A heat exchanger module, and a heat exchanger comprising said module

Abstract

The heat exchanger module comprises a first fluid domain defining a first fluid flow path extending in a general first fluid flowing path from a first fluid inlet to a first fluid outlet, and a second fluid domain defining a second fluid flow path extending in a general second fluid flowing path from a second fluid inlet to a second fluid outlet. A solid domain forms a separation between the first fluid domain and the second fluid domain. The first fluid domain extends from the first fluid inlet to the first fluid outlet and comprises a plurality of primary ducts adjacent the first fluid inlet and the first fluid outlet and a plurality of secondary ducts.

Description

A HEAT EXCHANGER MODULE, AND A HEAT EXCHANGER COMPRISINGSAID MODULEDESCRIPTIONTECHNICAL FIELD

[0001] The disclosure concerns heat exchangers. Embodiments disclosed herein specifically concern heat exchangers manufactured by additive manufacturing.BACKGROUND ART

[0002] Heat exchangers are used in a variety of systems and where heat shall be transferred from one fluid to another. For instance, heat exchangers are used to remove heat from a liquid, such as oil used as bearing fluid in hydrodynamic or hydrostatic bearings in a turbomachine.

[0003] Indirect heat exchangers usually include a first fluid domain and a second fluid domain separated by solid walls. The two fluids flow through the heat exchanger in the first fluid domain and in the second fluid domain. A temperature gradient causes thermal energy to transfer from the warmer fluid to the colder fluid through the solid domain which separates the first fluid domain and the second fluid domain from one another.

[0004] Presently known heat exchangers typically use shell-in-tube, alternating plates and fins, or alternating plate-plate configurations.

[0005] These known configurations are expensive to produce as they require extensive welding to assemble the solid domain which separates the two fluid domains from one another. Moreover, these structures are not particularly efficient from a thermodynamic point of view. Recently, more complex, and more efficient heat exchanger structures have been developed, using additive manufacturing. Typically, heat exchanger structures including a monolithic core having a bi-continuous or polycontinuous structure useful in heat exchange have been developed. These structures usually include a replicated unit cell.

[0006] There is still a need for further improving the heat transfer efficiency in heat exchangers, such that a compact heat exchanger with a volume significantly lower than conventional heat exchangers can be obtained.SUMMARY

[0007] According to one aspect, disclosed herein is a heat exchanger module, comprising: a first fluid domain defining a first fluid flow path extending in a general first fluid flowing path from a first fluid inlet to a first fluid outlet; and a second fluid domain defining a second fluid flow path extending in a general second fluid flowing path from a second fluid inlet to a second fluid outlet. The first fluid domain and the second fluid domain are separated by a solid domain forming a separation membrane between the first fluid domain and the second fluid domain. The first fluid domain extends from the first fluid inlet to the first fluid outlet. The first fluid domain comprises: a plurality of primary ducts adjacent the first fluid inlet and the first fluid outlet, each primary duct having a hydraulic diameter comprised between 0.2L’ and 0.3L’; a plurality of secondary ducts, each secondary duct having a hydraulic diameter comprised between 0.1L’ and 0.2L’; wherein: the hydraulic diameter is defined asDh = 4Vi / S in whichVi is the volume of the respective primary or secondary duct;S is the wetted inner surface of respective primary or secondary duct; and wherein L’ is defined asL' = 76 wherein V0 is the inner volume of a parallelepiped enveloping the first fluid domain, the second fluid domain and the solid domain of the heat exchanger module.

[0008] In some embodiments, the heat exchanger module can further comprise aplurality of tertiary ducts, wherein each tertiary duct may have a hydraulic diameter smaller than 0.1L’.

[0009] By these arrangements, a tradeoff between the heat transfer efficiency of the heat exchanger and the pressure drop along the heat exchange flow path can be achieved.

[0010] The secondary ducts can extend from the primary ducts to regions of higher heat transfer, while the tertiary ducts can extend between any of: two different primary ducts, two different secondary ducts, a primary duct and a secondary duct, and a secondary duct and a primary duct.

