Thermal control device with network of interconnected capillary heat pipes

Abstract

The thermal control device comprises at least one network of capillary heat pipes, in which each heat pipe comprises a tube enclosing an essentially annular longitudinal capillary structure, for the circulation of a two-phase heat-transfer fluid in the liquid phase, and surrounding a central channel for the circulation of said two-phase fluid in the vapor phase. The tubes of at least two heat pipes of the network intersect and are interconnected in such a way that at each intersection of heat pipes forming a node of the network, an exchange of fluid in the liquid phase can take place by capillary action between the capillary structures of said two or more heat pipes, and such that, simultaneously, an exchange of fluid in the vapor phase can take place by free circulation between the central channels of said two or more heat pipes.

1 . A thermal control device, comprising at least one network of capillary heat pipes, in which each heat pipe comprises a tube enclosing a longitudinal and substantially annular capillary structure, for circulating a two-phase heat transfer fluid in liquid phase, and surrounding a central channel for circulating said two-phase fluid in vapor phase, and wherein said tubes of at least two heat pipes of said network intersect and are interconnected in such a way that at each intersection of heat pipes forming a node of said network, an exchange of fluid in liquid phase can take place by capillary action between said capillary structures of said at least two heat pipes, and such that, simultaneously, an exchange of fluid in vapor phase can take place by free circulation between said central channels of said at least two heat pipes. 
     
     
         2 . The device according to  claim 1 , wherein at each node of said network all heat pipes interconnected at said each node have branches respectively ending at said node and having respective capillary structures providing capillary continuity for said fluid in liquid phase, such that said fluid in liquid phase arriving at said node in any heat pipe branch ending at said node can flow by capillary action into all other heat pipe branches ending at said node. 
     
     
         3 . The device according to  claim 2 , wherein at each said node of said network, said capillary structures of said heat pipe branches ending at said node have no discontinuity between them of a size greater than a typical dimension of a pore or groove of said capillary structure of said heat pipes, depending on whether said capillary structure respectively consists of porous material or of internal grooves in the corresponding tube. 
     
     
         4 . The device according to  claim 1 , wherein at each node of the said network, all heat pipes interconnected at said each node have branches respectively ending at said node and having respective central channels assuring flow continuity for said fluid in vapor phase, such that said fluid arriving at said node in vapor phase via any heat pipe branch ending at said node can flow into all other heat pipe branches ending at said node. 
     
     
         5 . The device according to  claim 4 , wherein at each said node of said network, flow continuity of said fluid in vapor phase is assured between said central channels of said heat pipe branches ending at said node, by a flow conduit having a flow area or at least one typical dimension that is substantially equal to said flow area or to said at least one typical dimension of said central channels of said heat pipe branches ending at said node. 
     
     
         6 . The device according to  claim 1 , wherein at least one heat pipe of said network comprises at least one branch ending at a node and which differs from at least one branch of at least one other heat pipe ending at said node of said network, in a capillary structure and/or in at least one typical dimension of said heat pipe branch. 
     
     
         7 . The device according to  claim 1 , wherein said at least one network of heat pipes is a two-dimensional network, comprising two pluralities of heat pipes such that the heat pipes of each plurality are substantially oriented, along at least a portion of their length, in one of two respective directions sloped relative to one another such that the heat pipes of said two pluralities intersect and are interconnected at their intersection. 
     
     
         8 . The device according to  claim 1 , wherein said at least one network of heat pipes is a three-dimensional network, comprising, in at least one node of said network, at least three heat pipe branches ending at said node and oriented for at least a portion of the length of said branches in one of three respective directions, each direction branch sloped relative to any one the other two of said branches, with said at least three heat pipe branches intersecting with each other and being interconnected to each other. 
     
     
         9 . The device according to  claim 1 , wherein, in at least one node of said network, said at least two heat pipes which intersect and are interconnected at said node have cutouts of complementary shapes cut into their respective tube and capillary structure such that said heat pipes fit together at said cutouts and reestablish the continuity of tube walls, integrally attached all along said cutouts, the capillary continuity in said capillary structures, and the flow continuity along said central channels of said heat pipes. 
     
     
         10 . The device according to  claim 1 , wherein each of said heat pipes of said network has at least one branch ending at a node of said network, at least one node of said network comprises a hollow connecting piece, referred to as a cross-piece, interconnecting all the heat pipe branches ending at said one node, said cross-piece comprising tubular connecting arms of an equal number as said heat pipe branches which interconnect at said one node, each connecting arm with an internal and substantially annular capillary structure surrounding a central channel of said connecting arm, each connecting arm connecting to the other connecting arms by a longitudinal end, referred to as the inside end, and to a respective heat pipe branch by a longitudinally opposite end, referred to as the outside end, of said connecting arm such that said capillary structure of each connecting arm has capillary continuity at said outside end of said connecting arm with a capillary structure of said corresponding heat pipe branch, and has capillary continuity at said inside end of said connecting arm with said capillary structure of each of the other connecting arms, and such that said central channel of said connecting arm communicates at said outside end of said connecting arm with a central channel of said corresponding heat pipe branch, and at said inside end of said connecting arm with said central channel of each of said other connecting arms. 
     
