Fan containment structure having contoured shroud for optimized tip clearance

摘要

An abradable fan containment structure within a fan section of a turbofan engine is provided. The fan section of the turbofan engine has fan blades and an abradable fan shroud. The abradable fan shroud includes an inner fan casing circumscribing the fan blades such that the inner annular surface of the fan shroud is disposed adjacent the blade tips of the fan blades within the fan section. The inner annular surface is formed from an abradable material. The abradable material contour is substantially triangular along the axial length from the leading edge to the trailing edge. The abradable material has a contoured surface characterized by a trapezoidal shape after being worn when rubbed by the tips of the fan blades during operation of the engine.