Airfoil insert

Abstract

An airfoil insert comprises an insert wall, a contact element and a flow director. The insert wall defines an interior extending inside the insert wall from a first end to second end, and an exterior extending outside the insert wall from the first end to the second end. The contact element is formed on the exterior of the insert wall. The flow director is formed on the insert wall at a boundary between the interior and the exterior. The flow director increases a heat transfer coefficient of convective flow along the insert wall by directing the convective flow to the exterior of the insert wall.

Description

BACKGROUND OF THE INVENTION[0001]The subject matter of this application relates generally to gas turbine engines, and specifically to cooling techniques for the airfoil sections of turbine blades and vanes. In particular, the invention concerns an insert for convective cooling the interior surfaces of turbine airfoils exposed to high-temperature working fluid flow.[0002]Gas turbine engines are built around a power core comprising a compressor, a combustor and a turbine, which are arranged in flow series with a forward (upstream) inlet and an aft (downstream) exhaust. The compressor compresses air from the inlet, which is mixed with fuel in the combustor and ignited to produce hot combustion gases. The hot combustion gases drive the turbine section, and are exhausted with the downstream flow.[0003]The turbine drives the compressor via a shaft or a series of coaxially nested shaft spools, each driven at different pressures and speeds. The spools employ a number of stages comprised of ...

AI Technical Summary

Benefits of technology

[0011]The contact element is formed on the exterior of the insert wall between the first end and the second end, for attaching the insert to an airfoil and for spacing the insert wall from the internal airfoil surfaces. The flow director is formed on the insert wall at a boundary between the exterior and interior, and increases the heat transfer coefficient of convective flow along the insert by directing the convective flow to the exterior region, between the insert wall and the surface of the cooling passage.

[0012]The method comprises positioning the insert along an internal surface of an airfoil, spacing the insert from the internal surface, and restricting convective flow along the insert to a region between the insert and the inner surface. This increases the Reynolds number of the convective flow, which in turn increases the heat transfer coefficient.

Problems solved by technology

Low-bypass turbofans are louder and less fuel efficient, but provide greater response and specific thrust.

Unfortunately, high combustion temperatures also increase thermal and mechanical loads, particularly on turbine airfoils downstream of the combustor.

This reduces service life and reliability, and increases operational costs associated with maintenance and repairs.

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