[0011] Further features of heat exchanger modules according to the present disclosure are defined in the dependent claims and described below with reference to exemplary embodiments.

[0012] According to a further aspect, disclosed herein is a heat exchanger including a plurality of heat exchanger modules as outlined above, stacked one on the other.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Reference is now made briefly to the accompanying drawings, in which:Fig. l is a schematic axonometric view of a heat exchanger in one embodiment;Fig.2 is an axonometric view of a module of the heat exchanger shown in Fig. l;Fig.3 is an axonometric view of a heat exchanger as shown in Fig. l, without an outer solid envelope enclosing the second fluid domain;Fig.4 is a top plan view of a heat exchanger including four heat exchanger modules, according to IV-IV of Fig.4A;Fig.4A is a side view according to A-A of Fig.4;Fig.4B is an axonometric view of the first fluid domain of a heat exchanger module of the heat exchanger shown in Fig.4;Fig.4C is an axonometric view of the second fluid domain of a heat exchanger module of the heat exchanger shown in Fig.4;Fig.4D is an axonometric view of the combined first fluid domain, secondfluid domain and solid domain of a heat exchanger module of the heat exchanger shown in Fig.4;Figs 5 A, 5B, 5C and 5D are cross-sectional views of a heat exchanger module of Fig.4 according to planes orthogonal to a first direction;Figs 6A, 6B, 6C and 6D are cross-sectional views of a heat exchanger module of Fig.4 according to planes orthogonal to a second direction, orthogonal to the first direction;Figs 7A, 7B, 7C and 7D; 7E, 7F are cross-sectional views of a heat exchanger module of Fig.4 according to planes orthogonal to a third direction, orthogonal to the first direction and the second direction;Figs. 8 A to 19D are views of a further embodiment of a heat exchanger according to the present disclosure.DETAILED DESCRIPTION

[0014] In the following description and enclosed drawings, exemplary embodiments of an oil / air heat exchanger are illustrated. The first fluid is oil and the second fluid is air. The heat exchanger can feature a cooler for an oil stream, for instance oil from bearings of a turbomachine, e.g., a turbine.

[0015] Fig.1 illustrates a schematic axonometric view of a heat exchanger 1. The heat exchanger 1 comprises a plurality of modules or units 3, one of which is shown in an axonometric view and in isolation in Fig.2. A single module 3 will be described in detail below. The modules 3 can be identical to one another or mirror-symmetrical to one another, for instance.

[0016] In Figs 1 and 2 the heat exchanger 1 and a single module 2 thereof are pictorially represented as having an outer parallelepiped body. However, as will become apparent from the description below, the outer planar walls of the heat exchanger 1 and of each module 3 thereof shown in Figs 1 and 2 can in fact be replaced by geometrical planes enveloping the structure of the heat exchanger and relevant modules, rather than being solid walls surrounding the inner volume of the heat exchanger 1 and of each module 3 thereof. In other words, the planar walls may pictorially represent a geometrical surface which envelopes the solid domain contained therein.

[0017] Fig. 3 shows an embodiment wherein the heat exchanger is not closed by outer planar solid walls, but simply enveloped in a geometrical volume of parallelepiped shape. Whether the outer parallelepiped envelope of the heat exchanger 1 is a physical structure formed by solid walls or simply represents the geometrical boundary of the heat exchanger depends, for instance, upon the nature of the second fluid flowing in the heat exchanger. If the second fluid is air, for instance, the outer envelope can be at least partly open, i.e., not represented by solid closure walls.

[0018] As shown in Figs. 1 and 3, the parallelepiped envelope enclosing the heat exchanger 1 has a first fluid inlet side la and a first fluid outlet side lb. In some embodiments, the first fluid inlet side la and the first fluid outlet side lb are arranged on two opposite and parallel faces of the parallelepiped enveloping the heat exchanger 1.

