MODULAR HEAT EXCHANGER, PARTICULARLY FOR TURBOMACHINES IN MOTOR VEHICLES

Abstract

Heat exchanger (1) configured to circulate a first fluid (F1) and a second fluid (F2) with mutual heat exchange in order to cool the first fluid (F1) and heat the second fluid (F2), with a modular construction, comprising a first module M1, with a general inlet of first fluid (EG1) and a general outlet of second fluid (SG2), a second module Mii, ii ranging from 2 to N, receiving a flow of first fluid from module Mii-1 via one or more transfer passages (81,82), and delivering a flow of second fluid to module ii-1 via a buffer space (91,92,93), the Nth module MN having a general inlet of second fluid (EG2) and a general outlet of first fluid (SG1), the second fluid (F2) circulating in tubes along a longitudinal axis and the first fluid (F1) circulating around the tubes. Figure 5

Description

Title of the invention: MODULAR HEAT EXCHANGER, PARTICULARLY FOR TURBOMACHINES IN MOTOR VEHICLES

[0001] The present disclosure relates generally to the field of heat exchangers. A heat exchanger of the type considered is configured to circulate a first fluid and a second fluid, without mixing of the fluids, and with heat exchange between the two fluids in order to cool one of the fluids and heat the other of the fluids.

[0002] This document focuses in particular on heat exchangers used in gas turbine cycle type turbogenerator devices and systems, otherwise known as "turbomachines". Here, we are in the context of a motor vehicle, where the turbomachine is involved in a range extender system for an electric or hybrid vehicle.

[0003] The present invention generally relates to a heat exchanger architecture for such turbomachinery. More particularly, the invention relates to a heat exchanger known as a recuperative heat exchanger, which allows intake air to be heated by means of hot exhaust gases.

[0004] This recuperative exchanger makes it possible to improve the overall efficiency of the turbomachine, particularly but not exclusively, in the case of a two-stage compression turbomachine.

[0005] We seek to optimize all aspects of the heat exchanger because it represents the largest volume of the turbo generator system. We also seek to have the lowest possible production cost.

[0006] After seeking to make the best use of heat exchangers obtained by additive manufacturing (i.e. 3D printing) and plate heat exchangers, the inventors came to the conclusion that there remained a need to offer a modular heat exchanger that satisfies the criteria expressed above, in terms of performance, compactness and cost.

[0007] It is in this context that the present invention proposes a heat exchanger, for example for a turbomachine, configured to circulate a first fluid and a second fluid with mutual heat exchange in order to cool the first fluid and heat the second fluid, characterized in that the exchanger is of modular construction, and comprises: - a first module Ml, comprising a general inlet of the first fluid and a general outlet of the second fluid, - one, or more, ii-th module Mii, for ü ranging from 2 to N, receiving a flow of first fluid from module Mii-1 via one or more transfer passages, and delivering a flow of second fluid to module Mii-1 via a buffer space, - the N-th module MN having a general inlet of second fluid and a general outlet of first fluid.

[0008] The number of ii-th modules Mii amounts to Nl. For example, for a 4-stage exchanger, there are 4 modules, i.e., N=4, the exchanger consists of an assembly of modules M1, M2, M3 and M4.

[0009] Advantageously, each module can be manufactured individually and the modules are assembled together to form the complete heat exchanger. The process and costs associated with manufacturing and assembling the modules prove to be advantageous.

[0010] Also, the definition of the first module M1 is not dependent on the number N of modules, thus demonstrating a perfectly modular aspect of this construction. Similarly, the module M2 is the same whether N is equal to 3 or equal to 4.

[0011] Thanks to these provisions, the solution therefore makes it possible to offer a range of exchangers with different numbers of modules, the first module or modules being used for several possible configurations.

[0012] It should be noted that, according to a first possibility, the modules can have a general prismatic shape, or according to a second possibility, the modules can have a general cylindrical shape.

