Abstract:
A method for forming a manifold for use with a heat exchanger is disclosed. The method may involve forming a plurality of vanes. Opposing surfaces of each of the vanes may define a pair of adjacent flow channels for receiving portions of first and second fluids to be flowed through the flow channels. Each of the flow channels may have a changing aspect ratio along its length.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 11/868,202 filed on Oct. 5, 2007. The entire disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to heat exchangers, and more particularly to heat exchanger having a manifold design that enables a counter-parallel flow of fluids, as well as increased surface contact area for the fluids, that contributes to increased heat exchange efficiency without significantly adding to the manufacturing complexity of the manifold. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     Heat exchangers are traditionally used to transfer heat from one fluid flowing therethrough to a different medium, for example to air or to a different fluid. Heat exchangers that attempt to provide a counter flowing arrangement, where the fluid to be cooled is flowed in a direction opposite to a cooling fluid, have generally proved to be quite complex and expensive to manufacture, or of limited effectiveness in increasing the heat exchange performance of the device. The manifolds used with such devices have typically been even more expensive and complex to construct than the heat exchanger core of the apparatus. A heat exchanger having improved cooling efficiency, that does not add appreciably to the overall cost or complexity of the apparatus, nor specifically to the cost and complexity of the manifolds used therewith, would be highly advantageous. 
     SUMMARY 
     In one aspect the present disclosure relates to a method for forming a manifold for use with a heat exchanger is disclosed. The method may involve forming a plurality of vanes. Opposing surfaces of each of the vanes may define a pair of adjacent flow channels for receiving portions of first and second fluids to be flowed through the flow channels. Each of the flow channels may have a changing aspect ratio along its length. 
     In another aspect the present disclosure may relate to a method for exchanging heat. The method may comprise providing a heat exchanger core and using a manifold in fluid flow communication with the heat exchanger core. The manifold may be used to receive a first fluid to be cooled and a second fluid to absorb heat from the first fluid. A plurality of vanes within the manifold may be used to define a plurality of first and second parallel arranged flow channels. Each of the first and second flow channels may have a changing aspect ratio along its length. The first flow channels may further each form a spiral flow path along their lengths. The first fluid may be flowed through the first flow channels and, simultaneously, the second fluid may be flowed through the second channels. 
     In still another aspect the present disclosure relates to a method for exchanging heat. The method may comprise providing a heat exchanger core and using a manifold in fluid flow communication with the heat exchanger core to receive a first fluid to be cooled and a second fluid to absorb heat from the first fluid. The method may further involve using a plurality of vanes within the manifold to define a plurality of first and second parallel arranged flow channels, and such that each of the first and second flow channels has a changing aspect ratio along its length. The method may further involve configuring the first flow channels to each form a spiral flow path along their lengths. The first fluid flow may be flowed through the first flow channels. Simultaneously, the second fluid may be flowed through the second flow channels and further such that the first and second fluids flow in a spiral path over lengths of the first and second flow channels. The method may further involve flowing said first and second fluids such that adjacent flowing portions of said first fluid are separated by portions of said second fluid. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is a perspective view of one embodiment of a heat exchanger in accordance with the present disclosure that includes a counter-parallel-flow manifold; 
         FIG. 2  is a view in accordance with directional line  2  in  FIG. 1  looking directly into a manifold of the heat exchanger, and further illustrating how fluid may flow into an inlet port of the manifold and be deflected upwardly and to the right by the construction of vanes within the manifold; 
         FIG. 3  is a highly simplified plan representation of the heat exchanger of  FIG. 1 , but with a portion of the left manifold removed to illustrate the fluid flow paths of the counter-parallel flow arrangement that the heat exchanger provides; 
         FIG. 4  is a view of the vanes taken from the perspective of  FIG. 2 , with the inlet and outlet structure removed to better illustrate the spacing of the vanes and their external shape; 
         FIG. 5  is a partial perspective view of one manifold of the heat changer with a portion of its wall structure broken away to help illustrate the shape of the vanes; and 
         FIGS. 6 through 13  are cross sections through the manifold in  FIG. 5  to illustrate the changing aspect ratio and changing orientation of the vane along its length. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a heat exchanger  10  in accordance with one embodiment of the present disclosure is illustrated. The heat exchanger in this example includes manifolds  12  and  14  that are arranged on opposite sides of a heat exchanger core  16 . In this example the manifolds  12  and  14  are identical in construction, but they need not be. It will be appreciated also that the dimensions and construction of the heat exchanger core  16  will dictate, at least in part, the outer dimensions of the manifolds  12  and  14 , as well as their dimensions. 