[0019] Each module 3 (see Figs. 1, 2, 3, 4, 4A, 4B, 4C) can include a first fluid inlet side 3a and a first fluid outlet side 3b. The modules 3 are stacked one on top of the other such that all first fluid inlet sides 3 a of the modules 3 are located on the first fluid inlet side la of the heat exchanger 3 and all first fluid outlet sides 3b of the modules 3 are located on the first fluid outlet side lb of the heat exchanger.

[0020] Referring to Figs 1 and 2, each module 3 extends from the first fluid inlet side 3a to the first fluid outlet side 3b in a direction X and the modules are stacked one on top of the other in a direction Z. Each module 3 furthermore extends in a direction Y, perpendicular to X and Y.

[0021] In the illustrated embodiment, each module 3 includes a plurality of first fluid inlet ports 5 aligned along the Y direction on the first fluid inlet side 3a. Each module 3 further includes a plurality of first fluid outlet ports 7 aligned along the Y direction on the first fluid outlet side 3b.

[0022] Each module 3 comprises a first fluid domain 10 extending in a general first fluid flowing path from the first fluid inlet 3a to the first fluid outlet 3b. The general first fluid flowing path is therefore direction X.

[0023] Figs 4B, 4C, 4D show axonometric view of a single module. Figs. 5A-5D, 6A-6D, and Figs. 7A-7F illustrate cross-sectional views according to planes orthogonal to directions X, Y, Z, in different positions along the development of the singlemodule. Referring specifically to Figs. 4, 5A-5D, 6A-6D, 7A-7F, each heat exchanger module 3 further comprises a solid domain 9. The solid domain 9 defines the boundaries of the first fluid domain 10 and fluidly separates the first fluid domain 10 from a second fluid domain 11. In some embodiments, the solid domain can be made of a metal structure generated by additive manufacturing. In each module, the solid domain9 extends between the first fluid inlet 3a and the first fluid outlet 3b.

[0024] In some embodiments, solid domains 9 of adjacent modules 3 are separated from one another, or can be in contact or integrated with one another with no fluid coupling between the respective modules, i.e. with no fluid connection between the first fluid domain of the two adjacent modules.

[0025] In other embodiments, as shown in Figs 5A, 5B, 5C, 5D, 6A, 6B, 6C 6D, 7A, 7B, 7C, 7D, 7E, and 7F, the solid domains 9 of adjacent modules 3 are in contact with one another and also form a fluid connection therebetween, such that the first fluid domains 10 and the second fluid domains 11 of two adjacent modules are fluidly coupled to one another. In some embodiments a fluid connection can be formed between each pair of mutually adjacent modules, such that a fluid connection will be established between all first fluid domains 10 of the heat exchanger 1.

[0026] Still referring to Figs 5A, 5B, 5C, 5D, 6A, 6B, 6C 6D, 7A, 7B, 7C, 7D, 7E, and 7F, the second fluid domain 11 is represented by the volume contained within the parallelepiped boundaries of the heat exchanger 1 and the outer surface of the solid domain 9. In the illustrated embodiment, the second fluid domain is an air domain, as the heat exchanger can be a liquid / air heat exchanger. In some embodiments, the heat exchanger 1 can be a liquid cooler, adapted to cool a liquid circulating in the first fluid domain 10 by transfer of heat through the solid domain 9 from the first fluid domain10 to the second fluid domain 11. In some embodiments, the first fluid can be oil.

[0027] The second fluid domain 11 defines a second fluid flow path which extends in a general second fluid flowing direction from a second fluid inlet side 3c to a second fluid outlet side 3d.

[0028] In the illustrated embodiment, the second fluid inlet side 3c of each heat exchanger module 3 is located on a side of the module 3, which is orthogonal to the firstfluid inlet side 3a, and the first fluid outlet side 3b. The second fluid outlet side 3d of each heat exchanger module 3 is located on a side of the module 3 opposite to the second fluid inlet side 3c, parallel thereto and distanced therefrom in the general direction of flow of the second fluid, i.e., in the direction Y.

