Abstract:
A tubular fin heat exchanger is provided with an integrated fan within the confines of a duct assembly. The tubular heat exchanger provides a structure and pathway to minimize space and weight of the integrated heat exchanger into the gas turbine engine.

Description:
BACKGROUND 
       [0001]    The present embodiments generally pertain to heat exchangers. More particularly, the present embodiments relate, without limitation, to assemblies of ducted tubular coolers with integral fans. 
         [0002]    Turbine engines are utilized generally in the power industry to create energy which is utilized in communities&#39; residential and commercial use, as well as powering aviation and marine crafts. These turbine systems may utilize heat exchangers in order to cool temperatures of fluids from within the turbine engine during operation. 
         [0003]    During operation, significant heat is generated by the combustion and energy extraction processes with gas turbine engines. It is necessary to manage heat generation within the engine so as not raise engine temperatures to unacceptable levels, which may cause engine failure. One method of controlling heat and improving engine life is to lubricate engine components and cool lubricating fluids. In such heat exchanger embodiments, the air stream is utilized to cool the hot fluid of the turbine engine. 
         [0004]    It would be desirable to improve aerodynamics and packaging of the heat exchanger cooling assemblies such that systems may improve air performance therein. This would eliminate the need for large volumes for existing coolers and reduce weight of the gas turbine engine. 
         [0005]    Additionally, existing heat exchangers may utilize welded or brazed fin connections to structures wherein fluid may pass through for cooling. The process of brazing multiple fins along the fluid carrying ducts is time consuming tedious and very expensive for manufacturing. 
         [0006]    It is desirable to provide a heat exchanger which is capable of being formed in non-traditional shapes. For example, many heat exchangers which utilize fin structures are not capable of being formed in an annular or tubular configuration due to the fin arrangement or the manifold or core of the heat exchanger. 
         [0007]    In order to improve efficiency of gas turbine engine aircraft, a continuing goal is to reduce weight and provide cost savings associated with fan, fan motors, drive shafts and ducting. Additionally, this will result in lower fuel and operating costs. Additionally, it would be desirable to provide space and weight savings for aircraft airframe and other gas turbine engine applications. Reducing the weight and volume of these thermal management systems may result in improved efficiency of the aircraft or gas turbine engine. 
         [0008]    The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded subject matter by which the scope of the invention is to be bound. 
       SUMMARY 
       [0009]    According to present embodiments, a tubular fin heat exchanger is provided with an integrated fan within the confines of a duct assembly. The tubular heat exchanger provides a structure and pathway to minimize space and weight of the integrated heat exchanger into the gas turbine engine. A fan is additionally provided for connection to the duct or within the duct in order to provide desirable cooling over the heat transfer fins of the assembly. 
         [0010]    According to some embodiments, a tubular cooler with integrated fan assembly comprises a duct having an inlet end and an outlet end, a heat exchanger disposed within said duct, the heat exchanger may have an annular shape and may extend axially at least partially between the first end and the second end of the duct. A fan is disposed in flow communication with the duct, the fan forcing airflow through the heat exchanger. The heat exchanger may comprise an extrusion core body in flow communication with a fluid inlet and a fluid outlet and, a plurality of fins extending from and integrally formed with the extrusion core body and positioned within the duct. 
         [0011]    Optionally, the extrusion core body may have a plurality of circumferentially extending channels therein. The tubular cooler with integrated fan assembly may further comprise fins extending from one side of the extrusion core body or alternatively from two sides of the extrusion core body. The tubular cooler with integrated fan assembly may further comprise an outer flowpath and an inner flowpath corresponding to said fins extending from the two sides of the extrusion core body. The fan may be disposed in the duct or may be connected to the duct. The fan may be connected to one of the inlet end or the outlet end. Further, the fan may be disposed intermediate to the inlet and the outlet. The duct having a single heat exchanger therein or may have a plurality of the heat exchangers therein. 
