FR3059413A1 - HEAT EXCHANGER COMPRISING A REFRIGERANT FLUID CIRCUIT - Google Patents

Abstract

The invention relates to a heat exchanger (5) comprising a first number of tubes (10a, 10b). The heat exchanger (5) is equipped with a homogenization device (18) for the distribution of a refrigerant fluid (FR) inside the tubes (10a, 10b). The homogenizing device (18) comprises at least one duct (19) provided with at least one window through which the refrigerant fluid (FR) is able to enter the duct (19). The conduit (19) is provided with a second number of orifices (22) through which the refrigerant (FR) is able to exit the conduit (19). The second number is between 0.7 times and once the first number.

Description

© Publication no .: 3,059,413 (to be used only for reproduction orders)

©) National registration number: 16 61736 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY

COURBEVOIE © Int Cl ⁸ : F28 F13 / 06 (2017.01), F28 F 1/00

A1 PATENT APPLICATION

©) Date of filing: 30.11.16. © Applicant (s): VALEO THERMAL SYSTEMS ©) Priority: Simplified joint stock company - FR. @ Inventor (s): BLANDIN JEREMY, TISSOT JULIEN, LEBLAY PATRICK and AZZOUZ KAMEL. (43) Date of public availability of the request: 01.06.18 Bulletin 18/22. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ® Holder (s): VALEO THERMAL SYSTEMS related: Joint stock company. ©) Extension request (s): © Agent (s): VALEO THERMAL SYSTEMS.

HEAT EXCHANGER CONSTITUTING A REFRIGERANT FLUID CIRCUIT.

FR 3 059 413 - A1

The invention relates to a heat exchanger (5) comprising a first number of tubes (10a, 10b). The heat exchanger (5) is equipped with a homogenization device (18) for the distribution of a refrigerant fluid (FR) inside the tubes (10a, 10b). The homogenization device (18) comprises at least one conduit (19) provided with at least one window through which the coolant (FR) is able to enter inside the conduit (19). The conduit (19) is provided with a second number of orifices (22) through which the refrigerant (FR) is able to leave the conduit (19). The second number is between 0.7 times and once the first number.

i

Heat exchanger constituting a refrigerant circuit

The field of the present invention is that of the heat exchangers constituting a refrigerant circuit fitted to a motor vehicle. The invention relates to a device for homogenizing the distribution of a refrigerant fluid inside the tubes of such a heat exchanger.

A motor vehicle is commonly equipped with a ventilation, heating and / or air conditioning installation for thermally treating the air present or sent inside a passenger compartment of the motor vehicle. To do this, such an installation is associated with a closed circuit inside which a refrigerant circulates. The refrigerant circuit successively comprises a compressor, a gas condenser or cooler, an expansion member and a heat exchanger. The heat exchanger is housed inside the ventilation, heating and / or air conditioning installation to allow heat exchange between the refrigerant and an air flow circulating inside said installation delivery of the air flow inside the passenger compartment.

According to an operating mode of the refrigerant circuit, the heat exchanger is used as an evaporator to cool the air flow. In this case, the refrigerant is compressed inside the compressor, then the refrigerant is cooled inside the condenser or gas cooler, then the refrigerant undergoes expansion inside the expansion member and finally the refrigerant captures calories from the air flow inside the heat exchanger. The refrigerant, at the outlet of the expansion member and at the inlet of the heat exchanger, is in the two-phase state and is present in a liquid phase and a gaseous phase.

The heat exchanger includes a manifold and a return box between which a bundle of tubes is interposed. During the operation of the refrigerant circuit, the refrigerant is admitted inside the heat exchanger through an inlet that includes the manifold. Then, the refrigerant flows between the manifold and the return box through the bundle tubes.

A general problem posed resides in a difficulty in supplying the tubes of the bundle in a homogeneous manner with regard to the different phases, liquid and gaseous, of the refrigerating fluid.

In fact, a heterogeneity in the supply of coolant to the tubes of the bundle generates a heterogeneity in the temperature of the air flow which passes through the heat exchanger. This heterogeneity is likely to induce untimely and unwanted temperature differences between areas of the passenger compartment, which is detrimental.

Document US2015 / 0121950 proposes to house, inside the manifold, a device for homogenizing the distribution of the coolant inside the bundle tubes. This device comprises a conduit provided with a plurality of orifices. The duct has a first end portion which is in relation to a first inlet for the refrigerant fluid inside the heat exchanger. The duct is arranged in a cylindrical tube defining an interior volume inside which the refrigerant circulates. The liquid phase refrigerant is sprayed through the orifices provided through the duct in the form of droplets.

Such an organization is not optimal from the point of view of the homogenization of the distribution of refrigerant fluid inside the heat exchanger. More particularly, the tubes of the bundle furthest from the first end part are frequently under-supplied with refrigerant.

This results in heterogeneity in the temperature of the air flow leaving the heat exchanger, which is unsatisfactory.

An object of the invention is to perfect the homogeneity of the distribution of refrigerant fluid inside the heat exchanger, in order to finally improve its efficiency and output, with a view to delivering inside the passenger compartment. an air flow at the desired temperature.

