EP3548826B1 - Device for mixing a refrigerant fluid inside a collector box of a heat exchanger - Google Patents

Description

The field of the present invention is that of heat exchangers fitted to air conditioning installations for a vehicle, in particular an automobile. The invention relates more specifically to the methods of distributing a refrigerant fluid inside a header box that includes such a heat exchanger.

A vehicle is commonly equipped with an air conditioning installation for thermally treating the air present or sent into the passenger compartment of the vehicle. Such an installation comprises a closed circuit inside which a refrigerant fluid circulates. Successively depending on the direction of circulation of the refrigerant through it, the circuit essentially comprises a compressor, a condenser, an expansion valve and at least one heat exchanger.

The heat exchanger commonly comprises a bundle of tubes interposed between a header box and a coolant fluid return box. The refrigerant fluid is admitted through an inlet mouth inside a collector box, circulates along successive paths in the tubes of the bundle between the collector box and a return box, then is evacuated out of the exchanger heat through an outlet. The outlet mouth is likely to be formed through the collector box or through the return box.

The heat exchanger is for example an evaporator providing a heat exchange between the refrigerant fluid and an air flow passing through it. In this case, the refrigerant fluid circulates inside the tubes of the bundle and the air flow circulates along the tubes of the bundle for its cooling.

A problem posed lies in the fact that the refrigerant fluid is in the two-phase liquid/gaseous state when it is admitted inside the heat exchanger. Due to the difference in physical properties between liquid and gas, the refrigerant tends to separate into its liquid phase and its gas phase.

This results in heterogeneity in the supply of the tubes of the bundle with regard to the different phases of the refrigerant fluid, depending on their position relative to the inlet mouth of the refrigerant fluid inside the header box. More particularly, the tubes of the bundle located closest to the inlet mouth are mainly supplied with liquid and conversely the tubes of the bundle furthest from the inlet mouth are mainly supplied with gas.

This phenomenon generates heterogeneity in the temperature of the air flow which has passed through the heat exchanger in operation. This heterogeneity complicates the thermal management of the device which receives the heat exchanger and ultimately involves temperature differences between two areas of the passenger compartment, while the same air flow temperature is required.

It is known to house a conduit provided with a plurality of orifices inside a header box. The refrigerant in the liquid phase is thus projected through the orifices in the form of droplets over the entire length of the pipe, as appears from the document EP 2 392 886 A2 .

Such an organization is however not optimal from the point of view of the homogenization of the temperature of the air flow at the outlet of the heat exchanger.

The subject of the present invention is a device for mixing a refrigerant fluid configured to be housed inside a header box of a heat exchanger into which tubes of a bundle of tubes comprising the heat exchanger open. . The mixing device is in particular intended to mix a gaseous phase with a liquid phase of the refrigerant fluid distributed by the mixing device inside the header box. A mixing device according to the preamble of claim 1 is known from JP2002-22313 .

The invention also relates to a heat exchanger comprising a header box housing a mixing device according to the invention. The heat exchanger is in particular arranged to equip an air conditioning installation of a vehicle, in particular an automobile.

An object of the invention is to perfect the uniformity of the temperature of the heat exchanger in operation and finally to improve its efficiency. It is more specifically aimed by the invention to perfect a distribution in the header box of the coolant in a homogeneous manner between its liquid phase and its gaseous phase.

It is even more specifically targeted by the invention to provide a uniform supply of coolant to the tubes of the bundle opening out to the header box. It is in particular intended to propose a header box housing a mixing device capable of supplying refrigerant fluid to the tubes of the heat exchanger bundle, by providing efficient homogenization of the refrigerant fluid between its liquid phase and its gaseous phase, and a distribution homogeneous coolant fluid inside each of the tubes of the bundle.

Another object of the invention is to propose a mixing device which can be obtained industrially at lower cost.

Another object of the invention is to provide a mixing device whose organization allows it to be easily and inexpensively adapted to heat exchangers of various structures.

Such a diversity of structures of the heat exchangers is in particular to be assessed with regard to the number of tubes of the bundle that they comprise, the methods of circulation of the refrigerant fluid inside the heat exchanger and/or the relative positions between the mouth inlet and the outlet mouth of the coolant contained in the heat exchanger.

The mixing device of the invention comprises a conduit with a longitudinal axis provided with an inlet mouth for the admission of the refrigerant fluid into the conduit and with at least one orifice for the spraying of the refrigerant fluid out of the conduit. The duct comprises at least one mixing member arranged on an internal face of the duct and capable of modifying the flow of the refrigerant fluid circulating inside the duct.

In other words, the internal face of the conduit is configured as a mixing means comprising at least one mixing member capable of mixing the refrigerant fluid between a liquid phase and a gaseous face inside the conduit. The mixing member disturbs a laminar flow of the refrigerant fluid circulating inside the duct from the inlet mouth towards the orifice or orifices.

More particularly, the internal face of the duct comprises at least one mixing member which modifies the regularity of the extension of the internal face of the duct along a guideline, or more specifically along a generatrix, which is parallel to the longitudinal axis of the leads. The mixing member thus provides a relief on the internal face of the duct which projects towards the inside of the duct with respect to a direction of extension of the internal face of the duct parallel to its longitudinal axis. The extension of the projection of the relief towards the interior of the duct is liable to vary between two mixing members.

Thus, the mixing member generates disturbances in the flow of the refrigerant fluid inside the conduit, which promotes its mixing between a liquid phase and a gaseous phase inside the conduit. A mixture of the refrigerant fluid between a liquid phase and a gaseous phase is thus produced inside the conduit prior to its evacuation through the orifice or orifices. The coolant sprayed at the level of each of the orifices is thus formed of a more homogeneous liquid/gas mixture, and this for each of the orifices distributed over the length of the pipe.