         [0012]    This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. A more extensive presentation of features, details, utilities, and advantages of the present invention is provided in the following written description of various embodiments of the invention, illustrated in the accompanying drawings, and defined in the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE ILLUSTRATIONS 
         [0013]    The above-mentioned and other features and advantages of these exemplary embodiments, and the manner of attaining them, will become more apparent and the conformal heat exchanger for aircraft will be better understood by reference to the following description of embodiments taken in conjunction with the accompanying drawings, wherein: 
           [0014]      FIG. 1  is a perspective view of an assembly including inline heat exchanger and duct; 
           [0015]      FIG. 2  is a perspective view of an exemplary axial fan; 
           [0016]      FIG. 3  is a portion of an exemplary heat exchanger for use in the assembly of  FIG. 1 ; 
           [0017]      FIG. 4  is a circumferential view of an exemplary single sided fin heat exchanger; 
           [0018]      FIG. 5  is a circumferential view of an alternative single sided fin heat exchanger; 
           [0019]      FIG. 6  is a circumferential view of an exemplary double sided fin heat exchanger; 
           [0020]      FIG. 7  is a circumferential view of an alternative double sided fin heat exchanger; 
           [0021]      FIG. 8  is a side section view of a heat exchanger assembly including single-side fin arrangement; and, 
           [0022]      FIG. 9  is a side section view of a heat exchanger assembly including double-side fin arrangement. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    Reference now will be made in detail to embodiments provided, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation, not limitation of the disclosed embodiments. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present embodiments without departing from the scope or spirit of the disclosure. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to still yield further embodiments. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0024]    The heat exchanger is annular or circular in cross-section and is mounted coaxially within a tube and with an axial fan. The fan and heat exchanger are ducted to ensure air flows over the heat exchanger fins. The heat exchanger may be a single fin heat exchanger or a double fin heat exchanger. 
         [0025]    Referring to  FIGS. 1-9 , various embodiments of a tubular heat exchanger with integral fan are shown. The assembly includes a duct wherein an annular or tubular heat exchanger is positioned in-line with an axial fan. The assembly forces air through fins of the heat exchanger to reduce fluid temperature of fluid passing through channels in the heat exchanger. The annular design of the heat exchanger allows for improvements over prior art. 
         [0026]    As used herein, the terms “axial” or “axially” refer to a dimension along a longitudinal axis of an engine. The term “forward” used in conjunction with “axial” or “axially” refers to moving in a direction toward the engine inlet, or a component being relatively closer to the engine inlet as compared to another component. The term “aft” used in conjunction with “axial” or “axially” refers to moving in a direction toward the engine outlet, or a component being relatively closer to the engine outlet as compared to an inlet. 
         [0027]    As used herein, the terms “radial” or “radially” refer to a dimension extending between a center longitudinal axis of the engine and an outer engine circumference. The use of the terms “proximal” or “proximally,” either by themselves or in conjunction with the terms “radial” or “radially,” refers to moving in a direction toward the center longitudinal axis, or a component being relatively closer to the center longitudinal axis as compared to another component. The use of the terms “distal” or “distally,” either by themselves or in conjunction with the terms “radial” or “radially,” refers to moving in a direction toward the outer engine circumference, or a component being relatively closer to the outer engine circumference as compared to another component. 
         [0028]    As used herein, the terms “lateral” or “laterally” refer to a dimension that is perpendicular to both the axial and radial dimensions. 
         [0029]    All directional references (e.g., radial, axial, proximal, distal, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise) are only used for identification purposes to aid the reader&#39;s understanding of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. The exemplary drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto may vary. 
         [0030]    Referring now to  FIG. 1 , a perspective view of a tubular heat exchanger with integral fan assembly  10  is depicted. The assembly  10  includes a duct  12  which is depicted as circular in cross-section. The duct  12  may be of various cross-sectional shapes including the circular or annular shape depicted, but not limited to such. Additionally, other duct shapes, such as square, rectangular, octagonal or other geometric polygons or otherwise may be utilized. The duct  12  includes a forward inlet end  14  and an outlet end  16  defining a flow path  18  therebetween, wherein airflow  20  moves between the inlet  14  and the outlet  16 . Within the duct  12  is an integral fan  24 . The fan  24  may be located at a forward inlet end of the duct  12  or at the outlet end  16 . 
         [0031]    Disposed between the inlet end and outlet end  14 ,  16  of the duct  12  is a tubular heat exchanger  30 . The heat exchanger  30  includes a fluid inlet  31 , fluid outlet  34  and one or more extrusion core segments  50  ( FIG. 3 ) extending between the inlet and outlet  31 ,  34 . 
         [0032]    Referring now to  FIG. 2 , an exemplary axial fan  24  is depicted. The fan  24  includes a rotor or disc  26  or alternatively, may be a blisk wherein the discs and blades  28  are integrally formed together. Although not shown in this view, the fan  24  may also include a nose cone to direct air radially outward, as well as protect the fan  24  from foreign objects. 
         [0033]    The fan  24  may be bolted or welded to an end of a duct  12 . Alternatively, the fan may be positioned intermediate to the ends  14 ,  16  within the duct  12  according to some embodiments. In the exemplary embodiment, the fan  24  is connected at an end of the duct  12 . In the previous embodiment of  FIG. 1 , the fan  24  is located within the duct  12 . Either embodiment is within the scope of the present disclosure. 
