Patent Description:
Gas turbine engines, such as those utilized in commercial and military aircraft, include a compressor section that compresses air, a combustor section in which the compressed air is mixed with a fuel and ignited, and a turbine section across which the resultant combustion products are expanded. The expansion of the combustion products drives the turbine section to rotate. As the turbine section is connected to the compressor section via a shaft, the rotation of the turbine section drives the compressor section to rotate. In some configurations, a fan is also connected to the shaft and is driven to rotate via rotation of the turbine.

Typically, liquid fuel is employed for combustion onboard an aircraft, in the gas turbine engine. The liquid fuel has conventionally been a hydrocarbon-based fuel. Alternative fuels have been considered, but suffer from various challenges for implementation, particularly on aircraft. Hydrogen-based and/or methane-based fuels are viable effective alternatives which may not generate the same combustion byproducts as conventional hydrocarbon-based fuels. The use of hydrogen and/or methane, as a gas turbine fuel source, may require very high efficiency propulsion, in order to keep the volume of the fuel low enough to feasibly carry on an aircraft. That is, because of the added weight associated with such liquid/compressed/supercritical fuels, such as related to vessels/containers and the amount (volume) of fuel required, improved efficiencies associated with operation of the gas turbine engine may be necessary.

<CIT> discloses a hybrid expander cycle with turbo-generator and cooled power electronics.

<CIT> discloses a hybrid expander cycle with pre-compression cooling and a turbo-generator.

<CIT> discloses a hybrid expander cycle with intercooling and a turbo-generator.

According to an aspect of the present invention, a turbine engine system is provided as claimed in claim <NUM>.

Optionally, the core flow path heat exchanger is a hydrogen-to-air heat exchanger.

Optionally, the turbine section further includes a high pressure turbine and a low pressure turbine arranged downstream of the high pressure turbine and the combustor section. The core flow path heat exchanger is arranged in the core flow path downstream of the low pressure turbine.

Optionally, the turbine section further comprises a high pressure turbine and a low pressure turbine arranged downstream of the high pressure turbine and the combustor section, wherein the core flow path heat exchanger is arranged in the core flow path between the low pressure turbine and the high pressure turbine.

Optionally, the main engine core further includes an outlet arranged downstream of the low pressure turbine. The core flow path heat exchanger is arranged in the core flow path downstream of the low pressure turbine and upstream of the outlet.

Optionally, each of the plurality of heat transfer tubes is configured to convey the hydrogen fuel therein across the core flow path of the turbine engine system.

Optionally, the hydrogen fuel is configured to absorb heat from the core flow path through each of the plurality of heat transfer tubes while traversing the core flow path within each of the plurality of heat transfer tubes.

Optionally, the radially outward plenum assembly further includes a plurality of radially outward plenum layers. A radially outward plenum is formed between each of the plurality of radially outward plenum layers. The radially outward plenum is configured to convey the hydrogen fuel to the plurality of heat transfer tubes or receive the hydrogen fuel from the plurality of heat transfer tubes.

Optionally, the radially outward plenum extends circumferentially around an engine central longitudinal axis of the turbine engine system.

Optionally, the radially outward plenum assembly further includes one or more radially outward plenum orifices fluidly connecting the radially outward plenum to other radially outward plenum within the radially outward plenum assembly.

Optionally, the radially outward plenum assembly further includes a plurality of radially outward plenum layers. A radially outward tube receiving orifice is formed between each of the plurality of radially outward plenum layers. The radially outward tube receiving orifice being configured to receive therein a heat transfer tube of the plurality of heat transfer tubes.

Optionally, the radially inward plenum assembly further includes a plurality of radially inward plenum layers. A radially inward plenum is formed between each of the plurality of radially inward plenum layers. The radially inward plenum is configured to convey the hydrogen fuel to the plurality of heat transfer tubes or receive the hydrogen fuel from the plurality of heat transfer tubes.

Optionally, the radially inward plenum extends circumferentially around an engine central longitudinal axis of the turbine engine system.

Optionally, the radially inward plenum assembly further includes one or more radially inward plenum orifices fluidly connecting the radially inward plenum to other radially inward plenum within the radially inward plenum assembly.

Optionally, the radially inward plenum assembly further includes a plurality of radially inward plenum layers. A radially inward tube receiving orifice is formed between each of the plurality of radially inward plenum layers. The radially inward tube receiving orifice being configured to receive therein a heat transfer tube of the plurality of heat transfer tubes.

According to another aspect of the present invention, a method of assembling a core flow path heat exchanger for a turbine engine system is provided as claimed in claim <NUM>.

Optionally, the metallurgically bonding includes at least one of field assisted sintering technology (FAST) and spark plasma sintering (SPS).

Optionally, the metallurgically bonding includes applying a load to compress the plurality of radially outward plenum layers together, the plurality of radially inward plenum layers together, the radially outward end of the heat transfer tube within the radially outward tube receiving orifice, and the radially inward end of the heat transfer tube within the radially inward tube receiving orifice. The metallurgically bonding may also include applying an electrical current to the core flow path heat exchanger.

Optionally, this may include forming each of the plurality of radially outward plenum layers and forming each of the plurality of radially inward plenum layers.

The gas turbine engine <NUM> is disclosed herein as a two-spool turbofan that generally incorporates a fan section <NUM>, a compressor section <NUM>, a combustor section <NUM>, and a turbine section <NUM>.

In some embodiments, stator vanes <NUM> in the low pressure compressor <NUM> and stator vanes <NUM> in the high pressure compressor <NUM> may be adjustable during operation of the gas turbine engine <NUM> to support various operating conditions. In other embodiments, the stator vanes <NUM>, <NUM> may be held in a fixed position.

