Apparatus, turbine nozzle and turbine shroud

The United States Government retains license rights in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms by the terms of Government Contract No. DE-FE0024006 awarded by the United States Department of Energy.

The present invention is directed to apparatuses, turbine nozzles, and turbine shrouds. More particularly, the present invention is directed to apparatuses, turbine nozzles, and turbine shrouds including cooling fluid channels.

Gas turbines operate under extreme conditions. In order to drive efficiency higher, there have been continual developments to allow operation of gas turbines at ever higher temperatures. As the temperature of the hot gas path increases, the temperature of adjacent regions of the gas turbine necessarily increase in temperature, due to thermal conduction from the hot gas path.

In order to allow higher temperature operation, some gas turbine components, such as nozzles and shrouds, have been divided such that the higher temperature regions (such as the fairings of the nozzles and the inner shrouds of the shrouds) may be formed from materials, such as ceramic matrix composites, which are especially suited to operation at extreme temperatures, whereas the lower temperature regions (such as the outside and inside walls of the nozzles and the outer shrouds of the shrouds) are made from other materials which are less suited for operation at the higher temperatures, but which may be more economical to produce and service.

Joining the portions of gas turbines in higher temperature regions to the portions of gas turbines in lower temperature regions may present challenges, particularly with regard to interfaces between metals and ceramic matrix composite materials. Large thermal gradients between the metal portion and the ceramic matrix composite portion may result in high thermal strain in the component, reducing performance and component service life. Further, in many instances, components having a metal portion and a ceramic matrix composite portion include a volume between metal and ceramic matrix composite portions for which a flow of a purge gas is appropriate. Purge gas may be used, among other purposes, to minimize leaks between adjacent turbine components. However, providing both a purge fluid to purge the volume between the metal and the ceramic matrix composite portions as well as a temperature modulation fluid to reduce temperature differentials and thermal strain across the interface between the metal portion and the ceramic matrix composite portion may reduce the efficiency of the turbine by requiring a greater flow of fluid to be diverted from the compressor than either a purge fluid or a temperature modulation fluid would alone.

In an exemplary embodiment, an apparatus includes a first article, a second article, a first interface volume disposed between and enclosed by the first article and the second article, a cooling fluid supply, and at least one cooling fluid channel in fluid communication with the cooling fluid supply and the first interface volume. The first article includes a first material composition. The second article includes a second material composition. The at least one cooling fluid channel includes a heat exchange portion disposed in at least one of the first article and the second article downstream of the cooling fluid supply and upstream of the first interface volume.

In another exemplary embodiment, a turbine nozzle includes an outside wall, a fairing, a first interface volume disposed between and enclosed by the outside wall and the fairing, an inside wall, a second interface volume disposed between and enclosed by the inside wall and the fairing, a cooling fluid supply, and at least one cooling fluid channel in fluid communication with the cooling fluid supply, the first interface volume, and the second interface volume. The outside wall includes a metal. The fairing includes a ceramic matrix composite. The inside wall includes a metal. The at least one cooling fluid channel includes a heat exchange portion disposed downstream of the cooling fluid supply and upstream of the first interface volume and the second interface volume.

In another exemplary embodiment, a turbine shroud includes an outer shroud, an inner shroud, a first interface volume disposed between and enclosed by the outer shroud and the inner shroud, a cooling fluid supply, and at least one cooling fluid channel in fluid communication with the cooling fluid supply and the first interface volume. The outer shroud includes a metal. The inner shroud includes a ceramic matrix composite. The at least one cooling fluid channel includes a heat exchange portion disposed downstream of the cooling fluid supply and upstream of the first interface volume.

Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.

FIG. 1 is a schematic sectioned view of an apparatus, according to an embodiment of the present disclosure.

FIG. 2 is a schematic sectioned view of an apparatus including sequential heat exchange portions, according to an embodiment of the present disclosure.

FIG. 3 is a schematic sectioned view of an apparatus including sequential heat exchange portions, according to an embodiment of the present disclosure.

FIG. 4 is a perspective view of a turbine nozzle, according to an embodiment of the present disclosure.

FIG. 5 is a perspective view of turbine shroud, according to an embodiment of the present disclosure.

Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts.