         [0034]    Referring now to  FIG. 3 , a perspective view of an exemplary annular heat exchanger is depicted. According to the depicted embodiment, an upper half  32  of the annular heat exchanger  30  is shown. However, in use, the half or portion  32  would be combined with a lower half or portion (not shown) to provide an assembly. The heat exchanger  30  may be one piece or multiple portions  32 . The heat exchanger  30  is disposed within the duct  12  ( FIG. 1 ) as previously described and the airflow  20  passes through heat exchanger  30  to remove heat from a fluid flow within the heat exchanger  30 . 
         [0035]    The heat exchange portion  32  includes an inlet end or face  41 , an outlet end or face  43  and a passageway  45  therebetween. The passageway  45  is coaxial with the flowpath  18  ( FIG. 1 ) so that the airflow  20  passes between the inlet  41  and the outlet  43 . 
         [0036]    At each of the inlet  41  and the outlet  43  is a flange  40  which allows for connection to the duct  12  or to the fan  24  or both. Axially extending between the flanges  40  and the inlet and outlet  41 ,  43  are manifolds  46 ,  47  which receive engine cooling fluids and direct the fluid into extrusion core segments  50 . 
         [0037]    The heat exchanger portions  32  further comprise a plurality of extrusion core segments  50  which extend between an axially forward end  42  and an axially aft end  44 . The extrusion core segments  50  include fluid channels and heat exchange fins that are disposed in the flowpath  18  and bathed in airflow  20  moving through the duct  12 . This results in removal of heat from fluid passing through the extrusion core segments  50 . In addition to extending the extrusion core segment  50  in an axial direction, the extrusion core segments  50  are stacked on top of one another in a radial direction to increase the radial dimension of the heat exchanger portion  32 . Thus, the heat exchanger portions  32  are formed of annular ring sections or segments which span a flow duct and allowing penetration flow for heat exchange. The extrusion core segment  50  laid in the radial direction provide for a cylindrical mesh which allows heat transfer as air flows through the heat exchanger  30 . The heat exchanger  30  of the embodiment shown is generally cylindrical however other shapes may be utilized to conform the heat exchanger to a duct wherein the exchanger  30  is positioned. Moreover, the structure may be tapered in a radial direction across an axial length. Additionally, other geometric shapes than the circular cross-section depicted may be also utilized. Additionally, the heat exchanger  30  may be curved to match a curved axis of a curved duct, as previously noted. 
         [0038]    Referring now to  FIG. 4 , a circumferentially oriented view is shown of one embodiment of an extrusion core segment  50 . The extrusion core segment  50  includes an extrusion body  52  having a first end  54  and an opposite second end (not shown) which is spaced circumferentially from the first end  54 . The spacing may vary depending on circumferential length of the extrusion core segment  50 . This is not limited. Extrusion body  52  also includes a radially inner surface  56 , a radially outer surface  58 . 
         [0039]    The airflow  20  is also shown passing over the extrusion body  52  and relative to fins  70  extending from the extrusion body  52 . The plurality of cooling fins  70  extend in a radial direction from the radially inner surface  56 . This embodiment is referred to as a single sided fin arrangement. Alternatively, fins  70  may extend from the radially outer surface  58 . As will be described further herein, the extrusion core segment  50  is capable of being embodied by a double sided fin embodiment as well. 
         [0040]    Extrusion body  52  also includes a plurality of cooling channels  60  extending lengthwise (circumferentially) through each arcuate extrusion core segment  50 . Cooling channels  60  are selectively sized to receive fluid to be cooled therethrough. In the exemplary embodiment, extrusion body  52  includes a plurality of cooling channels  60  extending circumferentially. In the depicted embodiment, there may be three channels however, this is non-limiting and merely exemplary. Various numbers of channels  60  may be utilized based on the axial length of the extrusion body  52 . Likewise, the channels  60  may vary in size and shape depending on the cooling desired and the volume of fluid being pumped through the extrusion body  52 . 
         [0041]    In the exemplary embodiment, channels  60  have a geometrically shaped cross-sectional profile. According to the instant embodiment, the shape is generally rectangular with curved corners to improve flow characteristics. Alternatively, cooling channels  60  have a cross-sectional profile that is some other shape such as for example, circular, square, oval, triangular or the like. Furthermore, the channels  60  may be parallel and may all carry the same fluid, or they may be segregated into multiple groups where each group carries a different cooling fluid used for different cooling purposes. For example, one group may carry lubrication fluid for the bearings, and another group might carry a separate cooling fluid for electronic apparatuses in the engine. 