Another object of the invention is to improve the distribution of refrigerant fluid inside the heat exchanger, including when the latter is present inside the heat exchanger in two distinct phases, liquid and gas, in respective variable proportions.

Another object is to provide a heat exchanger provided with a device for distributing a coolant inside the bundle tubes which ensures an equivalent supply of coolant to the bundle tubes, including those which are the further away from the first end portion of the duct, which receives the refrigerant in the first place.

Another object is to provide a heat exchanger provided with a coolant distribution device which is arranged to prevent an accumulation of the coolant in an area of the latter.

A heat exchanger of the present invention is a heat exchanger comprising a first number of tubes. The heat exchanger is equipped with a device for homogenizing the distribution of coolant inside the tubes. The homogenization device comprises at least one duct provided with at least one window through which the refrigerant is able to enter inside the duct. The conduit is provided with a second number of holes through which the refrigerant is able to exit the conduit.

According to the present invention, the second number is between 0.5 times and twice the first number.

The heat exchanger advantageously comprises any one of the following characteristics, taken alone or in combination:

- the second number is between 0.8 times and twice the first number.

- the second number is between 0.9 and twice the first number.

- the second number is equal to the first number.

- the tubes are either obtained by extrusion or by brazing of plates.

- The heat exchanger comprises a return box which is subdivided into a plurality of compartments, each compartment being equipped with at least one end of a tube.

- the heat exchanger includes a manifold housing the homogenization device.

- The duct houses at least one mixing member comprising a plurality of identical and repeated mixing elements along an elongation axis.

The invention also relates to a refrigerant circuit comprising at least one such heat exchanger.

The invention also relates to the use of such a heat exchanger as an evaporator housed inside a housing of a ventilation, heating and / or air conditioning installation fitted to a motor vehicle.

Other characteristics, details and advantages of the invention will emerge on reading the detailed description given below by way of indication in relation to the drawings of the attached plates, in which:

FIG. 1 is a diagrammatic illustration of a refrigerant fluid circuit comprising a heat exchanger of the present invention,

FIG. 2 is a schematic perspective illustration of a first alternative embodiment of the heat exchanger illustrated in FIG. 1,

FIG. 3 is a schematic illustration of a cross section of the heat exchanger shown in FIG. 2,

FIG. 4 is a schematic perspective illustration of a second alternative embodiment of the heat exchanger illustrated in FIG. 1,

FIG. 5 is a diagrammatic illustration of a cross section of the heat exchanger shown in FIG. 4,

FIGS. 6 and 7 are diagrammatic illustrations in perspective of a device for homogenizing the distribution of the refrigerant fluid intended to equip the heat exchanger shown in FIGS. 2 or 4,

FIG. 8 is a schematic top view of the homogenization device shown in FIGS. 6 and 7,

FIG. 9 is a schematic view of a cross section of the homogenization device shown in FIGS. 6 to 8,

FIG. 10 is a schematic view of a longitudinal section of the homogenization device shown in FIGS. 6 to 9,

FIG. 11 is a curve representing a diameter ratio as a function of a surface ratio according to a first alternative embodiment,

FIG. 12 is a curve representing a mixing ratio as a function of the surface ratio, according to the first alternative embodiment also considered in FIG. 11,

FIG. 13 is a curve representing the diameter ratio as a function of the surface ratio, according to a second variant embodiment,

FIG. 14 is a curve representing the mixing ratio as a function of the surface ratio, according to the second alternative embodiment also considered in FIG. 13,

- Figure 15 is a curve representing the diameter ratio as a function of a hydraulic diameter,

FIG. 16 is a curve representing the mixing ratio as a function of the hydraulic diameter,

FIG. 17 is a curve representing a first number of orifices, which is provided with the conduit, as a function of a second number of tubes, which includes the heat exchanger,

- Figure 18 is a detail view in cross section of the heat exchanger illustrated in Figure 4, according to a third alternative embodiment.

The figures and their description show the invention in detail and according to specific methods of its implementation. They can be used to better define the invention, if necessary.

In Figure 1 is shown a closed circuit 1 inside which circulates a refrigerant FR. In the illustrated embodiment, the refrigerant circuit 1 successively comprises, in a direction SI of circulation of the refrigerant fluid FR inside the refrigerant circuit 1, a compressor 2 for compressing the refrigerant fluid FR, a condenser or a gas cooler 3 for cooling the refrigerant fluid FR, an expansion member 4 inside which the refrigerant fluid FR undergoes expansion and a heat exchanger 5. The heat exchanger 5 is housed inside d 'A housing 6 of a ventilation, heating and / or air conditioning installation 7 inside which an air flow circulates. The heat exchanger 5 allows a thermal transfer between the refrigerant fluid FR and the air flow FA coming into contact with it and / or passing through it, as illustrated in FIGS. 2 and 3. Depending on the operating mode of the circuit of refrigerant 1 described above, the heat exchanger 5 is used as an evaporator to cool the air flow FA, during the passage of the air flow FA in contact and / or right through the exchanger heat 5.