Provided are exemplary apparatuses and gas turbine components, such as turbine nozzles and turbine shrouds. Embodiments of the present disclosure, in comparison to articles and methods not utilizing one or more features disclosed herein, decrease costs, decrease thermal strain, increase efficiency, improve elevated temperature performance, or a combination thereof.

Referring to FIG. 1 , in one embodiment an apparatus 100 includes a first article 102 , a second article 104 , a first interface volume 106 disposed between and enclosed by the first article 102 and the second article 104 , a cooling fluid supply 108 , and at least one cooling fluid channel 110 in fluid communication with the cooling fluid supply 108 and the first interface volume 106 . The first article 102 includes a first material composition. The second article 104 includes a second material composition. The at least one cooling fluid channel 110 includes a heat exchange portion 112 disposed in at least one of the first article 102 (not shown) and the second article 104 (shown) downstream of the cooling fluid supply 108 and upstream of the first interface volume 106 . In a further embodiment, the first material composition of the first article 102 includes a first thermal tolerance, and the second material composition of the second article 104 includes a second thermal tolerance greater than the first thermal tolerance.

In another embodiment, the apparatus 100 further includes a third article 114 and a second interface volume 116 disposed between and enclosed by the third article 114 and the second article 104 . The third article 114 includes a third material composition. The at least one cooling fluid channel 110 is upstream of and in fluid communication with the second interface volume 116 , and the heat exchange portion 112 is upstream of the second interface volume 116 . In a further embodiment, the third material composition of the third article 114 includes a third thermal tolerance less than the second thermal tolerance.

The apparatus 100 may further include a sealing member 118 disposed between the first article 102 and the second article 104 , wherein the sealing member 118 encloses the first interface volume 106 , a sealing member 118 disposed between the second article 104 and the third article 114 , wherein the sealing member 118 encloses the second interface volume 116 , or both. The sealing member 118 may form a hermetic seal or a non-hermetic seal.

The first interface volume 106 , the second interface volume 116 , or both may be arranged and disposed to exhaust a cooling fluid from the cooling fluid supply 108 to an external environment 120 . In one embodiment, wherein the sealing member 118 forms a non-hermetic seal, a partially restricted flow of the cooling fluid may pass by the sealing member 118 to exhaust to the outside environment. In another embodiment (not shown), the apparatus 100 may include a valve or restricted flow path independent of the sealing member 118 through which a partially restricted flow of the cooling fluid may pass to exhaust to the outside environment.

Utilizing the cooling fluid to purge the first interface volume 106 , the second interface volume 116 , or both, whether through a non-hermetic seal enclosed by sealing member 118 , a valve, or a restricted flow path independent of the sealing member 118 , may reduce the amount of a cooling fluid diverted from a cooling fluid supply 108 , increasing efficiency of the apparatus 100 relative to a comparable apparatus using separate flows of the cooling fluid to thermally regulate the apparatus 100 and to purge the first interface volume 106 , the second interface volume 116 , or both.

The first material composition may be any suitable material, including, but not limited to, a metal, a nickel-based alloy, a superalloy, a nickel-based superalloy, an iron-based alloy, a steel alloy, a stainless steel alloy, a cobalt-based alloy, a titanium alloy, or a combination thereof. The second material composition may be any suitable material, including, but not limited to, a refractory metal, a superalloy, a nickel-based superalloy, a cobalt-based superalloy, a ceramic matrix composite, or a combination thereof. The ceramic matrix composite may include, but is not limited to, a ceramic material, an aluminum oxide-fiber-reinforced aluminum oxide (Ox/Ox), carbon-fiber-reinforced carbon (C/C), carbon-fiber-reinforced silicon carbide (C/SiC), and silicon-carbide-fiber-reinforced silicon carbide (SiC/SiC). In one embodiment, the first material composition is a metal and the second material composition is a ceramic matrix composite.

In an embodiment having a first article 102 and a third article 114 , the third material composition may be the first material composition, or the third material composition may include a distinct material composition from the first material composition. As used herein, a “distinct” material composition indicates that the first material composition and the third material composition differ from one another by more than a difference in trace impurities such that the first material composition and the third material composition have material properties which are sufficiently different from one another to have a material affect at the operating conditions to which the article 100 is subjected. Also in an embodiment having a first article 102 and a third article 114 , the third thermal tolerance may be the first thermal tolerance, or the third thermal tolerance may be distinct from the first thermal tolerance.

