Airfoil for turbomachine and airfoil cooling method

A turbomachine comprising:

• a housing having a housing inlet and a housing outlet;
• an airfoil within the housing and positioned in a flow path of fluid conveyed through the housing between the housing inlet and the housing outlet, the airfoil including an outer body wall having a pressure side and a suction side extending between a leading edge and a trailing edge, and a plurality of inner walls including a flow-distributing forward wall and an inner cooling wall;
• the airfoil including a forward cavity defined in part by the flow-distributing forward wall and in part by the outer body wall, a switchbacked passage extending between an inlet and a plurality of outlets, and a second passage defined in part by the inner cooling wall and in part by the outer body wall;
• a plurality of jetting orifices formed within the flow-distributing forward wall and defined by the outer body wall, and fluidly connecting the switchbacked passage to the forward cavity, and oriented to produce wall jets of incoming cooling fluid from the switchbacked passage directed in an upstream direction toward a back side surface of the leading edge, the plurality of jetting orifices being located directly adjacent to the outer body wall;
• and
• the second passage extending between the forward cavity and the plurality of outlets and fluidly connecting with the switchbacked passage within the elongate hollow body, such that a flow of outgoing cooling fluid from the forward cavity and a flow of outgoing cooling fluid from the switchbacked passage are conveyed in a downstream direction through the airfoil toward the plurality of outlets and merged prior to discharging through the plurality of outlets.

A method of cooling an airfoil comprising:

• conveying a cooling fluid from a switchbacked passage extending through the airfoil into a plurality of jetting orifices formed within a flow-distributing forward wall and defined by an outer body wall of the airfoil, the plurality of jetting orifices fluidly connecting the switchbacked passage with a forward cavity positioned adjacent to a leading edge of the airfoil and being located directly adjacent to an outer body wall of the airfoil;
• directing jets of the cooling fluid produced by the jetting orifices in an upstream direction along a back side surface of the leading edge so as to dissipate heat of the leading edge;
• and
• directing the cooling fluid having dissipated heat of the leading edge in a downstream direction through a second passage defined by an outer body wall and an inner cooling wall of the airfoil, such that the cooling fluid dissipates heat of the outer body wall prior to discharging through a plurality of outlets.