[0013] It should also be noted that the definition given above implies that the circulation of the first and second fluids generally occurs in counter-current flow, which, as is known, is optimal for maximizing heat exchange. Indeed, the general outlet of the second fluid crosses the general inlet of the first fluid, and at the other end, the general outlet of the first fluid crosses the general inlet of the second fluid.

[0014] Of course, in a heat exchanger of the aforementioned type, the two fluids do not mix; they exchange heat but do not exchange molecules. It should be noted that the pressure of the first fluid can be significantly different from the pressure of the second fluid.

[0015] It should be noted that each of the fluids can be a gaseous fluid or a liquid fluid.

[0016] According to an advantageous option, in each module, the second fluid flows in tubes along a longitudinal axis and the first fluid flows in an inter-tube space around the tubes, generally also along the longitudinal axis but in the opposite direction.

[0017] We thus have not only a general counter-current but also a local counter-current inside each module.

[0018] According to one embodiment, all the tubes are parallel to the longitudinal axis. This forms a rational and optimized construction. The tubes are arranged parallel to each other, grouped into N groups, the groups being organized in cascade, that is to say in series, corresponding to the respective stages and modules.

[0019] According to one embodiment, a radial direction is defined perpendicular to the longitudinal axis, the modular construction being characterized in that the module Mii surrounds the module Mii-1 in the radial direction.

[0020] Wherefore, the inlet of the hot fluid (first fluid Fl) is located in the center of the exchanger, so the loss of heat on the outer walls of the exchanger (i.e. the walls of the module MN) is minimized.

[0021] According to one embodiment, each module Mk, for k from 1 to Nl, comprises an outer envelope which delimits the inter-tube space of the module Mk radially on the outside and which delimits the inter-tube space of the module Mk+1 radially on the inside.

[0022] Thus, the outer wall of one module acts as the inner wall of the module with the immediately higher index, forming an optimized solution with regard to the walls, whereas the complete heat exchanger is formed by an assembly of individually manufactured modules. In other words, the walls are shared and form party walls.

[0023] According to one embodiment, the transfer passages are provided in the envelope of the Mk module at the radial interface with the Mk+1 module.

[0024] In other words, the transfer passages are formed as openings in the envelope of the modules. The openings of the MN module form the general outlet of the first fluid.

[0025] The placement of the lights in each module determines the shape of the path of the first fluid in the inter-tube spaces.

[0026] According to an advantageous embodiment, the lights are placed in the vicinity of the longitudinal ends along the axis of the tubes, so as to generate a counter-current circulation of the first fluid in each of the modules, i.e. in each of the heat exchange stages.

[0027] According to one embodiment, the number of modules N is between 3 and 5.

[0028] However, it is also possible to have configurations where N=2 and to have configurations where N is greater than 5.

[0029] According to one embodiment, the material of each module is distinct from the material of another module. Thus, for example, the hottest module(s) (e.g., M1) can be made of special metal alloys, conversely the coldest module(s) (e.g., MN) can be made of copper, and the intermediate temperature modules can be made of aluminum.

[0030] According to one embodiment, the buffer spaces are located at the longitudinal ends of the exchanger. In the buffer spaces, the second fluid makes a U-turn to pass from the tubes of one module to the tubes of another module, e.g. from Mk+1 to Mk.

[0031] According to one embodiment, the number of tubes decreases from the first module M1 to the Nth module MN.

[0032] According to one characteristic, if we consider the cumulative cross-sectional area of ​​passage in the tubes of each module, it decreases from the first module M1 to the Nth module MN. According to one characteristic, if we consider the cumulative cross-sectional area of ​​passage in the inter-tube space of each module, it decreases from the first module M1 to the Nth module MN.

[0033] The characteristics related to the passage sections and / or the number of tubes stated above contribute to minimizing the aerodynamic or hydraulic pressure loss when the first fluid and the second fluid pass through the exchanger.