In one disclosed embodiment, the engine <NUM> bypass ratio is greater than about ten (<NUM>:<NUM>), the fan diameter is significantly larger than that of the low pressure compressor <NUM>, and the low pressure turbine <NUM> has a pressure ratio that is greater than about five <NUM>: <NUM>. The geared architecture <NUM> may be an epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about <NUM>:<NUM>. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines including direct drive turbofans.

The fan section <NUM> of the engine <NUM> is designed for a particular flight condition--typically cruise at about <NUM> Mach and about <NUM>,<NUM> feet (<NUM>,<NUM> meters). "Low corrected fan tip speed" is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tram °R)/(<NUM> °R)<NUM>, wherein °R = °K*<NUM>/<NUM>.

Gas turbine engines generate substantial amounts of heat that is exhausted from the turbine section <NUM> into a surrounding atmosphere. This expelled exhaust heat represents wasted energy and can be a large source of inefficiency in gas turbine engines. Further, transitioning away from hydrocarbon-based engines may be significant advantages, as described herein.

One option to replace hydrocarbon-based fuel is hydrogen fuel. Hydrogen fuel is required to be store at low temperatures in order to maintain them in a liquid state. A heat source is required to increase the temperature of the hydrogen fuel prior to combustion. Embodiments disclosed herein relate to the design and manufacture of a lightweight heat exchanger that can be packaged into the hydrogen based engine and heat up the hydrogen fuel prior to combustion.

Field assisted sintering technology (FAST), also known as spark plasma sintering (SPS), is a consolidation process at temperatures lower than the melting point of the materials being worked on. Similar to hot pressing, FAST forms bonds between materials but at temperatures that are about ~200C lower than their melting point(s). FAST utilizes a high amperage pulsed direct current (DC) electrical current to heat the materials to be bonded through Joule heating while under uniaxial compression. The consolidation is a combination of solid-state transport mechanisms including primarily diffusion and creep. The result is a metallurgical bond between the materials to be joined. Consolidation or joining can be accomplished in a variety of conductive and non-conductive materials and forms. Recently, FAST/SPS has been gaining acceptance for consolidation of powder materials into dense compacts with significantly greater efficiency than hot pressing. Due to the lower processing temperatures over other consolidation methods, FAST/SPS mitigates significant grain growth common in other diffusional bonding methods.

As will be described below, a multi-layer build-up of a heat exchanger by FAST processing can allow for heat transfer tubes to be attached to a radially outward plenum assembly and a radially inward plenum assembly.

After machining preparation of multiple layers of the radially outward plenum assembly and the radially inward plenum assembly, the multiple layers of the radially outward plenum assembly, the radially inward plenum assembly, and the heat transfer tubes are bonded using FAST processing. This FAST processing can occur between similar or dissimilar materials. For example, a hot side part can be constructed of an alloy optimized for oxidation and a cold side part can be constructed from an alloy optimized for corrosion resistance.

Referring now to <FIG>, a schematic diagram of a turbine engine system <NUM> is illustrated, in accordance with an embodiment of the present disclosure. The turbine engine system <NUM> may be similar to that shown and described above but is configured to employ a non-hydrocarbon fuel source, such as hydrogen. The turbine engine system <NUM> includes an inlet <NUM>, a fan <NUM>, a low pressure compressor <NUM>, a high pressure compressor <NUM>, a combustor <NUM>, a high pressure turbine <NUM>, a low pressure turbine <NUM>, a turbine exhaust case <NUM>, and an outlet <NUM>. A core flow path is defined through, at least, the compressor <NUM>, <NUM>, the turbine <NUM>, <NUM>, and the combustor sections <NUM>. The compressor <NUM>, <NUM>, the turbine <NUM>, <NUM>, and the fan <NUM> are arranged along a shaft <NUM>. The shaft <NUM> is aligned along the engine central longitudinal axis A of the turbine engine system <NUM>.

As shown, the turbine engine system <NUM> includes a hydrogen fuel system <NUM>. The hydrogen fuel system <NUM> is configured to supply a hydrogen fuel from a hydrogen fuel tank <NUM> to the combustor <NUM> for combustion thereof. In this illustrative embodiment, the hydrogen fuel may be supplied from the hydrogen fuel tank <NUM> to the combustor <NUM> through a hydrogen fuel supply line <NUM>. The hydrogen fuel supply line <NUM> may be controlled by a flow controller <NUM> (e.g., pump(s), valve(s), or the like). The flow controller <NUM> may be configured to control a flow through the hydrogen fuel supply line <NUM> based on various criteria as will be appreciated by those of skill in the art. For example, various control criteria can include, without limitation, target flow rates, target pressure, target hydrogen expansion turbine output, cooling demands at one or more heat exchangers, target flight envelopes, etc. The pressure of the hydrogen fuel will be increased at the flow controller <NUM>, preferably when the hydrogen fuel is in the liquid state for low pressurization power. As shown, between the hydrogen fuel tank <NUM> and the flow controller <NUM> may be one or more heat exchangers <NUM>, which can be configured to provide cooling to various systems onboard an aircraft by using the hydrogen fuel as a cold-sink. Such hydrogen heat exchangers <NUM> may be configured to warm the hydrogen and aid in a transition from a liquid state to a gaseous state for combustion within the combustor <NUM>. As shown, between the hydrogen fuel tank <NUM> and the heat exchangers <NUM> may be one or more fluid pumps <NUM>, which can be configured to increase the pressure of the hydrogen fuel flowing from the hydrogen fuel tank <NUM>. The heat exchangers <NUM> may receive the hydrogen fuel directly from the hydrogen fuel tank <NUM> as a first working fluid and a component-working fluid for a different onboard system. For example, the heat exchanger <NUM> may be configured to provide cooling to power electronics of the turbine engine system <NUM> (or other aircraft power electronics). In some non-limiting embodiments, an optional secondary fluid circuit may be provided for cooling one or more aircraft loads. In this secondary fluid circuit, a secondary fluid may be configured to deliver heat from the one or more aircraft loads to a single liquid hydrogen heat exchanger. As such, heating of the hydrogen fuel and cooling of the secondary fluid may be achieved. The above described configurations and variations thereof may serve to begin raising a temperature of the hydrogen fuel to a desired temperature for efficient combustion in the combustor <NUM>.

