HEAT EXCHANGER WITH IMPROVED LIQUID/GAS MIXING DEVICE

Abstract

The invention concerns a heat exchanger comprising several plates arranged parallel to one another and to a longitudinal direction so as to define a first series of passages for channeling at least one first fluid and a second series of passages for channeling at least one second fluid which is to be brought into a heat-exchange relationship with at least said first fluid, a mixer device being arranged in said at least one passage of the first series and comprising at least one first channel for the flow of a first phase of the fluid in the longitudinal direction, at least one second channel for the flow of a second phase of the fluid, and a plurality of orifices fluidically connecting the first channel to the second channel, said orifices occupying successive positions in the longitudinal direction. According to the invention, the distances between two successive positions, measured parallel to the longitudinal direction, are variable.

Claims

1-16. (canceled)

17. A heat exchanger comprising several plates arranged parallel to one another and to a longitudinal direction so as to define a plurality of passages for channeling at least a first fluid which is to be brought into a heat-exchange relationship with at least a second fluid, a mixer device being arranged in at least one passage and comprising: at least one first channel for the flow of a first phase of the first fluid parallel to the longitudinal direction; at least one second channel for the flow of a second phase of the first fluid; and a plurality of orifices fluidically connecting the first channel to the second channel, said orifices occupying successive positions in the longitudinal direction, wherein the distances between the successive positions, measured parallel to the longitudinal direction, are variable.

18. The exchanger as claimed in claim 17, wherein the distances between the successive positions vary monotonically or near-monotonically in the longitudinal direction.

19. The exchanger as claimed in claim 17, wherein the exchanger exhibits, in the longitudinal direction, an increase in the distances between two successive positions.

20. The exchanger as claimed in claim 17, wherein the exchanger exhibits, in the longitudinal direction, a decrease in the distances between two successive positions.

21. The exchanger as claimed in claim 17, wherein the exchanger is divided, in the longitudinal direction, into at least a first portion and a second portion, the first portion exhibiting, in the longitudinal direction, an increase in the distances between two successive positions, and the second portion exhibiting, in the longitudinal direction, a decrease in the distances between two successive positions.

22. The exchanger as claimed in claim 17, wherein the mixer device is configured for a separate introduction of the first phase and of the second phase into the at least one first channel and into the at least one second channel, respectively, the first channel comprising a first inlet designed to supply said first channel with the first phase of the first fluid and a second inlet, separate from the first inlet, designed to supply said at least one second channel with the second phase of the first fluid.

23. The exchanger as claimed in claim 17, wherein the first channel and the second channel are rectilinear in shape.

24. The exchanger as claimed in claim 17, wherein the the mixer device comprises several first channels and several second channels, each first channel comprising at least one orifice fluidically connecting said first channel to a given second channel.

25. The exchanger as claimed in claim 17, wherein the mixer device comprises several first channels succeeding one another in a lateral direction orthogonal to the longitudinal direction.

26. The exchanger as claimed in claim 17, wherein the second channel extends in a lateral direction orthogonal to the longitudinal direction.

27. A method for distributing a two-phase liquid/gas mixture in an exchanger as claimed in claim 17, said method comprising the following steps: i) arranging a mixer device in at least one passage of the exchanger; ii) supplying said first channel of the mixer device with the first phase of the first fluid; iii) supplying said second channel of the mixer device with the second phase of the first fluid, which is distinct from the first phase; iv) establishing fluidic communication between the first channel and the second channel via the orifices so that a mixing between the first phase and the second phase takes place within the mixer device; and v) distributing a mixture of the first phase and of the second phase at the outlet of the mixer device.

28. A method for adjusting the position of the orifices of a mixer device incorporated into an exchanger as claimed in claim 17, said method comprising the following steps: a) positioning the orifices in such a way that their successive positions are separated by predetermined distances; b) supplying the first channel with the first phase of the fluid such that the first phase of the first fluid flows in the longitudinal direction; c) determining the mass flow rates of the first phase flowing through each orifice; and d) for each orifice, repositioning the next orifice so that it is separated from the orifice by a modified distance equal to the mean of the predetermined distances multiplied by a correction factor, said correction factor being determined on the basis of the mass flow rate flowing through the orifice.

29. The method as claimed in claim 28, wherein the correction factor is a function of the ratio between the mass flow rate flowing through the orifice and the mass flow rate averaged over all the orifices.

