United Technologies Corporation

Kenneth B Hall

Thomas A Auxier

Kenneth K Landis

Wesley D Brown

Robert J Kildea

Robert J McClelland

Internal heat transfer of air cooled turbine blades of a gas turbine engine is enhanced by orienting the impingement holes that interconnect the air-cooled feed passage to the hybrid passageway internally of the blade in a more radial direction to minimize pressure drop losses. By improved mixing of the cooling air in the hybrid passageway the additional mechanical turbulence promoters can be utilized without sacrificing pressure losses.

Turbine blade cooling

An internally cooled turbine blade for a gas turbine engine is modified at the leading and trailing edges to include a dynamic cool air flowing radial passageway with an inlet at the root and a discharge at the tip feeding a plurality of radially spaced film cooling holes in the airfoil surface. Replenishment holes communicating with the serpentine passages radially spaced in the inner wall of the radial passage replenish the cooling air lost to the film cooling holes. The discharge orifice is sized to match the backflow margin to achieve a constant film hole coverage throughout the radial length. Trip strips may be employed to augment the pressure drop distribution

Cooled blades for a gas turbine engine

A bulkhead in the form of a rib extending spanwise adjacent the leading edge of the airfoil of a turbine blade of a gas turbine engine serves to stiffen the airfoil to attain protection from impact by foreign objects, but doesn't materially affect cooling effectiveness in the event of a puncture of the skin. Holes extending spanwise in the rib reduce the mass, allow radial flow, and restrict flow into the leading edge. This construct allows a reduction in the thickness of the skin of the airfoil, and hence a weight reduction.

Turbine blade

The leading edge of the turbine airfoil of a turbine blade for a gas turbine engine is cooled by utilizing helix shaped holes that are rectangular in cross-section and curved to produce film holes egressing at low angles adjacent the outer surface of the leading edge. The helix holes extend from the root to the tip of the blade and are parallelly and longitudinally spaced.

Leading edge cooling of turbine airfoils

Internal cooling of the trailing edge of the airfoil of the turbine blade for a gas turbine engine includes a cascade formed from juxtaposed rows of longitudinally extending spaced airfoil shaped vanes or ribs leading cooling air from a supply source through the space between adjacent vanes and discharging out of the blade.

Turbine blade trailing edge cooling construction

The flow rate of the cooling air at the trailing edge of the airfoil of a turbine blade for a gas turbine engine is established by casting the blade to include judiciously located radially spaced projections adjacent to or in the ribs in the trailing edge which serve to meter the flow in the channels formed between the ribs. The holes for forming the projections in the core that are used to form the internal cooling passages in the trailing edge are intentionally undersized. After the core is cleaned and flashed, the blade is cast in a mold and the ceramic core is leached out. The internal cooling passages in the trailing edge are flow tested to obtain the flow rate and pressure and this data is used to resize the projection. Resizing the projection is made by reforming the core with the same die, and with the information previously obtained in the flow test, the holes that form the projections are enlarged by drilling to obtain the desired flow rate. This process is repeated until the desired flow rate for each trailing edge channel is achieved. The die may be changed at this juncture to provide the ultimate dimensioned hole in the core to provide the necessary metering of the cooling air to attain the predetermined flow rate.

Method of casting to control the cooling air flow rate of the airfoil

The airfoil shaped body has a separate leading edge portion (14) spaced from the main body (12). Slots (22) thereby formed discharge cooling air parallel to surface (38) of the main body. A step change across the slot between the leading edge surface (52) and the main body surface (38) facilitates smooth introduction of cooling air.

Cooled gas turbine blade

A turbine blade is formed from an airfoil blade 10 having V-grooves 12 in the outer surface and indentations 26 in the inner surface. A slot 30 is machined at the root of the groove intersecting the slots, and providing a smooth flow path for the cooling air discharging along the blade surface.

Method of fabricating an air cooled turbine blade

Dirt removal means for an internally air cooled blade for a gas turbine engine of the type that includes multi passes some of which are serpentine as made in situ by casting the ribs so as to be angularly disposed at the root of the blade and a straight through passageway with an opening at the tip. The velocity of the airstream in the straight through passageway being sufficiently high to carry the dirt through the opening and the angularly disposed ribs overlying the entrance to the other passageway so as to divert the dirt entrained airstream into the straight through passageway while allowing relatively dirt-free air to turn the angle of the rib to enter the serpentine passes.

Dirt removal means for air cooled blades

A dirt removal means for air cooled blades for removing dirt at the blade of a gas turbine engine. The means is a stamped out sheet metal that defines a deflector or plurality of deflectors adapted to overlie the inlets of the blade's internal cooling passages for diverting the dirt entrained air through a high velocity air stream and discharging the dirt entrained air while allowing the cleaner portion of air to turn the corner of the deflector and flow through the blades cooling passages. These means can be applied to existing blades.

A hollow, cooled airfoil has a pair of nested, coolant channels therein which carry separate coolant flows back and forth across the span of the airfoil in adjacent parallel paths. The coolant in both channels flows from a rearward to forward location within the airfoil allowing the coolant to be ejected from the airfoil near the leading edge through film coolant holes.

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Jupiter, FL, United States of America

Kenneth B Hall