Method and Apparatus For Heat Exchange Using Hollow Foams And Interconnected Networks And Method of Making The Same

Abstract

A method and an apparatus for the efficient transfer of heat utilizing micro heat pipes that include a cellular foam or interconnected cellular/truss network having hollow ligaments. A predetermined fraction of the internal volume of the hollow ligaments is filled with a carefully chosen working fluid, and the ends of the hollow ligaments are sealed. In operation, the working fluid evaporates in the region of high heat flux and condenses in regions of lower temperature, resulting in the transfer or redistribution of the fluid's latent heat of vaporization. For open cell foams and interconnected networks, a second fluid flowing through the open cells, separate from the working fluid but also in thermal contact with the hollow ligaments, assists in the transfer of heat from the foam and networks.

1 . A method of redistributing heat, comprising:
 providing an open cell foam having hollow ligaments;   partially filling said hollow ligaments of said foam with a working fluid;   evacuating the contents of said hollow ligaments except for the desired quantity of said working fluid;   sealing the ends of said hollow ligaments to contain said working fluid; and   placing one portion of said foam proximal to a heat source.   
   
   
       2 . The method of  claim 1 , wherein said foam is made of a material selected from the group consisting of a metal, metallic alloy, ceramic, polymer, and composite material. 
   
   
       3 . The method of  claim 1 , wherein said hollow ligaments of said foam are stochastically ordered. 
   
   
       4 . The method of  claim 1 , wherein said hollow ligaments of said foam are periodically ordered. 
   
   
       5 . The method of  claim 1 , wherein said heat source possess a surface temperature less than about 200K, and said working fluid is selected from the group consisting of H 2 , NO, N 2 , O 2 , and CH 4 . 
   
   
       6 . The method of  claim 1 , wherein said heat source possess a surface temperature less than about 200K, and said working fluid is made of a material having a melting point less than about 200K. 
   
   
       7 . The method of  claim 1 , wherein said heat source possesses a surface temperature between about 150K and about 1000K, and said working fluid is chosen from the group consisting of F-21, F-11, C 6 H 6 , (CH 3 )CO, CH 3 OH, NH 3 , H 2 O, and Hg. 
   
   
       8 . The method of  claim 1 , wherein said heat source possesses a surface temperature between about 150K and about 1000K, and said working fluid is made of a material having a melting point less than about 1000K. 
   
   
       9 . The method of  claim 1 , wherein said heat source possesses a surface temperature greater than about 500K, and said working fluid is chosen from the group consisting of Cs, K, Na, Li, and Ag. 
   
   
       10 . The method of  claim 1 , wherein said working fluid is made of a material having a melting point less than the operating temperature of said heat source. 
   
   
       11 . The method of  claim 1 , wherein said working fluid in the liquid phase fills less than about 50% of the internal volume of said hollow ligaments of said foam. 
   
   
       12 . The method of  claim 11 , wherein said working fluid fills between about 0.05% and about 15% of the internal volume of said hollow ligaments of said foam. 
   
   
       13 . The method of  claim 1 , wherein said hollow foam is formed by a method comprising:
 providing a solid ligament foam;   coating said solid ligament foam with a material of higher melting temperature than said solid ligament foam; and   evaporating said solid ligament foam by heating the coated solid ligament foam combination to a temperature greater than vaporization temperature of said solid ligament foam, but below the melting temperature of said coating material.   
   
   
       14 . The method of  claim 13 , wherein said solid ligament foam is a polymer. 
   
   
       15 . The method of  claim 14 , wherein said polymer is made of a type selected from the group consisting of polyurethane, polyethylene, polyamide, polyvinyl chloride, polypropylene, and polystyrene. 
   
   
       16 . The method of  claim 13 , wherein said coating material is applied to the solid ligament foam by means of a vapor deposition process. 
   
   
       17 . The method of  claim 16 , wherein said deposition process utilizes a carrier gas stream to direct the material vapor. 
   
   
       18 . The method of  claim 16 , wherein said deposition process is directed vapor deposition. 
   
   
       19 . The method of  claim 13 , wherein said coating material is applied to the solid ligament foam by a process selected from the group consisting of CVD, high pressure thermal evaporation, and high pressure sputtering. 
   
   
       20 . The method of  claim 13 , wherein the ligaments of said solid ligament foam are stochastically ordered. 
   