30. The method as claimed in claim 29, said function is a polynomial function of the ratio, preferably an affine function of the ratio.

31. The method as claimed in claim 28, further comprising a step e) of defining the distances modified in step d) as predetermined distances, steps c) to d) being reiterated at least once.

32. The method as claimed in claim 31 wherein steps c) to d) are repeated between 1 and 5 times.

33. The method as claimed in claim 31 wherein steps c) to d) are repeated at most twice.

34. The method as claimed in claim 28, wherein the mixer device comprises several first channels, the method comprising, prior to step a), at least one step of selecting a subset of orifices which are arranged in one and the same first channel, steps a) to e) being applied to said sub set.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Further features, advantages and possible applications of the invention are apparent from the following description of working and numerical examples and from the drawings. All described and/or depicted features on their own or in any desired combination form the subject matter of the invention, irrespective of the way in which they are combined in the claims or the way in which said claims refer back to one another.

[0052] The present invention will now be better understood by virtue of the following description, given solely by way of nonlimiting example and made with reference to the attached drawings, among which:

[0053] FIG. 1 is a schematic view, in a plane of section parallel to the plates of a heat exchanger, of part of a passage of an exchanger supplied with a two-phase liquid-gas mixture, according to one embodiment of the invention;

[0054] FIG. 2 is a schematic view in cross section, in a plane perpendicular to that of FIG. 1, of the mixer device of FIG. 1;

[0055] FIG. 3 is a three-dimensional schematic view illustrating a mixer device according to various embodiments of the invention;

[0056] FIG. 4 is a three-dimensional schematic view illustrating a mixer device according to various embodiments of the invention;

[0057] FIG. 5 presents results of simulations carried out with a mixer device according to the invention and with a mixer device outside of the invention;

[0058] FIG. 6 presents results of simulations carried out with a mixer device according to the invention and with a mixer device outside of the invention;

[0059] FIG. 7 presents results of simulations carried out with a mixer device according to the invention and with a mixer device outside of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0060] FIG. 1 illustrates a heat exchanger 1 comprising a stack of plates 2 (not shown) which extend in two dimensions parallel to a plane defined by a longitudinal direction z and a lateral direction y. The plates 2 are arranged parallel to and above one another with a spacing, and thus form a plurality of passages for fluids in an indirect heat-exchange relationship via said plates.

[0061] For preference, each passage has a flat and parallelepipedal shape. The separation between two successive plates is small in comparison with the length, measured in the lateral direction y, and the width, measured in the longitudinal direction z, of each passage.

[0062] The exchanger 1 may comprise a number of plates in excess of 20, or even in excess of 100, between them defining a first series of passages 10 for channeling at least one first fluid F1, and a second series of passages 20 (not visible in FIG. 1) for channeling at least one second fluid F2, the flow of said fluids being overall in the direction y. The passages 10 of the first series may be arranged, wholly or partially, to alternate with, or to be adjacent to, all or some of the passages 20 of the second series.

[0063] In a way known per se, the exchanger 1 comprises distribution and discharge means 40, 52, 45, 54, 55 configured to distribute the various fluids selectively into the passages 10, 20 and to discharge said fluids from said passages 10, 20.

[0064] The sealing of the passages 10, 20 along the edges of the plates 2 is generally afforded by lateral and longitudinal sealing strips 4 attached to the plates 2. The lateral sealing strips 4 do not completely block the passages 10, 20 but advantageously leave fluid inlet and outlet openings situated in the diagonally opposite corners of the passages.

[0065] The openings of the passages 10 of the first series are arranged in coincidence one above the other, whereas the openings of the passages 20 of the second series are arranged in the opposite corners. The openings placed one above the other are respectively united with one another in manifolds 40, 45, 50, 55 of semi-tubular shape via which the fluids are distributed and discharged.

[0066] In the depiction of FIG. 1, the semi-tubular manifolds 50, 45 are used to introduce the fluids into the exchanger 1, and the semi-tubular manifolds 40, 55 are used to discharge these fluids from the exchanger 1.

[0067] In this variant embodiment, the manifold supplying one of the fluids and the manifold discharging the other fluid are situated at one and the same end of the exchanger, the fluids F1, F2 thus flowing counter-currently through the exchanger 1.

[0068] According to another variant embodiment, the first and second fluids may equally circulate co-currently, the means supplying one of the fluids and the means discharging the other fluid then being situated at opposite ends of the exchanger 1.

