U.S. patent application number 16/978036 was filed with the patent office on 2020-12-31 for heat exchanger with improved liquid/gas mixing device.
This patent application is currently assigned to L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude. The applicant listed for this patent is L'Air Liquide, Societe Anonyme pour I'Etude et I'Exploitation des Procedes Georges Claude. Invention is credited to Marine ANDRICH, Ahlem DELEGUE, Philippe GRIGOLETTO, Natacha HAIK-BERAUD, Jean-Marc PEYRON.
Application Number | 20200408466 16/978036 |
Document ID | / |
Family ID | 1000005102284 |
Filed Date | 2020-12-31 |
United States Patent
Application |
20200408466 |
Kind Code |
A1 |
ANDRICH; Marine ; et
al. |
December 31, 2020 |
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.
Inventors: |
ANDRICH; Marine;
(Jouy-en-Josas, FR) ; HAIK-BERAUD; Natacha;
(Champigny-sur-Marne, FR) ; GRIGOLETTO; Philippe;
(Champigny-sur-Marne, FR) ; PEYRON; Jean-Marc;
(Champigny-sur-Marne, FR) ; DELEGUE; Ahlem;
(Jouy-en-Josas, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
L'Air Liquide, Societe Anonyme pour I'Etude et I'Exploitation des
Procedes Georges Claude |
Paris |
|
FR |
|
|
Assignee: |
L'Air Liquide, Societe Anonyme pour
l'Etude et l'Exploitation des Procedes Georges Claude
Paris
FR
|
Family ID: |
1000005102284 |
Appl. No.: |
16/978036 |
Filed: |
March 21, 2019 |
PCT Filed: |
March 21, 2019 |
PCT NO: |
PCT/FR2019/050642 |
371 Date: |
September 3, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28D 9/0068 20130101;
F25J 2290/32 20130101; F28F 3/048 20130101; F28F 2250/108 20130101;
F28F 3/12 20130101 |
International
Class: |
F28D 9/00 20060101
F28D009/00; F28F 3/04 20060101 F28F003/04; F28F 3/12 20060101
F28F003/12 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 22, 2018 |
FR |
1852469 |
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
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a .sctn. 371 of International PCT
Application PCT/FR2019/050642, filed Mar. 21, 2019, which claims
the benefit of FR1852469, filed Mar. 22, 2018, both of which are
herein incorporated by reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates to a heat exchanger comprising
series of passages for each of the fluids to be placed in a
heat-exchange relationship, the exchanger comprising at least one
mixer device for distributing at least one two-phase liquid/gas
mixture into one of the series of passages.
[0003] In particular, the present invention may apply to a heat
exchanger which vaporizes at least one flow of liquid-gas mixture,
particularly a flow of multi-constituent mixture, for example a
mixture of hydrocarbons, through exchange of heat with at least one
other fluid, for example natural gas.
BACKGROUND OF THE INVENTION
[0004] The technology commonly used for an exchanger is that of
aluminum brazed plate and fin exchangers, which make it possible to
obtain devices that are very compact and afford a large
heat-exchange surface area.
[0005] These exchangers comprise plates between which are inserted
heat-exchange corrugations, formed of a succession of fins or
corrugation legs, thus constituting a stack of vaporization
passages and of condensation passages, the former intended to
vaporize refrigerant liquid and the latter intended to condense a
calorigenic gas. The exchanges of heat between the fluids may take
place with or without phase change.
[0006] In order to ensure correct operation of an exchanger
employing a liquid-gas mixture, the proportion of liquid phase and
of gas phase needs to be the same in all of the passages and needs
to be uniform within one and the same passage.
[0007] The dimensions of the exchanger are calculated on the
assumption of a uniform distribution of the phases, and therefore
of a single temperature at the end of vaporization of the liquid
phase, equal to the dew point of the mixture.
[0008] In the case of a multi-constituent mixture, the temperature
at the end of vaporization is going to depend on the proportion of
liquid phase and of gas phase in the passages.
[0009] In the event of an unequal distribution of the two phases,
the temperature profile of the first fluid is then going to vary
from passage to passage, or even vary within one and the same
passage. Because of this non-uniform distribution, there is then
the possibility that the fluid(s) in a heat-exchange relationship
with the two-phase mixture may have an exchanger outlet temperature
that is higher than intended, and this consequently degrades the
performance of the heat exchanger.
[0010] One solution for distributing the liquid and gas phases of
the mixture as uniformly as possible is to introduce them into the
exchanger separately, then mix them together only once they are
inside the exchanger.
[0011] Document FR-A-2563620 describes such an exchanger in which a
grooved bar is inserted into the series of passages which is
intended to channel the two-phase mixture. This mixer device
comprises separate channels for a liquid phase and for a gas phase,
and an outlet for distributing the liquid-gas mixture to the
heat-exchange zone.
[0012] A problem which arises with this type of mixer device
concerns the distribution of the liquid-gas mixture in the width of
the passage containing the mixer device. In order to mix the two
phases, the mixer device generally comprises a first channel for
the flow of one phase. This channel is equipped with a series of
orifices arranged along the channel, each orifice being in fluidic
communication with the second channel for the flow of the other
phase. When the inlet to the first channel is supplied with fluid,
the flow rate of the fluid will tend to diminish as the fluid flows
along the channel. This is because the flow of fluid reduces as the
orifices are supplied.