         [0042]    With brief reference to  FIG. 5 , an alternative extrusion body  152  is depicted. The axial length, in the direction of the airflow  20 , is greater than the embodiment of  FIG. 4 . Accordingly, a plurality of channels  160  are depicted which is greater than the number of channels of the previous embodiment. The channels  160  extend circumferentially through each arcuate extrusion body  152  of extrusion core segment  150  and are selectively sized to receive fluid therethrough. In the exemplary embodiment, channels  160  have a substantially rounded rectangular cross-sectional profile. Alternatively, channels  160  may have a cross-sectional profile that is other than rectangular such as for example, circular. Furthermore, channels  160  are parallel channels that may all carry the same fluid, or they may be segregated into multiple groups where each group carries a different cooling fluid used for different cooling purposes. For example, one group may carry lubrication fluid for the bearings, and another group might carry a separate cooling fluid for electronic apparatus on the engine. 
         [0043]    In the instant embodiment, additional channels  161  are located radially inwardly from channels  160  and closer to the plurality of fins  70 . The channels  161  may be utilized which may be for a second fluid or may be used when additional cooling is needed. Alternatively, when less cooling is needed such as in extremely cold climates or at startup in cold climates, the channels  160  may be utilized. The channels  60 ,  160  may be of same or different slopes, sizes and orientations. 
         [0044]    In the exemplary embodiment, extrusion core segment  150  is formed such that cooling channels  161  are positioned radially inward from channels  160  and radially outward from cooling fins  70 . Alternatively, cooling channels  161  may be positioned radially outward from channels  160 . Generally, cooling channels  160 ,  161  may be positioned at any location within extrusion body  152  that facilitates operation of heat exchanger assembly as described herein. However, it may be desirable to position the cooling channels  161  more proximate to the fins to effectuate more efficient cooling of fluid and in most cases, the cooling channels  161  will be disposed between the channels  160  and the fins  70 . 
         [0045]    Referring now to both  FIGS. 4 and 5 , each of the extrusion core segments  50 ,  150  have a plurality of cooling fins  70 . With reference to  FIG. 4 , a plurality of fins are arranged in circumferential rows  72  and axial rows  74 . The fins  70  are generally extending in a radial direction inwardly. 
         [0046]    In the exemplary embodiment, cooling fins  70  extend along a width in the axial direction of extrusion body  52  between upstream end and downstream end. The fins  70  extend axially in parallel with the airflow direction and are arranged circumferentially around inside or outside surfaces of the bodies. In the exemplary embodiment, cooling fins  70  are coupled to extrusion body  52  such that each of the cooling fins  70  is substantially perpendicular to channels  161  and such that the direction of the fluid channeled through openings  161  is approximately perpendicular to the direction of airflow channeled through cooling fins  70 . More specifically, cooling fins  70  are aligned providing paths for the airflow  20  passing through the fins  70 . Alternatively, the fins  70  may be angled relative to the purely axial direction of the duct  12  since airflow  20  may rotate about the duct  12 . 
         [0047]    According to the instant embodiments, the extrusion core segment  50 ,  150  is formed in an extrusion process such that cooling fins  70  are integrally formed with extrusion body  52 ,  152 . A fin cutting process, for example, is then conducted to form the cooling fins  70 , for example in a direction perpendicular to the extrusion direction. Optionally, cooling fins  70  may be coupled to extrusion body  52 ,  152  utilizing a welding or brazing procedure, for example. In the exemplary embodiment, extrusion body  52 ,  152  and cooling fins  70  are fabricated from a metallic material, such as aluminum. Other metals or alloys may be used however. 
         [0048]    To facilitate channeling a fluid through extrusion body  52 , extrusion core segment  150  also includes at least one inlet connection  32  and at least one outlet connection  34  ( FIG. 1 ). The inlet and outlet may be in flow communication with the manifolds  46  depicted in  FIG. 2 . In the exemplary embodiment, connections  32 ,  34  ( FIG. 1 ) are each coupled to channels  60  of extrusion core segment  50  via a manifold  46 . 
         [0049]    The extrusion core segment  50 ,  150  can be configured to have one or a plurality of fluid circuits, each with an inlet connection and an outlet connection. These circuits can each have a separate and distinct purpose and carry non-mixing fluids, which are used for cooling different apparatus. 