In FIGS. 2 and 4, the heat exchanger 5 comprises a manifold 8 and a return box 9 between which a bundle of tubes 10, 10a, 10b is interposed. In general, the heat exchanger 5 extends parallel to a first plane P1 containing the manifold 8, the bundle of tubes 10, 10a, 10b and the return box 9. The manifold 8 overhangs the bundle of tubes 10, 10a, 10b, which are themselves located above the return box 9, in particular in the position of use of the heat exchanger 5 mounted inside the housing 6. In other words, according to this position of use, the manifold 8 is an upper box of the heat exchanger 5 while the return box 9 is a lower box of the heat exchanger 5. The air flow FA flows through the 'heat exchanger 5 in a direction preferably orthogonal to the foreground Pl.

The tubes 10, 10a, 10b are for example rectilinear and extend along a first axis of general extension A1 between the manifold 8 and the return box 9. The manifold 8 extends along a second axis of extension general A2 and the return box 9 extends along a third axis of general extension A3. Preferably, the second axis of general extension A2 and the third axis of general extension A3 are parallel to each other, being orthogonal to the first axis of general extension A1.

The bundle of tubes 10, 10a, 10b is provided with fins 15 which are interposed between two successive tubes 10, 10a, 10b, to promote a heat exchange between the air flow FA and the tubes 10, 10a, 10b, during of a passage of the air flow FA through the heat exchanger 5, the air flow FA circulating in a direction substantially orthogonal to the foreground Pl.

The heat exchanger 5 comprises a first mouth 16 through which the refrigerant FR enters the interior of the heat exchanger 5. The first mouth constitutes an inlet for the refrigerant FR into a first chamber 13, which is delimited inside the manifold 8. The heat exchanger 5 comprises a second mouth 17 through which the refrigerating fluid FR is evacuated from the heat exchanger 5.

In FIGS. 2 and 3, the heat exchanger 5 is a heat exchanger inside which the refrigerating fluid FR flows along a path arranged in "I". The tubes 10 are arranged parallel to each other and are aligned inside the first plane Pl.

In FIG. 2, the tubes 10 extend between a first end 101 which is in fluid communication with the return box 9 and a second end 102 which is in fluid communication with the manifold 8. In other words, the return box 9 forms the base of the "I" while the manifold 8 forms the top of the "I". According to this first variant, the second mouth 17 equips the return box 9.

In FIG. 3, the tubes 10 together provide a passage section S for the refrigerant fluid FR which is defined by the sum of passage surfaces S 'offered by each of the tubes 10. In other words, each tube 10 offers a passage surface S 'to the refrigerant FR, which corresponds to a surface through which the refrigerant FR flows orthogonally, the passage surface S' being considered inside a transverse plane Pt 'which is orthogonal to the first axis d' general extension A1. The passage section S is equal to the sum of the passage surfaces S 'of all the tubes 10 of the heat exchanger 5.

The tubes 10 together offer a perimeter of passage P for the refrigerant FR which is defined by the sum of passage contours P 'offered by each of the tubes 10. In other words, each tube 10 offers a passage contour P' which corresponds to a length of the transverse periphery of each tube 10 inside which the refrigerant fluid FR flows, the passage contour P 'being considered inside the transverse plane Pt', orthogonal to the first axis of general extension A1. passage perimeter P is equal to the sum of the passage contours P 'of all the tubes 10 of the heat exchanger 5.

The heat exchanger 5 comprises a first number NI of tubes 10. In other words, said first number NI of tubes 10 follow one another in the first plane PI one after the other. Commonly, the first NI number is between fifteen and one hundred, or even between twenty-five and seventy-five, or even is on the order of fifty to +/- 10%.

During an implementation of the refrigerant circuit 1, the refrigerant FR enters the interior of the heat exchanger 5 through the first mouth 16 that comprises the manifold 8. Then, the refrigerant FR is distributed along the manifold 8 along the second extension axis A2 by a device for homogenizing the distribution 18. Then, the refrigerant FR flows between the manifold 8 and the return box 9 using the tubes 10. Finally, the refrigerant FR is evacuated from the heat exchanger 5 through the second mouth 17 of the return box 9.

In FIGS. 4 and 5, the heat exchanger is a heat exchanger inside which the refrigerant FR flows along a path arranged in a "U" shape. The tubes 10a, 10b are arranged parallel to each other, being distributed in two layers 11, 12, including a first layer 11 of first tubes 10a and a second layer 12 of second tubes 10b. The first ply 11 and the second ply 12 are formed inside respective planes which are mutually parallel and parallel to the first plane PI.

In FIG. 4, the first tubes 10a of the first ply 11 extend between a first end 101 which is in fluid communication with the return box 9 and a second end 102 which is in fluid communication with the first chamber 13. The second tubes 10b of the second ply 12 extend between a third end 103 which is in fluid communication with the return box 9 and a fourth end 104 which is in fluid communication with a second chamber 14, also delimited inside the manifold 8. The first chamber 13 and the second chamber 14 are contiguous and sealed with each other. The first chamber 13 extends along a fourth axis of general extension A4 and the second chamber 14 extends along a fifth axis of general extension A5. Preferably, the fourth axis of general extension A4 and the fifth axis of general extension A5 are parallel to each other and parallel to the second axis of general extension A2. The fourth axis of general extension A4 and the fifth axis of general extension A5 together define a second plane P2, which is preferably orthogonal to the first plane PI. In other words, the return box 9 forms the base of the "U" while the first ply 11 and the second ply 12 of tubes 10a, 10b form the branches of the "U", the first chamber 13 and the second chamber 14 forming the ends of the "U". According to this second variant, the second mouth 17 equips the second chamber 14 of the manifold 8.