     
         11 . The device according to  claim 10 , wherein said capillary structure of said heat pipes is formed by grooves and has capillary continuity with said capillary structure of said connecting arms of said cross-pieces, which capillary structure of said connecting arms consists of a porous structure or porous material, having a high permeability, with a pore diameter of said porous structure or material no greater than twice an aperture of said grooves. 
     
     
         12 . The device according to  claim 10 , wherein said capillary structure of said heat pipes comprises a porous structure or a porous material and has capillary continuity with said capillary structure of said connecting arms of said cross-piece, also comprising a porous structure or a porous material, having a high permeability with a pore diameter no greater than a pore diameter of said porous structure or porous material of said heat pipes. 
     
     
         13 . The device according to  claim 10 , wherein at least a cross-piece is arranged to connect from two to eight heat pipe branches, in a two- or three-dimensional network. 
     
     
         14 . The device according to  claim 1 , wherein said at least one network of heat pipes is at least partially integrated into a structure having a temperature that is to be controlled. 
     
     
         15 . The device according to  claim 1 , wherein a portion of said at least one network of heat pipes is in thermal contact with at least one heat source or cold source, and another portion of said network is in thermal contact with at least one respective cold source or heat source. 
     
     
         16 . The device according to  claim 1 , additionally comprising at least one fluid loop for transporting heat from said at least one network of heat pipes to at least one distant cold source, an evaporation zone of said fluid loop being in thermal contact with at least a portion of said network of heat pipes. 
     
     
         17 . The device according to  claim 1 , additionally comprising at least one fluid loop for transporting heat from at least one distant heat source to said at least one network of heat pipes, a condensation zone of said fluid loop being in thermal contact with at least a portion of said network of heat pipes. 
     
     
         18 . The device according to  claim 1 , wherein said at least one network of heat pipes is an integral part of a supporting structure onto which at least one heat source and/or at least one cold source is mounted. 
     
     
         19 . The device according to  claim 18 , wherein said supporting structure is comprised of said at least one network of heat pipes, suitable for supporting heat dissipating equipment. 
     
     
         20 . The device according to  claim 1 , additionally comprising at least one temperature sensor placed on said at least one network of heat pipes or in the vicinity of at least one element in thermal contact with said at least one network, and at least one heating or cooling means in thermal contact with said at least one network, such that the temperature of said at least one network or said at least one element is controlled by applying a heat power setpoint for the heating or cooling to be produced by said at least one respective heating or cooling means, based on observed differences between temperature measurements obtained by said at least one temperature sensor and a temperature setpoint. 
     
     
         21 . A method for cooling an active antenna comprising radiofrequency tiles, having similar dimensional characteristics and which are arranged at regular intervals, on a supporting structure in the form of a grid with the help of a thermal control device, comprising at least one network of capillary heat pipes, in which each heat pipe comprises a tube enclosing a longitudinal and substantially annular capillary structure, for circulating a two-phase heat transfer fluid in liquid phase, and surrounding a central channel for circulating said two-phase fluid in vapor phase, and wherein said tubes of at least two heat pipes of said network intersect and are interconnected in such a way that at each intersection of heat pipes forming a node of said network, an exchange of fluid in liquid phase can take place by capillary action between said capillary structures of said at least two heat pipes, and such that, simultaneously, an exchange of fluid in vapor phase can take place by free circulation between said central channels of said at least two heat pipes, wherein at least one network of heat pipes of said device is integrated into said supporting structure of said active antenna, and the heat collected by said network is drawn off to at least one radiator by at least one of an extension from said network of heat pipes and at least one other network of heat pipes of said device and at least one fluid loop of said device. 
     
     
         22 . A method of cooling a supporting wall for mounting electronic equipment with the help of a thermal control device, comprising at least one network of capillary heat pipes, in which each heat pipe comprises a tube enclosing a longitudinal and substantially annular capillary structure, for circulating a two-phase heat transfer fluid in liquid phase, and surrounding a central channel for circulating said two-phase fluid in vapor phase, and wherein said tubes of at least two heat pipes of said network intersect and are interconnected in such a way that at each intersection of heat pipes forming a node of said network, an exchange of fluid in liquid phase can take place by capillary action between said capillary structures of said at least two heat pipes, and such that, simultaneously, an exchange of fluid in vapor phase can take place by free circulation between said central channels of said at least two heat pipes, wherein at least one network of heat pipes of said device is attached to at least one thermally conductive facesheet of the wall, and the heat collected by said at least one network of heat pipes is drawn off to at least one cold source, by at least one of an extension from said network of heat pipes and at least one other network of heat pipes of said device and at least one fluid loop of said device.