         [0050]    Referring now to  FIGS. 6 and 7 , core segments  250 ,  350  are depicted. These extrusion core segments  250 ,  350  are both formed with fins  70  on two sides of the core segment extrusion body  252 ,  352 . Accordingly, these embodiments are referred to as double sided fins. With reference first to  FIG. 6 , the extrusion core segment  250  includes an extrusion body  252  which extends circumferentially about the duct  12 . The circumferential length may vary either extending entirely about the duct or some preselected circumferential length. The extrusion body  252  also has an axial length in the direction of the airflow  20 . Across the axial length are a plurality of flow paths or channels  260  which extend in a circumferential direction through the extrusion body  252  allowing flow of for example, oil needing cooling or alternatively, a cooling fluid utilized to reduce air temperature moving through the heat exchanger. The extrusion core segment  250  also includes a plurality of fins  70  extending in a radial direction. The fins  70  are formed in a cutting process from a single piece of material which also defines the extrusion body  252 . By cutting the fins  70  from the extrusion, the process of brazing multiple fins to the extrusion body  52  is eliminated and therefore the costs for producing the extrusion core segments  50  may be reduced. The extrusion body  252  is generally extruded and in a subsequent process, the step carves the fins  70  from the single piece of metal. The fins  70  may be carved in one or more directions, for example as shown in the axial and circumferential directions. Alternatively, the fins  70  may extend at some angle similar to a helical fin structure as well. Additionally, the fins  70  are shown extending radially from the body so as to extend outwardly therefrom the extrusion body  252 . However, according to other embodiments fins  70  may be carved so as to extend either radially inward or both radially inward and outward. 
         [0051]    As described earlier, the extrusion body  252  includes a plurality of flow paths or channels  260  for a fluid to be cooled or a fluid to cool the airflow. As with the previous embodiments, the axially forwardmost flow channel  260  alternatively according to one embodiment may be a blank. That is to say, the forwardmost flow path may not receive any fluid flow therein so as to preclude fluid leakage from foreign objects entering the heat exchanger  30 , also referred to as foreign object damage. Additionally, at this forward end of the extrusion core segment  50 , relative to the airflow  20 , a leading edge  253  of the extrusion body  52  is curved to improve aerodynamics of the extrusion core segment  50 . Likewise, the leading edge may have an increased material thickness to decrease damage from foreign object in the airflow path encountering the heat exchanger  30 . The trailing edge may alternatively be curved for improving aerodynamic performance. Various other shapes or arrangements may be utilized for a leading edge to improve overall aerodynamics of the entire assembly of the heat exchanger  30 . 
         [0052]    With reference to  FIG. 7 , the extrusion core segment  350  comprises a core extrusion body  352 . The fins  70  extend from two sides of the body as previously described. The embodiment depicts that various size of extrusion body  352  may be utilized as well as various numbers of channels  360  as compared to other embodiments. The fins  70  are shown extending radially but may include some twist at an angle to a purely axial direction  20 . The channels may vary in size, shape and orientation. 
         [0053]    With reference now to  FIG. 8 , a heat exchanger with integral fan assembly  110  is shown. An embodiment of the single sided fin extrusion core segment, for example  50 ,  150  is shown. The duct  112  has an inlet and an outlet  114 ,  116 . The fins  70  extend radially inwardly into a flowpath  18  wherein airflow  20  moves to remove heat from the fluid passing through the channels  60 . The extrusion core segment  50 ,  150  is disposed about the interior of the duct  12  and according to the instant embodiment, the fan  24  is disposed forward of the heat exchanger fins  70  for pushing air therethrough. 
         [0054]    With reference now to  FIG. 9 , an alternate embodiment of a heat exchanger with integral fan assembly  210  is depicted wherein the duct  212  is shown and the double sided fin extrusion core segment  250 ,  350  ( FIGS. 6, 7 ) is shown. The duct  212  includes an inlet  214  and an outlet  216 . The fins  70  extend in two radial directions in order to form two flowpaths, an inner flowpath  218  and an outer flowpath  219 . A fan (not shown) may be located upstream or downstream of the fins  70 . Additionally the fan  24  may be bolted to an inlet or outlet end of the duct  212  or may be positioned within the duct  212 . 
         [0055]    The foregoing description of structures and methods has been presented for purposes of illustration. It is not intended to be exhaustive or to limit the invention to the precise steps and/or forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. Features described herein may be combined in any combination. Steps of a method described herein may be performed in any sequence that is physically possible. It is understood that while certain embodiments of methods and materials have been illustrated and described, it is not limited thereto and instead will only be limited by the claims, appended hereto.