Two-phase thermodynamic system having compensational wick geometry to enhance fluid flow

Abstract

A thermodynamic system includes a compensational wick geometry to enhance fluid flow between a condenser region and an evaporator region. Geometric features are modulated between a condenser region and an evaporator region to increase capillary forces within wicking structures without excessively increasing hydraulic resistance to the liquid flowing through these return-path wicking structures. The thermodynamic system may include a liquid flow path having channels extending from the condenser region to the evaporator region. At various segments of the channels, individual cavity sizes are reduced to induce capillary action toward the evaporator region. Various geometric features compensate for these cavity size reductions, to mitigate the effects of increased resistances to liquid flow. In this way, capillary forces toward evaporator regions remain sufficiently high, while hydraulic resistance to fluid flow remains sufficiently low so as to prevent evaporator regions from drying out even at high thermal absorption rates.

What is claimed is: 
     
         1 . A thermodynamic system that contains a bi-phase fluid, the thermodynamic system comprising:
 an evaporator region ( 108 ) for absorbing heat to convert a liquid fraction of the bi-phase fluid into a vapor fraction of the bi-phase fluid;   a condenser region ( 110 ) for dissipating the heat out of the bi-phase fluid to convert the vapor fraction of the bi-phase fluid into the liquid fraction of the bi-phase fluid;   a vapor flow path ( 109 ) extending from the evaporator region ( 108 ) to the condenser region ( 110 ); and   a liquid flow path ( 203 ) that includes a plurality of channels ( 112 ) extending from the condenser region ( 110 ) to the evaporator region ( 108 ),
 wherein the liquid flow path ( 203 ) includes a first segment ( 105 ), that is disposed at least partially within the condenser region ( 110 ), at which the plurality of channels ( 112 ) have a first width and a first depth, and 
 wherein the liquid flow path ( 203 ) further includes a second segment ( 105 ), that is disposed at least partially within the evaporator region ( 108 ), at which the plurality of channels ( 112 ) have a second width that is less than the first width and a second depth that is greater than the first depth. 
   
     
     
         2 . The thermodynamic system of  claim 1 , wherein the first segment includes a first number of channels spanning across a particular distance that is substantially perpendicular to the liquid flow path, and wherein the second segment includes a second number of channels spanning across the particular distance, the second number of channels greater than the first number of channels. 
     
     
         3 . The thermodynamic system of  claim 1 , wherein individual channels of the plurality of channels are formed by ribs having at least one first undercut angle within the condenser region and at least one second undercut angle within the evaporator region, and wherein the at least one first undercut angle is less than the at least one second undercut angle. 
     
     
         4 . The thermodynamic system of  claim 3 , wherein the at least one first undercut angle within the condenser region is within a range of 25 degrees to 35 degrees, and wherein the at least one second undercut angle within the evaporator region is within a range of 5 degrees to 15 degrees. 
     
     
         5 . The thermodynamic system of  claim 1 , wherein individual channels of the plurality of channels are formed by ribs that include rounded shoulders having a first radius within the condenser region and a second radius, that is different than the first radius, within the evaporator region. 
     
     
         6 . The thermodynamic system of  claim 5 , wherein the first radius that the rounded shoulders have within the condenser region is greater than the second radius that the rounded shoulders have within the evaporator region. 
     
     
         7 . The thermodynamic system of  claim 1 , wherein a first cross-sectional area of the liquid flow path within the first segment is equal to or greater than a second cross-sectional area of the liquid flow path within the second segment. 
     
     
         8 . The thermodynamic system of  claim 1 , wherein the second depth is at least two times greater than the first depth, and wherein the first width is at least three times greater than the second width. 
     
     
         9 . An apparatus, comprising:
 an evaporator region ( 108 ) for absorbing heat to convert a liquid fraction of a bi-phase fluid into a vapor fraction of the bi-phase fluid;   a condenser region ( 110 ) for dissipating the heat to convert the vapor fraction into the liquid fraction;   a plurality of first ribs ( 114 ) that are spaced apart a first width and that extend down a first depth to a first bottom surface, wherein the plurality of first ribs form first channels ( 112 ) that extend into the condenser region ( 110 ), and   a plurality of second ribs ( 114 ) that are spaced apart a second width and that extend down a second depth to a second bottom surface, wherein the plurality of second ribs form second channels ( 112 ) that extend into the evaporator region, and wherein the second channels ( 112 ) are deeper and narrower than the first channels ( 112 ).   
     
     
         10 . The apparatus of  claim 9 , wherein the second ribs that are within the evaporator region include a smaller shoulder radius than the first ribs that are within the condenser region. 
     
     
         11 . The apparatus of  claim 9 , wherein the first ribs have a first undercut angle within the condenser region that is different than a second undercut angle that the second ribs have within the evaporator region. 
     
     
         12 . The apparatus of  claim 11 , wherein the second undercut angle is at least two times greater than the first undercut angle. 
     
     
         13 . The apparatus of  claim 9 , wherein a second number of the second channels that are formed by the second ribs is at least three times greater than a first number of the first channels that are formed by the first ribs. 
     
     
         14 . The apparatus of  claim 9 , wherein a first cross-sectional area of a liquid flow path within the first channels is substantially equal to or less than a second cross-sectional area of the liquid flow path within the second channels. 
     
     
         15 . A thermodynamic system, comprising:
 an evaporator region ( 108 ) for absorbing heat into a bi-phase fluid;   a condenser region ( 110 ) for releasing and dissipating the heat out of the bi-phase fluid; and   a plurality of interconnected pores extending from the evaporator region ( 108 ) to the condenser region ( 110 ), wherein individual pores of the plurality of interconnected pores are smaller in the evaporator region ( 108 ) than within the condenser region ( 110 ).   
     
     
         16 . The thermodynamic system of  claim 15 , wherein a first aggregated cross-sectional area of the plurality of interconnected pores within the evaporator region is equal to or greater than a second aggregated cross-sectional area of the plurality of interconnected pores within the condenser region. 
     
     
         17 . The thermodynamic system of  claim 15 , wherein the plurality of interconnected pores includes a first number of pores within the condenser region and a second number of pores within the evaporator region, and wherein the second number of pores is at least three times greater than the first number of pores. 
     
     
         18 . The thermodynamic system of  claim 17 , wherein a third number of pores within an adiabatic region is greater than the first number of pores in the condenser region and less than the second number in the evaporator region. 
     
     
         19 . The thermodynamic system of  claim 15 , wherein the plurality of interconnected pores is formed at least in part by one or more random structures. 
     
     
         20 . The thermodynamic system of  claim 15 , wherein the plurality of interconnected pores are at least partially arranged in accordance with an ordered arrangement.