HEAT EXCHANGER MODULE OF THE TYPE HAVING PLATES COMPRISING CHANNELS INCORPORATING AT LEAST ONE FLUID SUPPLY AND DISTRIBUTION ZONE FORMED BY STUDS

Abstract

A heat exchanger module having at least two fluid circuits, of longitudinal axis including a stack of plates, defining at least two fluid circuits, at least a part of the plates each including fluid circulation channels, the channels of at least one of the two circuits, referred to as first circuit, having at least one fluid supply and distribution zone for supplying and distributing fluid from outside the stack, forming a fluid pre-header, in which zone the channels are delimited by studs distributed over the surface of the plate; an exchange zone continuous with the pre-header and wherein the channels are each delimited by a groove separated from one another by a rib and extending along the longitudinal axis.

Claims

1. A heat exchanger module having at least two fluid circuits, of longitudinal axis comprising a stack of plates, defining at least two fluid circuits, at least a part of the plates each comprising fluid circulation channels, the channels of at least one of the two circuits, referred to as first circuit, having: at least one fluid supply and distribution zone for supplying and distributing fluid from outside the stack, forming a fluid pre-header, in which zone the channels are delimited by studs distributed over the surface of the plate; an exchange zone continuous with the pre-header and in which wherein the channels are each delimited by a groove separated from one another by a rib and extending along the longitudinal axis, wherein the channels of the other of the two circuits, referred to as second circuit, have: at least one fluid supply and distribution zone for supplying and distributing fluid from outside the stack, forming a fluid pre-header, in which zone the channels are delimited by studs distributed over the surface of the plate; an exchange zone continuous with the pre-header and wherein the channels are each delimited by a groove, separated from one another by a rib and extending along the longitudinal axis.

2. The heat exchanger module according to claim 1, comprising two first-circuit pre-headers each arranged at one of the longitudinal ends of the stack, one of the two pre-headers forming a fluid inlet pre-header, the other forming a fluid outlet pre-header.

3. The heat exchanger module according to claim 1, comprising two second-circuit pre-headers each arranged at one of the longitudinal ends of the stack, one of the two pre-headers forming a fluid inlet pre-header, the other forming a fluid outlet pre-header.

4. The heat exchanger module according to claim 1, wherein the studs of the first circuit and/or of the second circuit are solid.

5. The heat exchanger module according to claim 1, wherein the studs of the first circuit and/or of the second circuit are holed and open-ended so as to allow communication between channels of the plates of the supply and distribution zone of the first or of the second circuit but not with those of the plates of the second or respectively of the first circuit.

6. The heat exchanger module according to claim 1, comprising at least at one of the longitudinal ends of the stack, a fluid header opening onto a lateral base plate of the stack onto which baseplate the channels of the first circuit pre-header open but not those of the second circuit pre-header.

7. The heat exchanger module according to claim 6, comprising at one of the longitudinal ends, a fluid header forming the first circuit inlet header and, at the other of the longitudinal ends, a fluid header forming the first circuit outlet header.

8. The heat exchanger module according to claim 1, comprising at least on one lateral side of the stack, a fluid header passing through the stack transversely to the axis and opening onto the second channels of the pre-header of the second circuit but not onto those of the first circuit.

9. The heat exchanger module according to claim 8, comprising at least on one same lateral side of the stack, a fluid header forming the second circuit inlet header and a fluid header forming the second circuit outlet header.

10. The heat exchanger module according to claim 1, wherein the studs are uniformly distributed in a staggered configuration over the surface of the plate of the pre-header in a triangular pattern.

11. The heat exchanger module according to claim 1, wherein the studs are uniformly distributed over the surface of the plate of the pre-header in a rectangular or square pattern.

12. The heat exchanger module according to claim 1, wherein the studs are of cylindrical overall shape.

13. The heat exchanger module according to claim 1, wherein the channels of the exchange zone of the first circuit and of the second circuit are straight, mutually parallel, and extending parallel to the longitudinal axis.

14. The heat exchanger module according to claim, 1, wherein the stack is made up of metal plates assembled with one another either by hot isostatic pressing or by uniaxial hot pressing so as to obtain diffusion welding between the metal plates, or by brazing, or produced using additive manufacturing.

15. The heat exchanger module according to claim 1, wherein a plate of the first circuit is interposed between two plates of the second circuit at least in the central part of the stack.

16. The heat exchanger comprising a plurality of heat exchanger modules according to claim 1.

17. The heat exchanger according to claim 16, wherein the modules are arranged side by side with the second circuit inlet and outlet headers passing through and laterally connecting the modules.

