Patent Description:
Additive manufacturing processes or systems can be used to print or build three-dimensional parts or components from digital models, which can be beneficial for rapid prototyping and manufacturing. During manufacture of the component, support structures may be included within the part to provide added rigidity for partially-formed portions. Such support structures are typically removed from the completed component after manufacture. In some cases the completed component can fully enclose an interior space, where removal of interior support structures can be difficult, impractical or even impossible.

<CIT> discloses a heat exchanger that has a plurality of sets of fluid channels, each fluid channel having first and second end portions and an intermediate portion between the first and second end portions. <CIT> discloses a heat generating component such as a microprocessor in a small form factor, or a low profile electronic device, e.g. a laptop computer, being cooled by using an elongated hollow heat exchanger with a fan at one end of the heat exchanger. <CIT> discloses a thermoconductive fluid-confining tube having a plurality of thermoconductive elements each having opposed major surfaces. <CIT> discloses providing a large number of slit holes, in the vicinity of an end face located in an upstream side of air flow, in a line along the end face of a fin and spaced apart by a specified distance from each other.

Claim <NUM> is directed at an additively manufactured heat-carrying component. In the following, apparatus and/or methods referred to as embodiments that nevertheless do not fall within the scope of the claims should be understood as examples useful for understanding the invention.

Aspects of the present disclosure relate to a heat-carrying component, and examples of such a component are described herein in the context of a turbine engine and gearbox. It will be understood that the disclosure may have general applicability within an engine, including turbines and compressors and non-airfoil engine components, as well as in non-aircraft applications, such as other mobile applications and non-mobile industrial, commercial, and residential applications.

All directional references (e.g., radial, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise) are only used for identification purposes to aid the reader's understanding of the disclosure, and do not create limitations, particularly as to the position, orientation, or use thereof. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and can include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. The exemplary drawings are for purposes of illustration only and the dimensions, positions, order, and relative sizes reflected in the drawings attached hereto can vary.

As used herein, the term "forward" or "upstream" refers to moving in a direction toward the engine inlet, or a component being relatively closer to the engine inlet as compared to another component. The term "aft" or "downstream" refers to a direction toward the rear or outlet of the engine relative to the engine centerline. Additionally, as used herein, the terms "radial" or "radially" refer to a dimension extending between a center longitudinal axis of the engine and an outer engine circumference. It should be further understood that "a set" can include any number of the respectively described elements, including only one element.

An exemplary turbine engine <NUM> is illustrated in <FIG>. The turbine engine <NUM> can be a gas turbine engine, including a turbofan, turboprop, or turboshaft engine in non-limiting examples. The turbine engine <NUM> can include an air intake with a fan <NUM> that supplies air to a high pressure compression region <NUM>. The air intake with a fan <NUM> and the high pressure compression region <NUM> collectively are known as the 'cold section' of the turbine engine <NUM> upstream of the combustion. It is also contemplated that multiple high pressure compression regions can be provided in the turbine engine <NUM>.

The high pressure compression region <NUM> provides a combustion chamber <NUM> with high pressure air. In the combustion chamber <NUM>, the high pressure air is mixed with fuel and combusted. The hot and pressurized combusted gases pass through a high pressure turbine region <NUM> and a low pressure turbine region <NUM> before exhausting from the turbine engine <NUM>.

As the pressurized gases pass through the high pressure turbine (not shown) of the high pressure turbine region <NUM> and the low pressure turbine (not shown) of the low pressure turbine region <NUM>, the turbines extract rotational energy from the flow of the gases passing through the turbine engine <NUM>. The high pressure turbine of the high pressure turbine region <NUM> can be coupled to the compression mechanism (not shown) of the high pressure compression region <NUM> by way of a shaft to power the compression mechanism. The low pressure turbine can be coupled to the fan <NUM> of the air intake by way of a shaft to power the fan <NUM>. The turbine engine can also have an afterburner that burns an additional amount of fuel downstream of the low pressure turbine region <NUM> to increase the velocity of the exhausted gases, and thereby increasing thrust. In this manner the turbine engine <NUM> can include at least a compressor, combustor, and turbine in axial flow arrangement.

An air turbine starter or generator <NUM> can be mounted to the turbine engine <NUM>. An accessory gearbox (AGB) <NUM>, also referred to herein as "gearbox <NUM>," can be coupled to the generator <NUM> and mounted to the turbine engine <NUM>. Together, the generator <NUM> and gearbox <NUM> can define an assembly which is commonly referred to as an Integrated Starter/Generator Gearbox (ISGB) <NUM>.

