Method and apparatus for aircraft inlet ice protection

An ice protection system for an aircraft turbine engine inlet, comprising:

• an external surface;
• an internal surface positioned radially inwardly of the external surface;
• a lip surface extending between the external surface and the internal surface to define a hilite, the lip surface and the internal surface together defining an inlet flow surface having a minimum flow area aft of the hilite, the inlet flow surface having first apertures extending therethrough;
• a back surface offset from the inlet flow surface and having second apertures extending therethrough sized to pass a selected quantity of pressurized, heated gas to the inlet flow surface sufficient to at least restrict ice formation on the inlet flow surface, the second apertures positioned only in a region that extends from the minimum flow area forward;
• a sound-attenuating acoustic core positioned between the back surface and the inlet flow surface with at least a portion of the first apertures in fluid communication with the second apertures through the acoustic core;
• a plenum wall adjacent to the back surface forward of the minimum flow area, the plenum wall and the back surface defining at least a portion of a plenum in fluid communication with the second apertures;
• a conduit coupleable to a source of the heated gas, the conduit terminating at a single opening in the plenum wall;
• and
• a gas deflector positioned within the plenum and facing the conduit and the opening in the plenum wall.

An ice protection system for an aircraft engine inlet, comprising:

• an external surface portion;
• an internal surface portion positioned inwardly of the external surface portion;
• a lip surface portion extending between the external surface and the internal surface portion to define a hilite at least one of the lip surface and the internal surface portion defining an inlet flow surface having a minimum flow area aft of the hilite, the inlet flow surface having first apertures in a first region proximate to the hilite and a second region proximate to the minimum flow area, the first region having a first heat transfer rate, the second region having a second heat transfer rate less than the first heat transfer rate;
• a back surface offset from the inlet flow surface and having second apertures coupleable to a source of pressurized, heated gas, the second apertures being sized to direct through the first apertures a quantity of the gas sufficient to at least restrict ice formation on the inlet flow surface;
• an acoustic core positioned between the back surface and the inlet flow surface with the first apertures in fluid communication with the second apertures through the acoustic core.

A method for inhibiting ice from forming at an inlet at an aircraft engine, the inlet having a flow surface, a back surface offset from the flow surface, and an acoustic core between the flow surface and the back surface, the method comprising:

• directing pressurized, heated gas through back surface of the inlet;
• directing the gas through the acoustic core and through the flow surface only in a region at or forward of a minimum flow area of the inlet at a rate sufficient to at least restrict ice formation on the flow surface;
• and
• attenuating sound waves in the inlet by receiving the sound waves in the acoustic core.