[0034] The present invention also relates to a turbomachine system configured to provide electrical power in a motor vehicle, as a range extender, and comprising a heat exchanger as defined above.

[0035] According to one option, the turbomachine system comprises two compression stages.

[0036] The present invention also relates to a motor vehicle comprising a turbomachine system as defined above.

[0037] The present invention also relates to a method of obtaining a heat exchanger comprising an individual manufacturing step of N modules as defined above, the modules prepared separately then being assembled together to form a complete heat exchanger.

[0038] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates a turbomachine system for a motor vehicle; - [Fig.2] schematically illustrates an example of a heat exchanger, for turbomachine, seen in perspective; - [Fig.3] schematically illustrates an example of a heat exchanger, at four floors, in front view in section along section line III visible in [Fig.2], with only about fifteen tubes represented per heat exchange zone, the others not being represented; - [Fig.4] schematically illustrates an example of a heat exchanger, at four stories, top view in section along section line IV visible in [Fig.2], with only a few tubes represented per heat exchange zone; - [Fig.5] schematically illustrates an example of a modular, four-stage heat exchanger, in cross-sectional view along an XY plane, with the tubes not shown, in the situation after assembly of the modules; - [Fig.6] is analogous to [Fig.5], in the situation before assembly of the modules; - [Fig.7] schematically illustrates an example of the heat exchanger modular of figures 5 and 6, according to another cross-sectional view along an XZ plane, the tubes not being shown, in the situation after assembly of the modules; - [Fig.8] is analogous to [Fig.7], in the situation before assembly of the modules; - [Fig.9] schematically illustrates an example of a heat exchanger modular, three-story, with doubled floor modules, top view; - [Fig. 10] shows a schematic front view of the modular heat exchanger of [Fig. 9]; - [Fig. 11] shows a detail of the modular heat exchanger of [Fig.9] concerning the transfer passages; - [Fig. 12] illustrates a diagram of the evolution of temperatures in the exchanger; - [Fig. 13] shows a schematic detail view illustrating the passage of the tubes through the perforated plate; - [Fig. 14] shows a modular heat exchanger of cylindrical shape, in contrast to the prismatic shape of the previous examples.

[0039] In the various figures, the same reference numerals designate identical or similar elements. For the sake of clarity, some elements are not necessarily shown to scale.

[0040] Gas turbine-type energy converters are currently being studied as range extenders in electric or hybrid vehicles. They are also more simply called "turbogenerators" or "turbomachines".

[0041] This type of converter can operate in APU (Auxiliary Power Unit) mode, where its role is to recharge the batteries of an electric vehicle. It is thus mechanically decoupled from the powertrain and operates at its maximum efficiency point.

[0042] Several types of cycles are possible, including simple regenerative cycles (RGT for Regenerative Gas Turbine), but also regenerative cycles with a cooler (IRGT) and cycles with a cooler, recuperator and reheat or "Intercooled Regenerative Reheat Gas Turbine" in English.

[0043] The gas turbine cycle with cooler, recuperator and reheater (IRReGT) is an interesting cycle for automotive applications. This cycle makes it possible to achieve high efficiency but also a high power density (high specific net work).

[0044] This technology has the following advantages: low emission levels, low emission noise levels, ability to operate with several types of fuels.

[0045] The heat recovery exchanger is a critical component of the turbomachinery system. This document focuses on the architecture and manufacturing process of these heat exchangers.

[0046] Figure 1 shows a system diagram of a TBG turbomachine of interest according to the present invention.

[0047] A first stage called low pressure comprises a low pressure compressor CLP and a low pressure turbine TLP, these two entities being linked together via a first shaft AL. This first shaft Al drives a first electric machine MGLP, which is used essentially as a generator and secondarily as a motor for the start-up phase of the first stage.

[0048] A second stage, referred to as the high-pressure stage, comprises a high-pressure compressor CHP and a high-pressure turbine THP, these two entities being linked together via a second shaft A2. This second shaft A2 drives a second electrical machine MGHP, which is used primarily as a generator and secondarily as a motor for the start-up phase of the second stage.

