Abstract:
Aspects of the disclosure are directed to a screen configured for use in association with a cooler of an aircraft, the screen comprising: a first portion arranged as a grid and located in a line-of-sight of the cooler with respect to a fluid inlet, and a second portion located out of the line-of-sight of the cooler with respect to the fluid inlet, wherein the second portion is grid-free.

Description:
[0001]    This application claims priority to U.S. Patent Appln. No. 62/055,318 filed Sep. 25, 2014. 
     
    
     BACKGROUND 
       [0002]    Within an aircraft, an oil system is frequently used. Oil is used for cooling and lubricating various aircraft entities, such as rotating shaft bearings, a fan drive gear system, and a gearbox, where the gearbox extracts power from an engine for purposes of driving generators, pumps, and auxiliary components/devices. The oil system includes a tank for storing bulk oil and pipes that connect the tank to the various entities that require the oil. 
         [0003]    A cooler may be used to remove heat from the oil. An air-oil cooler uses air for purposes of providing a cooling fluid. For example, air is taken from the fan bypass, flowed through the cooler, and returned to the fan bypass as an exhaust. 
         [0004]    Foils located in the cooler are fragile, such that the foils are susceptible to damage if subjected to a direct impact from large objects (e.g., hail stones). Measures need to be taken to ensure that the foils are not damaged; otherwise, the reliability and availability of the aircraft may be compromised. 
       BRIEF SUMMARY 
       [0005]    The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosure. The summary is not an extensive overview of the disclosure. It is neither intended to identify key or critical elements of the disclosure nor to delineate the scope of the disclosure. The following summary merely presents some concepts of the disclosure in a simplified form as a prelude to the description below. 
         [0006]    Aspects of the disclosure are directed to a screen configured for use in association with a cooler of an aircraft, the screen comprising: a first portion arranged as a grid and located in a line-of-sight of the cooler with respect to a fluid inlet, and a second portion located out of the line-of-sight of the cooler with respect to the fluid inlet, wherein the second portion is grid-free. In some embodiments, the dimensions of the grid of the first portion are configured to enable the screen to withstand a hail stone striking the screen. In some embodiments, the grid of the first portion is composed of segments, and each segment measures approximately 0.04 inches or 0.10 centimeters across and/or 0.38 inches or 0.97 centimeters in terms of depth. In some embodiments, the screen is configured to be mounted between a bellows seal coupled to the fluid inlet and an inlet duct coupled to the cooler. In some embodiments, the screen comprises a flange, and the flange comprises holes configured for mounting the screen. In some embodiments, the grid of the first portion is shaped as one of a square and a rectangle. 
         [0007]    Aspects of the disclosure are directed to a system for an aircraft comprising: a fluid inlet, a screen coupled to the fluid inlet, and a cooler coupled to the screen, wherein the screen comprises: a first portion arranged as a grid and located in a line-of-sight of the cooler with respect to the fluid inlet, and a second portion located out of the line-of-sight of the cooler with respect to the fluid inlet, wherein the second portion is grid-free. In some embodiments, the fluid inlet is configured to receive air from a fan, and wherein the cooler is configured to remove heat from a fluid using the air. In some embodiments, the dimensions of the grid of the first portion are configured to enable the screen to withstand a hail stone striking the screen. In some embodiments, the grid of the first portion is composed of metal segments, wherein each segment measures approximately 0.04 inches or 0.10 centimeters across and/or approximately 0.38 inches or 0.97 centimeters in terms of depth. In some embodiments, the system further comprises: a bellows seal coupled to the fluid inlet, and an inlet duct coupled to the cooler, wherein the screen is configured to be mounted between the bellows seal and the inlet duct. In some embodiments, the screen comprises a flange, wherein the flange comprises bolt holes configured for mounting the screen. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The present disclosure is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements. 
           [0009]      FIG. 1  illustrates an air-oil cooler system incorporating a hail screen. 
           [0010]      FIG. 2  illustrates a portion of the system of  FIG. 1 . 
           [0011]      FIG. 3A  is a side perspective view of a hail screen. 
           [0012]      FIG. 3B  illustrates a cross section of a hail screen. 
           [0013]      FIG. 3C  illustrates a perspective view of a hail screen. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    It is noted that various connections are set forth between elements in the following description and in the drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities. 
         [0015]    In accordance with various aspects of the disclosure, apparatuses, systems and methods are described for making and using a hail screen. In some embodiments, a hail screen is designed and manufactured to minimize/reduce a flow area blockage in order to minimize/reduce losses resulting from its inclusion. The hail screen may be designed to have a minimal weight. An area/portion of the hail screen that includes a mesh/grid may correspond to an area/portion that is in a line-of-sight with respect to a cooler (e.g., an air-oil cooler) and/or a fluid inlet (e.g., an air inlet) to minimize flow blockage. The hail screen may include an attachment flange that can easily be inserted into a flange stack within the compression capability of an inlet bellows seal. 
         [0016]    Referring to  FIG. 1 , a system  100  is shown. The system  100  may be included as part of a larger system. For example, the system  100  may be included in, or associated with, an engine of an aircraft. 
         [0017]    The system  100  includes an inlet  102 . The inlet may be used to receive a cooling fluid, such as air. The air may include a free stream air. Alternatively or additionally, the inlet  102  may include a fan air inlet that receives air from a fan in the event that air is used as the cooling fluid. 