[0029] The first fluid inlet side 3a, the second fluid inlet side 3c, the first fluid outlet side 3b and the second fluid outlet side 3d thus form the side surfaces of the parallelepiped-shaped heat exchanger module 3.

[0030] As the heat exchanger modules 3 are stacked one on top of the other along direction Z (Figs 1, 3, 4A), with all first fluid inlet sides 3a of the modules 3 located on the first fluid inlet side la of the heat exchanger 1 and all first fluid outlet sides 3b of the modules 3 located on the first fluid outlet side lb of the heat exchanger 1, the second fluid inlet sides 3c are positioned on a second fluid inlet side 1c of the parallelepiped-shaped envelope of the heat exchanger 1, and the second fluid outlet sides 3d are positioned on a second fluid outlet side Id of the parallelepiped-shaped envelope of the heat exchanger 1, with the side surfaces 1c and Id parallel to one another, distanced from one another in the general direction of flow of the second fluid (direction Y) and orthogonal to the sides la and lb on which the first fluid inlets ports 5 and the first fluid outlet ports 7 are located.

[0031] The direction Y, which extends from the second fluid inlet side 3 c, 1c of the heat exchanger module 3 and of the heat exchanger 1 to the second fluid outlet side 3d, Id of the heat exchanger module 3 and of the heat exchanger 1 (Figs. 1, 2, 3, 4, 4A, 4B, 4C, 4D), defines the general second fluid flowing direction, extending from the second fluid inlet to the second fluid outlet.

[0032] Here below the three dimensions of each parallelepiped enveloping a respective heat exchanger module 3 are labeled L, W and H, wherein L (also referred to as “length”) is the dimension in the X direction, W (also referred to as “width”) is the dimension in the Y direction and H (also referred to as “height”) is the dimension in the Z direction.

[0033] The parallelepiped envelope of each heat exchanger module 3 has an inner volume V0 given by L*H*W (V=LxHxW). In the following description, reference willbe made to a characteristic length L ’ of the heat exchanger module 3 defined as:L' = / V

[0034] The shape of the solid domain 9 and therefore of the first liquid domain 10 contained therein, and of the second liquid domain 11 surrounding the solid domain, is best shown in Figs. 4 to 7. Specifically, Fig.4 is a top plan view of a heat exchanger module 3. Figs 5 A, 5B, 5C and 5D are cross-sectional views of the heat exchanger modules 3 according to planes orthogonal to the direction X, i.e. along the length L of the heat exchanger module 3. More specifically, Figs 5 A, 5B, 5C and 5D are cross sectional views at a distance of L / 5, 2L / 5, 3L / 5 and 4L / 5, respectively, from the first fluid inlet side 3a of the heat exchanger module 3.

[0035] Figs 6A, 6B, 6C, 6D are cross-sectional views of the heat exchanger module 3 according to planes orthogonal to the direction Y, i.e. along the width W of the heat exchanger module 3. More specifically, Figs 6A, 6B, 6C and 6D are cross sectional view at a distance of W / 5, 2W / 5, 3W / 5 and 4W / 5, respectively, from the second fluid inlet side 3c of the heat exchanger module 3.

[0036] Figs 7A, 7B, 7C, 7D and 7E are cross-sectional views of the heat exchanger modules 3 according to planes orthogonal to the direction Z, i.e. along the height H of the heat exchanger module 3. More specifically, Figs 7A, 7B, 7C, 7D and 7E are cross sectional view at a distance of 0, H / 5, 2H / 5, 3H / 5 and H, respectively, from the bottom flat surface or from the top flat surface delimiting the respective heat exchanger module 3.

[0037] The combination of Figs. 4, 5A, 5B, 5C, 5D; 6A, 6B, 6C, 6D; 7A, 7B, 7C, 7D, 7E show the complex shape of the solid domain 9 of an individual heat exchanger module 3. The remaining heat exchanger modules 3 are either identical or symmetrical to the one shown in the above-mentioned figures, with respect to a plane parallel to the direction X and Y, i.e., orthogonal to the direction Z (conventionally the “height”) of the heat exchanger module 3.