[0049] In addition, an AF air filter is located upstream of the low-pressure compressor. Furthermore, a cooling heat exchanger IC cools the air taken from the outlet of the low-pressure compressor and supplied to the inlet of the high-pressure compressor.

[0050] A first CCLP combustion chamber supplies hot gases to the low-pressure turbine TLP. The first CCLP combustion chamber is supplied with air by the high-pressure turbine outlet THP.

[0051] A second CCHP combustion chamber supplies hot gases to the THP high-pressure turbine. The second CCHP combustion chamber is supplied with air by the CHP high-pressure compressor via a heat exchanger, which is the main object of the present invention.

[0052] The first combustion chamber and the second combustion chamber are each supplied with a hydrocarbon fuel. The hydrocarbon fuel can be, for example, methanol or ethanol.

[0053] The air exiting the high-pressure compressor CHP passes through a heat exchanger designated 1, before reaching the second combustion chamber CCHP to supply air to said second combustion chamber CCHP. This airflow forms the second fluid F2, which will be discussed in relation to the heat exchanger described in detail below.

[0054] Furthermore, the heat exchanger 1 receives as its first fluid Fl the burnt gases at the outlet of the low pressure turbine TLP via the pipe 18.

[0055] The heat exchanger described below can also be used in a single-stage turbogenerator (not shown). The first fluid Fl entering the exchanger is the exhaust gases exiting the turbine. The second fluid F2 entering the exchanger is the fluid exiting the compressor, which enters the combustion chamber downstream.

[0056] Turning to figures 2 to 4, the heat exchanger 1 comprises an envelope 6 delimiting an internal volume E0.

[0057] A reference frame XYZ is defined for the heat exchanger. In the vehicle, the X direction corresponds to the longitudinal direction of the vehicle. The Y direction corresponds to the transverse direction of the vehicle. The Z direction can be substantially vertical.

[0058] In the example shown, the heat exchanger 1 is the largest component of the turbomachinery system. In this example, the heat exchanger 1 has a generally parallelepiped shape, which facilitates good integration into the vehicle architecture, particularly in the lower chassis section. The longest dimension, LY, extends along the transverse Y direction. In one example, the length LY extends across almost the entire width of the vehicle, for example, at least 100 cm. The other dimensions, LX and LZ, along the other two directions, can typically range from 10 cm to 20 cm.

[0059] This form factor is conducive to optimized integration into a series hybrid powertrain electric vehicle architecture.

[0060] Other shape and dimension factors are of course possible.

[0061] The envelope 6 comprises a front wall 10, a back wall 15, a bottom wall 13, a top wall 11, a left side wall 12 and a right side wall 14. These walls delimit the internal volume E0, in a hermetically sealed manner, except for the fluid inlets and outlets provided for their respective purposes.

[0062] Arranged on the front wall 10 of the heat exchanger 1 are: on the one hand the general inlet of the second fluid EG2 on a peripheral area, and on the other hand in the center, the general inlet of the first fluid EG1 and the general outlet of the second fluid SG2.

[0063] The outlet of the first SGI fluid is located on one or both side walls. Curved return inlets may be provided on the sides of the front face, so that all fluid inlets and outlets are located on the same side of the heat exchanger 1, for optimal integration into the vehicle architecture.

[0064] Inside the exchanger, according to the multi-stage principle (here with 4 stages) there is provided a first heat exchange zone Z1, a second heat exchange zone Z2, a third heat exchange zone Z3 and a fourth heat exchange zone Z4, arranged in series.

[0065] As can be seen in [Fig. 4], the order of the heat exchange zones follows the path of the first fluid Fl, namely the hot gases exiting the exhaust of the first stage, i.e., the low-pressure stage. The fluid Fl flows from Z1 to Z4.