The generator <NUM> and gearbox <NUM> can be selectively operably coupled with the turbine engine <NUM> at either the high pressure or low pressure turbine region <NUM>, <NUM> by way of a mechanical power take-off <NUM>. The mechanical power take-off <NUM> contains multiple gears and means for mechanical coupling of the gearbox <NUM> to the turbine engine <NUM>. Under normal operating conditions, the power take-off <NUM> translates power from the turbine engine <NUM> to the gearbox <NUM> to power accessories of the aircraft for example but not limited to fuel pumps, electrical systems, and cabin environment controls. The generator <NUM> can be mounted on the outside of either the air intake region containing the fan <NUM> or on the core near the high pressure compression region <NUM>.

The turbine engine <NUM> can include at least one heat-carrying component <NUM> (also referred to herein as "component <NUM>"). According to the invention, the heat-carrying component <NUM> is an additively manufactured component. As used herein, an "additively manufactured" component will refer to a component formed by an additive manufacturing (AM) process, wherein the component is built layer-by-layer by successive deposition of material. AM is an appropriate name to describe the technologies that build 3D objects by adding layer-upon-layer of material, whether the material is plastic or metal. AM technologies can utilize a computer, 3D modeling software (Computer Aided Design or CAD), machine equipment, and layering material. Once a CAD sketch is produced, the AM equipment can read in data from the CAD file and lay down or add successive layers of liquid, powder, sheet material or other material, in a layer-upon-layer fashion to fabricate a 3D object. It should be understood that the term "additive manufacturing" encompasses many technologies including subsets like 3D Printing, Rapid Prototyping (RP), Direct Digital Manufacturing (DDM), layered manufacturing and additive fabrication. Non-limiting examples of additive manufacturing that can be utilized to form an additively-manufactured component include powder bed fusion, vat photopolymerization, binder jetting, material extrusion, directed energy deposition, material jetting, or sheet lamination.

Turning to <FIG>, one example of such an additively-manufactured heat-carrying component <NUM> is illustrated in the form of a generator housing <NUM> for the generator <NUM> of <FIG>. It is contemplated that other portions of the generator <NUM> not shown can also be formed by additive manufacturing such that the generator <NUM> itself can be an additively-manufactured component. It is further contemplated that any component within the turbine engine <NUM> can be additively manufactured, and that aspects of the present disclosure can have general applicability to any additively-manufactured component or heat-carrying component formed by a variety of manufacturing methods such as casting, including in non-engine environments.

The completed additively-manufactured generator housing <NUM> is illustrated in a cross-sectional view. An exemplary base plate <NUM> is shown beneath the generator housing <NUM> that can be utilized during an additive manufacturing process to form the generator housing <NUM>. The generator housing <NUM> can be built or printed layer-by-layer, illustrated with exemplary layers <NUM> intersecting the completed generator housing <NUM> wherein successive layers <NUM> are added in a direction illustrated by a direction arrow <NUM>. It should be understood that other components such as exterior supporting arms, a printing head, and the like can be utilized during the additive manufacturing process and are omitted for clarity.

The generator housing <NUM> includes an outer casing <NUM> bounding an interior <NUM>. It can also be appreciated that the outer casing <NUM> of the completed generator housing <NUM> can define an exteriorly inaccessible portion <NUM> (also referred to herein as "inaccessible portion <NUM>") within the interior <NUM>. As used here, an "exteriorly inaccessible portion" of a component will refer to a portion that cannot be accessed from outside the component, such as by hand and/or with tools, for performing operations such as machining or assembly within the component. Such an exteriorly inaccessible portion can also be fluidly separated from the exterior of the component, such as being airtight or watertight, although this need not be the case. In addition, while the outer casing <NUM> is illustrated as rectangular or box-like, it is also contemplated that the outer casing <NUM> can be curved to match an exterior surface <NUM> of the turbine engine <NUM> (<FIG>).

At least one conduit <NUM> is located within the interior <NUM>, and at least a portion <NUM> of the conduit <NUM> can be located within the inaccessible portion <NUM>. The conduit <NUM> can be configured to direct fluids or coolant, including oil, through the generator <NUM> during operation of the turbine engine <NUM>. The conduit <NUM> is unitarily formed with the outer casing <NUM>.