The modalities providing a mixture of the refrigerant fluid between its liquid phase and its gaseous phase inside the conduit are thus advantageously dissociated from the modalities of spraying the refrigerant fluid out of the conduit further causing a mixture of the refrigerant fluid between its liquid phase and its phase. gas at the outlet of the mixing device.

The refrigerant fluid is thus mixed between its liquid phase and its gaseous phase by means of the mixing device in successive stages. A first mixing step is carried out inside the conduit by one or more mixing members and a second mixing step is carried out during the spraying of the refrigerant fluid out of the conduit through the orifice(s).

A heat exchanger equipped with a collector box housing the mixing device is thus obtained with particularly high performance, in particular by presenting a substantially balanced temperature over the whole of its heat exchange surface formed by the tubes of a bundle of tubes which it includes.

More particularly, the mixing member extends inside the duct at least transversely to its longitudinal axis and partially inside the recess of the duct delimited by its wall, forming an obstacle opposing a laminar flow of the refrigerant fluid inside the duct.

The transverse extension of the mixing member with respect to the duct is capable of being perpendicular or inclined with respect to the longitudinal axis of the duct. The obstacle formed by the mixing member is in particular configured in a relief extending partially towards the inside of the duct. The central zone of the duct is unoccupied by the relief and provides a passage for the refrigerant inside and along the duct.

The obstacle is capable of disturbing a laminar flow of the refrigerant fluid inside the duct and of forcing its passage through the orifice or orifices located downstream of the mixing member. The upstream and downstream concepts are relative concepts considered with regard to the intended direction of circulation of the refrigerant fluid inside the duct or in other words with regard to a path of circulation of the refrigerant fluid arranged inside the duct. from the inlet mouth to the orifice.

According to an advantageous embodiment, the mixing member is incorporated into the wall of the duct.

The mixing device can thus be obtained at moderate costs by incorporating the mixing member into the inner face of the duct. The mixing device is easily adaptable for conduits having different dimensions of extension along their longitudinal axis depending on the configuration of the heat exchanger, in particular with regard to the number of tubes of a bundle to be supplied with refrigerant fluid that the exchanger comprises and which lead to a header box housing the mixing device.

The incorporation of the mixing member into the wall of the duct can be carried out at lower cost using various techniques. For example, the mixing member is incorporated into the wall of the duct by brazing, by molding, by adding material, by deforming the wall of the duct or by machining the wall of the duct.

More particularly according to one embodiment, the mixing member is incorporated into the wall of the duct by brazing, the mixing member and the duct being at least in this case made of metallic material, in particular based on aluminium.

The brazing between the mixing device and the wall of the duct is in particular carried out during a brazing operation between them of the components that comprise a heat exchanger and comprising at least one header box housing the mixing device and preferably also tubes a bundle of tubes to be supplied with coolant by the mixing device.

The brazing between the mixing device and the wall of the duct can also be carried out prior to the installation of the mixing device inside the collector box. The mixing device then forms a unitary assembly that can be easily mounted and positioned inside the header box.

More particularly still according to one embodiment, the mixing member is incorporated into the wall of the molding duct or in other words during manufacture by molding of the duct. A molding operation can be carried out to form simultaneously in the same body the duct provided with the mixing member. The incorporation by molding of the mixing member into the duct can also be carried out in several steps, including a first step of molding the duct and a second step of overmolding the mixing member inside the duct.

More particularly still according to one embodiment, the mixing member is incorporated into the wall of the duct by machining the wall of the duct leaving at least one projecting relief oriented towards the inside of the duct, the relief then forming the mixing. More particularly still according to another embodiment, the mixing member is incorporated into the wall of the duct by deformation of the wall of the duct causing a discharge of material towards the inside of the duct which spares at least the relief then forming the mixing member.

According to the invention, the incorporation of the mixing member into the duct induces a variation in the thickness of its wall. More particularly, the thickness of the wall of the duct varies in planes perpendicular to the longitudinal axis of the duct and longitudinally distant. The thickness of the wall of the duct is in particular increased by at least one mixing member. The internal section of the duct is reduced by at least one mixing member.

The mixing member then modifies the conformation of the wall of the duct by varying its thickness longitudinally. In other words, a first thickness of the wall of the conduit measured in a first perpendicular plane crossing a relief formed by the mixing member is greater than a second thickness of the wall of the conduit measured in a second perpendicular plane considered at the longitudinal edge of the relief .

According to one embodiment, at least one mixing member extends perpendicular to the longitudinal axis of the duct.

According to another embodiment, at least one mixing member is inclined at least in a longitudinal extension plane and relative to the longitudinal axis of the duct, forming a guide ramp for the refrigerant fluid towards the orifice. The mixing member is in particular oriented according to the intended direction of circulation of the coolant fluid inside the duct to direct the coolant fluid towards the inner face of the duct delimiting its recess and more particularly towards the orifice or orifices.

For example, the mixing member may be of planar configuration, in particular being arranged in a ring. Such a ring can be oriented perpendicular to the longitudinal axis of the duct. The ring can also be inclined with respect to the longitudinal axis of the duct in a longitudinal extension plane parallel to the longitudinal axis of the duct and/or be oriented along a transverse plane inclined at an angle less than 90° by relative to the longitudinal extension plane.

The inclination of the mixing member may also involve its extension inside the duct along a curve defined by a combination between a perpendicular direction and a longitudinal direction with respect to the longitudinal axis of the duct, in particular a helical extension. For example, at least one mixing member is formed by at least one helical thread formed in the wall of the duct and wound around the longitudinal axis of the duct.