In FIG. 5, the first tubes 10a together offer a passage section S for the refrigerant fluid FR which is defined by the sum of passage surfaces S ’offered by each of the first tubes 10a. In other words, each first tube 10a offers a passage surface S 'for the refrigerant fluid FR, which corresponds to a surface through which the refrigerant fluid FR flows orthogonally, the passage surface S' being considered inside of a transverse plane Pt 'which is orthogonal to the first axis of general extension A1. The passage section S is equal to the sum of the passage surfaces S' of all the first tubes 10a of the heat exchanger 5.

The first tubes 10a together offer a perimeter of passage P for the refrigerating fluid FR which is defined by the sum of contours of passage P ’offered by each of the first tubes 10a. In other words, each first tube 10a has a passage contour P 'which corresponds to a length of the transverse periphery of each first tube 10a inside which the refrigerant fluid FR flows, the passage contour P' being considered at 'inside the transverse plane Pt', orthogonal to the first axis of general extension A1. The passage perimeter P is equal to the sum of the passage contours P 'of all the first tubes 10a of the heat exchanger 5.

The heat exchanger 5 comprises a first number NI of first tubes 10a. Otherwise, said a first number NI of first tubes 10a follow one another in a plane parallel to the first plane PI one after the other. Commonly, the first NI number is between fifteen and one hundred, or even between twenty-five and seventy-five, or even is on the order of fifty to +/- 10%.

During an implementation of the refrigerant circuit 1, the refrigerant FR enters the interior of the heat exchanger 5 through the first mouth 16 of the first chamber 13, being distributed along the manifold 8 along the second axis of general extension A2 by the homogenization device of the distribution 18. Then, the refrigerant FR flows between the first chamber 13 of the manifold 8 and the return box 9 by borrowing the first tubes 10a of the first ply 11. Then, the refrigerant FR flows between the return box 9 and the second chamber 14 using the second tubes 10b of the second ply 12. Finally, the refrigerant FR is evacuated out of the heat exchanger 5 through the second mouth 17, after having circulated through the second chamber 14.

Preferably, a first tube 10a of the first ply 11 is aligned with a second tube 10b of the second ply 12 inside a third plane P3 which is perpendicular to the first plane PI and which is parallel to the first axis of general extension Al.

Whatever the variant embodiment of the heat exchanger 5 presented above, the manifold 8 houses the homogenization device 18 for the distribution of the refrigerant fluid FR inside the tubes 10, 10a, 10b. Such a homogenization device 18 aims to distribute homogeneously the refrigerant fluid FR, in the two-phase liquid-gas state, along the manifold 8 and ultimately inside the set of tubes 10, 10a , 10b. Such a homogenization device 18 more particularly aims to distribute the FR refrigerant fluid evenly inside the heat exchanger 5, including when the FR coolant is present inside the heat exchanger 5 under two distinct phases, liquid and gas, in variable respective proportions.

In FIGS. 6 to 10, the homogenization device 18 comprises for example a conduit 19 extending along a sixth axis of general extension A6, parallel, or even coincident, with the second axis of general extension A2 and / or the fourth axis of general extension A4, between a first end portion 20 and a second end portion 21 of the conduit 19.

It will be noted that any element which extends along the sixth axis of general extension A6 which is defined by the largest dimension of the duct 19 is described as longitudinal. Any element which extends inside d 'a transverse plane Pt which is orthogonal to the general axis of extension A6.

The first end portion 20 is formed at one end of the conduit 19, while the second end portion 21 is formed at the other end of the conduit 19, longitudinally opposite the first end portion 20.

According to an alternative embodiment, the first end portion 20 is intended to be placed in fluid communication with the first mouth 16 of the heat exchanger 5. According to another alternative embodiment, the first mouth 16 houses the conduit 19, the first of which end part 20 is placed in fluid communication with a pipe of the refrigerant fluid circuit 1. According to these two variants, the second end part 21 is blind and forms a dead end with regard to the circulation of the coolant FR inside of duct 19.

The conduit 19 is for example shaped as a cylinder formed around an axis of symmetry A7, which is preferably parallel, or even coincident, with the sixth axis of general extension A6. The conduit 19 comprises a peripheral wall 23 which is of cylindrical cross section. The peripheral wall 23 is that which gives the overall shape of the conduit 19. The conduit 19 constitutes an envelope which delimits an internal space 24 around which the conduit 19 is formed. In other words, the conduit 19 borders the internal space 24 that the conduit 19 surrounds. The internal space 24 is cylindrical and is formed around the axis of symmetry A7. The peripheral wall 23 of the duct 19 has an internal face 23a which adjoins and which delimits the internal space 24, the internal face 23a being of circular cross section.