18. A use of the heat exchanger according to claim 16, wherein the fluid of the first circuit, with primary fluid, is a liquid metal and the fluid of the second circuit, with secondary fluid, is a gas or a gas mixture.

19. The use of the exchanger according to claim 18, wherein the fluid of the second circuit mainly containing nitrogen and the fluid of the first circuit is liquid sodium.

20. The use according to claim 18, the fluid of the first or of the second circuit coming from a nuclear reactor.

21. A nuclear facility comprising a liquid metal fast neutron reactor, notably a sodium fast reactor SFR or Na-called SNR and a heat exchanger comprising a plurality of exchanger modules according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0076] FIG. 1A is a view of a plate with liquid sodium circulation channels for a heat exchanger module according to the prior art, intended for an SFR reactor.

[0077] FIG. 1B is a view of a plate with gas circulation channels for the exchanger module with sodium circulation plate according to FIG. 1A.

[0078] FIG. 2 is a longitudinal side view of a heat exchanger module according to the invention.

[0079] FIG. 3 is a face-on view of the exchanger module according to FIG. 2.

[0080] FIG. 4A is a perspective view with partial cutaway of an exchanger module according to a first alternative of the invention, FIG. 4A showing the circulation of the liquid sodium within a dedicated channel plate.

[0081] FIG. 4B is a perspective view with partial cutaway of an exchanger module according to the first alternative of the invention, FIG. 4B showing the circulation of the gas typically N.sub.2, in a dedicated channel plate.

[0082] FIG. 4C is a detailed view of FIG. 4A showing the alternating stack of liquid sodium and gas circulation plates in the region of their homogenization zones.

[0083] FIG. 5 is a face-on view of a plate with liquid sodium circulation channels according to the first alternative of the invention.

[0084] FIG. 5A is a partial perspective view of the plate according to FIG. 5.

[0085] FIG. 6 is a face-on view of a plate with gas circulation channels according to the first alternative of the invention.

[0086] FIG. 6A is a partial perspective view of the plate according to FIG. 6.

[0087] FIG. 7A is a perspective view with partial cutaway of an exchanger module according to a second alternative of the invention, FIG. 7A showing the circulation of the liquid sodium within a dedicated channel plate.

[0088] FIG. 7B is a perspective view with partial cutaway of an exchanger module according to the second alternative of the invention, FIG. 7B showing the circulation of the gas, typically N.sub.2, within a dedicated channel plate.

[0089] FIG. 7C is a detailed view of FIG. 7A showing the alternating stack of liquid sodium and gas circulation plates at the region of their homogenization zone.

[0090] FIG. 8 is a face-on view of a plate with liquid sodium circulation channels according to the second alternative of the invention.

[0091] FIG. 8A is a partial perspective view of the plate according to FIG. 8.

[0092] FIG. 9 is a face-on view of a plate with gas circulation channels according to the second alternative of the invention.

[0093] FIG. 9A is a partial perspective view of the plate according to FIG. 9.

[0094] FIG. 10 is a face-on detailed view showing a staggered distribution in a regular triangular pattern of the studs of a channel plate according to the invention.

[0095] FIG. 11 is a face-on detail view showing the distribution in a regular square pattern of the studs of a channel plate according to the invention.

[0096] FIG. 12A is a perspective view with partial cutaway of an exchanger module according to a liquid sodium carrying variant, FIG. 12A showing the circulation of the liquid sodium within a dedicated channel plate.

[0097] FIG. 12B is a perspective view with partial cutaway of an exchanger module according to the liquid sodium conveying variant, FIG. 12B showing the circulation of the gas in a dedicated channel plate.

[0098] FIG. 13 is a schematic view showing an advantageous arrangement of several exchanger modules according to the invention.

[0099] FIG. 14 illustrates a numerical simulation showing the flow of fluid notably in a homogenization zone forming a pre-header according to the invention for a stack of nine N.sub.2 circulation plates.

[0100] FIG. 15 illustrates a numerical simulation showing the flow of fluid notably in a homogenization zone forming a pre-header according to the invention for a stack of ten Na circulation plates.

DETAILED DESCRIPTION

[0101] For the sake of clarity, the same elements are denoted by the same numerical references according to the prior art and according to the invention.

[0102] It is emphasized that throughout the application, the terms “inlet”, “outlet”, “upstream”, “downstream” are to be understood in relation to the direction in which the fluid concerns circulates in the heat exchange module according to the invention.

[0103] FIGS. 1A and 1B relating to the prior art were already commentated on in the preamble. They will therefore not be commented upon hereafter.