The orifice(s) can be oriented perpendicular to the longitudinal axis of the duct or be inclined towards one and/or the other of the longitudinal ends of the duct.

The cross-section of at least one orifice along a plane perpendicular to the longitudinal axis of the duct may for example be of circular, oblong and/or polygonal conformation such as triangular, hexagonal or cross-shaped for example. By way of indication, the section of the orifice(s) along a plane perpendicular to the longitudinal axis of the duct has a maximum surface area of between 2 mm ² and 5 mm ² .

Preferably, several orifices are distributed along the duct along its longitudinal axis. Various configurations of distributions of the orifices along the duct can be applied. For example, the orifices can be distributed by being aligned along several straight lines parallel to the longitudinal axis of the duct. For example again, the orifices can be staggered along the duct. For example again, the orifices can be distributed along a line configured as a helix wound around the duct.

According to a preferred embodiment aimed at simplifying the structure of the mixing device and/or enabling it to be obtained at moderate cost, the orifices are distributed along a straight line parallel to the longitudinal axis of the duct.

In addition, the inlet mouth is preferably made at a first longitudinal end of the duct. A second longitudinal end of the conduit is closed. The second longitudinal end is understood as being the longitudinal end of the duct axially located opposite its first longitudinal end provided with the inlet mouth.

The inlet mouth is in particular provided by an outlet from the recess of the duct towards the outside of the duct. In this case, the inlet is in particular connectable to a source of refrigerant fluid directly via the first end of the duct or via a hydraulic member interposed between the duct and the fluid source. The source of fluid is in particular formed by a circuit of refrigerant fluid comprising the heat exchanger.

The second end of the duct is for example closed by a plug, by an end fitting capping the second end of the duct and/or by a cap that can be integrated into the duct, in particular by brazing. The plug can also, for example, still be formed by a wall of the header box bearing against an end edge of the duct.

The characteristics relating to the orifice(s) presented below relate to a plane which extends parallel to the longitudinal axis of the duct and which passes through the duct(s). This plane is referred to below as the longitudinal plane passing through at least one orifice.

According to one embodiment and in a longitudinal plane passing through at least one orifice, several mixing members are distributed along the longitudinal axis of the duct. It is understood here that in this plane, the mixing members are separated from each other by a non-zero longitudinal distance along the longitudinal axis of the duct.

In this longitudinal plane passing through at least one orifice, at least one mixing device is arranged upstream of at least one orifice, in a flow direction of the coolant fluid inside the duct defined from the inlet mouth towards the orifice. The obstacle formed by the mixing member disturbs the flow of the refrigerant fluid and promotes its entrainment towards the orifice located downstream of the mixing member.

According to one feature and in a longitudinal plane passing through at least one orifice, at least one mixing member is interposed between at least two orifices distributed along the longitudinal axis of the duct.

Thus, the mixture between a liquid phase and a gaseous phase of the coolant can be obtained homogeneous between the fractions of coolant flowing through each of the orifices. To this end, the relative positions between the orifices and the mixing devices along the duct are adapted taking into account in particular the speed of the refrigerant fluid inside the duct and/or the variation in the state of the mixture of the refrigerant flowing along the pipe.

According to one embodiment, in a longitudinal plane passing through at least one orifice, the mixing devices are arranged at a first separation distance between two adjacent mixing devices which is equal to a second separation distance between two adjacent orifices. According to an exemplary embodiment, at least one orifice is equidistant from two mixing members.

According to another embodiment, in a longitudinal plane passing through at least one orifice, the mixing devices are arranged at a first separation distance between two adjacent mixing devices which is greater than a second separation distance between two adjacent orifices.

According to one embodiment, in a longitudinal plane passing through at least one orifice, at least one mixing member is interposed between two groups of orifices each comprising as an indication a number of orifices comprised between one and four.

According to one embodiment, the mixing member is shaped like a ring, the opening of which provides through it a passage for the refrigerant fluid.

The periphery of the ring marries in particular the internal face of the wall of the duct or in other words is in contact with the internal face of the duct along its circumference. The ring is preferably centered on the longitudinal axis of the duct. Such a ring can advantageously be secured by brazing to the conduit or, for example, be formed by deformation of the wall of the conduit causing a discharge of material constituting the ring.

As an indication, the dimension of the opening of the ring is between 10% and 70% of the largest dimension of the recess of the duct measured in a plane perpendicular to the longitudinal axis of the duct.

According to one embodiment, the openings of at least two successive rings along the longitudinal axis of the duct have identical sections in the plane of the rings.

According to one embodiment, the openings of at least two successive rings along the longitudinal axis of the duct have different sections in the plane of the rings.

Preferably, the sections of the openings of the rings vary according to their position along the longitudinal axis of the duct. The variations of the sections of the openings of the rings can be regular or irregular, in particular depending on the successive positions of the rings, along the longitudinal axis of the duct.

More particularly according to one embodiment, the openings of the rings are progressively narrowed along the longitudinal axis of the duct from the first longitudinal end towards the second longitudinal end of the duct or in other words according to the direction of circulation of the refrigerant fluid from the entrance mouth to the orifices.

According to one embodiment, at least one mixing member is shaped as at least one helix portion wound around the longitudinal axis of the duct. It will be noted that at least one mixing member is capable of being shaped like a ring and at least one mixing member is capable of being shaped like at least one portion of a helix.

According to one embodiment, several mixing members are shaped as helices of the same pitch angularly distributed around the longitudinal axis of the duct. More particularly, each of the helices is wound around the longitudinal axis of the duct, extending along the duct in its part comprising the orifice or orifices.