[0069] For preference, the direction y is oriented vertically when the exchanger 1 is in operation. The first fluid F1 flows generally vertically and in the upward sense of that direction. Other directions and senses for the flow of the fluids F1, F2 are of course conceivable, without departing from the scope of the present invention.

[0070] It should be noted that, in the context of the invention, one or more first fluids F1 and one or more second fluids F2 of different natures may flow within the passages 10, 20 of the first and second series of one and the same exchanger.

[0071] As a preference, the first fluid F1 is a refrigerant fluid and the second fluid F2 is a calorigenic fluid.

[0072] The distribution and discharge means of the exchanger advantageously comprise distribution corrugations 51, 54, arranged between two successive plates 2 in the form of corrugated sheets, which extend from the inlet and outlet openings. The distribution corrugations 51, 54 ensure the uniform distribution and recovery of the fluids across the entire width of the passages 10, 20.

[0073] Furthermore, the passages 10, 20 advantageously comprise heat-exchange structures arranged between the plates 2. The purpose of these structures is to increase the heat-exchange surface area of the exchanger and to increase the coefficient of exchange between the fluids by making the flows more turbulent. Specifically, the heat-exchange structures are in contact with the fluids circulating in the passages and transfer thermal flux by conduction to the adjacent plates 2, to which they may be attached by brazing, thereby increasing the mechanical strength of the exchanger.

[0074] The heat-exchange structures also act as spacers between the plates 2, notably while the exchanger is being assembled by brazing, and in order to avoid any deformation of the plates during use of pressurized fluids. They also provide guidance for the flows of fluid in the passages of the exchanger.

[0075] For preference, these structures comprise heat-exchange corrugations 11 which advantageously extend across the width and the length of the passages 10, 20, parallel to the plates 2, in the prolongation of the distribution corrugations along the length of the passages 10, 20. The passages 10, 20 of the exchanger thus exhibit a main part of their length, constituting the heat-exchange part proper, which is covered with a heat-exchange structure, said main part being flanked by distribution parts covered with the distribution corrugations 51, 54.

[0076] FIG. 1 illustrates a passage 10 of the first series 1, configured to distribute a first fluid F1 in the form of a two-phase mixture also referred to as a biphasic mixture. The first fluid F1 is separated in a separator device 6 into a first phase 61 and a second phase 62 which are introduced separately into the exchanger 1 via a first manifold 30 and a second manifold 50 which are distinct from one another. The first and second phases 61, 62 are then mixed together by means of a mixer device 3 arranged in the passage 10. Advantageously, several passages 10, or even all of the passages 10 of the first series, comprise a mixer device 3. In the case illustrated in FIG. 1, the first phase 61 is liquid and the second phase 62 is gaseous.

[0077] FIG. 2 is a schematic view in cross section, in a plane perpendicular to that of FIG. 1, of a mixer device 3 advantageously comprising a bar or rod housed in a passage 10.

[0078] The mixer device 3 preferably extends in the section of the passage 10 over almost all of the, or even the entire, height of the passage 10, such that the mixer device is in contact with each plate 2 that forms the passage 10.

[0079] The mixer device 3 is advantageously fixed to the plates 2 by brazing.

[0080] The mixer device 3 is advantageously of generally parallelepipedal shape.

[0081] As a preference, the mixer device 3 is a monolithic component, namely formed as a block or as a single piece. The mixer device 3 may have, parallel to the lateral direction y, a first dimension of between 20 and 200 mm and, parallel to the longitudinal direction z, a second dimension of between 100 and 1400 mm.

[0082] As a preference, the first channel 31 extends over the entirety of the second dimension and/or the second channel extends over the entirety of the first dimension.

[0083] The mixer device 3 comprises at least a first channel 31 for the flow of the first phase 61 parallel to the longitudinal direction z, and at least a second channel 32 for the flow of the second phase 62. Said first channel 31 extends parallel to the longitudinal direction z. As a preference, the first channel 31 and/or the second channel are rectilinear in shape. As a preference, the second channel 32 extends parallel to the lateral direction y which is orthogonal to the longitudinal direction z and parallel to the plates 2.

[0084] A plurality of orifices 34.sub.i, 34.sub.i+1, . . . are distributed over the mixer device 3 so as to fluidically connect at least a first channel 31 with at least a second channel 32 designed for the flow of the second phase 62. The mixer device 3 is configured so that when the first phase 61 is flowing along the first channel 31 and the second phase 62 is flowing along the second channel 32, a two-phase liquid/gas mixture F1 is distributed at outlet from the mixer device 3.