After the flow controller increases the H2 pressure, pumping it to high pressure as a liquid in one embodiment, the hydrogen fuel may then pass through an optional supplemental heating heat exchanger <NUM>. The supplemental heating heat exchanger <NUM> may be configured to receive hydrogen fuel as a first working fluid and as the second working fluid may receive one or more aircraft system fluids, such as, without limitation, engine oil, environmental control system fluids, pneumatic off-takes, or cooled cooling air fluids. As such, the hydrogen fuel will be heated, and the other fluid may be cooled. The hydrogen fuel will then be injected into the combustor <NUM> through one or more hydrogen fuel injectors, as will be appreciated by those of skill in the art.

When the hydrogen fuel is directed along the hydrogen fuel supply line <NUM>, the hydrogen fuel can pass through a core flow path heat exchanger <NUM> (e.g., an exhaust waste heat recovery heat exchanger) or other type of heat exchanger. The core flow path heat exchanger <NUM> is a hydrogen-to-air heat exchanger. In this embodiment, the core flow path heat exchanger <NUM> is arranged in the core flow path downstream of the combustor <NUM>, and in some embodiments, downstream of the low pressure turbine <NUM>. In this illustrative embodiment, the core flow path heat exchanger <NUM> is arranged downstream of the low pressure turbine <NUM> and at or proximate the turbine exhaust case <NUM> upstream of the outlet <NUM>. In this embodiment, the core flow path heat exchanger <NUM> is arranged in the core flow path between the low pressure turbine <NUM> and the high pressure turbine <NUM>. As the hydrogen fuel passes through the core flow path heat exchanger <NUM>, the hydrogen fuel will pick up heat from the exhaust of the turbine engine system <NUM>. As such, the temperature of the hydrogen fuel will be increased.

The heated hydrogen fuel may then be passed into an expansion turbine <NUM>. As the hydrogen fuel passes through the expansion turbine <NUM> the hydrogen fuel will be expanded. The process of passing the hydrogen fuel through the expansion turbine <NUM> cools the hydrogen fuel and extracts useful power through the expansion process. Because the hydrogen fuel is heated from a cryogenic or liquid state in the hydrogen fuel tank <NUM> through the various mechanisms along the hydrogen fuel supply line <NUM>, combustion efficiency may be improved.

Advantageously, embodiments of the present disclosure are directed to improved turbine engine systems that employ non-hydrocarbon fuels at cryogenic temperatures. In accordance with some embodiments, the systems described herein provide for a hydrogen-burning turbine engine that may allow the cryogenic fuel to recover heat from various systems such as waste heat-heat exchangers, system component heat exchangers, and expansion turbines. Accordingly, improved propulsion systems that burn hydrogen fuel and implement improved cooling schemes in both aircraft systems and engine systems are provided.

Referring now to <FIG>, an isometric rear view of the turbine exhaust case <NUM> of the turbine engine system <NUM> is illustrated, in accordance with an embodiment of the present disclosure. The turbine exhaust case <NUM> includes the core flow path heat exchanger <NUM>. The turbine exhaust case <NUM> includes a forward side 216a and an aft side 216b located aft of the forward side 216a as measured along the engine central longitudinal axis A.

As used herein the terms forward and aft-ward (or aft) is intended to be a direction that the surface is oriented within the <NUM> along the engine central longitudinal axis A when the component is installed. The term forward denotes that the surface is oriented or facing towards the forward end of the turbine engine system <NUM> when the component is installed. The forward end is at the inlet <NUM> of the turbine engine system <NUM>. The term aft or aft-ward denotes that the surface is oriented or facing towards the aft end of the turbine engine system <NUM> when the component is installed. The aft end is at the outlet <NUM> of the turbine engine system <NUM>.

The core flow path heat exchanger <NUM> includes a plurality of heat transfer tubes <NUM> extending across the core flow path C of the turbine engine system <NUM>. The heat transfer tubes <NUM> extend from a radially inward plenum assembly <NUM> to a radially outward plenum assembly <NUM> across the core flow path C. The radially outward plenum assembly <NUM> is located radially outward of the radially inward plenum assembly <NUM>. As used herein radially outward is intended to be in the direction away from the engine central longitudinal axis A. Each heat transfer tube <NUM> is configured to convey hydrogen fuel within the heat transfer tube <NUM> across the core flow path C of the turbine engine system <NUM>. The hydrogen fuel is configured to absorb heat from the core flow path C through the heat transfer tube <NUM> while traversing the core flow path C within the heat transfer tube <NUM>. In one embodiment, the core flow path heat exchanger <NUM> may be a single-pass heat exchanger, such that the hydrogen fuel may traverse the core flow path C a single time within the core flow path heat exchanger <NUM>. In another embodiment, the core flow path heat exchanger <NUM> may be a multi-pass heat exchanger, such that the hydrogen fuel may traverse the core flow path C multiple times within the core flow path heat exchanger <NUM>.