According to one embodiment, at least one orifice passes through at least one mixing member. Such a provision is particularly applicable in the case where the duct includes mixing members shaped as helices, at least one orifice being able to pass through the projecting relief formed by a helix and at least one orifice being able to pass through the wall of the duct between two helices. Such an arrangement is also applicable in the case where the duct comprises mixing members shaped as rings, at least one orifice which can pass through a ring and at least one orifice which can pass through the wall of the duct between two rings.

Thus, transversely to the longitudinal axis of the duct, a length of the orifices measured between these outlets is liable to vary, depending on its position along the longitudinal axis of the duct. At least one orifice is capable of extending through the wall of the duct by crossing a mixing member and at least one orifice is capable of extending through the wall of the duct in a zone of the duct devoid of a mixing member .

The mixing of the refrigerant fluid between a gaseous phase and a liquid phase can thus be controlled by varying the length of the orifices, along the duct. Depending on whether or not the orifices pass through a mixing device, the mixture of the refrigerant fluid evacuated through each of the orifices can be adjusted to provide a distribution of the refrigerant fluid outside the mixing device which is globally homogeneous along the longitudinal axis of the leads.

More particularly, the mixing of the refrigerant fluid between its gaseous phase and its liquid phase inside the duct can be controlled according to the relative positions of the orifices with respect to the mixing members. It can in particular be taken into account a proximity between the obstacles formed by the mixing members and the outlet of at least a part of the orifices inside the duct, and/or the crossing character or not of at least one member. mixing by at least one orifice.

The invention also relates to a heat exchanger equipped with a mixing device according to the invention.

More particularly, a heat exchanger of the invention comprises a header box providing a chamber housing a mixing device according to the invention. The heat exchanger also comprises tubes of a bundle of tubes opening into the chamber for their supply with refrigerant fluid by the mixing device.

The mixing device is in particular incorporated into a wall of the header box by brazing. The positioning of the mixing device inside the header box can advantageously be achieved via at least one angular and/or axial positioning device interposed between the mixing device and a wall of the header box. One or more such positioning devices are preferably provided at at least one of the longitudinal ends of the conduit along its longitudinal axis. Brazing between the mixing device and a wall of the header box can be performed via at least one such positioning device.

According to one embodiment, a space for the circulation of the refrigerant fluid is provided inside the chamber at least partly around the mixing device towards outlets of the tubes of the bundle on the chamber.

Thus, an additional step of mixing the coolant between its liquid phase and its gaseous phase can be carried out inside the chamber prior to its admission inside the tubes of the bundle.

According to one embodiment, the orifices and outlets of the tubes of the bundle on the chamber are angularly offset from each other around the longitudinal axis of the duct. The circulation path of the coolant fluid inside the collector box can thus be adjusted according to the mixture of the coolant fluid to be obtained inside the chamber. Such adjustment is in particular provided via one or more angular and/or axial positioning devices interposed between the mixing device and a wall of the header box.

For example, the orifices and the outlets of the tubes of the bundle on the chamber are arranged diametrically opposite each other with respect to the longitudinal axis of the duct, to optimize the circulation path of the refrigerant inside the chamber. bedroom.

Preferably, the outlets of the tubes of the bundle on the chamber are provided through a wall of the header box delimiting the chamber.

More particularly according to an advantageous embodiment, the tubes of the bundle are provided between plates incorporating the header box while being stacked along the longitudinal axis of the duct. The plates include eyelets which delimit the chamber and which are extended by extensions of the plates providing the tubes of the bundle between them. The eyelets are crossed by the mixing device. The mixing device can be placed in contact with the eyelets at at least one of its ends.

The heat exchanger is more particularly configured to be used as an evaporator.

The heat exchanger can be used to cool a flow of air passing through it or to cool a liquid dedicated to cooling a component, such as at least one battery of a vehicle supplying the energy necessary at least in part to its propulsion.

Another subject of the invention is a refrigerant fluid circuit comprising at least one compressor, a condenser, an expansion device and a heat exchanger in accordance with the invention, through which a refrigerant fluid passes.

The invention also relates to a ventilation, heating and/or air conditioning installation, or air conditioning installation, configured to equip a vehicle. The air conditioning installation of the invention comprises at least one heat exchanger in accordance with the invention.

• la figure 1 est une illustration schématique d'un circuit de fluide réfrigérant participant d'une installation de conditionnement d'air d'un véhicule.
• la figure 2 est une illustration schématique d'un échangeur thermique que comporte le circuit schématisé sur la figure 1.

• la figure 3 est une illustration en perspective d'un dispositif de mixage conforme à l'invention.
• les figures 4 et 5 sont des illustrations partielles d'un dispositif de mixage selon un exemple de réalisation de l'invention, représenté en perspective sur la figure 4 et en coupe longitudinale sur la figure 5.
• les figures 6 et 7 sont des illustrations partielles d'un dispositif de mixage selon un autre exemple de réalisation de l'invention, représenté en perspective sur la figure 6 et en coupe longitudinale sur la figure 7.
• les figures 8 et 9 sont des illustrations partielles d'un dispositif de mixage selon un autre exemple de réalisation de l'invention, représenté en perspective sur la figure 8 et en coupe longitudinale sur la figure 9.
• la figure 10 est une illustration partielle en coupe longitudinale d'un exemple de réalisation d'un échangeur thermique équipé d'un dispositif de mixage du type de celui représenté sur les figures 6 et 7.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the detailed description given below by way of indication and as an example in relation to the drawings of the appended plates, in which:

• there figure 1 is a schematic illustration of a refrigerant circuit participating in an air conditioning installation of a vehicle.
• there figure 2 is a schematic illustration of a heat exchanger that includes the circuit schematized on the figure 1 .