It can be appreciated that support structures can be utilized to support various components within the generator housing <NUM>, including during additive manufacture of the generator housing <NUM>. For example, the use of such support structures can prevent shifting or other undesired movement of components within the outer casing <NUM> during manufacture or during operation of the turbine engine <NUM>. One such example is illustrated as a first additive support structure <NUM> supporting the conduit <NUM>. The first additive support structure <NUM> is coupled to, or unitarily formed with, the conduit <NUM> as shown. The first additive support structure <NUM> can have any desired shape, size, or thickness. The generator housing <NUM> is formed by additive manufacturing, and the generator housing <NUM> includes a monolithic body having the outer casing <NUM>, the conduit <NUM>, and a support structure such as the first additive support structure <NUM>.

<FIG> illustrates a portion of the generator housing <NUM> in further detail. The first additive support structure <NUM> further includes at least two thermally-conductive support members <NUM> supporting the conduit <NUM> during the additive manufacturing process. The support members <NUM> are spaced apart to define at least two fins <NUM> which collectively form a heat exchanger <NUM> thermally coupled to the conduit <NUM>.

A second conduit <NUM> similar to the conduit <NUM> is also coupled to the first additive support structure <NUM>. More specifically, the second conduit <NUM> is thermally coupled to the fins <NUM> of the heat exchanger <NUM> defined by the first additive support structure <NUM>.

In addition, a second additive support structure <NUM> similar to the first additive support structure <NUM> is illustrated between the outer casing <NUM> and the conduit <NUM>. It is contemplated that the second additive support structure <NUM> can also define a second heat exchanger <NUM> similar to the heat exchanger <NUM> and having a plurality of fins <NUM>. The fins <NUM> can be thermally coupled to both the outer casing <NUM> and the conduit <NUM> as shown. In this manner, a single conduit within the generator housing <NUM> can have multiple heat exchangers formed by corresponding multiple support structures as desired.

In still another example, a third additive support structure <NUM> similar to the additive support structure <NUM> can be coupled to a third conduit <NUM> and the outer casing <NUM>. It will be understood that a plurality of additive support structures can be utilized within the generator housing <NUM> and coupled between conduits, or coupled between a conduit and the outer casing, or coupled to any component within the generator housing <NUM>, in non-limiting examples.

Turning to <FIG>, a cross-sectional view illustrates the conduit <NUM> and first and second additive support structures <NUM>, <NUM> as well as a heat-carrying fluid <NUM> within the conduit <NUM>. It is further contemplated that the conduit <NUM> can include an additively-manufactured monolithic conduit wall <NUM> having the heat exchanger <NUM> including the fins <NUM>. Adjacent fins <NUM> can be spaced apart by a distance <NUM> to define a cooling channel <NUM> therebetween. In addition, the monolithic conduit wall <NUM> can also include the second additive support structure <NUM> with the heat exchanger <NUM> and fins <NUM>.

It is also contemplated that the fins <NUM> can include cooling enhancement structures configured to improve cooling performance of the heat exchanger <NUM>. One cooling enhancement structure is illustrated in the form of an aperture or hole <NUM> through a first fin 74A, where air in adjacent cooling channels <NUM> can flow through the first fin 74A to increase a rate of heat transfer from the first fin 74A. Another cooling enhancement structure is illustrated in the form of dimples <NUM> in the surface of a second fin 74B. Such dimples <NUM> can increase the surface area of the second fin 74B and increase a rate of heat transfer from the fin 74B as compared to a smooth fin <NUM>. Other cooling enhancement structures can be in the form of local surface roughness, latticed structures, or cutouts can be included in any of the additive support structures <NUM>, <NUM> forming the heat exchangers <NUM>, <NUM>.

During operation, heat-carrying fluid <NUM> such as oil can flow through any or all of the conduits <NUM>, <NUM>, <NUM>. In one example, a first heat-carrying fluid can flow through the conduit <NUM> while additional or second heat-carrying fluid flows through the second conduit <NUM>. In another example, the same heat-carrying fluid can flow through all of the conduits <NUM>, <NUM>, <NUM>.

