Abstract:
A cabin air compressor assembly that include a cabin air compressor disposed at a compressor inlet and a cabin air compressor motor operably connected to the cabin air compressor. At least one cooling flow inlet is configured to direct a cooling flow through various pathways in the cabin air compressor assembly, including across the cabin air compressor motor. A blower is configured to boost the cooling flow across the cabin air compressor motor, thereby increasing cooling flow provided to the air compressor motor. A static seal plate is downstream of the blower and guides the boosted cooling flow toward a cooling flow exit. In addition, the static seal plate isolates boosted cooling flow from a moving rotor of the cabin air compressor, and also forms part of a containment structure that contains fragments and breakage that may come from the cabin air compressor rotor.

Description:
REFERENCE TO CO-PENDING APPLICATIONS FOR PATENT 
     The present Application for Patent is related to the following co-pending U.S. Patent Application: 
     “CABIN AIR COMPRESSOR MOTOR COOLING” by Harold W. Hipsky, having U.S. application Ser. No. 12/838,078, filed Jul. 16, 2010, assigned to the assignee hereof, and expressly incorporated by reference herein. 
     FIELD OF DISCLOSURE 
     The subject matter disclosed herein relates to aircraft environmental control and aircraft containment. More specifically, the subject disclosure relates to the cooling of a cabin air compressor motor for an aircraft environmental control system, as well as a containment structure for a compressor rotor of the aircraft. 
     BACKGROUND 
     Environmental control systems (ECS) are utilized on various types of aircraft for several purposes, such as in cooling systems for the aircraft. For example, components of the ECS may be utilized to remove heat from various aircraft lubrication and electrical systems and/or used to condition aircraft cabin air. The cabin air conditioner includes one or more cabin air compressors (CACs) which compress air entering the system. The compressed air is delivered to an environmental control system to bring it to a desired temperature then delivered to the aircraft cabin. After passing through the cabin, the air is typically exhausted to the outside. The air is at least partially recycled. The CACs are typically driven by air-cooled electric motors, which are cooled by a flow of cooling air typically drawn by a ram air system. Ram air systems typically pull ambient air in through a Ram air inlet 
     The flow of CAC motor cooling air and thus the performance of the electric motor and CAC are typically limited by the pressure drop from the CAC inlet to the ram air system. Such a limitation may result in reduced performance of the CAC. Thus, it would be advantageous to enhance the flow of cooling air. These and other issues are addressed by published U.S. Patent Application No. 2012-0011878-A1, which is owned by the assignee of the present disclosure, and is incorporated herein by reference in its entirety. U.S. Patent Application No. 2012-0011878-A1 discloses providing a blower in an exit channel of the aircraft engine. The blower increases a pressure differential and a mass flow, thereby increasing the flow of cooling air, thereby increasing the performance of the CAC and the ECS. 
     Aircraft compressors commonly include some form of containment structure for the rotors of the aircraft compressor. It is possible for rotors to fragment or break during operation. Thus, containment structures are provided to contain released blade fragments and/or broken rotor segments and prevent them from escaping the aircraft compressor. The effectiveness of the containment structure is generally improved with closer proximity of the containment structure to the rotor. 
     SUMMARY 
     The disclosed embodiments include an ECS comprising: a cooling gas inlet and a cooling gas exit connected by pathways wherein a pressure differential between said cooling gas inlet and said cooling gas exit draws cooling flow through said pathways; a movable blower disposed in at least one of the pathways that boosts a flow rate of said cooling flow; and a static structure; wherein said blower directs boosted cooling flow along a surface of said static structure toward said cooling gas exit. 
     The disclosed embodiments further include an ECS comprising: means for transporting cooling gas between a cooling gas inlet and a cooling gas exit; means for creating a pressure differential between said cooling gas inlet and said cooling gas exit that draws cooling flow through said means for transporting; means for boosting a flow rate of said cooling flow; and means for guiding said boosted cooling flow toward said cooling gas exit; wherein said means for boosting directs boosted cooling flow along a static surface of said means for guiding. 
     The disclosed embodiments further include a method of cooling a cabin air compressor assembly comprising: transporting cooling gas between a cooling gas inlet and a cooling gas exit; creating a pressure differential between said cooling gas inlet and said cooling gas exit that draws cooling flow through the assembly; boosting a flow rate of said cooling flow; and guiding said boosted cooling flow toward said cooling gas exit; wherein said boosting step also directs boosted cooling flow along a static surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are presented to aid in the description of embodiments of the invention and are provided solely for illustration of the embodiments and not limitation thereof. 
         FIG. 1  is a partial schematic view of an environmental control system capable of utilizing the disclosed embodiments; 
         FIG. 2  is a cross sectional view of a cabin air compressor assembly of the disclosed embodiments; and 
         FIG. 3  is a more detailed and expanded cross sectional view showing a portion of the cabin air compressor assembly in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Aspects of the invention are disclosed in the following description and related drawings directed to specific embodiments of the invention. Alternate embodiments may be devised without departing from the scope of the invention. Additionally, well-known elements of the invention will not be described in detail or will be omitted so as not to obscure the relevant details of the invention. 