[0038] As best shown in Fig.4, the solid domain 9 of a heat exchanger module 3 comprises a structure like a blood circulatory system with interconnected vessels ofvariable dimensions. The inner volume of the vessels cumulatively defines the first fluid domain 10.

[0039] In some embodiments, the ducts include two different types of ducts, namely primary ducts and secondary ducts, defined in more detail below. In other embodiments, the ducts include three different types of ducts, namely: primary ducts, secondary ducts, and tertiary ducts, described in more detail below.

[0040] The primary ducts extend from regions of relatively low heat transfer, positioned near the inlets and outlets of the fluid domains, to regions of high heat transfer, positioned near to the diagonal of the domain. The secondary ducts extend from the primary ducts to the regions of higher heat transfer, while the tertiary ducts extend between any of: two different primary ducts two different secondary ducts, a primary duct and a secondary duct, and a secondary and a primary duct. The primary ducts have greater dimensions than the secondary ducts, and the secondary ducts have greater dimension than the tertiary ducts, as quantified below. Recognizing that narrower ducts have higher pressure losses but also higher heat transfer (due to the increased heat transfer surface area), and wider ducts have the opposite, by adjusting the dimensions of the ducts in different regions of the domain, the heat transfer across a layer can be optimized.

[0041] More specifically, as shown in Fig.4, the interior of the solid domain 9 defines a plurality of primary ducts 21 belonging to the first fluid domain 10 and arranged adjacent to the first fluid inlet and the first fluid outlet. The primary ducts are the ducts having the largest cross section. The solid domain 9 further defines a plurality of secondary ducts 23, the inner volume whereof belongs to the first fluid domain 10, and which have an intermediate cross section, smaller than the first cross section, and further defines a plurality of tertiary ducts 25, the inner volume whereof belongs to the first fluid domain 10 and which have a cross section smaller than the first cross section and the second cross section.

[0042] In embodiments, the secondary ducts extend from the primary ducts adjacent to the first fluid inlet and the primary ducts adjacent the first fluid outlet. The tertiary ducts connect secondary ducts to one another.

[0043] The structure of the first fluid domain 10 and of the solid domain 9 forming the boundaries, which separate the first fluid domain 10 from the second fluid domain 11, is generated by a virtual topology optimization algorithm.

[0044] The optimal arrangement of the primary ducts, the secondary ducts, and the tertiary ducts found by the virtual topology optimization algorithm is visually reminiscent of a biological cardiovascular system. By this analogy with a cardiovascular system, the primary ducts are like large veins or arteries which carry high or low temperature fluids away from or towards the inlets and outlets, the secondary ducts are like arterioles or venules which lead from large vessels to smaller ones, and the tertiary ducts like capillaries, which have a maximal surface area to maximize heat transfer.

[0045] In some embodiments, the velocity boundary conditions for the first fluid side (oil side) can be set at a value ranging from 0.01 to 0.5 m / s, for instance 0.05 to 0.2 m / s at the inlet and the velocity boundary conditions for the second fluid side (air side) can be set at a value ranging from 0.01 to 0.5 m / s, for instance from 0.05 to 0.2 m / s.

[0046] In some embodiments, the temperature boundary conditions can be as follows: first fluid inlet temperature ranging between 110°C and 150°C, for instance between 120°C and 130°C; second fluid inlet temperature ranging between 40°C and 70°C, for instance between 50°C and 60°C.

[0047] As best shown in Fig. 4, the primary ducts, the secondary ducts and the tertiary ducts lack any regular or repetitive structure, since the virtual topology optimization algorithm takes into consideration the temperature variations of the first fluid and second fluid in each point of the first fluid domain 10 and second fluid domain 11.