The conduit 19 is provided with two end walls 27, 28, including a first end wall 27 fitted to the first end portion 20 and a second end wall 28 fitted to the second end portion 21. The first end wall 27 and the second end wall 28 are for example planes and arranged along the transverse plane Pt orthogonal to the sixth axis of general extension A6 and / or to the axis of symmetry A7. The first end wall 27 and the second end wall 28 are for example from a cover at least partially covering the manifold 8.

The first end wall 27 is equipped with at least one window 29 for the admission of the refrigerant fluid LR inside the internal space 24. In other words, the first end wall 27 of the conduit 19 is equipped with the window 29 which is for example in fluid relation with the first mouth 16 to admit the refrigerant fluid LR inside the heat exchanger 5 via the conduit 19.

Referring to FIG. 9, the duct 19 is characterized by a passage area A of the refrigerant fluid LR which is delimited inside the transverse plane Pt by the internal face 23a of the peripheral wall 23. The passage area A is the transverse surface that the refrigerant LR crosses during its circulation inside the duct 19. In other words, the passage area A is the surface, taken in the transverse plane Pt, which is offered to the refrigerant for its flow inside the duct 19.

The peripheral wall 23 comprises at least one orifice 22, and preferably orifices 22 which are formed through the peripheral wall 23 of the conduit 19. The orifices 22 are preferably aligned along an alignment axis A8 which is parallel to the sixth axis of general extension A6 and / or to the axis of symmetry A7.

The duct 19 more particularly comprises a second number N2 of orifices

22. Otherwise, said a second number N2 of orifices 22 follow one after the other along the alignment axis A8. Commonly, the second number N2 is between fifteen and one hundred, or even between twenty-five and seventy-five, or even is of the order of fifty to within +/- 10%.

According to a variant, the orifices 22 are equidistant from each other. According to another variant, the orifices 22 are spaced from each other by a variable distance. The orifices 22 are orifices of circular section. Preferably, the orifices 22 are circular openings made through the peripheral wall 23 of the conduit 19. The orifices 22 open on either side of the peripheral wall 23. Preferably, the orifices 22 are provided are a drilling axis A9, visible in Figure 9, which is orthogonal to the axis of symmetry A7. The orifices 22 are characterized by a first diameter D1, taken between two points Z and W of a contour 26 of each orifice, the points Z and W being diametrically opposite one another with respect to the axis of piercing A9, as shown in Figure 9.

In FIGS. 7 to 10, the duct 19 houses a mixing member 25 which extends inside the internal space 24. The mixing member 25 is intended to promote mixing between the liquid and gaseous phases of the FR refrigerant. The mixing member 25 is in particular provided for directing the refrigerant fluid FR from the axis of symmetry A7 of the duct 19 towards the internal face 23a of the duct 19. The mixing member 25 is a member allowing and facilitating circulation, in particular centrifugal of the refrigerant FR from the axis of symmetry A7 of the duct 19 towards the internal face 23a of the latter. The mixing member 25 is also provided to avoid an accumulation of the refrigerating fluid in the liquid state in a lower zone of the conduit 19, in the position of use of the latter. The mixing member 25 is also provided for disturbing a laminar flow of the FR refrigerant fluid inside the duct 19, with a view to mixing the liquid and gas phases of the FR refrigerant fluid. In other words, the mixing member 25 forms at least one baffle and preferably a plurality of baffles against a laminar flow, parallel to the sixth axis of general extension A6 and / or to the axis of symmetry A7. In general, the mixing member 25 forms an obstacle to the laminar flow of the refrigerating fluid FR inside the internal space 24.

The mixing member 25 is longitudinally extended between a first transverse rim 34 of the mixing member 25 and a second transverse rim 35 of the mixing member 25 along an elongation axis A10 which is preferably parallel, or even coincident, with the sixth general extension axis A6 and / or the axis of symmetry A7 of the conduit 19, when the mixing member 25 is positioned inside the conduit 19, as illustrated in FIGS. 7 to 10.

The mixing device 25 extends inside the entire internal space 24. In other words, the mixing device 25 fills the entire volume delimited by the conduit 19. In other words, the mixing member 25 has a conformity and / or a geometry similar to that of the internal space 24. The mixing member 25 is preferably of overall cylindrical conformation. It will be understood that such a shape is defined generally by a peripheral edge 31 of the mixing member 25. The peripheral edge 31 of the mixing member 25 is formed of the surfaces of the mixing member 25 which are arranged vis- opposite conduit 19.

Referring also to FIG. 8, the mixing member 25 is notably characterized by a first length L1, taken between the first transverse rim 33 of the mixing member 25 and the second transverse rim 34 of the mixing member 25 parallel to the elongation axis A10 of the mixing member 25. In other words, the mixing member 25 extends longitudinally along the elongation axis A10 over a first length L1.

Referring also to FIG. 9, the mixing member 25 is also characterized by a second diameter D2 taken transversely between two points X and Y of the peripheral edge 31 of the mixing member 25 which are diametrically opposite one to the other. the other relative to the elongation axis A10 of the mixing member 25.