     The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. Likewise, the term “embodiments of the invention” does not require that all embodiments of the invention include the discussed feature, advantage or mode of operation. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of embodiments of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
       FIG. 1  is a schematic diagram of the pertinent portions of an environmental control system (ECS)  10  for an aircraft. ECS  10  includes one or more cabin air compressors (CACs)  12 , which in some embodiments are centrifugal compressors. A gas flow  14 , which is preferably air, is generated from outside the aircraft or from another source. The flow  14  moves through an inlet  13  and enters the CAC  12  at a compressor inlet  16 . The CAC  12  compresses the flow  14  and urges the flow  14  from the compressor inlet  16  through various pathways that transport the flow  14  to a heat exchanger inlet  20 , a ram system  22 , an evaporator  24  and an aircraft cabin  26 . The ram system  22  includes a ram fan inlet  21  that draws air into the ram system  22 . Each CAC  12  is driven by a CAC motor  28  operably connected to the CAC  12  via a CAC shaft  30 . 
       FIGS. 2 and 3  are cross sectional views that illustrate more details of a CAC  12  embodying the present disclosure.  FIG. 3  is an expanded view of the area identified by the dotted line in  FIG. 2 . Note that the following discussion refers to elements illustrated in both  FIG. 2  and  FIG. 3 , and that certain elements within the dotted line of  FIG. 2  are best illustrated in the expanded view shown in  FIG. 3 . For ease of illustration, the reference numbers for certain elements within the dotted line of  FIG. 2  are only shown in  FIG. 3 . The compressor inlet  16  delivers gas  15  to be compressed to a CAC rotor  62 . A main compressor exit  82  is positioned downstream of the CAC rotor  62 . A main compressor diffuser  86  (best shown in  FIG. 3 ) controls a cross-sectional flow area of the compressor exit  82 . A compressor outlet  84  (shown in  FIG. 2 ) outputs compressed gas  17  from the CAC  12 . The CAC motor  28  is an electric motor in one embodiment and has a rotor  32  rotatably located at a CAC tie rod  33 . The CAC motor  28 , when implemented as an electric motor, also includes a stator  36  having a plurality of stator windings  38  disposed radially outboard of the rotor  32 . The CAC motor  28  also includes one or more bearings  40  disposed at a CAC shaft  30  coupled through a compressor tie rod support  31  to a CAC tie rod  33 . To prevent overheating of the CAC motor  28 , particularly the stator windings  38  and the bearings  40 , a cooling flow is drawn across the CAC motor  28 . The cooling flow is driven generally by a pressure drop from the compressor inlet  16  to the ram system  22 , for example, ram fan inlet  21  (as shown in  FIG. 1 ). In some embodiments, as shown in  FIGS. 2 and 3 , the cooling flow includes a motor gap cooling flow  42  and a motor cooling flow  44 . The motor gap cooling flow  42  is supplied via motor gap cooling inlet  46  at a first end  48  of the CAC motor  28  opposite a second end  50  at which the CAC  12  is disposed. The motor gap cooling flow  42  proceeds across thrust bearings  52  located at the first end  48 , and across shaft bearings  54  located, for example, at the CAC shaft  30  at the first end  48  and/or the second end  50 , thereby removing thermal energy from the thrust bearings  52  and the shaft bearings  54 . The motor gap cooling flow  42  exits the CAC motor  28  and moves primarily into a blower gas path  60  (best shown in  FIG. 3 ). The blower gas path  60  includes an inlet path section upstream of a plurality of blower blades  70 , along with an exit path section immediately downstream of the plurality of blower blades  70 . In some embodiments, the CAC motor  28  includes a motor shroud  58  which directs the motor gap cooling flow  42  primarily toward the blower gas path  60 . A small portion of the motor gap cooling flow  42  directed by the motor shroud  58  may divert through a bleed opening  59  directly to a motor cooling exit  64 . 
     The disclosed embodiments include a static structure that performs multiple functions, including for example, interference and/or isolation functionality, guide functionality and containment functionality. More specifically, the disclosed static structure guides cooling gas flow  42 ,  44 , interferes with cooling gas flow  42 ,  44  impacting the compressor rotor  62 , and provides some isolation of the cooling gas flow  42 ,  44  from the compressor rotor  62 . The static structure further provides containment functionality by forming a part of a containment structure that forms a containment area  100  of the compressor rotor  62 . In one embodiment as illustrated and described herein, the static structure may be implemented as a static seal plate  96  (best shown in  FIG. 3 ) having a first seal plate surface  97  and a second seal plate surface  98 . 
     As best shown in  FIG. 3  collector  90  extends from the compressor housing  80  and includes a first collector section  91  and a second collector section  92 . The blower gas path  60  is formed by the first collector section  91 , the blower  68  and the first surface  97  of the static seal plate  96 . After passing through the blower gas path  60 , the motor gap cooling flow  42  proceeds substantially radially outwardly toward a collector gas path  61 . The collector gas path  61  is formed by the second section  92  of the collector  90 . The collector gas path  61  collects motor gap cooling flow  42  and directs it toward the motor cooling exit  64 , which further feeds to, for example, the ram fan inlet  21  (shown in  FIG. 1 ). 
