Patent Description:
Traditionally, turbomachines, as in gas turbine engines, include multiple stages of rotor blades and vanes to condition and guide fluid flow through the compressor and/or turbine sections. Due to the high temperatures in the turbine section, turbine vanes are often cooled with cooling air ducted into an internal cavity of the vane through a vane platform. In order to reduce the amount of cooling air required to cool turbine vanes, space filling baffles can be provided in the vane cavity to reduce the cavity volume, thereby increasing Mach numbers and heat transfer coefficients for the cooling flow. In certain vane designs, Mach numbers and heat transfer coefficients are not always uniform across various regions of the vane.

Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved blades and vanes. The present disclosure provides a solution for these problems.

<CIT> discloses an airfoil body having a plurality of internal ribs extending inwardly within an interior hollow portion.

<CIT> discloses an airfoil body, the inner surface of which is provided with confronting grooves for receiving two inserts.

<CIT> discloses a cooling apparatus for a turbine vane having a plurality of impingement cavities.

<CIT> discloses a vane for gas turbine engines which distributes cooling air.

Viewed from one aspect the present invention provides an airfoil according to claim <NUM>.

Specific embodiments are described in the appended claims.

The features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings.

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, a cross-sectional side elevation view of an exemplary embodiment of a gas turbine engine accordance with the disclosure is shown in <FIG> and is designated generally by reference character <NUM>. Other embodiments of gas turbine engines in accordance with the disclosure, or aspects thereof, are provided in <FIG>, as will be described. Vanes shown and described herein provide for increased control over Mach numbers and heat transfer between cooling flow paths in the vanes and vane surfaces exposed to high-temperature gases from the gas path.

The fan section <NUM> drives air along a bypass flow path B in a bypass duct defined within a fan case <NUM>, while the compressor section <NUM> drives air along a core flow path C for compression and communication into the combustor section <NUM> then expansion through the turbine section <NUM>.

With continued reference to <FIG>, the exemplary engine <NUM> generally includes a low speed spool <NUM> and a high speed spool <NUM> mounted for rotation about an engine central axis X relative to an engine static structure <NUM> via several bearing systems <NUM>.

The inner shaft <NUM> and the outer shaft <NUM> are concentric and rotate via bearing systems <NUM> about the engine central axis X which is collinear with their longitudinal axes.

The mid-turbine frame includes airfoils which are in the core airflow path C.

Now with reference to <FIG> and <FIG>, compressor section <NUM>, combustor section <NUM> and turbine section <NUM> include vanes <NUM>. Each vane <NUM> includes a vane body <NUM> extending from an inner diameter platform <NUM> to an opposed outer diameter platform <NUM> along a longitudinal axis A. Vane body <NUM> defines a leading edge <NUM> and a trailing edge <NUM>. A cavity <NUM> is defined between leading edge <NUM>, trailing edge <NUM>, inner diameter platform <NUM> and outer diameter platform <NUM>.

As shown in <FIG>, cavity <NUM> includes airfoil protrusions <NUM> extending inward from an inner surface <NUM> of vane body <NUM>. Vane <NUM> includes baffle bodies <NUM> within cavity <NUM>. Each baffle body <NUM> extends from a first end <NUM> to a second end <NUM> along respective baffle body axes Z. Each baffle body <NUM> has baffle protrusions <NUM> extending along respective central protrusion axes Q at an angle with respect to baffle body axis Z. Protrusions extend from a leading edge side of one of the baffle bodies <NUM>, e.g. the side proximate to leading edge <NUM>, and a trailing edge side of the other baffle body <NUM>, e.g. the side proximate to trailing edge <NUM>. An end <NUM> of each baffle protrusion <NUM> abuts an end <NUM> of each respective airfoil protrusion <NUM> to maintain the position of baffle body <NUM> within vane body <NUM>. Because both vane and baffle bodies <NUM> and <NUM>, respectively, both have protrusions, part of a flow path <NUM>, described in more detail below, is set by baffle protrusions <NUM> and part of flow path <NUM> is set by airfoil protrusions <NUM>, making insertion of baffle bodies <NUM> into vane cavity <NUM> during assembly easier. Inner surface <NUM> of vane body <NUM> includes inwardly extending raised tripping portions <NUM>. Vane body <NUM> includes cooling holes <NUM> in fluid communication with flow path <NUM> to provide cooling air to an exterior surface of vane body <NUM>.