[0066] By contrast, the path of the second fluid F2 is in the opposite direction and passes first through the fourth heat exchange zone Z4, then the third heat exchange zone Z3, then the second heat exchange zone Z2 and finally the first heat exchange zone Zl.

[0067] Therefore, the heat exchanger considered here is a so-called counter-current exchanger.

[0068] The path of the first fluid Fl zigzags as illustrated by the arrowed path PI in dotted lines shown in [Fig.4], against the path P2.

[0069] The path of the second fluid F2 zigzags as illustrated by the arrowed path P2 in dashed line shown in [Fig.4], contrary to the path PL Between two floors, the second fluid F2 passes through buffer spaces (91,92,93) also called plenums or 'calming spaces' which will be described later.

[0070] Within the heat exchange zones, the second fluid F2 circulates in tubes 2. Here the tubes 2 have a round cross-section, but they could have another cross-sectional shape. The tubes 2 are fixed to perforated plates 70, 79.

[0071] The tubes 2 are arranged parallel to each other. The axes of the tubes extend along an axis A which is parallel to the longitudinal direction X.

[0072] More specifically, the heat exchanger 1 comprises a plurality of tubes, the first internal circulation space for the second fluid F2 is defined as comprising the internal area of ​​the plurality of tubes 2.

[0073] The total number of tubes can be significant, up to 2000 or even 3000. The tubes 2 are made of copper, aluminum, or an alloy resistant to temperatures up to 800°C. The internal diameter of the tubes 2 is between 1 mm and 5 mm. The first fluid Fl circulates in the inter-tube space around the tubes in the exchange zones, licking the outer walls of the tubes, while the second fluid F2 licks the inner walls of the tubes.

[0074] Thus, tubes 2 form the main site of heat exchange.

[0075] A first partition 41 comprises four faces (as seen in [Fig. 3]) and delimits the first heat exchange zone Z1. A second partition 42 also comprises four faces and delimits the second heat exchange zone Z2, together with the first partition 41. A third partition 43 also comprises four faces and delimits the third heat exchange zone Z3 with the second partition 42.

[0076] In these partitions are arranged lights 8 which allow the first fluid to flow from one heat exchange zone to the next (i.e. from Z1 to Z2, from Z2 to Z3 and from Z3 to Z4).

[0077] Modular construction

[0078] Let us now look, with reference to Figures 5 to 8, at an example of the embodiment of a modular 4-stage heat exchanger (i.e., like the previous example in Figures 3 and 4). Everything described concerning the operating principle relating to Figures 3 and 4 is not repeated here, but is of course applicable.

[0079] The heat exchanger here is mainly made up of an assembly of 4 modules, identified respectively as M1, M2, M3 and M4. Each module generally corresponds to a heat exchange stage: M1 corresponds to the first heat exchange zone Z1, M2 corresponds to Z2, M3 corresponds to Z3, M4 corresponds to Z4.

[0080] According to the illustrated example, we have four cascaded stages for the fluid flow. Of course, the number of cascaded stages (and therefore modules) could be different: less than 4, namely 3 or 2, or even more than 4.

[0081] For generic description reasons, Mii denotes the ii-th module, ii ranging from 2 to N, N being the total number of modules, Mk denotes the k-th module, k ranging from 1 to Nl.

[0082] In the first module M1, a first group of tubes is arranged in the first heat exchange zone Z1, the total tube passage area being designated SP1. In the second module M2, there is a second group of tubes with a total tube passage area designated SP2. In the third module M3, there is a third group of tubes with a total tube passage area designated SP3. In the fourth module M4, there is a fourth group of tubes with a total tube passage area designated SP4.

[0083] In the illustrated example, as seen in Figures 6 and 8, each module is manufactured independently of the others, in a specific material, which may differ from one module to another. The modules are then assembled together with each other and a front closing plate 4 to form the complete heat exchanger.

[0084] The tubes are fixed in perforated plates which will be described later.

[0085] Partitions are provided which delimit the distinct heat exchange zones.