Referring now to <FIG>, an isometric cross-sectional view of the core flow path heat exchanger <NUM> is illustrated, in accordance with an embodiment of the present disclosure. The core flow path heat exchanger <NUM> includes the radially outward plenum assembly <NUM> and the radially inward plenum assembly <NUM>.

The radially outward plenum assembly <NUM> includes a plurality of radially outward plenum layers <NUM>. As illustrated in <FIG>, there may be seven radially outward plenum layers <NUM>. It is understood however, that the radially outward plenum assembly <NUM> is not limited to seven radially outward plenum layers <NUM> and the radially outward plenum assembly <NUM> may have more or less than seven radially outward plenum layers <NUM>.

The radially outward plenum assembly <NUM> includes a radially outward plenum <NUM> formed between each of the plurality of radially outward plenum layers <NUM>. The radially outward plenum <NUM> is configured to convey the hydrogen fuel to the plurality of heat transfer tubes <NUM> or receive the hydrogen fuel from the plurality of heat transfer tubes <NUM>. The radially outward plenum <NUM> extends circumferentially C1 around the engine central longitudinal axis A of the turbine engine system <NUM>. The radially outward plenum <NUM> may be fluidly connected to other radially outward plenum <NUM> through one or more radially outward plenum orifices <NUM> (See <FIG>). The radially outward plenum assembly <NUM> includes a radially outward tube receiving orifice <NUM> formed between each of the radially outward plenum layers <NUM>. The radially outward tube receiving orifice <NUM> is configured to receive therein a heat transfer tube <NUM> of the plurality of heat transfer tubes <NUM>. The radially outward tube receiving orifice <NUM> is fluidly coupled to the radially outward plenum <NUM>.

The radially outward plenum layers <NUM> include a forward radially outward layer 352a and an aft-ward radially outward layer 352b. Located between the forward radially outward layer 352a and the aft-ward radially outward layer 352b may be a first radially outward interposed layer 352c, a second radially outward interposed layer 352d, a third radially outward interposed layer 352e, a fourth radially outward interposed layer 352f, and a fifth radially outward interposed layer <NUM>.

The radially inward plenum assembly <NUM> includes a plurality of radially inward plenum layers <NUM>. As illustrated in <FIG>, there may be seven radially inward plenum layers <NUM>. It is understood however, that the radially inward plenum assembly <NUM> is not limited to seven radially inward plenum layers <NUM> and the radially inward plenum assembly <NUM> may have more or less than seven radially inward plenum layers <NUM>.

The radially inward plenum assembly <NUM> includes a radially inward plenum <NUM> formed between each of the plurality of radially inward plenum layers <NUM>. The radially inward plenum <NUM> is configured to convey the hydrogen fuel to the plurality of heat transfer tubes <NUM> or receive the hydrogen fuel from the plurality of heat transfer tubes <NUM>. The radially inward plenum <NUM> extends circumferentially C1 around the engine central longitudinal axis A of the turbine engine system <NUM>. The radially inward plenum <NUM> may be fluidly connected to other radially inward plenum <NUM> through one or more radially inward plenum orifices <NUM> (See <FIG>). The radially inward plenum assembly <NUM> includes a radially inward tube receiving orifice <NUM> formed between each of the radially inward plenum layers <NUM>. The radially inward tube receiving orifice <NUM> is configured to receive therein a heat transfer tube <NUM> of the plurality of heat transfer tubes <NUM>. The radially inward tube receiving orifice <NUM> is fluidly coupled to the radially inward plenum <NUM>.

The radially inward plenum layers <NUM> include a forward radially inward layer 332a and an aft-ward radially inward layer 332b. Located between the forward radially inward layer 332a and the aft-ward radially inward layer 332b may be a first radially inward interposed layer 332c, a second radially inward interposed layer 332d, a third radially inward interposed layer 332e, a fourth radially inward interposed layer 332f, and a fifth radially inward interposed layer <NUM>.

During a FAST or SPS assembly of the core flow path heat exchanger <NUM> a force or load F1 is applied to the forward radially outward layer 352a, the aft-ward radially outward layer 352b, the forward radially inward layer 332a, and the aft-ward radially inward layer 332b to compress the core flow path heat exchanger <NUM> together. While the core flow path heat exchanger <NUM> is under compression a high amperage pulsed DC electrical current E1 is applied to the core flow path heat exchanger <NUM>. The electrical current heats the materials to be bonded through Joule heating while under uniaxial compression. The consolidation of the materials within the core flow path heat exchanger <NUM> is a combination of solid-state transport mechanisms including primarily diffusion and creep. The electrical current E1 is applied simultaneously to the load F1.

Referring now to <FIG>, an isometric cross-sectional view of a forward layer 300a of the core flow path heat exchanger <NUM> is illustrated, in accordance with an embodiment of the present disclosure. The forward layer 300a includes the forward radially inward layer 332a and the forward radially outward layer 352a.

