FIELD OF THE INVENTION

The present subject matter relates generally to a gas turbine engine, or more particularly to features for cooling internal components of gas turbine engines. Most particularly, the present subject matter relates to non-line of sight cooling holes for gas turbine engine airfoils.

BACKGROUND OF THE INVENTION

A gas turbine engine generally includes a fan and a core arranged in flow communication with one another. Additionally, the core of the gas turbine engine generally includes, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air is provided from the fan to an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section to the turbine section. The flow of combustion gases through the turbine section drives the turbine section and is then routed through the exhaust section, e.g., to atmosphere.

In general, turbine performance and efficiency may be improved by increased combustion gas temperatures. However, increased combustion temperatures can negatively impact the gas turbine engine components, for example, by increasing the likelihood of material failures. Thus, while increased combustion temperatures can be beneficial to turbine performance, some components of the gas turbine engine may require cooling features or reduced exposure to the combustion gases to decrease the negative impacts of the increased temperatures on the components.

Film cooling gas turbine engine components, e.g., by directing a flow of cooler fluid over the surface of the component, can help reduce the negative impacts of elevated combustion temperatures. For example, cooling apertures may be provided throughout a component; the cooling apertures may allow a flow of cooling fluid from within the component to be directed over the outer surface of the component. However, in areas of high curvature of the component, it can be difficult to direct the flow of cooling fluid from the cooling apertures over the outer surface of the component to form a cooling film of fluid. Further, known methods of forming cooling apertures, e.g., by boring or otherwise machining apertures in the component, can be ineffective in producing optimal cooling aperture lengths for controlling bore cooling and in producing cooling apertures having optimal fluid exit surface angles. In addition, known methods of machining cooling apertures are prone to through-hole scarfing and often present challenges to properly positioning the cooling apertures.

Therefore, improved cooling features for gas turbine components that overcome one or more disadvantages of existing cooling features would be desirable. In particular, an airfoil for a gas turbine engine having features for reducing an angle between a cooling aperture and an outer surface of the airfoil to reduce a surface angle of cooling fluid exiting the cooling aperture would be beneficial. Further, an airfoil having a cooling aperture including a change in direction between a first section and a second section of the cooling aperture would be advantageous. Additionally, a method for forming an airfoil for a gas turbine engine, the airfoil having features for improved surface cooling of the airfoil, would be useful.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In one exemplary embodiment of the present disclosure, an airfoil for a gas turbine engine is provided. The airfoil includes a first portion defining an inner surface of the airfoil. The first portion is formed from a first plurality of plies of a ceramic matrix composite material. The airfoil also includes a second portion defining an outer surface of the airfoil. The second portion is formed from a second plurality of plies of a ceramic matrix composite material. The first portion and the second portion define a non-line of sight cooling aperture extending from the inner surface to the outer surface of the airfoil.

In another exemplary embodiment of the present disclosure, an airfoil for a gas turbine engine is provided. The airfoil includes a first portion defining an inner surface of the airfoil. The first portion is formed from a first plurality of plies of a ceramic matrix composite material. The airfoil also includes a second portion defining an outer surface of the airfoil. The second portion is formed from a second plurality of plies of a ceramic matrix composite material. The first portion defines a first aperture and the second portion defines a second aperture. The first aperture and the second aperture extend along different directions and define a cooling aperture forming a continuous pathway through the airfoil from the inner surface to the outer surface. Further, a surface angle is defined between the second aperture and the outer surface. The surface angle is less than 45°.

In a further exemplary embodiment of the present disclosure, a method for forming an airfoil for a gas turbine engine is provided. The method includes laying up a first plurality of plies of a ceramic matrix composite material; processing the first plurality of plies to form a first portion of the airfoil; laying up a second plurality of plies of a ceramic matrix composite material, the second plurality of plies laid up on the first portion of the airfoil; and processing the second plurality of plies and the first portion to form a second portion of the airfoil adjacent the first portion. The first and second portions define a non-line of sight cooling aperture.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