[0086] The first module Ml has a general prismatic shape and comprises four lateral walls 41 (also called outer shell) which radially delimit the inter-tube space of the first module Ml. Furthermore, the inter-tube space of Zl is delimited at each of the longitudinal ends by perforated plates 71,72 which receive the tubes, the holes being traversed without play by the tubes and the perforated plates thus forming a hermetic wall for the first fluid contained in Zl.

[0087] The first module Ml comprises an upstream collector zone 80 which channels (arrow 61 in [Fig.5]) the beginning of the path PI of the first fluid Fl from the general inlet EG1 before its entry into the inter-tube heat exchange space ZL

[0088] The first fluid Fl flows by licking the outside of the tubes to the other longitudinal end of the module Ml where the first fluid passes through a transfer passage 81 to join the second module M2 and the inter-tube space of the second zone Z2 (arrow 62 in [Fig.5]).

[0089] The second module M2 has a generally prismatic shape, larger in Y and Z, and is designed to surround the first module ML

[0090] Similar to the first, the second module M2 comprises four side walls 42 (also called outer shell) which radially delimit the inter-tube space of the second module M2. In addition, the side walls 41 of the first module M1 radially delimit the inter-tube space of the second module M2 after assembly.

[0091] Furthermore, the inter-tube space of Z2 is delimited at each of the longitudinal ends by perforated plates 73,74 which receive the tubes, the holes being crossed without play by the tubes and the perforated plates thus forming a hermetic wall for the first fluid contained in Z2.

[0092] The first fluid Fl flows by licking the outside of the tubes to the other longitudinal end of the module M2 where the first fluid passes through a transfer passage 82 to join the third module M3 and the inter-tube space of the third zone Z3 (arrow 63 in [Fig.5]).

[0093] The third module M3 has a similar general prismatic shape, larger in Y and Z and is intended to surround the second module M2.

[0094] Similarly, the third module M3 comprises four side walls 43 (also called outer shell) which radially delimit the inter-tube space of the third module M3. In addition, the side walls 42 of the second module M2 radially delimit, after assembly, the inter-tube space of the third module M3.

[0095] Furthermore, the inter-tube space of Z3 is delimited at each of the longitudinal ends by plates with holes 75,76 which receive the tubes, as described previously.

[0096] The first fluid Fl flows by licking the outside of the tubes to the other longitudinal end of the module M3 where the first fluid passes through a transfer passage 83 to join the fourth module M4 and the inter-tube space of the fourth zone Z4 (arrow 64 in [Fig.5]).

[0097] The fourth module M4 has a similar general prismatic shape, larger in Y and Z and is intended to surround the third module M3.

[0098] Similarly, the fourth module M4 comprises four side walls 44 which form the general outer shell of the exchanger after assembly.

[0099] The side walls 44 radially delimit the inter-tube space of the fourth module M4. In addition, the side walls 43 of the third module M3 radially delimit, after assembly, the inter-tube space of the fourth module M4.

[0100] Furthermore, the inter-tube space of Z4 is delimited at each of the longitudinal ends by plates with holes 77,78 which receive the tubes, as described previously.

[0101] The first fluid Fl, after passing through the inter-tube space of Z4, arrives at the general outlet SGI via the outlet lights 84.

[0102] Advantageously, the lights 81,82,83,84 are placed so as to generate a counter-current circulation of the first fluid in each of the modules, i.e. in each of the heat exchange stages.

[0103] Each of the lights 81,82,83,84 can be formed as a multi-light passage.

[0104] The path P2 of the second fluid F2 enters through a buffer space 90 (arrow 21) receiving the general inlet EG2. The second fluid then passes through the tubes of the fourth stage in M4 to the opposite buffer space marked 91. The second fluid F2 makes a U-turn at this point in the buffer space 91 (arrow 22).

[0105] The second fluid then passes through the tubes of the third module in M3 to the opposite buffer space marked 92. Then, the second fluid F2 makes a half turn at this point in the buffer space 92 (arrow 23).