     As best shown in  FIG. 2 , the motor cooling flow  44  is drawn from the compressor inlet  16 , enters at a motor inlet  66  and proceeds toward the first end  48  via a cooling conduit  67 . The motor cooling flow  44  proceeds through the CAC motor  28 , substantially from the first end  48  to the second end  50  removing thermal energy from the stator windings  38  and other components of the CAC motor  28 . As best shown in  FIG. 3 , the motor cooling flow  44  then proceeds on substantially the same path as the motor gap cooling flow  42 , passing through the blower gas path  60 , the collector gas path  61  and the motor cooling exit  64  toward, for example, the ram fan inlet  21  (shown in  FIG. 1 ). 
     As best shown in  FIG. 3 , the blower  68  includes a plurality of blower blades  70  that extend into the blower gas path  60 . The blower  68  is coupled to the compressor shaft  30  such that when the motor  28  operates to rotate the CAC rotor  62 , the motor  28  also rotates the blower  60  and the blower blades  70 . The rotating blower blades  70  urge the motor gap cooling flow  42  and the motor cooling flow  44  through the blower gas path  60 . Inclusion of the blower  68  in the CAC  12  increases the pressure differential between the compressor inlet  16  and the ram fan inlet  21  (shown in  FIG. 1 ) and increases a mass flow of the motor gap cooling flow  42  and the motor cooling flow  44  across the CAC motor  28 . The increased pressure differential and increased mass flow increase the cooling of the CAC motor  28  thus increasing performance of the CAC  12  and the ECS  10 . An example of providing a blower integral with the compressor rotor is shown in U.S. Patent Application No. 2012-0011878-A1, which is incorporated herein by reference. An example of providing a blower separate from the compressor rotor is described and illustrated in the present disclosure. Thus, the blower  68  may be either separate from or integral with the compressor rotor  62 . Because cooling flow is low temperature, where the blower  68  is a separate element from the compressor rotor  62 , the blower  68  may be made from lightweight materials such as aluminum, plastic or composite. The first seal plate surface  97  forms a portion of the exit path section of the blower gas path  60  and essentially isolates cooling flow  42 ,  44  from the rotating compressor rotor  62 . Because the seal plate  96  is static and does not move, as the cooling flow  42   44  moves downstream of the blower  68  the cooling flow  42 ,  44  is not subject to additional swirl from the rotating compressor rotor  62 . 
     In addition to boosting and guiding motor gap cooling flow  42  and motor cooling flow  44 , the blower  68  and the static seal plate  96  also form a containment structure that defines a containment area  100  (best shown in  FIG. 3 ) for the compressor rotor  62 . Aircraft compressors commonly include some form of containment structure for the rotors of the aircraft compressor. It is possible for rotors to fragment or break. Thus, the containment structure  68 ,  96  functions to contain released blade fragments and prevent them from escaping the aircraft compressor. In one instance, the effectiveness of the containment structure  68 ,  96  may be generally improved because mounting the blower  68  to the compressor shaft  30  as shown allows the static seal plate  96  to be placed in relatively close proximity to the compressor rotor  62 . 
     Accordingly, it can be seen from the foregoing disclosure and the accompanying illustrations that one or more embodiments may provide some advantages. For example, the blower  68  and the static seal plate  96  fulfill multiple roles. The blower&#39;s  68  roles and features include but are not limited to (i) forming part of the blower gas path  60  for passing cooling flow  42 ,  44 , (ii) boosting cooling flow  42 ,  44 , (iii) forming part of the containment structure  68 ,  96  for the compressor rotor  62 , (iv) coupling the blower  68  to the compressor shaft  30  to allow the static seal plate  96  to be place in relatively close proximity to the compressor rotor  62 , thereby keeping the containment area  100  relatively small, which is optimum, and (v) where the blower  68  is not integral with the compressor rotor  62 , allowing the blower  68  to be made from lightweight materials such as aluminum, plastic or composite. The static seal plate&#39;s  96  roles and features include but are not limited to (i) forming part of the exit path section of the blower gas path  60 , (ii) interfering with and/or providing some isolation of cooling flow  42 ,  44  to limit the cooling flow  42 ,  44  from impacting the compressor rotor  62  to thereby reduce the potential for the rotating compressor to add swirl to the cooling flow  42   44 , (iii) guiding the cooling flow  42 ,  44  into the collector gas path  61  and toward the motor cooling exit  64 , (iv) forming part of the containment structure  68 ,  96  for the compressor rotor  62 , and (v) in combination with the location of the blower  68  on the compressor shaft  30 , allowing the static seal plate  96  to be placed in relatively close proximity to the compressor rotor  62 , thereby keeping the containment area  100  relatively small, which is optimum. Because cooling flow is low temperature, both the blower  68  and the static seal plate  96  can be constructed from lightweight material that does not add significant weight to the aircraft compressor. Also, adding the blower  68  increases the axial length of the compressor/blower rotor by less than 5%. 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. The functions, steps and/or actions of the method claims in accordance with the embodiments of the invention described herein need not be performed in any particular order. Furthermore, although elements of the invention may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.