The forward radially outward layer 352a includes a forward radially outward side 354a and an aft-ward radially outward side 356a located opposite and aft of the forward radially outward side 354a. The aft-ward radially outward side 356a includes an aft-ward radially outward groove 358a that extends circumferentially C1 around the central longitudinal axis A. The aft-ward radially outward groove 358a is configured to align with a forward radially outward groove <NUM> of an adjacent layer to form a radially outward plenum <NUM> (see <FIG>) in the radially outward plenum assembly <NUM>. The aft-ward radially outward side 356a also includes a plurality of aft-ward radially outward tube grooves 360a. The aft-ward radially outward tube grooves 360a are oriented about perpendicular to the aft-ward radially outward groove 358a and point radially towards the engine central longitudinal axis A. The heat transfer tube <NUM> includes a radially outward end <NUM> and a radially inward end <NUM>. The radially outward end <NUM> is configured to fit within the aft-ward radially outward tube grooves 360a. The heat transfer tube <NUM> fluidly connects to the aft-ward radially outward groove 358a at the radially outward end <NUM>. The forward radially outward side 354a may be flat with no groove.

The forward radially inward layer 332a includes a forward radially inward side 334a and an aft-ward radially inward side 336a located opposite and aft of the forward radially inward side 334a. The aft-ward radially inward side 336a includes an aft-ward radially inward groove 338a that extends circumferentially C1 around the central longitudinal axis A. The aft-ward radially inward groove 338a is configured to align with a forward radially inward groove <NUM> of an adjacent layer to form a radially inward plenum <NUM> (See <FIG>) in the radially inward plenum assembly <NUM>. The aft-ward radially inward side 336a also includes a plurality of aft-ward radially inward tube grooves 340a. The aft-ward radially inward tube grooves 340a are oriented about perpendicular to the aft-ward radially inward groove 338a and point radially towards the engine central longitudinal axis A. The radially inward end <NUM> is configured to fit within the aft-ward radially inward tube grooves 340a. The heat transfer tube <NUM> fluidly connects to the aft-ward radially inward groove 338a at the radially inward end <NUM>. The forward radially inward side 334a may be flat with no groove.

Referring now to <FIG>, an isometric cross-sectional view of an aft layer 300b of the core flow path heat exchanger <NUM> is illustrated, in accordance with an embodiment of the present disclosure. The aft layer 300b includes the aft-ward radially inward layer 332b and the aft-ward radially outward layer 352b.

The aft-ward radially outward layer 352b includes a forward radially outward side 354b and an aft-ward radially outward side 356b located opposite and aft of the forward radially outward side 354b. The forward radially outward side 354b includes a forward radially outward groove 362b that extends circumferentially C1 around the central longitudinal axis A. The forward radially outward groove 362b is configured to align with an aft-ward radially outward groove <NUM> of an adjacent layer to form a radially outward plenum <NUM> (see <FIG>) in the radially outward plenum assembly <NUM>. The forward radially outward side 354b also includes a plurality of forward radially outward tube grooves 366b. The forward radially outward tube grooves 366b are oriented about perpendicular to the forward radially outward groove 362b and point radially towards the engine central longitudinal axis A. The radially outward end <NUM> is configured to fit within the forward radially outward tube grooves 366b. The heat transfer tube <NUM> fluidly connects to the forward radially outward groove 362b at the radially outward end <NUM>. The aft-ward radially outward side 356b may be flat with no groove.

The aft-ward radially inward layer 332b includes a forward radially inward side 334b and an aft-ward radially inward side 336b located opposite and aft of the forward radially inward side 334b. The forward radially inward side 334b includes a forward radially inward groove 342b that extends circumferentially C1 around the central longitudinal axis A. The forward radially inward groove 342b is configured to align with an aft-ward radially inward groove <NUM> of an adjacent layer to form a radially inward plenum <NUM> (see <FIG>) in the radially inward plenum assembly <NUM>. The forward radially inward side 334b also includes a plurality of forward radially inward tube grooves 346b. The forward radially inward tube grooves 346b are oriented about perpendicular to the forward radially inward groove 342b and point radially towards the engine central longitudinal axis A. The radially inward end <NUM> is configured to fit within the forward radially inward tube grooves 346b. The heat transfer tube <NUM> fluidly connects to the forward radially inward groove 342b at the radially inward end <NUM>. The aft-ward radially inward side 336b may be flat with no groove.

Referring now to <FIG>, an isometric cross-sectional view of the radially outward plenum layers <NUM> is illustrated, in accordance with an embodiment of the present disclosure. Each of the radially outward interposed layers 352c, 352d, 352e, 352f, <NUM> includes a forward radially outward side <NUM> and an aft-ward radially outward side <NUM> located opposite and aft of the forward radially outward side <NUM>. The aft-ward radially outward side <NUM> includes an aft-ward radially outward groove <NUM> that extends circumferentially C1 around the central longitudinal axis A. The forward radially outward side <NUM> includes a forward radially outward groove <NUM> that extends circumferentially C1 around the central longitudinal axis A.

The forward radially outward groove <NUM> is configured to align with an aft-ward radially outward groove <NUM>, 358a of an adjacent layer to form a radially outward plenum <NUM> in the radially outward plenum assembly <NUM>.

The forward radially outward groove <NUM> of the first radially outward interposed layer 352c is configured to align with the aft-ward radially outward groove 358a of the forward radially outward layer 352a to form a first radially outward plenum 364a in the radially outward plenum assembly <NUM>.

The forward radially outward groove <NUM> of the second radially outward interposed layer 352d is configured to align with the aft-ward radially outward groove <NUM> of the first radially outward interposed layer 352c to form a second radially outward plenum 364b in the radially outward plenum assembly <NUM>.

The forward radially outward groove <NUM> of the third radially outward interposed layer 352e is configured to align with the aft-ward radially outward groove <NUM> of the second radially outward interposed layer 352d to form a third radially outward plenum 364c in the radially outward plenum assembly <NUM>.