[0013] Now, the orifices are generally machined perpendicularly to
the direction of flow of the fluid, and are therefore less well
supplied when the fluid speed is higher. The orifices arranged on
the channel inlet side therefore have a tendency to be
under-supplied, whereas the orifices situated on the bottom of the
channel are over-supplied. The result is an uneven introduction of
the respective phase into the channel for the other phase, and
hence an uneven distribution of the liquid-gas mixture in the width
of the exchanger passage.
[0014] In order to minimize this phenomenon, one solution is to
supply the channel concerned via two opposite inlets of the
channel. However, this results in a complication of the exchanger,
and the problem of uneven distribution remains at least in the
central part of the channel.
[0015] Increasing the number of channels is also not an ideal
solution in view of the mechanical strength and brazing of the
device.
[0016] Another known solution is to arrange orifices of cylindrical
form with different diameters along the channel. However, this
solution may prove insufficient for certain processes.
SUMMARY OF THE INVENTION
[0017] It is an object of certain embodiments of the present
invention to fully or partially solve the above-mentioned problems,
notably by proposing a heat exchanger in which the distribution of
the liquid and gas phases of a mixture is as uniform as possible,
and to do so without excessively adding to the complexity of the
structure of the exchanger, or increasing the size thereof.
[0018] The solution according to the invention is therefore 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 one fluid which is to be
brought into a heat-exchange relationship with at least one other
fluid, a mixer device being arranged in at least one passage and
comprising: [0019] at least one first channel for the flow of a
first phase of the fluid parallel to the longitudinal direction,
[0020] at least one second channel for the flow of a second phase
of the fluid, and [0021] a plurality of orifices fluidically
connecting the first channel to the second channel, said orifices
occupying successive positions in the longitudinal direction,
[0022] wherein the distances between the successive positions,
measured parallel to the longitudinal direction, are variable.
[0023] Depending on the case, the exchanger of the invention may
comprise one or more of the following technical features: [0024]
the distances between the successive positions vary monotonically
or near-monotonically in the longitudinal direction. [0025] the
mixer device exhibits, in the longitudinal direction, an increase
in the distances between two successive positions. [0026] the mixer
device exhibits, in the longitudinal direction, a decrease in the
distances between two successive positions. [0027] the mixer device
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. [0028] 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. [0029] the first channel and/or the
second channel are rectilinear in shape. [0030] the mixer device
comprises a first inlet and an additional first inlet which are
designed to supply said at least one first channel with the first
phase of the fluid, the first portion being situated on the side of
the first inlet and the second portion being situated on the side
of the additional first inlet. [0031] 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. [0032] the mixer device
comprises several first channels succeeding one another in a
lateral direction orthogonal to the longitudinal direction. [0033]
the second channel extends in a lateral direction orthogonal to the
longitudinal direction.
[0034] Furthermore, the invention relates to a method for
distributing a two-phase liquid/gas mixture in an exchanger
according to the invention, said method comprising the following
steps: [0035] i) arranging a mixer device in at least one passage
of the exchanger, [0036] ii) supplying said first channel of the
mixer device with the first phase of the first fluid, [0037] iii)
supplying said second channel of the mixer device with the second
phase (62) of the first fluid (F1), which is distinct from the
first phase (61), [0038] 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 [0039] distributing a mixture of
the first phase and of the second phase at the outlet of the mixer
device.
[0040] According to another aspect, the invention relates to a
method for adjusting the positions of the orifices of a mixer
device which is arranged in an exchanger according to the
invention, said method comprising the following steps: [0041] a)
positioning the orifices in such a way that their successive
positions are separated by predetermined distances, [0042] b)
supplying the first channel with the first phase of the fluid such
that the first phase of the fluid flows in the longitudinal
direction, [0043] c) determining the mass flow rates of the first
phase flowing through each orifice, [0044] 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. [0045] 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.
[0046] said function is a polynomial function of the ratio between
the mass flow rate flowing through the orifice and the mass flow
rate averaged over all the orifices, preferably an affine function
of said ratio. [0047] the method further comprises a step e) of
defining the distances modified in step d) as predetermined
distances, steps c) to d) being reiterated at least once,
preferably between 1 and 5 times, more preferably at most twice.
[0048] 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 subset.
[0049] The present invention may apply to a heat exchanger which
vaporizes at least one flow of liquid-gas mixture, particularly a
flow of multi-constituent mixture, for example a mixture of
hydrocarbons, through exchange of heat with at least one other
fluid, for example natural gas.
[0050] The expression "natural gas" relates to any composition
containing hydrocarbons, including at least methane. This comprises
a "crude" composition (prior to any treatment or scrubbing) and
also any composition which has been partially, substantially or
completely treated for the reduction and/or removal of one or more
compounds, including, but without being limited thereto, sulfur,
carbon dioxide, water, mercury and certain heavy and aromatic
hydrocarbons.
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.i.times.d.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:
F i = A .times. Q i Q m + B ##EQU00001##
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
* * * * *