Arrows <NUM> (<FIG>) illustrate a conductive transfer of heat from the heat-carrying fluid <NUM> in contact with the conduit wall <NUM>, from the conduit wall <NUM> to the fins <NUM> of the heat exchanger <NUM>, and from the fins <NUM> to air within the cooling channel <NUM>. Heat can transfer similarly from the second conduit <NUM> (<FIG>) to the fins <NUM> and cooling channel <NUM>. With regard to the second heat exchanger <NUM>, it is further contemplated that heat illustrated by arrows <NUM> (<FIG>) can transfer from the third conduit <NUM> to the outer casing <NUM> or air within the interior <NUM> via the second additive support structure <NUM> and fins <NUM>. In this manner an additive support structure, such as the first or second additive support structures <NUM>, <NUM> in the form of the respective heat exchangers <NUM>, <NUM> can be configured to transfer heat away from any or all of the conduits <NUM>, <NUM>, <NUM>, including moving heat away from heat-carrying fluid <NUM> such as oil that may be flowing within the conduits <NUM>, <NUM>, <NUM>.

It can be appreciated that heat can also transfer away from the interior <NUM> of the generator housing <NUM> via the outer casing <NUM>. In another example, a plurality of vent holes (not shown) can be provided in the outer casing <NUM> to facilitate the transfer of heat from the interior <NUM> of the generator housing <NUM>. Such vent holes can be integrally formed with the outer casing <NUM>, and can be of a size that does not permit access to the interior <NUM> with tools or other devices while permitting air to flow into or out of the interior <NUM>.

Aspects of the present disclosure provide for a method of cooling a monolithic heat-carrying component such as the component <NUM> having the outer casing <NUM> bounding the interior <NUM>. The method can include moving heat-carrying fluid <NUM> through a conduit, such as the conduit <NUM>, <NUM>, <NUM>, located within the interior <NUM> and unitarily formed with the outer casing <NUM>. The method can also include transferring heat from the heat-carrying fluid <NUM> to an additively-manufactured support structure, such as the first or second additive support structures <NUM>, <NUM> (<FIG>) having the at least two spaced fins <NUM>, <NUM> collectively forming the heat exchanger <NUM>, <NUM>, wherein the additively-manufactured support structures <NUM>, <NUM> are located within the interior <NUM> or the exteriorly inaccessible portion <NUM>. Optionally, the method can include conducting heat from the heat-carrying fluid <NUM> to a conduit wall, such as the conduit wall <NUM> thermally coupled to the first additive support structure <NUM>. The method can also optionally include conducting heat from the heat-carrying fluid <NUM> to the outer casing <NUM> via the second additive-manufactured support structure <NUM> as seen in <FIG>. The method can optionally further include moving additional heat-carrying fluid <NUM> through the second conduit <NUM> thermally coupled to the heat exchanger <NUM>, and transferring heat away from each of the conduit <NUM> and second conduit <NUM> via the heat exchanger <NUM> as shown in <FIG>. The method can optionally further include transferring heat from the fins <NUM> to air flowing between the fins <NUM> as shown in <FIG>.

The above described aspects provide for a variety of benefits. For power generator parts manufactured by additive printing technology, support structures utilized within exteriorly inaccessible spaces during printing cannot be removed (e.g. machined out). The use of fins as support structures can reduce the weight of the additively-manufactured component while adding improved functionality such as cooling, which can increase performance or efficiency during operation of the additively-manufactured component. In addition, the improved ability to cool such exteriorly inaccessible regions can increase the working lifetime of the part.

Claim 1:
An additively manufactured heat-carrying component (<NUM>), comprising:
an outer casing (<NUM>) bounding an interior (<NUM>);
a conduit (<NUM>, <NUM>, <NUM>) located within the interior (<NUM>);
a support structure (<NUM>, <NUM>, <NUM>) located within the interior (<NUM>) and having at least two thermally-conductive support members (<NUM>, <NUM>) supporting the first conduit (<NUM>, <NUM>, <NUM>), with the at least two support members (<NUM>, <NUM>) being spaced apart to define at least two fins (<NUM>, 74A, 74B, <NUM>) which collectively form a heat exchanger (<NUM>, <NUM>) thermally coupled to the conduit (<NUM>, <NUM>, <NUM>); and
a second conduit (<NUM>, <NUM>, <NUM>) spaced from the first conduit and located within the interior, the second conduit being thermally coupled to the at least two fins (<NUM>, 74A, 74B, <NUM>) of the heat exchanger (<NUM>, <NUM>),
wherein the component comprises a monolithic body having the outer casing (<NUM>), the first and second conduits (<NUM>, <NUM>, <NUM>), and the support structure (<NUM>, <NUM>, <NUM>)..