Low noise aeroengine inlet system

Abstract

An aeroengine has an inlet system with a forward end with respect to a flight direction. The inlet system includes a main inlet duct for selectively directing a first air flow from a forward main intake opening of the main inlet duct to a compressor rotor, the forward main intake opening being defined at the forward end of the inlet system and a secondary inlet duct for directing a second air flow from a secondary intake opening of the secondary inlet duct to the compressor rotor only when the main inlet duct is closed. A control apparatus is provided for selecting the first and second air flow to enter into the compressor rotor.

1 . An aeroengine having a compressor inlet system comprising a main inlet duct for directing a first air flow from a main intake opening to a compressor, the main intake opening defined at a forward end of the inlet system with respect to a flight direction, a secondary inlet duct for directing a second air flow from a secondary intake opening to the compressor, and a control apparatus for selecting which of the first and second air flows to provide to the compressor. 
     
     
         2 . The aeroengine as defined in  claim 1  wherein the control apparatus is configured so that the secondary airflow flows to the compressor only when the main inlet duct is closed to discontinue the first air flow. 
     
     
         3 . The aeroengine as defined in  claim 1  wherein the main inlet duct and the secondary inlet duct share a common downstream portion. 
     
     
         4 . The aeroengine as defined in  claim 1  wherein the compressor inlet system comprises an inertial particle separator (IPS) duct connected in fluid communication with the main inlet duct, extending from the main inlet duct rearward and terminating at a rear opening of the IPS duct, for directing a portion of the first air flow to bypass the compressor and to be discharged from the rear opening when the first air flow is selected to enter the compressor. 
     
     
         5 . The aeroengine as defined in  claim 4  wherein the control apparatus comprises a main valve selectively closing the main inlet duct to discontinue the first air flow and to thereby cause the IPS duct to draw air from the rear opening, functioning as the secondary inlet duct and the secondary intake opening for directing the second air flow to the compressor. 
     
     
         6 . The aeroengine as defined in  claim 5  wherein the main valve is positioned within the main inlet duct, upstream of a location at which the IPS duct is connected to the main inlet duct with respect to the first air flow. 
     
     
         7 . The aeroengine as defined in  claim 1  wherein the secondary inlet duct comprises an acoustic treatment area on an inner surface thereof. 
     
     
         8 . The aeroengine as defined in  claim 1  wherein the secondary inlet duct is in fluid communication with the main inlet duct and extends substantially in a transverse direction with respect to the flight direction. 
     
     
         9 . The aeroengine as defined in  claim 1  wherein the control apparatus comprises a main valve mounted to and for selectively closing the main inlet duct to discontinue the first air flow, and a secondary valve mounted to and for selectively closing the secondary inlet duct and being only open when the main valve is closed. 
     
     
         10 . The aeroengine as defined in  claim 1  wherein the secondary intake opening is oriented substantially facing a transverse direction with respect to the flight direction. 
     
     
         11 . The aeroengine as defined in  claim 1  wherein the secondary intake opening is oriented substantially facing forwardly with respect to the flight direction. 
     
     
         12 . An aeroengine having an inlet system with a forward end with respect to a flight direction, the inlet system comprising a main inlet duct for selectively directing a first air flow from a forward main intake opening of the main inlet duct to a compressor rotor, the forward main intake opening being defined at the forward end of the inlet system, an inertial particle separator (IPS) duct connected in fluid communication with the main inlet duct and extending rearward for directing a portion of the first air flow to bypass the compressor rotor and to be discharged through an exit opening of the IPS, the exit opening being disposed in a rear location with respect to the forward end of the inlet system, and a valve mounted to the main inlet duct in a location upstream of the IPS duct with respect to the first air flow for selectively closing the main inlet duct to discontinue the first air flow such that the IPS duct draws a second air flow from the exit opening and directs the second air flow to the compressor rotor. 
     
     
         13 . The aeroengine as defined in  claim 12  wherein the inlet system comprises an annular duct connected in fluid communication with the main inlet duct and positioned immediately upstream of the compressor rotor, the IPS duct being connected to the main inlet duct immediately upstream of the annular duct. 
     
     
         14 . The aeroengine as defined in  claim 12  wherein the IPS duct extends from the main inlet duct substantially rearward and terminates at the exit opening. 
     
     
         15 . The aeroengine as defined in  claim 12  wherein the IPS duct comprises an acoustic treatment area on an inner surface thereof. 
     
     
         16 . An aeroengine having an inlet system with a forward end with respect to a flight direction, the inlet system comprising a main inlet duct connected in fluid communication with an annular duct for selectively directing a first air flow from a forward main intake opening of the main inlet duct to a compressor rotor located downstream of the annular duct with respect to the first air flow, the forward main intake opening being defined at the forward end of the inlet system, and a secondary inlet duct having a secondary intake opening and extending substantially in a transverse direction with respect to the flight direction and being connected in fluid communication with the annual duct, the secondary inlet duct selectively directing a secondary air flow from the secondary intake opening through the annular duct to the compressor rotor, the inlet system including a valve apparatus having a main valve for selectively closing the main inlet duct to discontinue the first air flow, and a secondary valve device for selectively closing the secondary inlet opening duct and being only open when the main inlet duct is open. 
     
     
         17 . The aeroengine as defined in  claim 16  wherein the secondary inlet duct comprises a pair of secondary inlet branches in a bifurcated configuration, the secondary inlet branches being connected in fluid communication with the annular duct, each of the secondary inlet branches having said secondary intake opening, the secondary valve device selectively and simultaneously closing or opening both of the secondary inlet branches. 
     
     
         18 . The aeroengine as defined in  claim 16  wherein the inlet system comprises an inertial particle separator (IPS) duct connected in fluid communication with the main inlet duct immediately upstream of the annular duct and extending rearward for directing a portion of the first air flow to bypass the compressor rotor and to be discharged through an exit opening at a rear end of the IPS duct. 
     
     
         19 . The aeroengine as defined in  claim 18  wherein each of the secondary intake openings is oriented facing forwardly with respect to the flight direction in order to increase a pressure of the secondary air flow to a level greater than an ambient air pressure in order to prevent the IPS duct from drawing the ambient air through the exit opening. 
     
     
         20 . The aeroengine as defined in  claim 16  wherein each of the secondary inlet branches comprises an acoustic treatment area on an inner surface thereof.