Low-ductility turbine shroud flowpath and mounting arrangement therefor

A turbine flowpath apparatus for a gas turbine engine having a centerline axis, the apparatus comprising:

• an annular shroud support;
• an annular shroud hanger engaged with the shroud support;
• an annular flowpath member comprising low-ductility material, the flowpath member having a primary flowpath surface and an opposed back surface, and having a cross-sectional shape including the flowpath surface comprising a generally cylindrical forward section and an aft section, wherein substantially all of the aft section extends aft and radially outward at a non-perpendicular, non-parallel angle to the centerline axis, where a forward end of the flowpath member abuts the hanger;
• an annular turbine case surrounding the flowpath member and the shroud support;
• an annular centering spring disposed between the turbine case and the flowpath member, the centering spring urging the flowpath member towards a centered position within the turbine case, wherein the centering spring includes an annular array of resilient spring fingers separated by generally axially-aligned slots;
• wherein radial pins are fixed to the centering spring and extend into corresponding slots formed in the back surface of the flowpath member, so as to prevent relative lateral movement and relative rotation of the flowpath member and the centering spring;
• and
• a rotor comprising a rotatable disk that carries an array of airfoil-shaped turbine blades, wherein the forward section of the flowpath member surrounds the turbine blades and defines a portion of a flowpath through the turbine blades.

A turbine flowpath apparatus for a gas turbine engine having a centerline axis, the apparatus comprising:

• an annular shroud support;
• an annular shroud hanger engaged with the shroud support;
• an annular flowpath member comprising low-ductility material, the flowpath member having a primary flowpath surface and an opposed back surface, and having a cross-sectional shape including the flowpath surface comprising a generally cylindrical forward section and an aft section, wherein substantially all of the aft section extends aft and radially outward at a non-perpendicular, non-parallel angle to the centerline axis, where a forward end of the flowpath member abuts the hanger;
• an annular turbine case surrounding the flowpath member and the shroud support;
• an annular centering spring disposed between the turbine case and the flowpath member, the centering spring urging the flowpath member towards a centered position within the turbine case, wherein the centering spring includes spring tabs which abut the annular retainer, such that the centering spring urges the retainer axially against the shroud support;
• a rotor comprising a rotatable disk that carries an array of airfoil-shaped turbine blades, wherein the forward section of the flowpath member surrounds the turbine blades and defines a portion of a flowpath through the turbine blades;
• a retaining ring engaging a groove in the shroud support and axially abutting the hanger;
• and
• a resilient, annular retainer having a C-shaped cross-section clamping the shroud support and the retaining ring together.