The internal face 23a of the peripheral wall 23 is preferably smooth to allow easy introduction of the mixing member 25 inside the duct 19, the peripheral edge 31 of the mixing member 25 being in abutment against the internal face 23a. This characteristic of the internal face 23a is particularly advantageously when the mixing member 25 fills the entire volume delimited by the conduit 19.

In FIG. 10, the mixing member 25 is formed of a plurality of mixing elements 30 which are identical to each other and which are abutted to each other along the elongation axis A10 of l mixing member 25. Preferably, the mixing member 25 is in one piece and made in one piece, so that the mixing elements 30 are constitutive of the mixing member 25 and form portions of the latter . The mixing elements 30 are similar to each other and are arranged in identical orientations inside the conduit 19. Each mixing element 30 extends longitudinally between a first transverse edge 32 and a second transverse edge 33.

Each mixing element 30 is notably characterized by a pitch Pa taken along the elongation axis A10 between the first transverse edge 32 and the second transverse edge 33 of the mixing element 30. It will be noted that an element of mixing 30 which is subjected to a translation of a distance equal to its pitch Pa along the elongation axis A10 is exactly superimposable on the following mixing element 30. In other words, the mixing member 25 is made up of a plurality of mixing elements 30 similar to one another and superimposed identically by translating an integer number of times the step Pa.

The mixing element 30 is for example a propeller portion whose pitch Pa corresponds to a pitch of the propeller portion.

To optimize the efficiency of the homogenization device 18, the designers of the present invention have made choices relating to the dimensional characteristics of the tubes 10, 10a, 10b, of the conduit 19 and of the mixing member 25. These choices are derived from '' a plurality of laboratory tests which lead to an analysis of the performance of the heat exchanger 5 as a function of the dimensional characteristics of the tubes 10, 10a, 10b, of the conduit 19 and of the mixing device 25. These dimensional choices aim to homogenize a distribution of the coolant inside the heat exchanger

5.

A first choice was made to consider a diameter ratio RI which is defined by the ratio between the second diameter D2 of the mixing member 25 and the first diameter DI of the orifices 22, the second diameter D2 and the first diameter DI being expressed in mm. The diameter ratio RI combines characteristics of the mixing member 25 and the orifices 22.

A second choice was made to consider a mixing ratio R2 which is defined by the ratio between the second diameter D2 of the mixing member 25 and the pitch Pa of the mixing element 30, the second diameter D2 and the pitch Pa being expressed in mm. The mixing ratio R2 combines characteristics of the mixing member 25 and the mixing element 30.

A third choice was made to consider a surface ratio R3 which is defined by the ratio between the passage area A of the conduit 19 and the first length L1 of the mixing member 25, the passage area A being expressed in mm and length in mm. The area ratio R3 combines characteristics of the conduit 19 and the mixing member 25.

A fourth choice was made to consider a hydraulic diameter Dh which is defined by the ratio between four times the passage section S of the tubes 10, 10a, 10b and the passage perimeter P of the tubes 10, 10a, 10b, the section of passage S being expressed in mm and the perimeter of passage P in mm. The hydraulic diameter Dh combines characteristics of the tubes 10, 10a, 10b of the heat exchanger 5.

According to a first approach of the present invention, and as illustrated in FIGS. 11 to 14, when the surface ratio R3 is between 0.02 and 1.38, the diameter ratio RI is between 0.2 and 50 and / or the mixing ratio R2 is between 0.01 and 2.5. A choice was made to consider together the abovementioned characteristics of the conduit 19, the orifices 22, the mixing member 25 and the mixing element 30 and to make them dependent on each other according to the law previously stated.

In other words, according to a first choice of embodiment, when the surface ratio R3 is between 0.02 and 1.38, the conduit 19, the orifices 22 and the mixing member 25 jointly have the dimensional characteristics which make it possible to verify that the diameter ratio RI is between 0.2 and 50.

In other words, according to a second choice of embodiment, when the surface ratio R3 is between 0.02 and 1.38, the orifices 22, the mixing member 25 and the mixing element 30 jointly have the dimensional characteristics which verify that the R2 mixing ratio is between 0.01 and 2.5.

In other words, according to a third choice of embodiment, when the surface ratio R3 is between 0.02 and 1.38, the duct 19, the orifices 22, the mixing element 25 and the mixing element 30 have jointly the dimensional characteristics which make it possible to verify that the diameter ratio RI is between 0.2 and 50 and that the mixing ratio R2 is between 0.01 and 2.5.

Furthermore, according to a first embodiment, when the surface ratio R3 is greater than 0.28, then the diameter ratio RI is between 10 and 50.

Still further, according to a second embodiment, when the surface ratio R3 is greater than 0.28, then the mixing ratio R2 is between 0.25 and 2.5.

On the other hand, according to a first embodiment option, when the diameter ratio RI is between 10 and 50, the surface ratio R3 is between 0.28 and 1.38, if the heat exchanger 5 is a exchanger whose tubes 10, 10a, 10b are obtained by brazing plates together, or even between 0.28 and 0.68, if the heat exchanger 5 is an exchanger whose tubes 10, 10a, 10b are obtained by extrusion .

