Abstract

An axial flow turbine incorporating an exhaust hood for receiving exhaust steam from the turbine and directing this exhaust steam through a discharge opening in the hood in a direction essentially normal to the axis of the turbine is disclosed. The exhaust hood includes a first set of guide vanes arranged in an exhaust duct connected to the turbine adjacent the last stage buckets thereof. These vanes are curved to provide a relatively smooth transition of steam flow from an axial direction to a generally radial direction. A guide ring circumferentially surrounds the first set of guide vanes and a plurality of secondary vanes are circumferentially spaced around this guide ring. Steam which is discharged radially from the first set of vanes to the secondary vanes is directed by the secondary vanes to the discharge opening of the exhaust hood. The secondary vanes are substantially equally spaced around the guide ring and are curved at different angles to effect different angles of discharge of steam from these vanes. The angles of discharge are chosen so as to direct the steam toward the discharge opening of the exhaust hood in a manner achieving substantially uniform flow distribution across the exit plane of the last stage buckets and across the plane of the discharge opening. The secondary vanes have an axial length which is a minimum at the inner edges and increases to a maximum at the outer edges.