Gas turbine engine bleed air flow control

Abstract

An engine includes a compressor including an inner casing and an outer casing where the inner casing defines a primary flow path for a primary airflow through the compressor. The inner casing and the outer casing define a bleed air cavity therebetween. The inner casing at least partially defines a bleed air channel extending circumferentially about the inner casing to direct a bleed airflow from the primary airflow into the bleed air cavity. One or more flow control devices located circumferentially about the compressor to actively or passively circumferentially balance a flow of the bleed airflow into the bleed air cavity or within the bleed air cavity, wherein the one or more flow control devices are disposed at least partially within the bleed air channel, form at least part of the bleed air channel, or extend axially aft from the bleed air channel.

1 . An engine, comprising:
 a compressor including an inner casing and an outer casing, the inner casing defining a primary flow path for a primary airflow through the compressor, the inner casing and the outer casing defining a bleed air cavity therebetween, the inner casing at least partially defining a bleed air channel extending circumferentially about the inner casing between the primary flow path and the bleed air cavity to direct a bleed airflow from the primary airflow into the bleed air cavity; and   one or more flow control devices located circumferentially about the compressor to actively or passively circumferentially balance a flow of the bleed airflow into the bleed air cavity or within the bleed air cavity, wherein the one or more flow control devices are disposed at least partially within the bleed air channel,   wherein the one or more flow control devices comprise one or more baffles defining one or more apertures, wherein the one or more baffles and the one or more apertures enable the flow of the bleed airflow to pass through the one or more baffles from the bleed air channel to the bleed air cavity.   
     
     
         2 . The engine of  claim 1 , wherein a size of the one or more apertures varies based on a circumferential location of the respective one or more apertures. 
     
     
         3 . The engine of  claim 2 , further comprising one or more pipes coupled to the outer casing and fluidly connected to the bleed air cavity, wherein the size of the one or more apertures circumferentially located proximate to the one or more pipes is less than the size of the one or more apertures circumferentially located distal from the one or more pipes. 
     
     
         4 . The engine of  claim 1 , wherein at least a portion of the one or more baffles extends axially in an aft direction with respect to the bleed air cavity, and wherein an at least one of an axial length or a radial location of the portion varies circumferentially based on a circumferential location of the portion. 
     
     
         5 . The engine of  claim 1 , wherein the inner casing comprises at least one wall defining the bleed air channel, and wherein the one or more baffles extend at least partially into the bleed air channel from the at least one wall. 
     
     
         6 . The engine of  claim 1 , wherein the one or more baffles of the one or more flow control devices comprise:
 one or more first baffles; and   one or more second baffles; and   wherein at least one of the one or more first baffles or the one or more second baffles comprises the one or more apertures, and wherein at least one of the one or more first baffles or the one or more second baffles is movable.   
     
     
         7 . The engine of  claim 6 , further comprising one or more actuators actuable to move the at least one of the one or more first baffles or the one or more second baffles. 
     
     
         8 . The engine of  claim 1 , wherein the inner casing comprises at least one wall defining the bleed air channel, and wherein the one or more flow control devices comprise at least one actuator actuatable to move at least a portion of the at least one wall to vary a size of the bleed air channel. 
     
     
         9 . The engine of  claim 1 , wherein the inner casing comprises at least one wall defining the bleed air channel, and wherein the one or more flow control devices comprises at least a portion of the at least one wall. 
     
     
         10 . The engine of  claim 1 , wherein the one or more baffles comprise a first material and a second material, wherein a coefficient of thermal expansion of the first material is greater than a coefficient of thermal expansion of the second material. 
     
     
         11 . The engine of  claim 1 , further comprising:
 one or more sensors disposed within the bleed air cavity, the one or more sensors configured to detect at least one of a pressure within the bleed air cavity or a flow rate of the bleed airflow within the bleed air cavity; and   a controller configured to control the one or more flow control devices to circumferentially balance a flow of the bleed airflow into the bleed air cavity or within the bleed air cavity based on at least one of the pressure or the flow rate.   
     
     
         12 . The engine of  claim 1 , further comprising at least one pipe fluidly coupled to the outer casing at a circumferential location to route the bleed airflow from the bleed air cavity to one or more downstream locations, and wherein the one or more flow control devices are configured to uniformly extract the bleed airflow circumferentially from the primary flow path about a circumference of the inner casing. 
     
     
         13 . An engine, comprising:
 a compressor including an inner casing and an outer casing, the inner casing defining a primary flow path for a primary airflow through the compressor, the inner casing and the outer casing defining a bleed air cavity therebetween, the inner casing at least partially defining a bleed air channel extending circumferentially about the inner casing between the primary flow path and the bleed air cavity to direct a bleed airflow from the primary airflow into the bleed air cavity, and wherein the bleed air channel comprises an inlet end located proximate to the primary flow path and an outlet end disposed proximate to the bleed air cavity and distal to the inlet end; and   one or more flow control devices located circumferentially about the compressor to actively or passively circumferentially balance a flow of the bleed airflow into the bleed air cavity or within the bleed air cavity, wherein the one or more flow control devices are disposed at least partially at the inlet end, at the outlet end, or between the inlet end and the outlet end,   wherein the one or more flow control devices comprise one or more baffles having one or more apertures, wherein the one or more baffles and the one or more apertures enable the flow of the bleed airflow to pass through the one or more baffles from the bleed air channel to the bleed air cavity.   
     
     
         14 . The engine of  claim 13 , wherein a size of the one or more apertures varies based on a circumferential location of the respective one or more apertures. 
     
     
         15 . The engine of  claim 13 , wherein the one or more flow control devices comprise:
 one or more first baffles; and   one or more second baffles; and   wherein at least one of the one or more first baffles or the one or more second baffles comprises one or more apertures, and wherein at least one of the one or more first baffles or the one or more second baffles is movable.   
     
     
         16 . The engine of  claim 13 , wherein the one or more baffles comprise a first material and a second material, wherein a coefficient of thermal expansion of the first material is greater than a coefficient of thermal expansion of the second material. 
     
     
         17 . An engine, comprising:
 a compressor including an inner casing and an outer casing, the inner casing defining a primary flow path for a primary airflow through the compressor, the inner casing and the outer casing defining a bleed air cavity therebetween, the inner casing at least partially defining a bleed air channel extending circumferentially about the inner casing between the primary flow path and the bleed air cavity to direct a bleed airflow from the primary airflow into the bleed air cavity, and wherein the bleed air channel comprises an inlet end located proximate to the primary flow path and an outlet end disposed proximate to the bleed air cavity and distal to the inlet end; and   one or more flow control devices located circumferentially about the compressor to actively or passively circumferentially balance a flow of the bleed airflow into the bleed air cavity or within the bleed air cavity, wherein at least a portion of the one or more flow control devices extends axially aft from the outlet end into the bleed air cavity,   wherein the one or more flow control devices comprise one or more baffles having one or more apertures, wherein the one or more baffles and the one or more apertures enable the flow of the bleed airflow to pass through the one or more baffles from the bleed air channel to the bleed air cavity.   
     
     
         18 . The engine of  claim 17 , wherein at least another portion of the one or more flow control devices extends radially outward with respect to the outlet end. 
     
     
         19 . The engine of  claim 17 , further comprising at least one pipe fluidly coupled to the outer casing at a circumferential location to route the bleed airflow from the bleed air cavity to one or more downstream locations, and wherein the one or more flow control devices have a length in an aft axial direction that varies based on the circumferential location of the at least one pipe. 
     
     
         20 . The engine of  claim 17 , wherein the one or more baffles comprise a first material and a second material, wherein a coefficient of thermal expansion of the first material is greater than a coefficient of thermal expansion of the second material.