• there picture 3 is a perspective illustration of a mixing device according to the invention.
• THE figures 4 and 5 are partial illustrations of a mixing device according to an exemplary embodiment of the invention, represented in perspective on the figure 4 and in longitudinal section on the figure 5 .
• THE figures 6 and 7 are partial illustrations of a mixing device according to another exemplary embodiment of the invention, represented in perspective on the figure 6 and in longitudinal section on the figure 7 .
• THE figures 8 and 9 are partial illustrations of a mixing device according to another exemplary embodiment of the invention, represented in perspective on the figure 8 and in longitudinal section on the figure 9 .
• there figure 10 is a partial illustration in longitudinal section of an embodiment of a heat exchanger equipped with a mixing device of the type shown in the figures 6 and 7 .

The figures and their description expose the invention in detail and according to particular methods of its implementation. They can of course be used to better define the invention.

On the figure 1 , an air conditioning installation for a vehicle, in particular a motor vehicle, comprises a closed circuit 1 inside which a refrigerant fluid FR circulates. In the illustrated embodiment, circuit 1 essentially comprises, successively in the direction S1 of circulation of the refrigerant fluid FR, a compressor 2, a condenser 3 or gas cooler, an expansion device 4 and at least one heat exchanger 5 .

The example given of a minimum architecture of circuit 1 is given for information only and is not restrictive as to the scope of the invention with regard to various potential architectures of circuit 1.

The heat exchanger 5 is for example dedicated to cooling an air flow FA passing through it, as illustrated in the figure 2 . Such an air flow FA is used in particular for thermally treating the air in the passenger compartment of the vehicle or, for example, to cool a component of the vehicle in operation. For example again, the heat exchanger 5 is dedicated to cooling a liquid used to cool a component of the vehicle in operation, such as one or more batteries supplying electrical energy to a propulsion electric motorization of the vehicle.

On the figure 1 and the figure 2 , the heat exchanger 5 comprises a bundle 6 interposed between a header box 7 and a return box 8. The header box 7 extends in a longitudinal direction D1 oriented perpendicular to a direction D3 of extension of the tubes 12 of the bundle 6 between the header box 7 and the return box 8. The header box 7 delimits a chamber 9 supplied with refrigerant fluid FR through an inlet 10. The refrigerant fluid FR circulates inside the heat exchanger 5 to cool at least the tubes 12 of the bundle 6 and the air FA passing through it, then is evacuated from the heat exchanger 5 through an outlet mouth 11.

In the example illustrated, the outlet mouth 11 is provided through the collector box 7, which implies that the heat exchanger 5 is a “U” circulation heat exchanger. According to a variant, the outlet mouth 11 can be provided through the return box 8, which then implies that the heat exchanger 5 is an “I” circulation heat exchanger.

On the picture 2 , the heat exchanger 5 is of the type with U-shaped circulation of the refrigerant fluid FR. In the example illustrated, the heat exchanger 5 is intended for cooling an air flow FA. The tubes 12 of the bundle 6 include fins 13 favoring the heat exchange between the air flow FA and the tubes 12 of the bundle 6. The air flow FA crosses the bundle 6 transversely to the general plane P1 of the heat exchanger 5, flowing along the tubes 12.

The refrigerant fluid FR circulates from the header box 7 to a first layer 12a of tubes 12 of the bundle 6 dedicated to supplying the return box 8 with refrigerant fluid FR. Then the refrigerant fluid FR circulates from the return box 8 to the collector box 7 through a second layer 12b of tubes 12 of the bundle 6. The first layer 12a and the second layer 12b are superimposed according to the direction of circulation of the flow of air FA through the heat exchanger 5.

Such a configuration of the heat exchanger 5 makes it particularly useful to obtain a homogeneous distribution of the refrigerant fluid FR between its liquid phase and its gaseous phase and a homogeneous distribution of the refrigerant fluid FR along the collector box 7 towards each of the tubes 12 of the first layer 12a of bundle 6.

The example described of the architecture of the heat exchanger 5 and of the methods of circulation of the refrigerant fluid FR between the header box 7 and the return box 8, are given for information only and are not restrictive as to the scope of the invention.

On the figure 1 and the figure 2 , the chamber 9 houses a mixing device 18 extending along a longitudinal direction D2 parallel to the longitudinal direction D1 of extension of the header box 7. The mixing device 18 comprises a duct 14 extending along a longitudinal axis A1 between a first end 15 and a second end 16 of the mixing device 18. The conduit 14 is intended in particular to provide homogenization of the refrigerant fluid FR between its liquid phase and its gaseous phase during its evacuation from the conduit 14.

The longitudinal axis A1 of the duct 14 is oriented parallel to the direction D1 of extension of the manifold 7 and defines the longitudinal direction D2 of extension of the mixing device 18. The mixing device 18 is potentially centered inside of the collector box 7 as shown in the figure 1 . Alternatively, the mixing device 18 may be offset inside the collector box 7 with respect to a median longitudinal axis A2 of extension of the collector box 7.

The mixing device 18 includes an inlet 10 for supplying it with refrigerant fluid FR. On the example illustrated in the figure 1 and the picture 2 , the inlet 10 is formed at a first longitudinal end of the duct 14. The inlet 10 is capable of receiving the refrigerant fluid FR from outside the mixing device 18 either directly or via a junction member of the heat exchanger 5 with the fluidic circuit 1 illustrated in the figure 1 . The second end of conduit 14 is closed.

