first fluid.

3. Heat exchanger according to one of claims 1 or 2, characterized in that at least one plate (20) for circulating said first fluid comprises at least one water circulation channel (17) 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 one of claims 1 to 3, characterized in that at least one plate (25) for circulating 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 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) for circulation of the first fluid of said heat exchanger.

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

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