An inlet ice protection system, and methods for making and using ice protection systems. In one embodiment, the inlet includes a tapered acoustic liner positioned forward of the inlet throat and has a perforated face sheet, a perforated back sheet, and an acoustic core between the face sheet and the back sheet. The perforations through the face sheet are sized to allow acoustic energy to be transmitted to and dissipated in the acoustic core, and the perforations in the back sheet are sized to transmit hot gas through the acoustic liner to the surface of the inlet to heat the inlet and prevent and/or restrict ice formation on the inlet. The face sheet can have a higher porosity than the back sheet, and both the sheets and the core can be formed from titanium to withstand high gas temperatures.

Method and apparatus for aircraft inlet ice protection

An aircraft gas turbine engine is provided with a starting air turbine that is directly connected through the starter gearbox to the high pressure (HP) shaft and is provided with an apparatus to extract excess energy from engine compressor bleed air, return it to the engine, and to start the engine with compressed air from starting air sources, and to cool and provide compressed air for powering the Environmental Control System (ECS) and using the bleed air for cabin refreshening. The air turbine may be connected to a nacelle boundary layer bleed compressor to bleed boundary layer air from a forward portion of the nacelle to reduce nacelle surface drag. The ECS may be provided with a wing boundary layer bleed means which uses a cooling air fan in the ECS to draw cooling air through the heat exchangers in the ECS pack from the boundary layer air from a forward portion of the aircraft's wing to reduce its surface drag.

Gas turbine engine powered aircraft environmental control system and boundary layer bleed

An environmental control system for supplying aircraft or cabin air to an aircraft is provided with a propulsive engine compressor bleed supply means and an ECS bleed air flow control means which includes an energy recovery means for using the unrequired or unused energy to pump boundary layer air from the surface of the aircraft, such as from the engine nacelle, and exhaust this air rearward of the engine to produce thrust, thus returning some of this unused energy to the propulsive engine.

Aircraft gas turbine engine bleed air energy recovery apparatus

A nacelle anti-icing system for a jet engine and a method for preventing icing of the nacelle. The nacelle anti-icing system includes a nose cowling assembly having a nose ring and an inlet duct connected to the nose ring, the nose ring including a plurality of openings formed therein; a nose cowling conduit positioned in the nose ring for communicating a heated gas to the plurality of openings formed in the nose ring and for creating a heated gas boundary layer on the inlet duct, and a mechanism connected to the nose cowling conduit for generating the heated gas. The method includes the steps of feeding a heated gas through the nose cowling conduit and through a plurality of openings formed in the nose ring and generating a heated gas boundary layer on the inlet duct so as to heat the inlet duct.

Nacelle anti-icing system

A precooler for cooling compressor bleed air for an environmental control system includes a heat exchanger in fluid communication with a source of cooling air and operable for cooling the bleed air. A variable bypass valve between a bleed air source and environmental control system is operable for bypassing at least a portion of the compressor bleed air around the heat exchanger. The cooling air may be a portion of fan air modulated by a variable fan air valve. The bleed air source may be selectable between the low pressure bleed air source and a high pressure bleed air source. One method includes flowing the compressor bleed air from a single low pressure source only and increasing thrust sufficiently to meet a minimum level of pressure of the bleed air during one engine out aircraft operating condition during approach or loitering.

Environmental control system supply precooler bypass

Hot compressed air is bled from the compressor of an engine and a portion of it is directed through a flow through type indirect heat exchanger of ring form located within an annular chamber in the engine cowl which is partially formed by lip surfaces of the inlet. Such air gives up heat to low pressure air within such chamber which carries the heat to the inlet surfaces. The compressed air is then removed from the heat exchanger and is admixed with additional hot compressed air. A part of the mixture is delivered to a wing TAI subsystem and a second portion is used for cabin conditioning and pressurization.

Kenneth L. Waters

Papers

Integrated thermal anti-icing and environmental control system