As shown in <FIG>, a distance d between inner surface <NUM> of vane body <NUM> and an outer surface <NUM> of baffle body <NUM>, taken in a direction normal to inner surface <NUM> of vane body <NUM>, varies along baffle body axis Z to control heat transfer and Mach numbers of fluid flowing through cavity <NUM>. For example, distance d is smaller proximate inner diameter platform <NUM> than proximate to outer diameter platform <NUM>.

A flow path <NUM> is defined between inner surface <NUM> of vane body <NUM> and outer surface <NUM> of baffle body <NUM>. Vane body <NUM> includes a fluid inlet <NUM> proximate to outer diameter platform <NUM>. The cross-sectional area of flow path <NUM> converges in a direction away from fluid inlet <NUM> to control Mach numbers and heat transfer in flow path <NUM>. For example, cross-sectional area of flow path <NUM> converges in a direction from outer diameter platform <NUM> toward inner diameter platform <NUM>, providing substantially constant Mach numbers and heat transfer throughout flow path <NUM> as flow is bled off through cooling holes <NUM>. Whereas, traditionally, the cross-sectional area of flow paths between a baffle body and an inner vane surface have been relatively constant in order to facilitate the insertion of the baffle. Since cooling flow typically enters through a fluid inlet on one side of the vane and is bled out through cooling holes, similar to cooling holes <NUM>, in the vane, Mach numbers and heat transfer, in traditional embodiments, tend to decrease the further the flow is from the inlet, resulting in high metal temperatures at the end of the flow path.

<FIG> shows a cross-sectional view of the contact surfaces for airfoil and baffle protrusions, <NUM> and <NUM>, respectively. As shown, the surface area <NUM> of end <NUM> of baffle protrusion <NUM> is greater than the surface area <NUM> of end <NUM> of airfoil protrusion <NUM>. However, it is contemplated that in alternate embodiments, surface area <NUM> of end <NUM> of airfoil protrusion <NUM> can be greater than surface area <NUM> of end <NUM> of baffle protrusion <NUM>. This difference in area ensures that end surfaces <NUM> of baffle protrusions <NUM> and end surfaces <NUM> of airfoil protrusions <NUM> abut one another despite manufacturing tolerances and thermal growth that occurs during engine operation. While both baffle protrusion <NUM> and airfoil protrusion <NUM> are shown as having a rectangular cross-sectional shape with rounded corners it is contemplated that baffle protrusions <NUM> and airfoil protrusions <NUM> can have a variety of cross-sectional shapes, for example, circular, oval, ellipse, and the like.

As shown in <FIG>, the distance f taken between outer surface <NUM> of baffle body <NUM> and baffle body axis Z in a direction normal to outer surface <NUM> of each baffle body <NUM> varies along baffle body axis Z. The distancep represents the maximum distance taken from baffle body axis Z to outer surface <NUM> of baffle body <NUM> in a transverse direction with respect to baffle body axis Z. In order to insert baffle <NUM>, distance p is less than or equal to the minimum of distances h taken from the baffle body axis Z to the end <NUM> of each baffle protrusion <NUM> in a transverse direction with respect to baffle body axis Z. Furthermore, the distance l between an end <NUM> of a first one of baffle protrusions <NUM> and an outer surface <NUM> of baffle body <NUM>, e.g. also at the base of protrusion <NUM>, taken along the respective central protrusion axis Q of the first protrusion is greater than a similar distance l taken along the respective central protrusion axis Q of a second one of baffle protrusions <NUM>. For example, baffle protrusions <NUM> proximate to second end <NUM> of baffle body <NUM> are longer than baffle protrusions <NUM> proximate to first end <NUM> of baffle body <NUM>.

With reference now to <FIG>, baffle protrusions <NUM> and corresponding airfoil protrusions <NUM> also extend from a suction side of baffle body <NUM>, e.g. the side facing a suction side <NUM> of vane body <NUM>, and a pressure side of baffle body <NUM>, e.g. the side facing a pressure side <NUM> of vane body <NUM>. Those skilled in the art will readily appreciate that baffle protrusions <NUM> can be positioned in a variety of places with respect to the airfoil body, e.g. vane body <NUM>, in which they are disposed, depending on the alignment and cooling required.

With reference now to <FIG>, vane <NUM> includes a vane body <NUM> extending from an inner diameter platform <NUM> to an opposed outer diameter platform <NUM> along a longitudinal axis A. Vane body <NUM> defines a leading edge <NUM> and a trailing edge <NUM>. A cavity <NUM> is defined between leading edge <NUM>, trailing edge <NUM>, inner diameter platform <NUM> and outer diameter platform <NUM>. Vane body <NUM> includes a fluid inlet <NUM>, similar to fluid inlet <NUM>, proximate to inner diameter platform <NUM> instead of outer diameter platform <NUM>. Vane cavity <NUM> includes baffle bodies <NUM> that increase in width approaching the center of baffle body <NUM>.