   
       21 . The method of  claim 13 , wherein the ligaments of said solid ligament foam are periodically ordered. 
   
   
       22 . A three-dimensional heat exchanger, comprising:
 an open cell foam having hollow ligaments with an evacuated internal volume;   a means for sealing the ends of said hollow ligaments of said foam; and   a working fluid confined within the interior volume of said hollow ligaments of said foam by said sealing means.   
   
   
       23 . The three-dimensional heat exchanger of  claim 22 , wherein said foam is made of a material selected from the group consisting of a metal, metallic alloy, ceramic, a polymer, and composite material. 
   
   
       24 . The three-dimensional heat exchanger of  claim 22 , wherein said hollow ligaments of said foam are stochastically ordered. 
   
   
       25 . The three-dimensional heat exchanger of  claim 22 , wherein said hollow ligaments of said foam are periodically ordered. 
   
   
       26 . The three-dimensional heat exchanger of  claim 22 , wherein said working fluid is selected from the group consisting of H 2 , NO, N 2 , O 2 , CH4, F-21, F-11, C 6 H 6 , (CH 3 )CO, CH 3 OH, NH 3 , H 2 O, Hg, Cs, K, Na, Li, and Ag. 
   
   
       27 . The three-dimensional heat exchanger of  claim 22 , wherein said working fluid is made of a material having a melting point less than about 1000K. 
   
   
       28 . The three-dimensional heat exchanger of  claim 22 , wherein said working fluid is made of a material having a melting point less than about 200K. 
   
   
       29 . The three-dimensional heat exchanger of  claim 22 , wherein said working fluid fills less than about 50% of the internal volume of said hollow ligaments of said foam. 
   
   
       30 . The three-dimensional heat exchanger of  claim 29 , wherein said working fluid fills between about 0.05% and about 15% of the internal volume of said hollow ligaments of said foam. 
   
   
       31 . The three-dimensional heat exchanger of  claim 22 , wherein said hollow foam is formed by a method comprising:
 providing a solid ligament foam;   coating said solid ligament foam with a material of higher melting temperature than said solid ligament foam; and   evaporating said solid ligament foam by heating the coated solid ligament foam combination to a temperature greater than vaporization temperature of said solid ligament foam, but below the melting temperature of said coating material.   
   
   
       32 . The three-dimensional heat exchanger of  claim 31 , wherein said solid ligament foam is a polymer. 
   
   
       33 . The three-dimensional heat exchanger of  claim 32 , wherein said polymer is made of a type selected from the group consisting of polyurethane, polyethylene, polyamide, polyvinyl chloride, polypropylene, and polystyrene. 
   
   
       34 . The three-dimensional heat exchanger of  claim 31 , wherein said coating material is applied to the solid ligament foam by means of a vapor deposition process. 
   
   
       35 . The three-dimensional heat exchanger of  claim 34 , wherein said deposition process utilizes a carrier gas stream to direct the material vapor. 
   
   
       36 . The three-dimensional heat exchanger of  claim 35 , wherein said deposition process is directed vapor deposition. 
   
   
       37 . The three-dimensional heat exchanger of  claim 31 , wherein said coating material is applied to the solid ligament foam by a process selected from the group consisting of CVD, high pressure thermal evaporation, and high pressure sputtering. 
   
   
       38 . The three-dimensional heat exchanger of  claim 31 , wherein the ligaments of said solid ligament foam are stochastically ordered. 
   
   
       39 . The three-dimensional heat exchanger of  claim 31 , wherein the ligaments of said solid ligament foam are periodically ordered. 
   
   
       40 . The three-dimensional heat exchanger of  claim 31 , wherein said solid ligament foam is selected from a material selected from the group consisting of water soluble salt, oxidizable graphite, an easily decomposed polymer, and meltable wax. 
   
   
       41 . A method of redistributing heat, comprising:
 providing an open cell interconnected network having hollow ligaments;   disposing at least one wicking structure within a plurality of each of said hollow ligaments;
 partially filling said hollow ligaments of said interconnected network with a working fluid; 
 evacuating the contents of said hollow ligaments except for the desired quantity of said working fluid; 
 sealing the ends of said hollow ligaments to contain said working fluid; and 
 placing one portion of said interconnected network proximal to a heat source. 
   
   
   
       42 . The method of  claim 41 , wherein said open cell interconnected network comprises a truss structure. 
   