[0085] As a preference, the mixer device 3 comprises at least one first inlet 311 in fluidic communication with the first manifold 30, and a second inlet 321, separated from the first inlet 311, in fluidic communication with the second manifold 50. The first manifold 30 is fluidically connected to a source of first phase 61, and the second manifold 50 is fluidically connected to another source of second phase 62. Said at least one first inlet 311 and said at least one second inlet 321 are placed in fluidic communication via the orifices 34.sub.i, 34.sub.i+1, . . .

[0086] As a preference, the mixer device 3 comprises a mixing volume situated in the second channel 32, downstream of the orifice 34i, when following the direction of flow of the first phase 61 through the orifice 34i. The two-phase liquid/gas mixture is distributed via a second outlet 322 of the second channel 32.

[0087] The first and second channels 31, 32 advantageously take the form of longitudinal recesses formed in the mixer device 3.

[0088] The orifices 34 are advantageously bores 34 made in the material of the device 3 and extending between the first channel 31 and the second channel 32, preferably in the vertical direction x. As a preference, the orifices 34 exhibit cylindrical symmetry.

[0089] As a preference, said at least one first channel 31 comprises a bottom wall 3c and said at least one second channel comprises a top wall 3d which faces the bottom wall 3c, the orifices 34 being pierced in the bottom wall of the first channel 31 and opening into the top wall of the second channel 32.

[0090] FIG. 3 is a three-dimensional view of the mixer device 3 of FIG. 2, FIG. 2 schematically showing the device 3 in a plane of section orthogonal to the longitudinal direction z and passing through the orifice 34.sub.i.

[0091] As can be seen in FIG. 3, the orifices 34.sub.i, 34.sub.i+1, . . . occupy successive positions z.sub.i, z.sub.i+1, . . . in the longitudinal direction z. Each orifice 34.sub.i is separated from the next orifice 34.sub.i+1 by a distance denoted d.sub.i which is measured parallel to the longitudinal direction z.

[0092] In the devices according to the prior art, the orifices occupy successive positions z.sub.i, z.sub.i+1, . . . that are situated at equal distances from one another. Now, the first phase 61 flows along the first channel 31 at different speeds along the length of the longitudinal direction z, and the flow of first phase 61 flowing through each orifice varies according to the speed of flow of the first phase 61 at the position z.sub.i of the orifice concerned.

[0093] In order to solve this problem, what is proposed is a mixer device 3 in which the distances between two successive positions z.sub.i, z.sub.i+1, . . . are variable. In other words, the distances between the successive positions z.sub.i, z.sub.i+1, . . . are not all identical. At least one pair of successive orifices exhibits a distance between two successive positions that differs from that of another pair of successive orifices.

[0094] By varying the distances between orifices in the longitudinal direction z, it is possible to compensate for nonuniformities of flow rates per unit length in the longitudinal direction z or, to put it another way, per unit width of exchanger passage, distributed by the orifices 34 by adapting the distribution of the orifices 34 across the width of the mixer device 3. Flow rate per unit length typically means a flow distributed by an orifice, divided by the distance between this orifice and the next one. For example, greater distances may be left between orifices which have a tendency to be oversupplied with a flow of fluid in the first phase 61, and this will have the effect of locally reducing the flow rate per unit width distributed by the orifices. In fact, the aim is not to make the flow of fluid passing through each of the orifices 34.sub.i, 34.sub.i+1, . . . uniform by adjusting the configuration of the orifices 34 or of the first channel 31, but rather to adapt the distribution of the points via which fluid is distributed by the orifices 34 in such a way as to render the flow rate of first phase 61 per unit length uniform in the longitudinal direction z.

[0095] This then results in a more uniform distribution of the liquid-gas mixture across the width of the passage 10. This solution offers the advantages of being simple to implement, of not altering the size of the exchanger, and of not making its structure more complex.

[0096] According to one embodiment, the distances between the successive positions z.sub.i, z.sub.i+1, . . . vary monotonically or near-monotonically in the longitudinal direction z. In other words, the direction of variation of the successive positions is constant or generally constant along the length of the longitudinal direction z.