The forward radially outward groove <NUM> of the fourth radially outward interposed layer 352f is configured to align with the aft-ward radially outward groove <NUM> of the third radially outward interposed layer 352e to form a fourth radially outward plenum 364d in the radially outward plenum assembly <NUM>.

The forward radially outward groove <NUM> of the fifth radially outward interposed layer <NUM> is configured to align with the aft-ward radially outward groove <NUM> of the fourth radially outward interposed layer 352f to form a fifth radially outward plenum 364e in the radially outward plenum assembly <NUM>.

The forward radially outward groove 362b of the aft-ward radially outward layer 352b is configured to align with the aft-ward radially outward groove <NUM> of the fifth radially outward interposed layer <NUM> to form a sixth radially outward plenum 364f in the radially outward plenum assembly <NUM>.

The forward radially outward side <NUM> also includes a plurality of forward radially outward tube grooves <NUM>. The forward radially outward tube grooves <NUM> are oriented about perpendicular to the forward radially outward groove <NUM> and point radially towards the engine central longitudinal axis A. The radially outward end <NUM> of the heat transfer tube <NUM> is configured to fit within the forward radially outward tube grooves <NUM>. The heat transfer tube <NUM> fluidly connects to the forward radially outward groove 362b at the radially outward end <NUM>.

The aft-ward radially outward side <NUM> also includes a plurality of aft-ward radially outward tube grooves <NUM>. The aft-ward radially outward tube grooves <NUM> are oriented about perpendicular to the aft-ward radially outward groove <NUM> and point radially towards the engine central longitudinal axis A. The radially outward end <NUM> of the heat transfer tube <NUM> is configured to fit within the aft-ward radially outward tube grooves <NUM>. The heat transfer tube <NUM> fluidly connects to the forward radially outward groove 362b at the radially outward end <NUM>.

The forward radially outward tube grooves <NUM> are configured to align with the aft-ward radially outward tube grooves <NUM> of an adjacent layer to form a radially outward tube receiving orifice <NUM> to contain the radially outward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially outward tube grooves <NUM> of the first radially outward interposed layer 352c are configured to align with the aft-ward radially outward tube grooves 360a of the forward radially outward layer 352a to form a radially outward tube receiving orifice <NUM> to contain the radially outward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially outward tube grooves <NUM> of the second radially outward interposed layer 352d are configured to align with the aft-ward radially outward tube grooves <NUM> of the first radially outward interposed layer 352c to form a radially outward tube receiving orifice <NUM> to contain the radially outward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially outward tube grooves <NUM> of the third radially outward interposed layer 352e are configured to align with the aft-ward radially outward tube grooves <NUM> of the second radially outward interposed layer 352d to form a radially outward tube receiving orifice <NUM> to contain the radially outward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially outward tube grooves <NUM> of the fourth radially outward interposed layer 352f are configured to align with the aft-ward radially outward tube grooves <NUM> of the third radially outward interposed layer 352e to form a radially outward tube receiving orifice <NUM> to contain the radially outward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially outward tube grooves <NUM> of the fifth radially outward interposed layer <NUM> are configured to align with the aft-ward radially outward tube grooves <NUM> of the fourth radially outward interposed layer 352f to form a radially outward tube receiving orifice <NUM> to contain the radially outward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially outward tube grooves <NUM> of the aft-ward radially outward layer 352b are configured to align with the aft-ward radially outward tube grooves <NUM> of the fifth radially outward interposed layer <NUM> to form a radially outward tube receiving orifice <NUM> to contain the radially outward end <NUM> of the heat transfer tube <NUM> therein.

Referring now to <FIG>, an isometric cross-sectional view of the radially inward plenum layers <NUM> are illustrated, in accordance with an embodiment of the present disclosure. Each of the radially inward interposed layers 332c, 332d, 332e, 332f, <NUM> includes a forward radially inward side <NUM> and an aft-ward radially inward side <NUM> located opposite and aft of the forward radially inward side <NUM>. The aft-ward radially inward side <NUM> includes an aft-ward radially inward groove <NUM> that extends circumferentially C1 around the central longitudinal axis A. The forward radially inward side <NUM> includes a forward radially inward groove <NUM> that extends circumferentially C1 around the central longitudinal axis A.

The forward radially inward groove <NUM> is configured to align with an aft-ward radially inward groove <NUM>, 338a of an adjacent layer to form a radially inward plenum <NUM> in the radially inward plenum assembly <NUM>.

The forward radially inward groove <NUM> of the first radially inward interposed layer 332c is configured to align with the aft-ward radially inward groove 338a of the forward radially inward layer 332a to form a first radially inward plenum 344a in the radially inward plenum assembly <NUM>.

The forward radially inward groove <NUM> of the second radially inward interposed layer 332d is configured to align with the aft-ward radially inward groove <NUM> of the first radially inward interposed layer 332c to form a second radially inward plenum 344b in the radially inward plenum assembly <NUM>.

The forward radially inward groove <NUM> of the third radially inward interposed layer 332e is configured to align with the aft-ward radially inward groove <NUM> of the second radially inward interposed layer 332d to form a third radially inward plenum 344c in the radially inward plenum assembly <NUM>.

The forward radially inward groove <NUM> of the fourth radially inward interposed layer 332f is configured to align with the aft-ward radially inward groove <NUM> of the third radially inward interposed layer 332e to form a fourth radially inward plenum 344d in the radially inward plenum assembly <NUM>.

The forward radially inward groove <NUM> of the fifth radially inward interposed layer <NUM> is configured to align with the aft-ward radially inward groove <NUM> of the fourth radially inward interposed layer 332f to form a fifth radially inward plenum 344e in the radially inward plenum assembly <NUM>.