   
       43 . The method of  claim 41 , wherein said open cell interconnected network comprises a cellular structure. 
   
   
       44 . The method of  claim 43 , wherein said cellular structure is comprised of woven material. 
   
   
       45 . The method of  claim 43 , wherein said cellular structure is comprised of textile layers. 
   
   
       46 . The method of  claim 45 , wherein at least some of said textile layers are a structure selected from the group consisting of woven mesh, square woven mesh, braid mesh, triaxial mesh, and quasi-triaxial mesh. 
   
   
       47 . The method of  claim 45 , wherein said textile layers are three-dimensional elements. 
   
   
       48 . The method of  claim 47 , wherein at least some of said three dimensional textile layers are a structure selected from the group consisting of braided, multi-ply, triaxial, multi axial, H-beam, I-beam, and honeycomb. 
   
   
       49 . A method of manufacturing a three-dimensional heat exchanger, comprising:
 providing an open cell interconnected network having hollow ligaments;
 disposing at least one wicking structure within a plurality of each of said hollow ligaments; 
 partially filling said hollow ligaments of said interconnected network with a working fluid; 
 evacuating all contents of said hollow ligaments except for the desired quantity of said working fluid; and 
 sealing the ends of said hollow ligaments to contain said working fluid. 
   
   
   
       50 . The method of  claim 49 , wherein said open cell interconnected network comprises a truss structure. 
   
   
       51 . The method of  claim 49 , wherein said open cell interconnected network comprises a cellular structure. 
   
   
       52 . The method of  claim 51 , wherein said cellular structure is comprised of woven material. 
   
   
       53 . The method of  claim 51 , wherein said cellular structure is comprised of textile layers. 
   
   
       54 . The method of  claim 53 , wherein at least some of said textile layers are a structure selected from the group consisting of woven mesh, square woven mesh, braid mesh, triaxial mesh, and quasi-triaxial mesh. 
   
   
       55 . The method of  claim 53 , wherein said textile layers are three-dimensional elements. 
   
   
       56 . The method of  claim 55 , wherein at least some of said three dimensional textile layers are a structure selected from the group consisting of braided, multi-ply, triaxial, multi axial, H-beam, I-beam, and honeycomb. 
   
   
       57 . A three-dimensional heat exchanger, comprising:
 an open cell interconnected network having hollow ligaments with an evacuated internal volume;   at least one wicking structure within a plurality of each of said hollow ligaments;   a means for sealing the ends of said hollow ligaments of said interconnected network; and   a working fluid confined within the interior volume of said hollow ligaments of said interconnected network by said sealing means.   
   
   
       58 . The three-dimensional heat exchanger of  claim 57 , wherein said open cell interconnected network comprises a truss structure. 
   
   
       59 . The three-dimensional heat exchanger of  claim 57 , wherein said open cell interconnected network comprises a cellular structure. 
   
   
       60 . The three-dimensional heat exchanger of  claim 59 , wherein said cellular structure being comprised of woven material. 
   
   
       61 . The three-dimensional heat exchanger of  claim 59 , wherein said cellular structure is comprised of textile layers. 
   
   
       62 . The three-dimensional heat exchanger of  claim 61 , wherein at least some of said textile layers are a structure selected from the group consisting of woven mesh, square woven mesh, braid mesh, triaxial mesh, and quasi-triaxial mesh. 
   
   
       63 . The three-dimensional heat exchanger of  claim 61 , wherein said textile layers are three-dimensional elements. 
   
   
       64 . The three-dimensional heat exchanger of  claim 63 , wherein at least some of said three dimensional textile layers are a structure selected from the group consisting of braided, multi-ply, triaxial, multi axial, H-beam, I-beam, and honeycomb. 
   
   
       65 . The method of  claim 1 , wherein said filling occurs after said evacuating. 
   
   
       66 . The method of  claim 1 , wherein said filling at least partially occurs after said evacuating. 
   
   
       67 . The method of  claim 1 , wherein said filling at least partially occurs during said evacuating. 
   
   
       68 . The method of  claim 1 , wherein said evacuating occurs after said filling. 
   
   
       69 . The method of  claim 1 , wherein said evacuating at least partially occurs after said filling. 
   
   
       70 . The method of  claim 1 , wherein said evacuating at least partially occurs during said filling.