[0104] FIGS. 2 and 3 depict an embodiment of a heat exchanger module according to the invention with two fluid circuits, which is employed by way of example for an exchange between liquid sodium (Na) and nitrogen (N.sub.2).

[0105] The module 1 is made up of an alternating stack of metal plates 10, 20 assembled with one another by the fusion welding, preferably using an HIP technique, or produced by additive manufacturing.

[0106] As visible in these figures, this module 1, which extends along a central axis (X), incorporates two headers 11, 12, these respectively being a liquid sodium (Na) inlet and outlet, one of them arranged at the top of the module along the axis X and the other being arranged also along the axis X of the module but at the bottom. As detailed hereinafter, each of the headers 11, 12 opens onto a lateral base plate of the stack of plates onto which base plate the channels of the Na circuit open, but those of the N.sub.2 circuit do not.

[0107] The module 1 also comprises two headers 21, 22, these respectively being the nitrogen (N.sub.2) inlet and outlet headers, arranged on the one same longitudinal face, respectively at the bottom of the module and at the top of the module. As detailed hereinafter, each of these inlet header 21 and outlet header 22 passes through the stack transversely to the axis X and opens onto the channels of the N.sub.2 circuit but not onto the Na circuit.

[0108] In such a module 1, the circulation of the fluids (Na, N.sub.2) is therefore counterflow circulation.

[0109] FIGS. 4A and 4B show the stack and respectively the circulation within an Na circulation plate 10 and an N.sub.2 circulation plate 20, the arrows symbolizing the circulation of each of the fluids in each plate concerned.

[0110] FIGS. 5, 5A show an Na circulation plate 10.

[0111] A plate 10 comprises two supply and distribution zones Z.sub.H each forming a fluid pre-header, these being arranged one on each side of a heat exchange zone Z.sub.E.

[0112] According to the invention, the channels 13 of a pre-header Z.sub.H are delimited by solid cylindrical studs 14 distributed over the surface of the plate. As a preference, as shown in FIGS. 4A, 5 and 5A, the solid cylindrical studs 14 are uniformly distributed in a staggered configuration on the surface of the plate of the pre-header. More specifically, this staggered distribution is in a triangular pattern that remains identical over the entire surface of the plates 10 of the pre-header Z.sub.H. A distribution in a triangular pattern allows better filling of the volume of the pre-header by the studs 14 and is accorded preference in order to ensure the ability of the exchanger module to withstand pressure.

[0113] The channels 13 delimited by the solid cylindrical studs 14 open onto the channels 15 of the heat exchange zone Z.sub.E which is continuous with the pre-header. As shown, the channels 15 of the exchange zone are each delimited by a groove 15 separated from one another by a rim 16 and extending along the longitudinal axis (X). As a preference, as shown, they are straight, mutually parallel, and run parallel to the longitudinal axis (X) of the module 1.

[0114] The studs 14 may be of a height such that they come to bear directly against a plate 20. As illustrates in FIG. 4C, it is also possible to envision two adjacent plates 10 with cylindrical studs 14 of which the height represents part of the height of a channel 13 and which, once the plates have been assembled with one another, define the total height of the channel. The same is true of the ribs 16. The arrangement of the studs 14 ensures the ability of the plates 10 to withstand pressure.

[0115] A ring 17 extends around each of two holes 18, 19 of circular section each opening through the plate 10 within one of the pre-headers. These open-ended holes 18, 19 form part of the tube of the respectively inlet and outlet circulation header of the other, N.sub.2 circuit. The ring 17 thus forms a fluid tight barrier between the Na and N.sub.2 circuits in the region of the pre-headers of the plates 10.

[0116] With such a plate 10, as illustrate in part in FIG. 4A, the liquid sodium is supplied form the inlet tubular header 11 to be distributed from the inlet 11 of the channels 13 delimited by the studs 14. The liquid sodium circulates in the channels 13 around the studs 14 of the inlet pre-header to arrive at the channels 15 of the heat exchange zone Z.sub.E then circulates around the studs 14 of the outlet pre-header to be removed via the outlet 101 of the channels 13 and recovered by the outlet header 12.

[0117] FIGS. 6, 6A show an N.sub.2 circulation plate 20 produced in a similar way to an Na circulate plate 10.

[0118] Thus, a plate 20 comprises two supplied distribution zones Z.sub.H each forming a fluid pre-header, and which are arranged one on each side of a heat exchange zone Z.sub.E.