[0106] The second fluid then passes through the tubes of the second module in M2 to the opposite buffer space marked 93. Then, the second fluid F2 turns around at this point in the buffer space 93 (arrow 24).

[0107] The second fluid then passes through the tubes of the first module ML. The second fluid exits through an outlet manifold 40 in the center of the exchanger, at the location of the general outlet SG2 of the second fluid.

[0108] According to an example of a turbomachine for range extender application, referring to [Fig. 12] which illustrates the evolution of the temperature of the first fluid TF1, the inlet of the first fluid Fl occurs at a temperature Tl 1 between 750°C and 820°C, the outlet of the first fluid occurs at a temperature T12 between 200°C and 300°C.

[0109] According to this same example, concerning the evolution of the temperature of the second fluid TF2, the entry of the second fluid F2 occurs at a temperature T21 between 100°C and 200°C, the exit of the second fluid occurs, after heating by the first fluid, at a temperature T22 between 600°C and 700°C.

[0110] It is noted that the pressure of the second fluid is significantly higher than the pressure of the first fluid. In the illustrated example, the pressure difference can be several bar.

[0111] The first fluid Fl is air in the illustrated example, but the first fluid could be any gas or any mixture of gases. Similarly, the second fluid F2 is air in the illustrated example, but it could be any gas or any mixture of gases, a liquid, or a two-phase fluid, hence the generic term "fluid" in this document.

[0112] As illustrated in figures 6 and 8, the modules may include all or part of the walls necessary for the formation of buffer spaces at the longitudinal ends of the exchanger, when assembled together by translation along the longitudinal direction X.

[0113] In addition or as an alternative, a closing plate may be provided such as the front closing plate identified as 4 in figures 5 and 6, this closing plate allows the buffer spaces 90,92 to be closed hermetically.

[0114] It is noted that the modules fit together. In other generic terms, the modular construction is such that module Mii surrounds module Mii-1 in the radial direction.

[0115] Regarding materials, the hottest module(s) (e.g. Ml) can be made of special metal alloy, conversely the coldest module(s) (e.g. MN) can be made of copper, and the intermediate temperature modules can be made of aluminum.

[0116] Regarding pressure losses, one can choose to have a decreasing number of tubes from the first module M1 to the Nth module MN. If one considers the cumulative cross-sectional area of ​​passage in the tubes of each module, one can choose a decreasing cumulative cross-sectional area from the first module M1 to the Nth module, e.g. MN.

[0117] If we consider the respective total cross-sectional areas of the tubes SP1, SP2, SP3 and SP4 mentioned above, they may be identical or close. However, from a From the point of view of pressure losses, we can choose decreasing sections namely SP1> SP2 > SP3 > SP4.

[0118] According to one characteristic, if we consider the cumulative section of passage in the inter-tube space of each module, and respective cumulative sections they can also be decreasing from the first module M1 to the Nth module MN.

[0119] The characteristics related to the passage sections and / or the number of tubes stated above contribute to minimizing the aerodynamic or hydraulic pressure loss when the first fluid and the second fluid pass through the exchanger.

[0120] According to another example of an exchanger illustrated in figures 9 to 11, a general linear arrangement can be had with the module M1 in the center, a double module M2 (M2a and M2b), arranged on either side of the module M1, and a double module 3e module M3 (M3a and M3b), located on either side of the modules M2.

[0121] As seen in [Fig.10], we find the transfer passages 81,82, and the buffer spaces.

[0122] The modules are manufactured as parallelepiped boxes with two perforated plates 70,79 inside and tubes 2 which extend from one perforated plate 70 to the other 79 without protruding too much into the buffer spaces.

[0123] For the openings and inter-module passages, it is proposed, as illustrated in [Fig. 11], to form two openings 87, 88 in the lateral faces 47, 48 opposite each other within the modules, and to arrange a sealing gasket J around the opening. It is necessary to penetrate a double wall at this point, both for the transfer passages of the first fluid and for the settling buffer spaces.