         [0018]    The inlet  102  is coupled to an inlet duct  104 . The inlet duct  104  is coupled to a cooler  106  that uses the cooling fluid (e.g., air) to remove heat from a secondary fluid (e.g., oil, hydraulic fluid, air, fuel, etc.). The air is removed from the system via an exhaust duct  108  coupled to the air-oil cooler  106 . 
         [0019]    The system  100  includes an oil inlet/input port  112  and an oil outlet/output port  114 . Within the system  100 , oil may be contained in a matrix of small diameter tubes (or plates) with cooling fins. Air may flow through the space between these tubes and absorb the heat as the air washes over the surface of the tubes and fins. 
         [0020]    The orientation of the system  100  relative to the orientation of the aircraft is reflected via the forward (FWD) and aft (AFT) arrows. 
         [0021]    The system  100  may be used to support any type of heat exchanger. The heat exchange relationship could involve fluids/materials of any type, such as fuel, oil, air, etc. 
         [0022]    While the system  100  may be utilized/deployed in connection with a cooler in a bypass flow, aspects of the disclosure may be used in other environments or contexts. For example, one or more portions of the system  100  may be mounted to a pylon, a pre-cooler, or a fan case and ducted from a fan inlet cowl. 
         [0023]    Referring to  FIGS. 1-2 , coupling the inlet  102  and the inlet duct  104  to one another are an inlet bellows seal  120  and a hail screen  122 . As shown in  FIG. 2 , the bellows seal  120  is compressible, such that the hail screen  122  may be inserted/mounted between the bellows seal  120  and the inlet duct  104 . In this respect, the hail screen  122  may be added to preexisting/legacy platforms/configurations/systems that otherwise did not provision for hail stone protection. The hail screen  122  may be made of one or more materials, such as one or more metals. 
         [0024]    Referring to  FIG. 2 , a dashed reference line  226  is superimposed for purposes of illustration/description. Due to the shape of the inlet duct  104 , or the relative positioning of the bellows seal  120  and the cooler  106 , the portion of the hail screen  122  above the line  226  does not lie within a line-of-sight of the cooler  106 . If a hail stone were to enter the inlet  102  /bellows seal  120  at a position above the line  226 , the hail stone would break apart or fragment upon contacting the upper edge/portion of the inlet duct  104 . Accordingly, and as shown in  FIGS. 3B-3C , a first portion/area  332  of the hail screen  122  below the line  226  may include a mesh/grid in order to provide hail stone protection due to being in the line-of-sight of the cooler  106 , whereas a second portion/area  334  of the hail screen  122  above the line  226  might not include a mesh/grid (e.g., may be grid-free) so as to avoid restricting air flow unnecessarily due to being out of the line-of-sight of the cooler  106 . 
         [0025]    Referring to  FIG. 3B , the material (reflected via the segments  336 ) of the mesh/grid portion  332  may be sized to avoid restricting airflow unnecessarily while still providing the requisite hail stone protection. In some embodiments, the material (segments  336 ) may each measure approximately 0.04 inches or 0.10 centimeters across (e.g., each of the segments  336  of the grid/mesh may be approximately 0.10 centimeters thick in  FIG. 3B ). Similarly, the material (reflected via the segments  336 ) of the mesh/grid portion  332  in  FIG. 3C  may measure approximately 0.38 inches or 0.97 centimeters in terms of depth and may be selected to provide sufficient strength in the event of a hail stone striking the hail screen  122 . Of course, the dimensions are illustrative and other dimensions may be used in the composition of the mesh/grid potion  332 . 
         [0026]      FIG. 3A  provides a general sense of the depth/thickness of the hail screen  122 . As described above, the hail screen  122  may be of relatively modest dimensions such that the hail screen  122  can be inserted/mounted between the bellows seal  120  and the inlet duct  104 . As shown in  FIGS. 3B-3C , the hail screen  122  may incorporate bolt holes  340  in a flange  342  to support such a mounting. 
         [0027]    In  FIGS. 3B-3C , the grid/mesh portion  332  is shown as being arranged using square/rectangular boxes or a square/rectangular geometry. Other geometries/shapes/patterns (e.g., triangles, circles, ovals, etc.) may be used for the grid in some embodiments. 
         [0028]    While some of the examples were described above in connection with protecting against hail stones, one skilled in the art would appreciate that aspects of the disclosure may be applied/used to protect against damage from any type of foreign object. Furthermore, a screen in accordance with one or more aspects of the disclosure may be incorporated on one or more systems or platforms, such as one or more types of aircraft. 
         [0029]    Technical effects and benefits of the disclosure include an enhancement in terms of safety/reliability of a cooler, and more specifically, foils located in the cooler. A hail screen of modest dimensions may be used to protect the foils without impacting surrounding/adjacent hardware and with a negligible impact on the performance of the cooler. 
         [0030]    Aspects of the disclosure have been described in terms of illustrative embodiments thereof. Numerous other embodiments, modifications, and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure. For example, one of ordinary skill in the art will appreciate that the steps described in conjunction with the illustrative figures may be performed in other than the recited order, and that one or more steps illustrated may be optional in accordance with aspects of the disclosure.