[0119] The channels 23 of a pre-header Z.sub.H are delimited by side cylindrical studs 24 distributed over the surface of the plate. As a preference, as shown in FIGS. 4B, 6 and 6A, the solid cylindrical studs 24 are uniformly distributed in a staggered configuration over the surface of the plate of the pre-header. Here again, this staggered configuration is in a triangular pattern that remains identical over the entire surface of the plates 20 of the pre-header ZH. A distribution in a triangular patterns allows better filling of the volume of the pre-header by the studs 24 and is accorded preference in order to ensure the ability of the exchanger module to withstand pressure.

[0120] The channels 23 delimited by the solid cylindrical studs 24 open onto the channels 25 of the heat exchange zone Z.sub.E which is continuous with the pre-header. As shown, the channels 25 of the exchange zone are each delimited by a groove 25 separated from one another by a rib 26 and extending along the longitudinal axis (X). As a preference, as shown, they are straight, mutually parallel, and run parallel to the longitudinal axis (X) of the module 1.

[0121] The studs 24 may be of a height such that they come to bear directly against a plate 20. As illustrated in FIG. 4C, it is also possible to envision two adjacent plates 20 with cylindrical studs 24 of which the height represents part of the height of a channel 23 and which once the plates have been assembled with one another define the total height of the channel. The same is true of the ribs 26. The arrangement of the studs 24 ensures the ability of the plates 20 to withstand pressure.

[0122] Two holes 28, 29 of circular cross section each open through the plate 20 in one of the pre-headers. These open-ended holes 28, 29 form part of the tube of the respectively inlet and outlet circulation header of the other, N.sub.2, circuit.

[0123] Studs 27 of trapezoidal shape are uniformly distributed around each of the holes 28, 29 to delimit inlet 200 or outlet 201 channels of uniform dimensions which therefore connect each of the holes 28, 29 to one of the respectively inlet and outlet pre-headers Z.sub.H.

[0124] With such a plate 10, as is illustrated in part in FIG. 4B, the nitrogen is supplied from the inlet tubular header 21 which passes through the stack of plates 10, 20 to be distributed into the inlet channels 200 and then into the channels 23 delimited by the studs 24. The nitrogen circulates around the studs 24 of the inlet pre-header to reach the channels 25 of the heat exchange zone Z.sub.E and then circulates in the channels 23 around the studs 24 of the outlet pre-header to be removed by the outlet channels 201 and then recovered by the outlet header 22.

[0125] Thus, according to the invention, the studs 14, 24 ensure homogeneous distribution of each of the fluids, i.e. the liquid sodium and the nitrogen respectively, independently of the geometry of the channels 15, 25 of their heat exchange zone Z.sub.E and do all of this while having low thermal inertia and minimizing added pressure drops. Furthermore, as already mentioned, the studs 14, 24 are dimensioned to ensure the ability to withstand the pressure. Typically the studs 24 are dimensioned to ensure an ability to withstand a nitrogen pressure of the order of 180 bar.

[0126] In the alternative of the module illustrates in FIGS. 4A to 6A, the studs 14, 24 of the plates 10, 20 of the two (Na, N.sub.2) fluid circuits are aligned, which is to say that the axis of revolution of a stud 14 is aligned with that of a stud 24. For each plate 10 or 20 the arrangement of the studs 14 or 24 of the one same plate is in a staggered configuration so as to have a stud 14, 24 facing a channel 17, 25 of the heat exchange zone Z.sub.E.

[0127] It is also possible to envision an offsetting, in other words a lateral offsetting of the studs over the surface of the plates. Such offsetting allows the creation of studs pierced with open-ended holes. This offsetting is accompanied by a change from a distribution in a triangular pattern as illustrated for the previous alternative to a distribution in a rectangular or square pattern.

[0128] Over the one same surface, there are fewer studs when they are distributed in a rectangular or square pattern than when they are distributed in a triangular pattern. As a result, this impairs the ability to withstand pressure, but does leave space for holing the studs.

[0129] Such an alternative embodiment of a module 1′ is shown in FIGS. 7A to 9A in which the studs 14′, 24′ of the plates 10′, 20′ respectively are holed, opening between the plates 10 or 10 of the one same fluid, Na or N.sub.2, circuit.

[0130] As shown in FIG. 7C, the hole studs 14′, 24′ thus create communications between the plates 10, 20 of the one same, Na or N.sub.2 circuit, in the region of the pre-headers Z.sub.H, while at the same time maintaining fluid tightness with the other, respectively N.sub.2 or Na, circuit.

[0131] This alternative with open-ended hole studs 14′, 24′, allows the fluid pressures to be equalized between the plates 10′, 20′.

[0132] FIG. 10 illustrates in detail an alternative staggered configuration of the studs 14 of a plate 10 of the Na circuit in an equilateral triangular pattern defined by a pitch spacing P1.