[0048] In Fig.4 the following is noted. The primary ducts 21 having the larger cross section are arranged on the first fluid inlet side 3a and on the first fluid outlet side 3b in different locations along the Y direction. More specifically, the primary ducts 21 are positioned near the second fluid inlet side 3c and near the first fluid inlet side 3a and in a diagonally opposite position, namely near the second fluid outlet side 3d and the first fluid outlet side 3b. The secondary ducts 23 having an intermediate dimension extend in a direction oriented in the X direction and W direction, i.e., they show a general inclination in the direction D of a diagonal in the rectangular top view, fromthe comer at the intersection of the first fluid inlet side and second fluid inlet side towards the comer at the intersection of the first fluid outlet side and second fluid outlet side.

[0049] The tertiary ducts 25 having the smallest cross-sectional direction fluidly connect adjacent intermediate secondary ducts 23 to one another.

[0050] The dimensions of the primary, secondary, and tertiary ducts 21, 23, 25 can be defined as follows, referring to a hydraulic diameter of the ducts. The hydraulic diameter is defined asDh = 4Vi / S in whichVi is the duct volume, i.e., the inner volume of the respective duct;S is the wetted inner surface of respective duct; and wherein L’ is defined asL' = o wherein V0 is the inner volume of a parallelepiped enveloping the first fluid domain, the second fluid domain and the solid domain of the heat exchanger module.

[0051] The primary, larger ducts 21 have a hydraulic diameter comprised between 0.2L’ and 0.3L’. The secondary, intermediate ducts 23 have a hydraulic diameter comprised between 0.1L’ and 0.2L’. The tertiary, smaller ducts 25 extending between adjacent intermediate ducts 23 ducts have a hydraulic diameter smaller than 0.1L’, for instance comprised between 0.06L’ and 0.09L’.

[0052] It shall be understood that all primary, secondary, and tertiary ducts of the heat exchanger can satisfy the above geometrical relationships. However, this is not mandatory. In some embodiments, most of the ducts can be classified as primary, secondary, and tertiary ducts based on the values of the hydraulic diameter outlined above, while additional ducts may be present in the heat exchanger which fall outside the ranges specified above.

[0053] From another perspective, the primary, secondary, and tertiary ducts 21, 23, 25 are characterized by a characteristic dimension defined as follows:Lx = VVx wherein Vx is the inner volume of the duct.

[0054] In some embodiments, each primary duct 21 has a characteristic dimension LI comprised between 0.8L’ and 0.2L ’, preferably between 0.55L ’ and 0.35L ’, wherein LI is defined asLI = 1 in which VI is the volume of the respective primary duct 21.

[0055] In some embodiment, each secondary duct 23 has a characteristic dimension L2 comprised between 0. VL ’ and 0.2Z ’, preferably between 0.15Z’ and 0. 17L ’, wherein L2 is defined asL2 = MV2 in which V2 is the volume of the respective secondary duct 23.

[0056] In some embodiments, each tertiary duct 25 has a characteristic dimension L3 smaller than 0.1L’, preferably comprised between 0.03Z ’ and 0.07Z ’, more preferably between 0.04Z ’ and 0.06Z ’ wherein L3 is defined asL3 = V73 in which V3 is the volume of the respective tertiary duct 25.

[0057] The embodiment described above has a cross-flow configuration, wherein: the first fluid domain 10 has respective inlet and outlet arranged at respective mutually opposite sides of the heat exchanger module; the second fluid domain has respective inlet and outlet arranged at respective mutually opposite sides of the heat exchanger module; and wherein the general flow directions are arranged orthogonal to one another. This is not the only possible configuration of the heat exchanger module.

[0058] A counter-flow arrangement would also be possible, with the inlet and outlet ports of the first fluid arranged on first and second opposite sides of the heat exchanger module, the inlet ports of the second fluid are arranged on the same side as the outletports of the first fluid, and the outlet ports of the second fluid are arranged on the same side as the inlet ports of the first fluid.

[0059] In some embodiments, one of the first fluid domain and second fluid domain may have an inlet and an outlet arranged on the same side of the heat exchanger module. The flow path of the fluid would in that case feature a U-turn inside the heat exchanger module.

