Clearance control for the turbine of a gas turbine engine
AssigneeUnited Technologies Corporation
InventorsFrank W. Huber, Douglas J. Dietrich
Life of this patent
Estimating the term…
Abstract
An aerodynamic buffer zone in the gap between the tip of an air cooled axial flow turbine blade of a gas turbine engine and its surrounding shroud or seal (outer air seal) is created by discretely discharging a high velocity stream of cooling air from the tip of the blade in a judicious direction. The stream is angularly oriented relative to the plane of rotation of the turbine so that it is discharged in the gap in the direction of the pressure side of the turbine and preferably at between a 15.degree.-45.degree. angle relative to the flat surface of the tip of the blade.
Claims8
An axial flow turbine for a gas turbine engine in combination with an annular shroud surrounding said turbine, said turbine including a plurality of internally air cooled turbine blades each having a tip section mounted adjacent said shroud and defining therewith a gap that is susceptible of leaking engine working medium, each of said internally cooled blades having an airfoil surface exposed to said engine working medium defining a pressure surface and a suction surface, means for minimizing said leakage by providing a buffer zone in said gap, said means including an orifice means located in said tip section adjacent said pressure surface and said orifice being skewed relative to the rotation axis of said blade for leading air from internally of said blade into said gap toward the pressure side of said blades whereby the stream of air discharging from said orifice means defines a buffer zone so as to minimize parasitic leakage of said engine working medium.
An axial flow turbine for a gas turbine engine in combination with an outer air seal surrounding said turbine, said turbine including a plurality of internally air cooled blades including a plurality of passageways for conducting air internally of said blade, said blade having an airfoil surface defining a tip section, a root section, a leading edge, a trailing edge, a pressure surface and a suction surface, at least one of said passageways extending radially straight through for conducting cooling air from said root section to said tip section having a relatively flat outer surface, said one passageway feeding a plurality of film cool holes radially spaced in said airfoil surface, said passageway being replenished with cooling air from another of said passageways through replenishment holes spaced radially along said one passageway, said outer air seal and said tip section defining a gap susceptible of parasitic leakage of engine working medium used in powering said turbine, means for minimizing said parasitic leakage including an orifice in said tip communicating with said one passageway and being oriented to discharge cooling air angularly with respect to the axis of rotation of said turbine and oriented in a direction toward said pressure side, and a source of cooling air supplying air to said root section for feeding cooling air to said passageways including said one passageway.
Dependencies are inferred from the claim text.