The forward radially inward groove 342b of the aft-ward radially inward layer 332b is configured to align with the aft-ward radially inward groove <NUM> of the fifth radially inward interposed layer <NUM> to form a sixth radially inward plenum 344f in the radially inward plenum assembly <NUM>.

The forward radially inward side <NUM> also includes a plurality of forward radially inward tube grooves <NUM>. The forward radially inward tube grooves <NUM> are oriented about perpendicular to the forward radially inward groove <NUM> and point radially towards the engine central longitudinal axis A. The radially inward end <NUM> of the heat transfer tube <NUM> is configured to fit within the forward radially inward tube grooves <NUM>. The heat transfer tube <NUM> fluidly connects to the forward radially inward groove 342b at the radially inward end <NUM>.

The aft-ward radially inward side <NUM> also includes a plurality of aft-ward radially inward tube grooves <NUM>. The aft-ward radially inward tube grooves <NUM> are oriented about perpendicular to the aft-ward radially inward groove <NUM> and point radially towards the engine central longitudinal axis A. The radially inward end <NUM> of the heat transfer tube <NUM> is configured to fit within the aft-ward radially inward tube grooves <NUM>. The heat transfer tube <NUM> fluidly connects to the forward radially inward groove 342b at the radially inward end <NUM>.

The forward radially inward tube grooves <NUM> are configured to align with the aft-ward radially inward tube grooves <NUM> of an adjacent layer to form a radially inward tube receiving orifice <NUM> to form a radially inward tube receiving orifice <NUM> to contain the radially inward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially inward tube grooves <NUM> of the first radially inward interposed layer 332c are configured to align with the aft-ward radially inward tube grooves 340a of the forward radially inward layer 332a to form a radially inward tube receiving orifice <NUM> to contain the radially inward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially inward tube grooves <NUM> of the second radially inward interposed layer 332d are configured to align with the aft-ward radially inward tube grooves <NUM> of the first radially inward interposed layer 332c to form a radially inward tube receiving orifice <NUM> to contain the radially inward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially inward tube grooves <NUM> of the third radially inward interposed layer 332e are configured to align with the aft-ward radially inward tube grooves <NUM> of the second radially inward interposed layer 332d to form a radially inward tube receiving orifice <NUM> to contain the radially inward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially inward tube grooves <NUM> of the fourth radially inward interposed layer 332f are configured to align with the aft-ward radially inward tube grooves <NUM> of the third radially inward interposed layer 332e to form a radially inward tube receiving orifice <NUM> to contain the radially inward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially inward tube grooves <NUM> of the fifth radially inward interposed layer <NUM> are configured to align with the aft-ward radially inward tube grooves <NUM> of the fourth radially inward interposed layer 332f to form a radially inward tube receiving orifice <NUM> to contain the radially inward end <NUM> of the heat transfer tube <NUM> therein.

The forward radially inward tube grooves <NUM> of the aft-ward radially inward layer 332b are configured to align with the aft-ward radially inward tube grooves <NUM> of the fifth radially inward interposed layer <NUM> to form a radially inward tube receiving orifice <NUM> to contain the radially inward end <NUM> of the heat transfer tube <NUM> therein.

Referring now to <FIG>, an isometric cross-sectional view of the radially outward interposed layers 352c, 352d, 352e, 352f, <NUM> is illustrated, in accordance with an embodiment of the present disclosure. Each of the radially outward interposed layers 352c, 352d, 352e, 352f, <NUM> may include a radially outward plenum orifice <NUM> fluidly connecting the forward radially outward groove <NUM> to the aft-ward radially outward groove <NUM>. The radially outward plenum orifice <NUM> may be located in the forward radially outward groove <NUM> and the aft-ward radially outward groove <NUM>.

Referring now to <FIG>, an isometric cross-sectional view of the radially inward interposed layers 332c, 332d, 332e, 332f, <NUM> is illustrated, in accordance with an embodiment of the present disclosure. Each of the radially inward interposed layers 332c, 332d, 332e, 332f, <NUM> may include a radially inward plenum orifice <NUM> fluidly connecting the forward radially inward groove <NUM> to the aft-ward radially inward groove <NUM>. The radially inward plenum orifice <NUM> may be located in the forward radially inward groove <NUM> and the aft-ward radially inward groove <NUM>.

Referring now to <FIG>, a cross-sectional view of the radially outward interposed layers 352c, 352d, 352e, 352f, <NUM> is illustrated, in accordance with an embodiment of the present disclosure. Each of the radially outward interposed layers 352c, 352d, 352e, 352f, <NUM> include the forward radially outward tube grooves <NUM> and the aft-ward radially outward tube grooves <NUM> configured to fit the radially outward end <NUM> of the heat transfer tubes <NUM>. The forward radially outward tube grooves <NUM> may be staggered circumferentially with the aft-ward radially outward tube grooves <NUM> as illustrated in <FIG>.

Referring now to <FIG>, a cross-sectional view of the radially inward interposed layers 332c, 332d, 332e, 332f, <NUM> is illustrated, in accordance with an embodiment of the present disclosure. Each of the radially inward interposed layers 332c, 332d, 332e, 332f, <NUM> include the forward radially inward tube grooves <NUM> and the aft-ward radially inward tube grooves <NUM> configured to fit the radially inward end <NUM> of the heat transfer tubes <NUM>. The forward radially inward tube grooves <NUM> may be staggered circumferentially with the aft-ward radially inward tube grooves <NUM> as illustrated in <FIG>.