At least one orifice 17 is provided through the duct 14 for the evacuation of the refrigerant fluid FR from the duct 14 to the chamber 9. The duct 14 preferably comprises a plurality of orifices 17 provided over at least a part of its length. to promote the homogenization of the refrigerant FR evacuated along the pipe 14 between its liquid phase and its gaseous phase.

Also referring to the figure 1 and at the figure 2 , the mixing device 18 illustrated for example on the figures 3 to 9 is arranged to be housed inside a chamber 9 of a header box 7 that includes a heat exchanger 5, as illustrated for example in the figure 10 . The mixing devices 18 comprise the duct 14 provided with orifices 17 which are made through the wall 14a of the duct 14 while being aligned along a straight line L1 oriented parallel to the longitudinal axis A1 of the duct 14.

As shown on the picture 3 , the duct 14 has the inlet 10 at its first longitudinal end 15 and is closed at its second longitudinal end 16. The duct 14 is for example closed by an end piece 16a which is brazed to the duct 14 at its second longitudinal end 16. The duct 14 can optionally also be equipped with a device 15a for angular and/or axial positioning of the duct inside the collector box 7. On the figure 4 And 6 , the duct 14 is for example still closed by a cover 16b which is formed and/or brazed on the duct 14 at its second longitudinal end 16. The orifices 17 extend along a straight line L1, advantageously parallel with the longitudinal axis of the duct 14.

On the figures 4 to 10 , the duct 14 houses a mixing means 19 arranged inside its recess 14b, the latter being delimited by the wall 14a of the duct 14. The mixing means 19 comprises several mixing members 19a or 19b which are integrated into the internal face 14c of conduit 14.

On the figures 4 to 7 for example, the mixing devices 19a are integrated by soldering to the internal face 14c of the wall 14a. On the figures 8 and 9 for example, the mixing elements 19b are integrated into the inner face 14c of the wall 14a by machining the duct 14 or by forming the mixing elements 19b during molding of the duct 14. Thus, the conduit 14 and the mixing devices 19a or 19b form a unitary assembly or in other words a one-piece assembly forming the mixing device 18.

The mixing devices 19a or 19b extend partially inside the duct 14 at least along a direction DT transverse to its longitudinal axis A1. The dimension DT1 of the transverse extension of the mixing members 19a or 19b towards the inside of the conduit 14, or in other words perpendicularly in the direction of its longitudinal axis A1, is included for information only between 30% and 90% of the largest transverse dimension DT2 of the recess 14b of the conduit 14.

In a longitudinal plane PL, the mixing members 19a or 19b form obstacles opposing a laminar flow of the refrigerant fluid FR inside the conduit 14. The obstacles are provided at least in part upstream of an orifice 17 along the direction S1 of circulation of the refrigerant fluid FR inside the conduit 14 from the inlet mouth 10 to the orifices 17.

The mixing members 19a or 19b thus disturb the laminar flow of the refrigerant fluid FR which promotes its mixing between a gaseous phase and a liquid phase inside the pipe 14. In addition, the flow of the refrigerant fluid FR is broken. against the obstacles formed by the mixing members 19a or 19b, with the effect of favoring the forced passage of the refrigerant fluid FR towards the orifices 17 and thus of again improving its mixing between its gaseous phase and its liquid phase during its spraying through the holes 17.

A central zone Za of conduit 14 is delimited locally along the longitudinal axis A1 of conduit 14 by mixing devices 19a or 19b, extending perpendicularly between the longitudinal axis A1 of conduit 14 and mixing devices 19a or 19b . A passage for the refrigerant fluid FR is thus made along the conduit 14 from its first longitudinal end 15 which is provided with the inlet mouth 10 towards its second longitudinal end 16 which is closed.

The refrigerant fluid FR is evacuated from the pipe 14 by fractions of liquid refrigerant FR, the quantities of which are dependent on the disturbances generated by the mixing devices 19a or 19b opposing the flow of the refrigerant fluid FR towards the second longitudinal end 16 of the conduit 14.

It is noteworthy that the thickness of the wall 14a of the conduit 14 varies along the conduit 14 due to the integration in its wall 14a of the mixing devices 19a or 19b. More particularly in a longitudinal plane PL, the thickness Ep1 of the duct in its zones free of mixing members 19a or 19b is less than its thickness Ep2 in the zones of the duct 14 comprising the mixing members 19a or 19b. In other words, and as visible on the figure 4 , the thickness Ep1, Ep2 of the wall 14a of the duct 14 varies in perpendicular planes PP spaced apart from each other along the longitudinal axis A1 of the duct 14, depending on the presence or not of the mixing devices 19a or 19b in the perpendicular planes PP considered.

More particularly on the figures 4 to 7 , the mixing devices 19a are formed by rings 20a which are oriented in their plane perpendicular to the longitudinal axis A1 of the duct 14. Alternatively, the rings 20a can also be inclined in the longitudinal plane PL relative to the longitudinal axis A1 of conduit 14 to form ramps forcing the refrigerant fluid FR to move towards the internal face 14c of the wall 14a of conduit 14 and more particularly towards the orifices 17.

The opening 21 of the rings 20a delimits the central zone Za of the conduit 14 forming a passage allowing the refrigerant fluid FR to flow towards the second longitudinal end 16 of the conduit 14.

The rings 20a are distributed along the duct 14, being arranged at a first distance Lg1 from each other along the longitudinal axis A1 of the duct 14. In the examples shown, the rings 20a are arranged at equidistance Lg1 from each other and each ring 20a is interposed between two orifices 17. The orifices 17 are aligned along the straight line L1 being separated from each other by a second distance Lg2 equal to the first separation distance Lg1 of the rings 20a from each other .