[0060] Figs. 8 to 19 illustrate an embodiment wherein the first fluid domain 10, for instance an oil domain, has a first fluid inlet port (or a plurality of first fluid inlet ports) and a first fluid outlet port (or a plurality of first fluid outlet ports) on a same side of a heat exchanger module, while the second fluid domain 11, for instance an air domain, has a second fluid inlet side 3c and a second fluid outlet side 3d, arranged at opposite sides of the heat exchanger module, different from the side where the first fluid inlet port(s) and the first fluid outlet port(s) are located.

[0061] Specifically, Figs.8 A to 8E illustrate five axonometric views of the solid domain 9 of the heat exchanger in this embodiment. The heat exchanger includes five modules 3. Reference numbers 5 and 7 indicate the inlet and outlet of the first fluid domain 10. Reference number 11 indicates the second fluid domain, which is separated from the first fluid domain 10 by the solid domain 9. Figs. 9 and 10 illustrate a bottom view and a top view of the solid domain of the heat exchanger in this embodiment.

[0062] The first fluid domain is shown in two axonometric views in Figs. 11 and 12. The second fluid domain is shown in two axonometric views in Figs. 13 and 14. Fig. 15 illustrates an axonometric view of the first fluid domain 10 and of the second fluid domain 11 in an axonometric view, while the solid domain, which separate the first fluid domain from the second fluid domain, is shown in an axonometric view in Fig.16.

[0063] With reference to Fig. 8C and with reference to the X, Y, Z directions shown therein, Figs 17A, 17B, 17C, 17D are cross-sectional views of the heat exchanger module of the second embodiment according to planes orthogonal to the X direction. More specifically, Figs 17A, 17B, 17C and 17D are cross sectional view at a distance of 1 / 5, 2 / 5, 3 / 5 and 4 / 5 of the dimension along direction X of the heat exchanger module 3. Figs 18 A, 18B, 17C and 18D are cross-sectional views of the heat exchanger moduleof the second embodiment according to planes orthogonal to the Y direction. More specifically, Figs 18A, 18B, 18C and 18D are cross sectional view at a distance of 1 / 5, 2 / 5, 3 / 5 and 4 / 5 of the dimension along direction Y of the heat exchanger module 3. Figs 19A, 19B, 19C, 19D are cross-sectional views of the heat exchanger module of the second embodiment according to planes orthogonal to the Z direction. More specifically, Figs 19A, 19B, 19C and 19D are cross sectional view at a distance of 1 / 5, 2 / 5, 3 / 5 and 4 / 5 of the dimension along direction Z of the heat exchanger module 3.

[0064] By “general” fluid flow path the overall direction of flow of the relevant fluid at macro-level within the respective fluid domain is understood. Inside the relevant fluid domain, the flow is divided into the primary, secondary and tertiary ducts, which as a general rule follow flow directions which depart from the main or general direction of flow of the relevant fluid.

[0065] As pictorially shown in Figs. 8 A to 19F, the first fluid domain is characterized by primary, secondary and tertiary ducts, dimensioned as described above in connection with Figs. 1 to 7.

[0066] Exemplary embodiments have been disclosed above and illustrated in the accompanying drawings. It will be understood by those skilled in the art that various changes, omissions and additions may be made to that which is specifically disclosed herein without departing from the scope of the invention as defined in the following claims.

Claims

CLAIMS1. A heat exchanger module, comprising: a first fluid domain defining a first fluid flow path extending in a general first fluid flowing path from a first fluid inlet to a first fluid outlet; a second fluid domain defining a second fluid flow path extending in a general second fluid flowing path from a second fluid inlet to a second fluid outlet; and a solid domain forming a separation between the first fluid domain and the second fluid domain; wherein the first fluid domain extends from the first fluid inlet to the first fluid outlet and comprises: a plurality of primary ducts adjacent the first fluid inlet and the first fluid outlet, each primary duct having a hydraulic diameter comprised between 0.2L’ and 0.3L’; and a plurality of secondary ducts, each secondary duct having a hydraulic diameter comprised between 0. IL’ and 0.2L’; wherein the primary ducts and the secondary ducts are defined by the solid domain; wherein: the hydraulic diameter is defined asDh = 4Vi / S in whichVi is the volume of the respective primary or secondary duct;S is the wetted inner surface of respective primary or secondary duct; wherein L’ is defined asL' = PO wherein VO is the inner volume of a parallelepiped enveloping the first fluid domain, the second fluid domain and the solid domain of the heat exchanger module.