[0097] According to one embodiment, the mixer device 3 exhibits, in the longitudinal direction z, an increase in the distances between two successive positions z.sub.i, z.sub.i+1, . . . . Such a configuration is implemented when the mixer device 3 is supplied with first phase 61 via a first inlet 311, the first phase flowing in the longitudinal direction z, as illustrated in the example of FIG. 3. The orifices situated on the side of the inlet 311 have a tendency to be undersupplied in comparison with the orifices situated further downstream, when following the direction of flow of the first phase 61.

[0098] According to an embodiment variant (not illustrated), the mixer device 3 exhibits, in the longitudinal direction z, a reduction in the distances between two successive positions z.sub.i, z.sub.i+1, . . . Such a configuration is implemented when the mixer device 3 is supplied with first phase 61 via an additional first inlet 312 arranged in such a way that the first phase 61 flows parallel but in the opposite sense to the longitudinal direction z.

[0099] FIG. 4 illustrates another embodiment of the invention which is particularly advantageous when the mixer device 3 has two inlets for supply of the first phase 61. More specifically, the mixer device 3 is supplied with first phase 61 via a first inlet 311 and an additional first inlet 312. The mixer device 3 is divided, in the longitudinal direction z, into at least a first portion 301 and a second portion 302, the first portion 301 exhibiting, in the longitudinal direction z, an increase in the distances between two successive positions z.sub.i, z.sub.i+1, . . . , and the second portion 302 exhibiting, in the longitudinal direction z, a decrease in the distances between two successive positions z.sub.i, z.sub.i+1, . . .

[0100] This embodiment allows the flow of first phase 61 distributed downstream of the orifices 34 to be made even more uniform along the length of the longitudinal direction z.

[0101] As a preference, the first inlet and the additional first inlet 311, 312 are arranged at two opposite ends of the mixer device 3. A first flow of first phase 61 is distributed by the first inlet 311 and flows in the direction of flow z, and a second flow of first phase 61 is distributed by the additional first inlet 312 and flows parallel, but in the opposite sense, to the longitudinal direction z.

[0102] Advantageously, the first portion 301 is situated on the side of the first inlet 311 and the second portion 302 is situated on the side of the additional first inlet 312.

[0103] As a preference, the first and second portions 301, 302 are arranged symmetrically relative to the center of the mixer device 3. However, said portions could be arranged in different numbers and exhibit different amplitudes of variations in distances between successive orifices on either side of the center of the mixer device 3.

[0104] Advantageously, a mixer device 3 according to the invention may be configured by adjusting the position of the orifices 34 according to the steps described hereinafter. Note that all or some of these steps may be performed by numerical simulation, for example using Computational Fluid Dynamics (CFD), or by correlating pressure drops along the first channel 31 and orifices 34, or by actual measurements, etc.

[0105] An initial state of the mixer device 3 is defined in which the orifices 34.sub.i, 34.sub.i+1, . . . are arranged in successive positions z.sub.i, z.sub.i+1, . . . that are separated by predetermined distances d.sub.i, d.sub.i+1, . . . As a preference, in the initial state, the predetermined distances di, d.sub.i+1, . . . are identical.

[0106] The first channel 31 is supplied in such a way that the first phase 61 flows in the longitudinal direction z. The mass flow rates Q.sub.i, Q.sub.i+1, . . . of the first phase 61 flowing through each orifice 34.sub.i, 34.sub.i+1, . . . of the mixer device 3 are determined and the orifices are repositioned in such a way that, for each orifice 34.sub.i, the next orifice 34.sub.i+1 is situated away from the previous orifice 34.sub.i by a modified distance d.sub.i that is expressed:

d.sub.i=F.sub.id.sub.m

where d.sub.m is the mean of the predetermined distances d.sub.i, d.sub.i+1, . . . and F.sub.i is a correction factor determined for each orifice as being a function of the flow rate Q.sub.i flowing through the orifice 34.sub.i.

[0107] It should be noted that, for preference, in the initial state, the mean distance between orifices corresponds to the identical distance separating all the orifices 34.sub.i, 34.sub.i+1, . . . .

[0108] Advantageously, the correction factor F.sub.i is a function of the ratio Q.sub.i/Q.sub.m between the mass flow rate Q.sub.i flowing through the orifice 34.sub.i and the mass flow rate Q.sub.m averaged over all the orifices.