     In  FIG. 1  manifold  12  has an inlet  18  and an outlet  20 . Manifold  14  similarly has an inlet  22  and an outlet  23 . In this example the inlets and outlets have different diameters, but they could just as readily have the same diameter. In general operation, a fluid  19  may enter the inlet  18  of manifold  12  and circulate through the heat exchanger core  16 , where a major portion of heat transfer occurs to a cooling medium  21 , before the fluid exits outlet  23 . The cooling medium  21  may flow from inlet  22  to outlet  20 , and counter and parallel to the fluid  19 . The cooling medium  21  may be comprised of a liquid, a gas or any other fluid cooling medium that is flowable and capable of assisting in absorbing heat from the fluid entering inlet  18 . Similarly, fluid  19  may be comprised of a liquid, a gas or any other flowable medium that requires cooling. 
     Referring to  FIGS. 2 and 4 , a portion of the interior construction of the manifold  12  can be seen from a view looking straight into the inlet port  18  and outlet port  20 . Since manifolds  12  and  14  are identical in construction, only the construction of manifold  12  will be described in detail. Manifold  12  includes a plurality of vanes  24  that are arranged generally parallel to one another and spaced apart from one another. Each of the vanes  24  forms two adjacent flow channels, first flow channel  26   a  and second flow channel  26   b . Each vane  24  further has a first end  24   a  and a second end  24   b . First flow channel  26   a  enables fluid  19  to flow therethrough, while the adjacent second flow channel  26   b  enables the cooling medium  21  to flow therethrough counter to, but generally parallel to, the fluid  19 . Each of channels  26   a  has an input end  26   a   1  and an output end  26   a   2 , and each of channels  26   b  has an input end  26   b   1  and an output end  26   b   2 .  FIG. 3  further schematically illustrates the counter flowing paths that the fluid  19  and the cooling medium  21  may take within the heat exchanger core  16 . It can also be seen From  FIGS. 2 and 3  that the flow paths for the fluid  19  and the cooling medium  21  are arranged in alternating fashion to maximize heat transfer from the fluid  19  to the cooling medium  21 . Opposing surface portions  30   a  and  30   b  ( FIGS. 2 and 5 ) of each vane  24  help to define the flow channels  26   a  and  26   b.    
     It is a benefit that the sum of cross sectional areas of all of the channels  26   a  and  26   b  defined by the vanes  24  approximately equals the cross sectional area of the inlet  18 . This is advantageous for maintaining a constant pressure in each manifold  12  and  14 , and avoiding a pressure drop across the heat exchanger  10 . However, it will be appreciated that if the needs of a particular application should dictate, that this ratio could be varied so that a greater or lesser cross sectional flow path area is provided for by the vanes  24 . Additionally, the first and second fluids  19  and  21  could be flowed in the same direction if desired. 
     Referring to  FIG. 4 , when the fluid  19  enters the inlet  18  and begins to flow into the first flow channel  26   a , a ramp portion  28  of each vane  24  deflects the fluid vertically and also turns the fluid  19  about a twisting or spiral path as the fluid  19  begins to flow into the first flow channel  26   a . Conversely, cooling fluid  21  returning to manifold  12  from the other manifold  14  will be deflected downwardly by each vane  24  as it enters the adjacent, second flow channel  26   b , and will flow along the second flow channel  26   b  in a twisting or spiral path, but in the opposite sense as the fluid  19  flowing through the first flow channel  26   a.    
     From  FIGS. 5-13 , the cross-sectional shape and orientation of the two adjacent flow channels (i.e., paths)  26   a  and  26   b  formed by each vane  24  can be seen to change along the length of the vane. In  FIGS. 6-12 , the wall portion bridging vane  24  and wall portion  32  of the manifold  12  has been removed to reveal the interior area that forms the first flow channel  26   a.    
     In particular, it will be noted that the aspect ratios (i.e., ratio of height-to-width) of the two adjacent flow channels  26   a  and  26   b  defined by the vane  24  both change over the length of the vane in a similar but opposite (i.e., mirror image) sense. This enables a counter-parallel-flow path configuration to be created. The adjacent flow channels  26   a  and  26   b  formed by each vane  24  also help to direct a greater portion of each the fluids  19  and  21  into contact with opposing wall surfaces of the vane  24  as each fluid flows through its respective flow channel  26   a  or  26   b  within the manifold  12 , thus ensuring more efficient cooling of the fluid  19 . 
     The manifolds  12  and  14 , and particularly the vanes  24 , may be made from any suitable materials that enable excellent thermal conduction between the fluid  19  and the cooling medium  21 . Suitable materials are aluminum, titanium, steel, etc., but it will be appreciated that any suitable having reasonably good thermal conductivity may potentially be employed. The specific materials employed for the manifolds  12  and  14  may also depend in part on the specific types fluid that the manifolds will be used with. 
     It will also be appreciated that the precise cross sectional shape and twisting orientation of the vanes  24  may be modified to suit the needs of a particular application. Also, the total cross sectional area of the vanes  24  relative to the flow paths  26  may be varied to be suit the needs of a particular application. 
     While various embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the present disclosure. The examples illustrate the various embodiments and are not intended to limit the present disclosure. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.