On the other hand, according to a second embodiment option, when the mixing ratio R2 is between 0.4 and 2.5, the surface ratio R3 is between 0.28 and 1.38, if the heat exchanger heat 5 is an exchanger whose tubes 10, 10a, 10b are obtained by brazing plates together, or even between 0.28 and 0.68, if the heat exchanger 5 is an exchanger whose tubes 10, 10a, 10b are obtained by extrusion.

In FIGS. 11 and 12, the diameter ratio RI and the mixing ratio R2 are shown respectively as a function of the surface ratio R3, for a heat exchanger 5 made up of plates brazed two by two at their ends.

In FIG. 11, it can be noted that the surface ratio R3 being between 0.02 and 0.68, the diameter ratio RI is between 0.2 and 50.

In FIG. 12, it is noted that the surface ratio R3 being between 0.02 and 0.68, the mixing ratio R2 is between 0.01 and 2.5.

In FIGS. 13 and 14, the diameter ratio RI and the mixing ratio R2 are shown respectively as a function of the surface ratio R3, for a heat exchanger 5 made up of tubes 10, 10a, 10b obtained by extrusion.

In FIG. 13, it is noted that the surface ratio R3 being between 0.02 and 1.38, the diameter ratio RI is between 0.2 and 50.

In FIG. 14, it is noted that the surface ratio R3 being between 0.02 and 1.38, the mixing ratio R2 is between 0.01 and 2.5.

According to a second approach of the present invention, and with reference to FIGS. 15 and 16, when the hydraulic diameter Dh is between 0.5 and 2.0, the diameter ratio RI is between 2.5 and 45 and / or the R2 mixing ratio is between 0.25 and 2.5. A choice was made to consider together the characteristics of the tubes 10, 10a, 10b, the orifices 22, the mixer 25 and the mixer 30, and to make them dependent on each other according to the law previously stated.

In other words, according to a first choice of embodiment, when the hydraulic diameter Dh is between 0.5 and 2.0, the tubes 10, 10a, 10b, the orifices 22 and the mixing member 25 jointly have the dimensional characteristics which allow check that the diameter ratio RI is between 2.5 and 45.

In other words, according to a second choice of embodiment, when the hydraulic diameter Dh is between 0.5 and 2.0, the tubes 10, 10a, 10b, the mixing member 25 and the mixing element 30, have jointly the dimensional characteristics which make it possible to verify that the mixing ratio R2 is between 0.25 and 2.5.

In other words again, according to a third choice of embodiment, when the hydraulic diameter Dh is between 0.5 and 2.0, the tubes 10, 10a, 10b, the orifices 22 and the mixing member 25 jointly have the dimensional characteristics which verify that the diameter ratio RI is between 2.5 and 45 and that the mixing ratio R2 is between 0.25 and 2.5.

Furthermore, according to a first embodiment, when the hydraulic diameter Dh is between 0.5 and 0.6, then the diameter ratio RI is between 2.5 and 17.5.

Still further, according to a second embodiment, when the hydraulic diameter Dh is between 0.6 and 0.9, then the diameter ratio RI is between 2.5 and 22.5.

Still further, according to a third embodiment, when the hydraulic diameter Dh is between 0.9 and 1.3, then the diameter ratio RI is between 5 and 30.

Still further, according to a fourth embodiment, when the hydraulic diameter Dh is between 1.3 and 1.6, then the diameter ratio RI is between 7.5 and 35.

Still further, according to a fifth embodiment, when the hydraulic diameter Dh is between 1.6 and 2, then the diameter ratio RI is between 10 and 40.

On the other hand, according to a first embodiment option, when the hydraulic diameter Dh is between 0.5 and 1, the mixing ratio R2 is between 0.25 and 2.5.

Furthermore, according to a second embodiment option, when the hydraulic diameter Dh is between 1 and 2, the mixing ratio R2 is between 0.5 and 2.5.

Furthermore, according to a first choice of embodiment, when the hydraulic diameter Dh is between 0.5 and 1, then the mixing ratio R2 is between 0.25 and 2.5.

Still further, according to a second embodiment, when the hydraulic diameter Dh is between 1 and 2, then the mixing ratio R2 is between 0.5 and 2.5.

According to a third approach of the present invention, and with reference to FIG. 17, the second number N2 of orifices 22 that comprises the conduit 19 is between 0.5 times and twice the first number NI of tubes 10, 10a, 10b .

In other words, the heat exchanger 5 comprises a first number NI of tubes 10, 10a, 10b which is between 50% and 200% of the second number N2 of orifices 22 ..

A choice was therefore made to consider together the digital characteristics of the tubes 10, 10a, 10b and the orifices 22 of the conduit 19, and to make them dependent on each other according to the law previously stated.

More particularly by referring to FIG. 17, a point having for abscissa the first number NI of tubes 10, 10a, 10b and for ordinate the second number N2 of orifices is preferentially located inside the hatched area of the figure 17.

Preferably, the second number N2 of orifices 22 is equal to the first number NI of tubes 10, 10a, 10b.