[0109] As a preference, this function is a polynomial function of the ratio Q.sub.i/Q.sub.m, more preferably an affine function of the ratio Q.sub.i/Q.sub.m, expressed:

[00001]$F_i=A\frac{Q_i}{Q_m}+B$

where Q.sub.i is the mass flow rate flowing through the orifice 34.sub.i, Q.sub.m is the mass flow rate averaged over all the orifices, A and B are predetermined constants dependent on the characteristics of the mixer device 3. According to one particular embodiment, A=1 and/or B=0.

[0110] It being emphasized that the adjustment method described can be applied whatever the configuration of supply with first phase 61 of the first channel 31 since it is in the determination of the flow rates Q.sub.i, Q.sub.i+1, . . . that the configuration of supply of the first channel 31 is involved.

[0111] According to the exchange method considered and its sensitivity to the uneven distribution of the phases of the first fluid F1, one single step of repositioning the orifices 34.sub.i, 34.sub.i+1, . . . may suffice to even out the distribution of the first phase across the width of the mixer device 3.

[0112] Optionally, the step of repositioning the orifices 34.sub.i, 34.sub.i+1, . . . may be reiterated at least once, preferably between 1 and 5 times, more preferably twice at most. The adjustment method then comprises a step of defining the distances d.sub.i, d.sub.i+1, . . . modified previously as predetermined distances. The new mass flow rates Q.sub.i, Q.sub.i+1, . . . of the first phase 61 flowing through each repositioned orifice 34.sub.i, 34.sub.i+1, . . . are determined. The mean distance d.sub.m between the orifices and the mean flow rate Q.sub.m flowing through the orifices are calculated and new modified distances d.sub.i, d.sub.i+1, . . . are determined, using the expressions given hereinabove.

[0113] In the case of a mixer device 3 having several first channels 31, the adjustment method may be performed generally on all of the first channels 31 together, by considering the distances d.sub.i, d.sub.i+1, . . . between two successive orifices, whether these orifices be arranged in one and the same first channel 31 or in different first channels 31.

[0114] Alternatively, the method may be performed by considering each first channel 31 individually. In order to do that, the method may optionally comprise, prior to step a), at least one step of selecting a subset of orifices 34.sub.i, 34.sub.i+1, . . . which are arranged in one and the same first channel 31, steps a) to e) being executed for said subset. At least one other subset of orifices 34.sub.i, 34.sub.i+1, . . . arranged in another first channel 31 may then be selected and steps a) to e) executed for this other subset.

[0115] In order to demonstrate the effectiveness of the invention, CFD simulations have been run with a mixer device 3 as illustrated in FIG. 4. A series of three first channels 31 was supplied via two opposed inlets 301, 302 with a first phase 61 in the liquid state. The orifices 34 were cylindrical in shape and extended in the vertical direction x. In order to simplify the simulations, only the first phase 61 was taken into consideration, the gaseous second phase 62 being considered to have a negligible influence on the distribution of the liquid first phase 61 through each orifice 34.

[0116] The results of these simulations are given in FIGS. 5 and 6, with a comparison between a mixer device 3 having equidistant orifices (outside of the invention) and a mixer device 3 comprising a first portion 301 exhibiting, in the longitudinal direction z, an increase in the distances between two successive positions , and the second portion 302 exhibiting, in the longitudinal direction z, a decrease in the distances between two successive positions z.sub.i, z.sub.i+1, . . . (of the invention). FIG. 5 shows the evolution of the distances between orifices in the longitudinal direction z. In the initial state, the orifices are equidistant (outside of the invention). As may be seen in FIG. 6, the phenomenon of nonuniformity of flow rate of the first phase 61 in the longitudinal direction z is greatly reduced with a device according to the invention. Typically, the nonuniformities of the flow rates distributed by the orifices are reduced in such a way as to observe variations of less than 10% between the flow rates of the various orifices.

[0117] Within the context of the invention, the evolution of the distances between two successive positions z.sub.i, z.sub.i+1, . . . can be assessed in the light of an evolution of actual, measured or simulated values, or of a so-called fitted or smooth evolution constructed from a mathematical fitting of the actual evolution in the distances between two successive positions z.sub.i, z.sub.i+1, . . . .

