Exhaust device and an associated method thereof

A combined cycle power plant comprising:

• an upstream device comprises an outlet, wherein the upstream device comprises a turbine;
• an exhaust device comprising:
• a diffuser comprising:
• an inner wall extending circumferentially about a centerline axis of the exhaust device;
• an outer wall extending circumferentially about the centerline axis and spaced radially outward from the inner wall;
• and
• a diffuser inlet coupled to the outlet, a diffuser outlet, and a diffuser flow path defined between interior surfaces of the inner and outer walls, wherein the diffuser flow path extends from the diffuser inlet to the diffuser outlet, wherein the inner and outer walls of the diffuser turn radially outward away from the centerline axis between the diffuser inlet and the diffuser outlet;
• and
• a plenum comprising an inlet wall portion and a non-circular plenum outlet,
• wherein the plenum comprises a cavity disposed downstream from the diffuser, wherein the cavity is in fluid communication with the diffuser flow path, wherein the cavity extends along an exterior surface of the inner wall of the diffuser, wherein the inlet wall portion is coupled to the diffuser outlet, and wherein the non-circular plenum outlet is spaced from the diffuser outlet along an axial direction relative to the centerline axis of the exhaust device;
• and
• a downstream device comprising an inlet coupled to the non-circular plenum outlet, wherein the non-circular plenum outlet is configured to discharge exhaust to the inlet in the axial direction relative to the centerline axis, wherein the downstream device comprises at least one of a heat recovery steam generator (HRSG) and a silencer.

A method of operating an exhaust device in a combined cycle power plant, comprising:

• receiving a fluid along an axial direction from an upstream device into a diffuser of an exhaust device;
• directing the fluid from a diffuser inlet to a diffuser outlet along a diffuser flow path defined between an inner wall and an outer wall of the diffuser, wherein the inner wall extends circumferentially about a centerline axis of the exhaust device, wherein the outer wall extends circumferentially about the centerline axis and is spaced radially outward from the inner wall;
• directing the fluid along a radial direction from the diffuser outlet into a plenum of the exhaust device, wherein the inner and outer walls of the diffuser turn radially outward away from the centerline axis between the diffuser inlet and the diffuser outlet, wherein an inlet wall portion of the plenum is coupled to the outer wall of the diffuser at a position between the diffuser inlet and the diffuser outlet, wherein the inlet wall portion is angled away from the outer wall of the diffuser;
• dispersing the fluid in the diffuser and the plenum;
• and
• discharging the fluid from the plenum axially to a downstream device via a non-circular plenum outlet disposed along the centerline axis, wherein the non-circular plenum outlet is spaced from the diffuser outlet along the axial direction.