Abstract: An exhaust stack having a junction tube and a flue is provided. The flue has a silencer portion, a converging duct portion, a tubular portion, and a diverging diffuser portion. The silencer portion fluidly communicates with the junction tube. The silencer portion has a first hydraulic mean cross-sectional flow path, and the tubular portion has a second hydraulic mean cross-sectional flow path less than or equal to the first hydraulic mean cross-sectional flow path. The converging duct portion is coupled between the silencer portion and the tubular portion.

Abstract: A system for thermal management of exhaust gas includes: a nozzle configured to be disposed in fluid communication with an exhaust of a turbomachine; a mixing conduit in fluid communication with the nozzle; at least one secondary inlet disposed around a periphery of the nozzle and extending between an exterior of the mixing conduit and an interior of the mixing conduit; a variable nozzle mechanism configured to be movable between i) a first position in which the mechanism is configured to close the at least one secondary inlet and ii) a second position in which the mechanism is configured to open the at least one secondary inlet and adjust a selected diameter of the nozzle; and an actuator configured to move the variable nozzle mechanism between the first position and the second position.

Abstract: An exhaust stack having a junction tube and a flue is provided. The flue has a silencer portion, a converging duct portion, a tubular portion, and a diverging diffuser portion. The silencer portion fluidly communicates with the junction tube. The silencer portion has a first hydraulic mean cross-sectional flow path, and the tubular portion has a second hydraulic mean cross-sectional flow path less than or equal to the first hydraulic mean cross-sectional flow path. The converging duct portion is coupled between the silencer portion and the tubular portion.