On the figures 4 and 5 , the openings 21 of the rings 20a are of identical sections in the plane of the rings 20a or in other words in a plane PP perpendicular to the axis longitudinal A1 of conduit 14.

On the figures 6 and 7 , the openings 21 of the rings 20a are of different sections in the plane of the rings 20a. More particularly, the sections of the openings 21 of the rings 20a vary along the longitudinal axis A1 of the duct 14, gradually decreasing from the first longitudinal end 15 of the duct 14 towards its second longitudinal end 16 of the duct 14 in its part comprising the rings 20a .

In the example illustrated, the variation of the section of the openings 21 rings 20a is regular. In the plane of the rings 20a, the variation of the section of the openings 21 of the rings 20a is defined by a cone C1 which delimits the openings 21 of each of the rings 20a and whose apex is oriented towards the second longitudinal end 16 of the conduit 14. The angle B1 of the cone C1 can be adapted according to the length dimension of the duct 14, at least in its part comprising the orifices 17 and/or the mixing members 19a. As an indication, the angle B1 of the cone C1 is between 3° and 6° for a length of the part of the duct 14 comprising the orifices 17 of between 200 mm and 300 mm and/or for a number of orifices 17 included between 15 and 30.

On the figures 8 and 9 , the mixing members 19b are inclined at least in a longitudinal plane PL extending along the longitudinal axis A1 of the duct 14. More particularly, the mixing members 19b are formed by threads 20b arranged in helices of the same pitch wound around of the longitudinal axis A1 of the duct 14. The threads 20b extend along the duct 14 along a helical curve defined by a combination between a perpendicular direction and a longitudinal direction with respect to the longitudinal axis A1 of the duct 14. In a plane PP perpendicular to the longitudinal axis A1 of the conduit 14, the threads 20b are angularly distributed around the longitudinal axis A1 of the conduit 14.

The mixing devices 19b thus each form a ramp 19c for guiding the refrigerant fluid FR towards the internal face 14c of the conduit 14. The ramps 19c progressively direct the refrigerant fluid FR towards at least part of the orifices 17 from the central zone Za of the conduit 14.

More specifically, in a plane PP perpendicular to the longitudinal axis A1 of the conduit 14, the ramps 19c progressively direct the refrigerant fluid FR towards each of the orifices 17a located immediately downstream of the mixing devices 20b in the direction S1 of circulation of the refrigerant fluid FR inside the duct 14 from the inlet mouth 10 to the orifices 17.

According to the embodiment illustrated in the figure 9 and in the longitudinal plane PL passing through the orifices 17, the threads 20b are arranged at a first distance Lg1 from each other and the orifices 17 are arranged at a second distance Lg2 from each other along the longitudinal axis A1 of the conduit 14. More particularly in a longitudinal plane PL passing through the orifices 17 and along the longitudinal axis A1 of the duct 14, the threads 20b are arranged equidistant from each other and the orifices 17 are arranged equidistant from each other.

The second distance Lg2 is of the order of half the first distance Lg1 and each thread 20b is interposed between two first orifices 17a separated from each other by a second orifice 17b passing through a thread 20b. In other words, in a longitudinal plane PL passing through the orifices 17 and along the longitudinal axis A1 of the duct 14, the threads 20b are equidistant from the first orifices 17a located immediately downstream of the threads 20b, and the threads 20b are crossed by second orifices 17b interposed equidistant between two successive first orifices 17a.

The orifices 17 thus have transverse extensions Ep1, Ep2 which are different between two successive orifices 17a, 17b along the longitudinal axis A1 of the duct 14. Orifices 17b extend through the wall 14a of the duct 14 crossing a mixing 19b, and have a transverse extension Ep2 greater than that Ep1 of other orifices 17a which pass through a zone of the wall 14a of conduit 14 which is free of mixing member 19b.

On the figure 10 , a heat exchanger 5 is equipped with a mixing device 18 housed inside a header box 7 that includes the heat exchanger 5. The mixing device 18 is installed inside a chamber 9 delimited by a wall 7a of the header box 7 to supply refrigerant fluid FR to the tubes 12 of a bundle 6 of tubes 12 which open into the chamber 9 while being aligned in the longitudinal direction D2 of extension of the mixing device 18.

According to the illustrated embodiment, the chamber 9 is delimited by eyelets 23 successively abutting and fixed to each other, in particular by brazing, in the longitudinal direction D2 of extension of the dispensing device 18. The eyelets thus form the wall 7a of the collector box delimiting the chamber 9. The eyelets 23 comprise collars 25 which are crossed by the distribution device 18 at a transverse distance relative to the longitudinal axis A1 of the conduit 14.

The eyelets 23 are made at the end of plates 26 forming between them the tubes 12 of the bundle 6. The outlets 24 of the tubes 12 of the bundle 6 are thus formed by openings made through the wall 7a of the header box 7 delimiting the chamber 9, the outlets 24 of the tubes 12 of the bundle 6 being more specifically provided through the eyelets 23. The outlets 24 of the tubes 12 of the bundle 6 are configured as a funnel to increase the velocity of the refrigerant fluid FR evacuated from the chamber 9 towards tubes 12 of bundle 6.

A space E1 for circulation of the refrigerant fluid FR around the first conduit 14 is thus formed inside the chamber 9 between the wall 7a of the manifold and the mixing device 18. The orifices 17 are oriented diametrically opposite outlets 24 of the tubes 12 of the bundle 6 with respect to the first longitudinal axis A1 of the first duct 14. The refrigerant fluid FR sprayed by the mixing device 18 is admitted inside the chamber 9, then circulates inside the space E1 around the conduit 14 to the outlets 24 of the tubes 12 of the bundle 6 for their supply with refrigerant fluid FR.

