Turbine blade with tip turn cooling

摘要

A turbine blade with a conical shaped tip for use in a first or second stage of a turbine. The airfoil includes an aft flowing 3-pass serpentine flow cooling circuit with a serpentine tip turn located between the first and the second legs and underneath the tip. Mini serpentine flow cooling circuits are formed in the end of the first leg and the beginning of the second leg to reduce or eliminate the cooling flow separation and over temperature issues at the tip portion of the blade. A leading edge cooling supply channel is located forward of the first leg and has a decreasing flow area with an exit cooling hole at the tip to discharge cooling air. The last leg of the main serpentine circuit is formed by a slanted rib that produces a decreasing flow area in the last leg and includes an exit cooling hole on the tip to discharge cooling air. The last leg is connected to a row of exit cooling holes or slots formed along the trailing edge of the airfoil. The main serpentine flow circuit is separated from the leading edge cooling channel so that no cooling air mixes.