[0133] FIG. 10 illustrates another alternative distribution whereby the studs 14 are distributed in a square pattern defined by a pitch spacing P2.

[0134] One or other of these alternatives can be implemented for the studs 24 of the plates 20 of the other circuit.

[0135] In FIGS. 2, 3, 4A, 4B, 7A, 7B the tube of the respectively inlet and outlet headers 11, 12, outside of the stack of plates, is arranged along the longitudinal axis X.

[0136] Other arrangements of the header tubes may also be envisioned.

[0137] Thus, a variant arrangement is illustrated in FIGS. 12A and 12B, whereby two tubes 11, 12 arranged orthogonally to the axis X and therefore parallel to the nitrogen circuit inlet and outlet headers 21, 22 are envisioned. As shown in FIGS. 12A, 12B, this arrangement still allows the plates 10 to be supplied with liquid sodium along the longitudinal axis of the exchanger module 1.

[0138] As already specified, creating pre-headers with studs 14, 24 according to the invention allows the inlet and outlet headers 21, 22 for one of the fluids to be arranged on the one same longitudinal face of a module 1.

[0139] This arrangement advantageously facilitates the relative arrangement of several modules and minimizes the lengths of piping connecting these.

[0140] One example of such an arrangement of exchange modules is shown in FIG. 13 which depicts three exchanger modules 1.1, 1.2, 1.3 arranged side by side and directly connected to one another by the tubes 21, 22 of the nitrogen circuit inlet and outlet headers, which tubes are rectilinear and straight.

[0141] The inventors have already mechanically predimensioned an exchanger module 1, 1′ according to the invention for use in the exchange of heat between sodium (Na) and gas (N.sub.2) as in the context of an SFR nuclear reactor.

[0142] The temperatures and pressures in the Na and N.sub.2 circuits are summarized in table 1 below.

TABLE-US-00001 TABLE 1 Na N.sub.2 circulation circulation plate 10 plate 20 T inlet 530 290 (° C.) T outlet 345 515 (° C.) Pressure  5 180 Bar

[0143] The predimensioning was performed with a range of triangular pitch spacing of channels 13, 23, i.e. with 6 to 12 mm spacing between studs 14, 24, and diameters from 4 to 8 mm of cylindrical studs 14, 24.

[0144] With these mechanical predimensionings thus achieved, the inventors concluded that an exchanger module 1 according to the invention had a good ability to withstand pressure.

[0145] Furthermore, fluid dynamic studies made is possible, through an iterative process of computational fluid dynamics (CFD) and computer aided design (CAD) made is possible to converge upon a design of exchange module 1 with a maldistribution of fluids, namely a standard deviation of flow rates between exchange channels for the one same fluid that is less than 5% across all of the channels 13, 23, 15, 25.

[0146] FIGS. 14 and 15 illustrate the flow in the pre-headers with studs for the stacks of, respectively, nine N2 circulation plates 20 and ten Na circulation plates 10. The modules 1 with such pre-headers respectively exhibit a maldistribution of 4.0% (N2) and 4.7% (Na).

[0147] Other variant sand improvements may be envisioned without thereby departing from the scope of the invention.

[0148] The stud geometries and the periodicity of the pitch spacing of the rectangular, square or triangular pattern and the distribution thereof needs to be determined according to the application by following the usual rules of sizing, mechanical ability to withstand pressure, pressure drops, and fluid flow distribution in the channels.

[0149] While in all of the examples illustrated, all the plates 10 and 20 are produced using pre-headers with studs 14, 24, it is possible to use this approach only on those of a single fluid circuit, it being possible for the other to comprise conventional pre-headers.

[0150] Shapes other than cylindrical studs 14, 24 may be envisioned. For example, it is possible to envision elliptical, teardrop, etc. geometries.

[0151] It is possible to envision combining the two alternatives, namely with the plates of one circuit, for example those referenced 10, having solid studs and the plates of the other circuit, for example those referenced 20, having open-ended holed studs.

[0152] Furthermore, while in the examples illustrated, the channels of the heat exchange zone (Z.sub.E) are straight channels, the pre-header according to the invention is independent of this particular geometry and it is therefore possible envision other geometries for the heat exchange channels (Z.sub.E), for example channels of curved, zigzag, double zigzag, etc. shape. Further, regardless of the geometry adopted, ultimately, the depth of the exchange channels determines the height of the studs of the pre-header according to the invention.

LIST OF CITED REFERENCES

[0153] [1]: D. Plancq et al. “Status of the astrid gas power conversion system option”; HAL Id: cea-02338590; https://hal-cea.archives-ouvertes.fr/cea-02338590, Feb. 21, 2020.