A propulsion system includes a gas turbine engine, an inlet particle separator, an infrared suppression system, and an engine controller. The engine controller may be configured to determine an activation state of the inlet particle separator, adjust one or more engine operating parameters based on the activation state, and control the gas turbine engine based on the adjusted engine operating parameters. The engine operating parameters may be adjusted based on inlet flow, which is determined based on the activation state. The engine controller may be further configured to determine an activation state of the infrared suppression system, adjust one or more engine operating parameters based on the activation state, and control the gas turbine engine based on the adjusted engine operating parameters. The engine operating parameters may be adjusted based on backpressure, which is determined based on the activation state.

An inlet assembly for an auxiliary power unit for an aircraft, including a particle separator and a plenum having first and second inlets. A first duct configured to deliver air to an engine of the auxiliary power unit is in fluid communication with an outlet of the plenum. A second duct configured to deliver air to a compartment containing the auxiliary power unit is in fluid communication with the outlet of the plenum. The assembly is selectively configurable between a first configuration where the plenum is in fluid communication with the environment of the aircraft through the second inlet and through the particle separator, and a second configuration where the plenum is in fluid communication with the environment of the aircraft through the first inlet independently of the particle separator. An auxiliary power unit assembly and a method of feeding air to an auxiliary power unit assembly are also discussed.

An inlet assembly for an auxiliary power unit for an aircraft, including a duct configured to provide fluid communication from an environment of the aircraft to an inlet of an engine of the auxiliary power unit, and a filter received in and extending across the duct. The filter includes a first filter portion permeable to air, positioned across only part of the duct and defining a transverse edge in the duct; a second filter portion permeable to air and extending from the transverse edge to an end downstream of the transverse edge, and a collection member impermeable to water. The collection member extends between the downstream end and a duct wall. The first and second filter portions are non-parallel and the second filter portion and the collection member are non-parallel. An auxiliary power unit assembly and a method of feeding air to an internal combustion engine are also discussed.

An aircraft having at least one first and one second engine, each engine comprising a main air inlet opening, a by-pass air inlet opening and a bleed air outlet, said main air inlet opening being provided with an inlet barrier filter for filtering a main air stream through said main air inlet opening into the engine, said by-pass air inlet opening being provided with a by-pass door that is operable by an associated operating element to enable a by-pass air stream through said by-pass air inlet opening into the engine, and said bleed air outlet being provided for creating an outgoing bleed air stream going out of the engine in operation, at least one associated operating element being controllable by an outgoing bleed air stream.

The present disclosure generally relates to separating entrained solid particles from an input airflow in a gas turbine engine. A cyclonic separator receives the input airflow from a compressor and separates a first portion of the input airflow. The cyclonic separator remove solid particles from the first portion of the input airflow to provide a first cleaned airflow to a first cooling system. A clean air offtake downstream from the cyclonic separator separates a second cleaned airflow from a remaining portion of the input air stream and provides the second cleaned airflow to a second cooling system. The remaining portion of the input airflow is provided to a combustor.

Engine inlets are disclosed that include an intake opening for the ingress of incoming air and acoustic filtration means for generating an acoustic wave that separates or clarifies material from the incoming air. The acoustic filtration means can include at least one ultrasonic transducer with a piezoelectric material configured to be driven to create an acoustic wave, such as a multi-dimensional acoustic wave or angled acoustic wave. Physical filtration means, such as an inertial or vortical separator, can be provided. Other engine inlets are also disclosed in which the acoustic filtration means are located within the physical filtration means. Further disclosed are methods for separating material from air employing acoustic separation means and physical filtration means.

A method of producing an operational data for an aircraft turbine engine is provided that including: sensing an inlet airflow to an aircraft turbine engine for CMAS particulate matter, the sensing performed during one or more ground portions of a flight operational cycle of the turbine engine, the sensing producing sensor signals indicative of the presence or absence of the CMAS particulate matter; determining a presence or absence of an exposure by the turbine engine to a CMAS environment based on the sensor signals; and producing an operational data indicative of the presence or absence of said exposure by the turbine engine to said CMAS environment.

An aircraft nacelle includes a forward cruise inlet, a forward-cruise-inlet conduit coupled to the forward cruise inlet and operable to supply air from the forward cruise inlet to an engine housed by the aircraft nacelle, an inlet barrier filter, an inlet-barrier-filter compartment coupled to the inlet barrier filter, a plurality of gills coupled between the inlet-barrier-filter compartment and the engine and operable to be in an open state and a closed state, a filter-purge door coupled to the inlet-barrier-filter compartment and operable to be in a closed state and an open state. When the plurality of gills are in the closed state and the filter-purge door is in the open state, air from the filter-purge door flows from the inlet-barrier-filter compartment through the inlet barrier filter.

A compartment based inlet particle separator system for an aircraft that includes an auxiliary power unit (APU) system compartment is provided. The system includes a separation barrier wall, a ram air inlet opening, a diffuser, and an inlet particle separator (IPS). The separation barrier wall is disposed within the APU system compartment and divides the APU system compartment into two compartments. The ram air inlet opening is formed one of the compartments. The diffuser receives ram air from a ram air inlet opening and discharges ram air into a compartment. The IPS is disposed within the a compartment between the diffuser outlet and the APU air inlet port.

An inlet particle separator system for a vehicle engine includes a hub section, a shroud section, and a splitter. The hub section has a hub outer surface that diverges, relative to the axis of symmetry, to a hub apex. The shroud section has a shroud inner surface that surrounds, and is spaced apart from, at least a portion of the hub section to define a main flow passageway between the hub outer surface and the shroud inner surface. The splitter is disposed downstream of the air inlet and extends into the main flow passageway to divide the main flow passageway into a scavenge flow path and an engine flow path. The hub section and the shroud section are configured such that the cross sectional flow area of the main flow passageway decreases downstream of the air inlet to define a throat section that is disposed upstream of the hub apex.