According to one embodiment of the present invention illustrated in FIG. 18, the heat exchanger 5 being a heat exchanger arranged in a "U" shape as illustrated in FIG. 4, the return box 9 is advantageously subdivided into a plurality of compartments 36, each compartment 36 being equipped with at least one end 101, 103 of a tube 10a, 10b. In this case, the return box 9 houses at least one partition 37 which delimits the return box 9 into at least two contiguous compartments 36. These provisions are such that a homogenization of the distribution of the refrigerant fluid FR, obtained by through the homogenization device 18, is perpetuated inside the second tubes 10b, through the compartmentalization of the return box 9.

From the abovementioned characteristics, the circulation of the refrigerating fluid FR inside the heat exchanger 5 is homogenized.

More particularly, the refrigerant FR penetrating inside the heat exchanger 5, penetrates inside the internal space 24 by borrowing the window 29 formed through the first end wall 27. Then, the refrigerant FR is spread inside the internal space 24 by being mixed by the mixing member 25. It results in particular from the dimensional choices above a mixing of the liquid and gas phases of the refrigerant FR which is then homogenized longitudinally , along the duct 19. Then, the refrigerant FR passes through the orifices 22 to flow out of the duct 19 towards the first chamber 13. Then, the refrigerant FR flows through the bundle of tubes 10, 10a, 10b, as described above, up to the return box 9, to be evacuated from the heat exchanger 5 via the second mouth 17.

During the transit of the FR refrigerant fluid through the conduit 19 thus equipped with such a mixing member 25, the FR refrigerant fluid encounters multiple obstacles which favor a mixture between its liquid and gas phases. In addition, such a duct 19 of such a homogenization device housing such a mixing member 25 promotes homogenization of the distribution of the refrigerant fluid FR inside the tubes 10, 10a, 10b, in particular thanks to the dimensional characteristics mentioned above. .

It will also be noted that the FR refrigerant is better sprayed, and in a homogeneous manner, during its passage through the orifices 22 that the two phases of the FR refrigerant, liquid and gas, are mixed by the mixing member. 25 inside the internal space 24 of the duct 19, with a view to then supplying the bundle of tubes 10, 10a, 10b in a homogeneous manner. In other words, initially, the mixing member 25 allows a longitudinal distribution of the refrigerant fluid FR which is homogeneous along the axis of symmetry A7, the spraying of the refrigerant fluid FR through the orifices 22 taking place in a second step, after homogenization of the FR refrigerant fluid in the internal space 24, which guarantees a better homogeneous distribution of the FR refrigerant fluid at the outlet of the duct 19, and consecutively inside the heat exchanger 5.

These arrangements are such that the refrigerant FR penetrating inside such a homogenization device 18 is distributed homogeneously to all of the tubes 10, 10a, 10b, including those supplied by the most openings 22 close to the second terminal part 21 and including for a refrigerant fluid FR present inside the heat exchanger 5 in two phases, liquid and gas.

In addition, the presence of such a mixing member 25 inside such a conduit 19 prevents an accumulation of the liquid phase of the refrigerant fluid FR in a lower zone of the conduit 19, in the position of use of the latter .

Claims (10)

1. Heat exchanger (5) comprising a first number (NI) of tubes (10, 10a, 10b), the heat exchanger (5) being equipped with a device for homogenizing (18) the distribution of a coolant (FR) inside the tubes (10, 10a, 10b), the homogenization device (18) comprising at least one conduit (19) provided with at least one window (29) through which the fluid refrigerant (FR) is able to enter the interior of the duct (19), the duct (19) being provided with a second number (N2) of orifices (22) through which the refrigerant fluid (FR) is capable of exit the conduit (19), characterized in that the second number (N2) is between 0.7 times and twice the first number (NI). 2. Heat exchanger (5) according to claim 1, wherein the second number (N2) is between 0.8 times and twice the first number (NI). 3. Heat exchanger (5) according to any one of the preceding claims, in which the second number (N2) is between 0.9 and twice the first number (NI). 4. Heat exchanger (5) according to any one of the preceding claims, in which the second number (N2) is equal to the first number (NI). 5. Heat exchanger (5) according to any one of the preceding claims, in which the tubes (10, 10a, 10b) are indifferently obtained by extrusion or by brazing of plates. 6. Heat exchanger (5) according to any one of the preceding claims, in which the heat exchanger (5) comprises a return box (9) which is subdivided into a plurality of compartments (36), each compartment ( 36) being equipped with at least one end (101, 103) of a tube (10a, 10b). 7. Heat exchanger (5) according to any one of the preceding claims wherein the heat exchanger (5) comprises a manifold (8) housing the homogenization device (18). 8. Heat exchanger (5) according to any one of the preceding claims, in which the duct (19) houses at least one mixing element (25) comprising a plurality of identical mixing elements (30) repeated over and over. '' an elongation axis (A10). 9. Refrigerant fluid circuit (1) comprising at least one heat exchanger (5) according to any one of the preceding claims. 10. Use of the heat exchanger (5) according to any one of claims 1 to 8 as an evaporator housed inside a housing (6) of an installation (7) for ventilation, heating and / or air conditioning fitted to a motor vehicle. 1/9