2. The heat exchanger module of claim 1 , further comprising a plurality of tertiary ducts, each tertiary duct having a hydraulic diameter smaller than 0. IL’ ; andwherein: the secondary ducts extend from the primary ducts to a regions of higher heat transfer, while the tertiary ducts extend between any of: two different primary ducts, two different secondary ducts, a primary duct and a secondary duct, and a secondary and a primary duct; wherein the tertiary ducts are defined by the solid domain.

3. The heat exchanger module of claim 1 or 2, wherein: the first fluid inlet is arranged at a first side of the heat exchanger module; the first fluid outlet is arranged at a second side of the heat exchanger module; and the first side and the second side are parallel to one another and distanced from one another along the general first fluid flowing path.

4. The heat exchanger module of claim 1 or 2 or 3, wherein: the second fluid inlet is arranged at a third side of the heat exchanger module; the second fluid outlet is arranged at a fourth side of the heat exchanger module; the third side and the fourth side are parallel to one another and distanced from one another along the general second fluid flowing path; and the general second fluid flowing path and the general first fluid flowing path are orthogonal to one another.

5. The heat exchanger module of claim 1 or 2, wherein the first fluid inlet and the first fluid outlet are arranged at a first side of the heat exchanger module; wherein the second fluid inlet is arranged at a second side of the heat exchanger module; the second fluid outlet is arranged at a third side of the heat exchanger; and the second side is opposite the third side.

6. The heat exchanger module of any one of the preceding claims, wherein the first fluid inlet comprises a plurality of first fluid inlet ports.

7. The heat exchanger module of claim 6, wherein the first fluid inlet ports are aligned along a direction orthogonal to the general first fluid flowing path and parallel to the general second fluid flowing path.

8. The heat exchanger module of any one of the preceding claims, wherein the first fluid outlet comprises a plurality of first fluid outlet ports.

9. The heat exchanger module of claim 8, wherein the first fluid outlet ports are aligned along a direction orthogonal to the general first fluid flowing pathand parallel to the general second fluid flowing path.

10. The heat exchanger module of any one of the preceding claims, wherein each primary duct has a characteristic dimension LI comprised between 0.8L’ and 0.2L’, preferably between 0.55L’ and 0.35L’, wherein LI is defined asLI = 1 in which VI is the volume of the respective primary duct.

11. The heat exchanger module of any one of the preceding claims, wherein each secondary duct has a characteristic dimension L2 comprised between 0.1L’ and 0.2L’, preferably between 0.15L’ and 0.17L’, wherein L2 is defined asL2 = MV2 in which V2 is the volume of the respective secondary duct.

12. The heat exchanger module of any one of the preceding claims, wherein each tertiary duct has a characteristic dimension L3 smaller than 0.1 L’, preferably between 0.03L’ and 0.07L’, more preferably between 0.04L’ and 0.06L’ wherein L3 is defined asL3 = MV3 in which V3 is the volume of the respective tertiary duct.

13. The heat exchanger module of any one of the preceding claims, wherein the solid region is generated by additive manufacturing.

14. The heat exchanger module of any one of the preceding claims, wherein the primary ducts and the secondary ducts lack any regular or repetitive structure.

15. The heat exchanger module of claim 14, when dependent on claim 2, wherein the tertiary ducts lack any regular or repetitive structure.

16. A heat exchanger comprising a plurality of heat exchanger modules according to one or more of the preceding claims, arranged one on top of the other along a direction orthogonal to the general first fluid flowing path and to the general second fluid flowing path.

17. The heat exchanger of claim 16, wherein adjacent heat exchanger modules are equal or mirror-symmetrical to one another.

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