Clearance control structure for a gas turbine engine

A gas turbine engine, wherein the engine defines an axial direction co-directional to a centerline axis, a radial direction extended from the centerline axis, and a circumferential direction relative to the centerline axis, the engine comprising:

• a first turbine rotor assembly comprising a plurality of first turbine rotor blades extended within a gas flowpath;
• a second turbine rotor assembly positioned aft along the gas flowpath of the first turbine rotor assembly, wherein the second turbine rotor assembly is rotatably separate from the first turbine rotor assembly;
• a casing surrounding the first turbine rotor assembly, wherein the casing comprises a unitary, integral outer casing wall extended forward of the first turbine rotor assembly and aft of the first turbine rotor assembly, and wherein the casing comprises a plurality of vanes extended from the outer casing wall and through the gas flowpath aft of the first turbine rotor assembly and forward of the second turbine rotor assembly, and further wherein the casing comprises a plurality of walls extended outward along the radial direction from the outer casing wall, and wherein the outer casing wall and the plurality of walls is a unitary, integral structure;
• an inner manifold wall surrounding the plurality of walls at the casing along the circumferential direction and the axial direction, wherein the inner manifold wall is extended forward along the axial direction of the plurality of vanes, and wherein the inner manifold wall is connected to the outer casing wall forward of the plurality of vanes;
• and
• an outer manifold wall surrounding the inner manifold wall, wherein the outer manifold wall and the inner manifold wall together form a unitary, integral structure.