With continued reference to <FIG>, a flow path <NUM> is defined between inner surface <NUM> of vane body <NUM> and outer surface <NUM> of baffle body <NUM>. The cross-sectional area of flow path <NUM> first converges in a radial direction away from fluid inlet <NUM> toward the center of baffle bodies <NUM> and then diverges from the center of the baffle bodies <NUM> towards outer diameter platform <NUM>. The configuration of vane <NUM> tends to assist in aiding heat transfer when the temperature of gas path, e.g. core flow path C, is hottest at midspan of vane body <NUM>. Thus, vanes <NUM> and <NUM> show that embodiments of the present disclosure allow the flow path to be tailored to meet heat transfer requirements. While vane bodies, e.g. vane bodies <NUM> and <NUM>, are shown and described herein as having fluid inlets, e.g. fluid inlets <NUM> and <NUM>, proximate to an inner diameter platform, e.g. inner diameter platform <NUM> or <NUM>, or an outer diameter platform, e.g. outer diameter platform <NUM> or <NUM>, of the vane body, it is contemplated that the vane body can include fluid inlets proximate to both the inner diameter platform and the outer diameter platform of the vane body. Moreover, while shown and described herein, cooling holes <NUM> may not be necessary in the vane bodies. In which case, the cooling flow can enter either the inner diameter platform or outer diameter platform and exit at the respective opposite end.

Those skilled in the art will readily appreciate that baffles, e.g. baffles <NUM> and <NUM>, and their respective protrusions, e.g. baffle protrusions <NUM> and <NUM>, can be manufactured in a variety of ways. For example, baffles can be made from sheet metal and protrusions can be stamped in before forming the baffle shape, baffles and protrusions can be cast together, and/or baffles and protrusions can be additively manufactured. Additionally, the baffles can be used in conjunction with other baffles that do not include baffle protrusions. It is also contemplated that embodiments described herein can readily be used in airfoils other than turbine vanes. For example, they can be used in turbine blades, compressor blades, compressor vanes, or any other suitable airfoil application.

Claim 1:
An airfoil (<NUM>; <NUM>) comprising:
an airfoil body (<NUM>; <NUM>) extending from an inner diameter platform (<NUM>; <NUM>) to an opposed outer diameter platform (<NUM>; <NUM>) along a longitudinal axis (A), wherein the airfoil body (<NUM>; <NUM>) defines a leading edge (<NUM>; <NUM>) and a trailing edge (<NUM>; <NUM>), and a cavity (<NUM>; <NUM>) defined between the leading edge (<NUM>; <NUM>), the trailing edge (<NUM>; <NUM>), the inner diameter platform (<NUM>; <NUM>) and the outer diameter platform (<NUM>; <NUM>), the cavity (<NUM>; <NUM>) having an airfoil protrusion (<NUM>) extending inward from an inner surface (<NUM>; <NUM>) of the airfoil body (<NUM>; <NUM>); and
a baffle body (<NUM>; <NUM>) within the cavity (<NUM>; <NUM>) extending along a baffle body axis (Z), the baffle body (<NUM>; <NUM>) having a baffle protrusion (<NUM>) extending along a central protrusion axis (Q) at an angle with respect to the baffle body axis (Z), wherein the end (<NUM>) of the baffle protrusion (<NUM>) abuts an end (<NUM>) of the airfoil protrusion (<NUM>) to maintain the position of the baffle body (<NUM>; <NUM>) within the airfoil body (<NUM>; <NUM>);
wherein at least one of the inner diameter platform or the outer diameter platform includes a fluid inlet (<NUM>), wherein the distance (d) between the inner surface (<NUM>) of the airfoil body (<NUM>) and the outer surface (<NUM>) of the baffle body (<NUM>) taken in a direction along the central protrusion axis (Q) of the baffle protrusion (<NUM>) is smaller proximate the platform (<NUM>) opposite the fluid inlet (<NUM>) than proximate to the other platform (<NUM>); and
wherein the surface area (<NUM>, <NUM>) of the end (<NUM>, <NUM>) of one of the baffle protrusion (<NUM>) or the airfoil protrusion (<NUM>) is greater than the surface area (<NUM>, <NUM>) of the end (<NUM>, <NUM>) of the other abutting protrusion (<NUM>, <NUM>),
characterized by:
a flow path defined between the inner surface of the airfoil body and the outer surface of the baffle body, and the cross-sectional area of the flow path converges in a direction away from the fluid inlet.