[0124] The first buffer space corresponds to the meeting of the two volumes 91a and 91b which are put into communication by the light 102. The first buffer space corresponds to the meeting of the two volumes 92a and 92b which are put into communication by the light 101.

[0125] As shown in [Fig. 9], the respective dimensions VI, W1, V2, W2, V3, W3 of the modules in a plane transverse to the axis of the tubes can be adapted to the desired configuration of the heat exchanger. Similarly, the height of each module could be varied. It is also noted that it is easy to add a fourth or even a fifth stage if necessary.

[0126] Regarding the fixing and sealing around the tubes, it is explained, with the details shown in [Fig. 13], that each of the tubes 2 is received in an opening 27 of a perforated plate 72. The tube can be pressed in using the shrink-fit technique or the tube can be brazed 28 to the perforated plate at the edge of the opening 27. Furthermore, the perforated plate 72 is welded to the side wall 41 of a module. General sealing of the inter-tube space of a module is thus achieved. The inlet and outlet ports allow the passage of the first fluid to enter and exit said inter-tube space.

[0127] The heat exchanger 1' shown in [Fig. 14], in front view, is also modular, but cylindrical in shape, in contrast to the prismatic shape of the previous examples.

[0128] Everything that has been written for the prismatic-shaped exchanger previously can be transposed here for the cylindrical-shaped exchanger mutatis mutandis.

[0129] The general inlet of the first fluid EG1 and the general outlet of the second fluid SG2 are located in the center of the front face. Furthermore, the general inlet of the second fluid EG2 and the general outlet of the first fluid SGI are located on the left in [Fig. 14].

Claims

Demands

1. Heat exchanger (1), for example for turbomachinery, configured to circulate a first fluid (Fl) and a second fluid (F2) with mutual heat exchange in order to cool the first fluid (Fl) and heat the second fluid (F2), characterized in that the exchanger is of modular construction, and comprises: - a first module Ml, having a general inlet of first fluid (EG1) and a general outlet of second fluid (SG2), - one, or more, ii-module Mii, for ii ranging from 2 to N, receiving a flow of first fluid from module Mii-1 via one or more transfer passages (8, 81,82), and delivering a flow of second fluid to module ii-1 via a buffer space (91,92,93), - the N-module MN having a general inlet of second fluid (EG2) and a general outlet of first fluid (SGI).

2. Heat exchanger (1) according to claim 1, characterized in that in each module, the second fluid (F2) flows in tubes along a longitudinal axis (A) and the first fluid (Fl) flows in an inter-tube space around the tubes generally also along the longitudinal axis (A) but in the opposite direction.

3. Heat exchanger (1) according to claim 2, wherein a radial direction (R) is defined perpendicular to the longitudinal axis (A), the modular construction being characterized in that the module Mii surrounds the module Mii-1 in the radial direction.

4. Heat exchanger (1) according to claim 3, wherein each module Mk, for k from 1 to Nl comprises an outer shell which delimits the inter-tube space of the module Mk radially on the outside and which delimits the inter-tube space of the module Mk+1 radially on the inside.

5. Heat exchanger according to any one of claims 3 to 4, wherein the transfer passages are provided in the envelope of the Mk module at the radial interface with the Mk+1 module.

6. Heat exchanger (1) according to any one of claims 1 to 5, characterized in that the number of modules N is between 3 and 5.

7. Heat exchanger according to any one of claims 1 to 6, characterized in that the material of each module is distinct from the material of another module.

8. Heat exchanger according to any one of claims 1 to 7, characterized in that the buffer spaces are located at the longitudinal ends of the exchanger.

9. Turbomachinery system (TBG) configured to provide electrical power in a motor vehicle, as a range extender, comprising a heat exchanger according to any one of claims 1 to 8.

10. Motor vehicle comprising a turbomachine system according to claim 9.

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