Abstract: Introducing a plurality of geometrically shaped members (27) into a cooling passage (16) of a gas turbine airfoil (10) will effectively reduce the cross-sectional flow area while simultaneously retaining a sufficiently thick external contour desired for proper gas path aerodynamic behavior. Small cooling sub-passages (18a, 18b) formed around the geometric members will create a preferentially higher coolant flow rate and heat transfer coefficient at the cooled surface (14) when compared to the interior of the cavity. The geometric shapes may be metal or ceramic spheres retained in the cooling cavity by a retaining structure such as a screen grid (30) or perforated plate (32). The openings (34) in the retaining structure may be unevenly distributed to preferentially allow more coolant to enter the cavity proximate the cooled walls. The size/shape of the geometrically shaped members may be varied to achieve a desired heat transfer coefficient along the cooled wall surface (17).

Abstract: Introducing a plurality of geometrically shaped members (27) into a cooling passage (16) of a gas turbine airfoil (10) will effectively reduce the cross-sectional flow area while simultaneously retaining a sufficiently thick external contour desired for proper gas path aerodynamic behavior. Small cooling sub-passages (18a, 18b) formed around the geometric members will create a preferentially higher coolant flow rate and heat transfer coefficient at the cooled surface (14) when compared to the interior of the cavity. The geometric shapes may be metal or ceramic spheres retained in the cooling cavity by a retaining structure such as a screen grid (30) or perforated plate (32). The openings (34) in the retaining structure may be unevenly distributed to preferentially allow more coolant to enter the cavity proximate the cooled walls. The size/shape of the geometrically shaped members may be varied to achieve a desired heat transfer coefficient along the cooled wall surface (17).