In one embodiment, the apparatus 100 includes a reduced thermal gradient 122 between the first article 102 and the second article 104 relative to a comparable apparatus (not shown) in which a comparable at least one cooling fluid channel is isolated from a comparable interface volume. In an embodiment having a first article 102 and a third article 114 , the apparatus 100 may also include a reduced thermal gradient 122 between the second article 104 and the third article 114 relative to the comparable apparatus. Without being bound by theory, it is believed that using a cooling fluid from a cooling fluid supply 108 which passes through a heat exchange portion 112 of a cooling fluid channel 110 prior to purging at least one of a first interface volume 106 and a second interface volume 116 may cool the second article 104 , may elevate the temperature of at least one of the first interface volume 106 and the second interface volume 116 , and may further elevate the temperature of at least one of the first article 102 and the third article 114 .

Referring to FIGS. 1-3 , in one embodiment, the heat exchange portion 112 includes a first heat exchange portion 124 and a second heat exchange portion 126 . The first heat exchange 124 portion and the second heat exchange portion 126 may be in parallel (as shown in FIG. 1 ) or in sequence (as shown in FIGS. 2-3 ).

Referring to FIGS. 2 and 3 , in one embodiment, the apparatus 100 includes a first heat exchange portion 124 disposed in the first article 102 and a second heat exchange portion 126 disposed in the second article 104 . The first heat exchange portion 124 may be downstream of the second heat exchange portion 126 (as shown in FIG. 2 ), or the first heat exchange portion 124 may be upstream of the second heat exchange portion 126 (as shown in FIG. 3 ). Passing the cooling gas through the first heat exchange portion 124 prior to passing the cooling gas through the second heat exchange portion 126 may preheat the cooling gas and reduce any negative effects of the second article 104 being exposed to a cooling gas which is too cold, such as, but not limited to, local thermal stresses or delamination. Passing the cooling gas through the second heat exchange portion 126 prior to passing the cooling gas through the first heat exchange portion 124 may preheat the cooling gas and reduce cooling of the first article 104 , thereby decreasing the thermal gradient 122 .

Referring to FIGS. 1-3 , the heat exchange portion 112 may include any suitable conformation, including, but not limited to, a serpentine configuration 128 , a 1-pass configuration 200 , a 1.5-pass configuration 202 , a 2-pass configuration 300 , or a combination thereof. As used herein, “serpentine configuration” is not limited to a configuration with sinuous curves, but may also include angled changes of direction. In one embodiment, the configuration of the heat exchange portion 112 is arranged and disposed to thermally regulate the apparatus 100 throughout the full extent of the apparatus 100 . Thermal regulation may be a function of the flow of the cooling fluid, cross-sectional flow area within the heat exchange portion 112 , surface area within the heat exchange portion 112 , cooling fluid temperatures, and the velocity of the flow of the cooling fluid through the cooling fluid channel 110 . These parameters may vary along the cooling fluid channel 110 to address variable thermal regulation conditions along the cooling fluid channel 110 . In one embodiment, the cooling fluid channel 110 includes turbulators (not shown) such as pin banks, fins, bumps, dimples, and combinations thereof. As used herein, “turbulator” refers to a features which disrupts laminar flow.

The apparatus 100 may be any suitable apparatus, including, but not limited to a turbine component. Suitable turbine components, may include, but are not limited to, nozzles (also known as vanes), shrouds, buckets (also known as blades), turbine cases, and combustor liners.

Referring to FIG. 4 , in one embodiment the apparatus 100 is a turbine nozzle 400 , the first article 102 is an endwall 402 , and the second article 104 is a fairing 404 . In a further embodiment, the apparatus 100 includes a third article 114 , which is also an endwall 402 , wherein the first article 102 is an outside wall 406 and the third article is an inside wall 408 . The heat exchange portion 112 may be disposed in a leading edge 410 of the fairing (shown), in a trailing edge 412 of the fairing (not shown), or between the leading edge 410 and the trailing edge 412 of the fairing (not shown).

Referring to FIG. 5 , in another embodiment, the apparatus 100 is a turbine shroud 500 , the first article is an outer shroud 502 , and the second article is an inner shroud 504 .

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.