Referring now to <FIG>, with continued reference to <FIG>, a method <NUM> of assembling the core flow path heat exchanger <NUM> for a turbine engine system <NUM> is illustrated in accordance with an embodiment of the present disclosure.

At block <NUM>, a plurality of radially outward plenum layers <NUM> are stacked on top of each other. A radially outward plenum <NUM> is formed between each of the plurality of radially outward plenum layers <NUM> when stacked. A radially outward tube receiving orifice <NUM> is formed between each of the plurality of radially outward plenum layers <NUM> when stacked.

At block <NUM>, a plurality of radially inward plenum layers <NUM> are stacked on top of each other. A radially inward plenum <NUM> is formed between each of the plurality of radially inward plenum layers <NUM> when stacked. A radially inward tube receiving orifice <NUM> is formed between each of the plurality of radially inward plenum layers <NUM> when stacked.

At block <NUM>, a radially outward end <NUM> of a heat transfer tube <NUM> is inserted into the radially outward tube receiving orifice <NUM>. The radially outward end <NUM> of a heat transfer tube <NUM> may inserted into the radially outward tube receiving orifice <NUM>, while the plurality of radially inward plenum layers <NUM> are being stacked. For example, the radially outward end <NUM> of a heat transfer tube <NUM> is inserted into the radially outward tube receiving orifice <NUM> in between the stacking of each of the plurality of radially inward plenum layers <NUM>.

At block <NUM>, a radially inward end <NUM> of a heat transfer tube <NUM> is inserted into the radially inward tube receiving orifice <NUM>. The radially inward end <NUM> of a heat transfer tube <NUM> may inserted into the radially inward tube receiving orifice <NUM>, while the plurality of radially inward plenum layers <NUM> are being stacked. For example, the radially inward end <NUM> of a heat transfer tube <NUM> is inserted into the radially inward tube receiving orifice <NUM> in between the stacking of each of the plurality of radially inward plenum layers <NUM>.

At block <NUM>, the plurality of radially outward plenum layers <NUM> are metallurgically bonded together, the plurality of radially inward plenum layers <NUM> are metallurgically bonded together, the radially outward end <NUM> of the heat transfer tube <NUM> is metallurgically bonded within the radially outward tube receiving orifice <NUM>, and the radially inward end <NUM> of the heat transfer tube <NUM> is metallurgically bonded within the radially inward tube receiving orifice <NUM>. The metallurgically bonding of block <NUM> can be preceded by an operation of preparing surfaces of the components for the metallurgically bonding by, for example, surface machining and/or cleaning that provides for good contact-making bonding surfaces. In an embodiment, the metallurgically bonding can include at least one of FAST and SPS. In an embodiment, the metallurgically bonding can include applying a load F1 to compress the plurality of radially outward plenum layers <NUM> together, the plurality of radially inward plenum layers <NUM> together, the radially outward end <NUM> of the heat transfer tube <NUM> within the radially outward tube receiving orifice <NUM>, and the radially inward end <NUM> of the heat transfer tube <NUM> within the radially inward tube receiving orifice <NUM>. In an embodiment, the metallurgically bonding can also include applying an electrical current E1 to the core flow path heat exchanger <NUM>. In an embodiment, the electrical current E1 is applied to the core flow path heat exchanger <NUM> while the load F1 is being applied to compress the plurality of radially outward plenum layers <NUM> together, the plurality of radially inward plenum layers <NUM> together, the radially outward end <NUM> of the heat transfer tube <NUM> within the radially outward tube receiving orifice <NUM>, and the radially inward end <NUM> of the heat transfer tube <NUM> within the radially inward tube receiving orifice <NUM>. The method <NUM> may further include forming each of the plurality of radially outward plenum layers <NUM> and forming each of the plurality of radially inward plenum layers <NUM>. The plurality of radially outward plenum layers <NUM> and the plurality of radially inward plenum layers <NUM> may be formed by casting or machining.

At block <NUM>, the core flow path heat exchanger <NUM> is operably connected to a hydrogen fuel tank <NUM>. Operably connecting may include fluidly connecting the core flow path heat exchanger <NUM> to the hydrogen fuel tank <NUM> so that hydrogen fuel may flow from the hydrogen fuel tank <NUM> to the core flow path heat exchanger <NUM>. Block <NUM> may include installing a hydrogen fuel line connector into the core flow path heat exchanger <NUM> to operably connect the core flow path heat exchanger <NUM> to the hydrogen fuel tank <NUM>.

Claim 1:
A turbine engine system (<NUM>;<NUM>), comprising:
at least one hydrogen fuel tank (<NUM>);
a core flow path heat exchanger (<NUM>) in a core flow path (C); and
a compressor section (<NUM>), a combustor section (<NUM>) having a burner, and a turbine section (<NUM>), each section located in the core flow path (C), wherein the core flow path heat exchanger (<NUM>) is arranged in the core flow path (C) downstream of the combustor section (<NUM>), wherein hydrogen fuel is supplied from the at least one hydrogen fuel tank (<NUM>) through a hydrogen fuel supply line (<NUM>), passing through the core flow path heat exchanger (<NUM>) and then supplied into the burner for combustion,
characterised in that the core flow path heat exchanger (<NUM>) comprises:
a radially outward plenum assembly (<NUM>);
a radially inward plenum assembly (<NUM>); and
a plurality of heat transfer tubes (<NUM>) extending from the radially inward plenum assembly (<NUM>) to the radially outward plenum assembly (<NUM>) across the core flow path (C).