The foregoing description clearly explains how the invention makes it possible to achieve the objectives it has set itself and in particular to propose a mixing device which homogenizes the distribution of the refrigerant fluid along the collector box to guarantee an admission quasi- identical refrigerant fluid in each tube of the bundle that includes the heat exchanger. Furthermore, the structural organization of the mixing device gives it easy adaptability that can be achieved at lower cost according to the layout of a specific heat exchanger, in particular with regard to the number of tubes of the bundle that it comprises.

Of course, various modifications can be made by those skilled in the art to the mixing device according to the invention, in particular as regards the methods of integration of the mixing device in the header box. The mixing device which has just been described by way of non-limiting example and its use will be formed when the mixing device comprises a conduit whose internal face is configured as a means for mixing the refrigerant fluid between a liquid phase and a gaseous phase, the mixing means comprising at least one mixing member arranged on the internal face of the duct.

Claims (15)

1. Mixing device (18) designed for mixing a gaseous phase with a liquid phase of a refrigerant fluid (FR) and configured to be accommodated inside a header tank (7) of a heat exchanger (5), the mixing device (18) comprising a pipe (14) of longitudinal axis (A1) provided with an inlet mouth (10) for admitting the refrigerant fluid (FR) into the pipe (14) and at least one aperture (17) for spraying the refrigerant fluid (FR) out of the pipe (14), which pipe (14) comprises at least one mixing means (19) that comprises a plurality of mixing members (19a, 19b) that are integrated with the internal face (14c) of the pipe (14) and capable of modifying the flow of the refrigerant fluid (FR) circulating inside the pipe (14), wherein the thickness (Ep1, Ep2) of the wall (14a) of the pipe (14) varies in planes (PP) perpendicular to the longitudinal axis (A1) of the pipe (14) and longitudinally distant from one another, the thickness (Ep2) of the wall (14a) of the pipe (14) being increased by at least one of said mixing members (19a, 19b), characterized in that said mixing means (19) is disposed inside a hollow (14b), said hollow (14b) being delimited by a wall (14a) of said pipe (14).
2. Mixing device (18) according to Claim 1, wherein the mixing member (19a, 19b) extends inside the pipe (14) at least transversely to the longitudinal axis (A1) thereof and partially inside the hollow (14b) of the pipe (14) delimited by the wall (14a) thereof, forming an obstacle opposing a laminar flow of the refrigerant fluid (FR) inside the pipe (14).
3. Mixing device (18) according to either one of the preceding claims, wherein the mixing member (19a, 19b) is incorporated into the wall (14a) of the pipe (14).
4. Mixing device (18) according to any one of the preceding claims, wherein at least one mixing member (19a, 19b) extends perpendicular to the longitudinal axis (A1) of the pipe (14).
5. Mixing device (18) according to any one of the preceding claims, wherein at least one mixing member (19a, 19b) is inclined at least in a longitudinal plane (PL) relative to the longitudinal axis (A1) of the pipe (14), forming a ramp (19c) for guiding the refrigerant fluid (FR) towards the aperture (17).
6. Mixing device (18) according to any one of the preceding claims, wherein a plurality of apertures (17) are distributed along the pipe (14) along the longitudinal axis (A1) thereof.
7. Mixing device (18) according to Claim 6, wherein the apertures (17) are distributed along a straight line (L1) parallel to the longitudinal axis (A1) of the pipe (14).
8. Mixing device (18) according to any one of the preceding claims, wherein, in a longitudinal plane (PL) passing through at least one aperture (17), at least one mixing member (19a, 19b) is disposed upstream of at least one aperture (17) in a direction (S1) of flow of the refrigerant fluid (FR) inside the pipe defined from the inlet mouth (10) towards the aperture (17).
9. Mixing device (18) according to any one of the preceding claims, wherein, in a longitudinal plane (PL) passing through at least one aperture (17), at least one mixing member (19a, 19b) is interposed between at least two apertures along the longitudinal axis of the pipe.
10. Mixing device (18) according to any one of the preceding claims, wherein, in a longitudinal plane (PL) passing through at least one aperture (17), a plurality of mixing members (19a, 19b) are distributed along the longitudinal axis (A1) of the pipe (14).
11. Mixing device (18) according to Claim 10, wherein, in a longitudinal plane (PL) passing through at least one aperture (17), the mixing members (19a, 19b) are disposed at a first distance (Lg1) of separation between two adjacent mixing members (19a, 19b) that is equal to a second distance (Lg2) of separation between two adjacent apertures (17).
12. Mixing device (18) according to either one of Claims 10 and 11, wherein, in a longitudinal plane (PL) passing through at least one aperture (17), the mixing members (19a, 19b) are disposed at a first distance (Lg1) of separation between two adjacent mixing members (19a, 19b) that is greater than a second distance (Lg2) of separation between two adjacent apertures (17).
13. Mixing device (18) according to any one of the preceding claims, wherein the mixing member (19a) is shaped into a ring (20a), the opening (21) of which provides therethrough a passage for the refrigerant fluid (FR) .
14. Mixing device (18) according to Claim 13, wherein the dimension of the opening (21) of the ring (20a) is between 10% and 70% of the greatest dimension (DT2) of the hollow (14b) of the pipe (14), which dimensions are measured in a plane (PP) perpendicular to the longitudinal axis (A1) of the pipe (14).
15. Heat exchanger (5) comprising a header tank (7) providing a chamber (9) accommodating a mixing device (18) according to any one of Claims 1 to 14, and comprising tubes (12) of a bundle (6) of tubes (12) that open out onto the chamber (9) so as to be supplied with refrigerant fluid (FR) by the mixing device (18).

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