[0118] Thus, the terms increase or decrease cover monotonic variations, like those illustrated in FIG. 5, or near-monotonic variations, which means to say variations which locally, when considering the actual, measured or simulated values, exhibit a direction of variation that differs from the overall direction of variation. For example, FIG. 7 schematically indicates the result of a simulation that has led overall to an increase in the distances between two successive positions z.sub.i, z.sub.i+1, . . . , but which, for certain points, exhibits a decrease in the distance between one orifice and the next. A mathematical fitting of this evolution, indicated by the dashed curve (----), results in a monotonic increase of said distances. It should be noted that, as the case may be, an orifice 34.sub.i, may be situated in the same first channel 31 as the successive orifice 34.sub.i+1, particularly in the case of a mixer device 3 that has a single first channel 31, or may be situated in another first channel 31. In the case of a mixer device 3 that has multiple first channels 31, a successive orifice 34.sub.i+1 of a first channel 31 is preferably situated in a different first channel 31 from the orifice 34.sub.i. The orifices 34.sub.i, 34.sub.i+1 are arranged at positions z.sub.i, z.sub.i+1, . . . , without necessarily being arranged at one and the same position in the lateral direction y.

[0119] The device 3 may comprise several first channels 31 arranged successively within the device 3, and/or several second channels 32, the first and/or the second channels 31, 32 being preferably parallel to each other.

[0120] As a preference, the first channels 31 and the second channels 32 extend parallel to the plates 2. According to the embodiment illustrated in FIG. 3, the first channels 31 succeed one another in the lateral direction y, and the second channels 32 succeed one another in the longitudinal direction z.

[0121] It being emphasized that the channels 31 and 32 may have the same or different shapes and quantities. The distances between the successive first channels 31 and the distances between the successive second channels 32 may also vary. As a preference, the distances between the channels 32, measured in the direction of the longitudinal direction z, are adjusted according to the position of the orifices 34.

[0122] FIGS. 3 to 4 show examples of a mixer device 3 in the form of a bar, where openings 34 of cylindrical shape are drilled in the bottom of several first channels 31.

[0123] In this embodiment, the mixer device 3 as a whole forms a parallelepiped, delimited in particular by a first surface 3a intended to be arranged facing one plate 2 of the exchanger, and a second surface 3b arranged facing another plate 2. The first and second surfaces 3a, 3b preferably extend generally parallel to the plates 2. The mixer device 3 is preferably arranged in the passage 10 such that the first and second surfaces 3a, 3b are in contact with the plates 2.

[0124] The channels 31, 32 advantageously take the form of recesses provided within the mixer device 3. They may or may not open onto the surfaces 3a and/or 3b.

[0125] The orifices 34 are advantageously bores 34 made in the material of the device 3 and extending between the first channel 31 and the second channel 32, preferably in the vertical direction x. As a preference, the orifices 34 exhibit cylindrical symmetry.

[0126] It should be noted that the orifices 34.sub.i, 34.sub.i+1, . . . do not necessarily have the same shape or the same dimensions. The number of different shapes, the dimensioning and the distribution of the orifices, in one and the same first channel 31 or between several first channels 31, might vary according to the desired distribution of liquid-gas mixture, so as to achieve even finer adjustment of the flow rate of fluid through the orifices 34. In particular, in the case of a first channel having an inlet 311, orifices of larger cross sections may be arranged upstream in the first channel 31, where the speed of the first phase 61 is greater, and orifices of smaller inlet cross section may be arranged downstream in the first channel 31. The shape and the dimensions of the first and/or second channels 31, 32 may also vary along the directions y and/or z, and from one channel 31, 32 to another.

[0127] Of course, the invention is not limited to the particular examples described and illustrated in the present application. Other alternative forms or embodiments within the competence of a person skilled in the art may also be considered without departing from the scope of the invention.

[0128] For example, the exchanger according to the invention is chiefly described for the case in which the passages 10, 20 extend in the lateral direction y, the first longitudinal channel 31 extending in the flow direction z, and the lateral channel 32 extending in the lateral direction y orthogonal to the direction z. The reverse is also conceivable, for example a first longitudinal channel 31 extending in the lateral direction y, and a lateral channel 32 extending in the flow direction z. The directions y and z may also not be mutually orthogonal.

[0129] While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example, it can be recognized by those skilled in the art that certain steps can be combined into a single step.

[0130] The singular forms a, an and the include plural referents, unless the context clearly dictates otherwise.

[0131] Comprising in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing (i.e., anything else may be additionally included and remain within the scope of comprising). Comprising as used herein may be replaced by the more limited transitional terms consisting essentially of and consisting of unless otherwise indicated herein.

[0132] Providing in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.

[0133] Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.

[0134] Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.

[0135] All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited