Abstract:
An engine includes a duct containing a flow of cool air and a pump system for providing air to an environmental control system. The pump system has an impeller having an inlet for receiving cool air from the duct and an outlet for discharging air to the environmental control system.

Description:
BACKGROUND 
       [0001]    The present disclosure relates to a pump system for use with a gas turbine engine to provide air to an aircraft environmental control system (ECS). 
         [0002]    Gas turbine engines typically provide high-pressure air for use in the passenger cabin via an environmental control system (ECS). This air is provided by bleed ports on the engine, typically on the high pressure compressor (HPC). Bleeding compressed air from an engine may result in performance loss. As a result, the engine may have to be upsized slightly to account for work lost due to the ECS flow. 
         [0003]    ECS air may be routed through a series of pipes and valves and then through a pre-cooler near the top of the engine/aircraft interface to cool air prior to entry into the aircraft wing, and then through the aircraft air cycle machine (ACM) for use in the cabin. 
       SUMMARY 
       [0004]    In accordance with the present disclosure, there is provided an engine which broadly comprises a duct containing a flow of cool air, a pump system for providing air to an environmental control system, and the pump system comprising an impeller having an inlet for receiving cool air from the duct and an outlet for discharging air to the environmental control system. 
         [0005]    In additional or alternative embodiments of any of the foregoing embodiments, the engine may further comprise an intake manifold for receiving the air from the duct and for delivering the air to the intake. 
         [0006]    In additional or alternative embodiments of any of the foregoing embodiments, the engine may further comprise a discharge manifold for delivering the air from the outlet to the environmental control system. 
         [0007]    In additional or alternative embodiments of any of the foregoing embodiments, the environmental control system may include an aircraft precooler and the discharge manifold may deliver the air to the aircraft precooler. 
         [0008]    In additional or alternative embodiments of any of the foregoing embodiments, the engine may further comprise a valve incorporated into the discharge manifold to control the flow of the air through the discharge manifold. 
         [0009]    In additional or alternative embodiments of any of the foregoing embodiments, the pump system may further comprise a towershaft for driving the impeller. 
         [0010]    In additional or alternative embodiments of any of the foregoing embodiments, the engine may further comprise a spool and the towershaft being connected to the spool by a drive gear. 
         [0011]    In additional or alternative embodiments of any of the foregoing embodiments, the spool may be a low spool connected to a fan. 
         [0012]    In additional or alternative embodiments of any of the foregoing embodiments, the spool may be a high spool connected to a high pressure compressor. 
         [0013]    In additional or alternative embodiments, the engine may have a fan and the duct may be a by-pass duct having an air stream created by the fan. 
         [0014]    Further in accordance with the present disclosure, there is provided a pump system for providing air to an environmental control system, which pump system broadly comprises an air intake for receiving air from a supply of air, an impeller having an intake for receiving the air and an outlet for discharging the air, and a discharge manifold for delivering the air from the outlet to the environmental control system. 
         [0015]    In additional or alternative embodiments of any of the foregoing embodiments, the pump system may further comprise a towershaft for driving the impeller. 
         [0016]    In additional or alternative embodiments of any of the foregoing embodiments, the towershaft may be driven by a spool of an engine. 
         [0017]    In additional or alternative embodiments of any of the foregoing embodiments, the spool may be a low spool. 
         [0018]    In additional or alternative embodiments of any of the foregoing embodiments, the spool may be a high spool. 
         [0019]    In additional or alternative embodiments of any of the foregoing embodiments, the towershaft may be connected to the spool by a drive gear. 
         [0020]    In additional or alternative embodiments of any of the foregoing embodiments, the pump system may further comprise a valve incorporated into the discharge manifold. 
         [0021]    Other details of the pump system for HPC ECS parasitic loss elimination are set forth in the following detailed description and the accompanying drawings wherein like reference numerals depict like elements. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a cross-section of an engine in side view; 
           [0023]      FIG. 2  is a side view of an engine having an ECS system; 
           [0024]      FIG. 3  is a side view of an engine having the pump system of the present disclosure; 
           [0025]      FIG. 4  is a sectional view taken along lines  4 - 4  of  FIG. 3 ; 
           [0026]      FIG. 5  illustrates a side view of an engine having a typical ECS system; and 
           [0027]      FIG. 6  illustrates a side view of an engine having the pump system of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    In accordance with the present disclosure, a pump is used to raise pressure of flow from an engine fan stream for use as ECS airflow. The flow is sent via single pipe up to the standard aircraft pre-cooler and the ACM. The pump can be sized to existing ECS system requirements, replacing the HPC bleed system, with its various bosses, ports, tubes, and valving. The pump consists of a radial compressor impeller which may be driven by an engine towershaft, and thus may be located in the relatively cool forward region of the engine cowl, immediately near the fan stream intake area. 
         [0029]    Referring now to  FIGS. 1 and 2 , there is shown an engine with an environmental control system (ECS). As can be seen from  FIG. 1 , the engine  10  has a high pressure compressor (HPC) forward bleed  12  and a HPC aft bleed  14 . In some engines, there may be two forward bleeds  12  and two aft bleeds  14 . As can be seen from  FIG. 2 , the ECS system  16  has plumbing  18  and valves  20 . Typically, there is a system ON-OFF valve, a high-pressure ON-OFF valve, and a low pressure anti-backflow check valve. The ECS system  16  requires considerable space around the engine core case  22 . 
         [0030]    Referring now to  FIG. 3 , there is shown an engine  100  having a pump system  102  for ECS parasitic loss elimination. The engine  100  includes a fan  104 , a high pressure compressor  106 , and a turbine section  108 . The high pressure compressor  106  and the turbine section  108  are connected by at least one spool  110 . As can be seen from  FIG. 3 , the high pressure compressor  106  and the turbine section  108  are housed in a core  112 . Further, the fan  104  is surrounded by a cowl  114 . A by-pass flow duct  116  is created between the cowl  114  and the core  112 . Air flow created by the fan  104  passes through the by-pass flow duct  116 . 
         [0031]    The pump system  102  includes an impeller  130  and an intake manifold  132  for delivering air from the by-pass flow duct  116  to the intake  133  of the impeller  130 . The pump system  102  further includes a pump discharge manifold  134  connected to an outlet  135  of the impeller  130 . The manifold  134  delivers air to an aircraft precooler  136  which forms part of the ECS system for the aircraft. The manifold  134  may have a valve  138  to control the amount of fluid flow through the manifold  134 . The valve  138  provides shutoff and failsafe capability. If desired, a 360 degree scroll collector  139  may surround the impeller  130 . 
         [0032]    The impeller  130  may be driven via a towershaft  140 . The towershaft  140  may be connected to either a high-spool which connects the high pressure compressor to a high pressure turbine section or a low-spool which connects the fan  104  to a low pressure turbine section. The towershaft  140  may be connected to the spool  110  via a drive gear  142 . 
         [0033]    As can be seen from the foregoing description, cool air from the fan stream is taken into the pump system via the manifold  132 . The discharge from the impeller  130  flows into a single duct (manifold  134 ) to the aircraft pre-cooler  136 . As a consequence, ECS plumbing and the bleeds from the HPC case are eliminated for Thrust Specific Fuel Consumption (TSCF) benefit which is fuel consumption input divided by engine thrust output. 
         [0034]    When the impeller  130  is driven by the high spool, favorable drive speed and excursions may be achieved. When the impeller  130  is driven by the low spool, high pressure compressor efficiency and Exhaust Gas Temperature (EGT) reduction at idle can be achieved. Higher EGT levels contribute to lower exhaust frame/hardware lives and thus increased cost to create an exhaust case/nozzle that is less affected by the increased temperature. 
         [0035]    As shown in  FIG. 4 , the pump system  102  can be located at any convenient tangential location. 
         [0036]    If desired, the towershaft  140  may be incorporated with an engine accessory gearbox (AGB) using the existing towershaft as a means of the drive power. If desired, the pump system may be incorporated into the AGB housing itself, the towershaft housing, or the layshaft housing to reduce packaging space. 
         [0037]    Referring now to  FIG. 5 , there is shown a sample of the plumbing and valves associated with a typical ECS system. Referring now to  FIG. 6 , there is shown the reduction of plumbing and valves that accompanies use of the pump system  102 . 
         [0038]    The pump system  102  disclosed herein provides benefits to the engine itself and engine externals system. HPC efficiency can increase measurably, approximately 2%, and with reduced distortion due to lack of ECS bleeds. EGT temperature at idle will also favorably decrease, approximately 240 degrees Fahrenheit. Overall ECS system weight will decrease due to the reduced size of necessary ECS plumbing. Accordingly, valuable externals packaging space will be created with the reduction of ECS size. 
         [0039]    There has been provided by the instant disclosure a pump system for an HPC ECS parasitic loss elimination. While the pump system has been described in the context of specific embodiments thereof, other unforeseen alternatives, modifications, and variations may become apparent to those skilled in the art having read the foregoing description. Accordingly, it is intended to embrace those alternatives, modifications, and variations as fall within the broad scope of the appended claims.