Patent ID: 8528344

Claim:
A turbofan gas turbine engine comprising an inner primary gas duct and a secondary gas duct and a bleed structure for at least one bleed passage between the inner primary gas duct and the secondary gas duct, the bleed structure comprising a first wall portion defining a first side of an opening for the at least one bleed passage, and a second wall portion defining a second side, opposite the first side of the opening, wherein a gas duct wall is substantially at a same level across the bleed passage opening, wherein the first and second wall portions end at different radial positions relative to a centerline axis of either the primary gas duct or the secondary gas duct in an extension direction of the bleed passage opening, one of the first and second wall portions is raised relative to immediately adjacent surfaces of the bleed structure, and the raised wall portion forms an elongated projection along a side of the opening so that the elongated projection is disposed at least one of downstream, in a gas flow intended direction in the gas ducts, of an inlet opening of the at least one bleed passage and upstream, in the gas flow intended direction in the gas ducts, of an outlet opening of the at least one bleed passage.