Heat pipe including enhanced nucleate boiling surface

Abstract

A device may include a boiling structure and a wick structure adjacent the boiling structure. The boiling structure may convert a coolant from liquid to vapor and may have a first thermal resistance. The wick structure may bring the coolant to the boiling structure and may have a second thermal resistance that is higher than the first thermal resistance of the boiling structure.

1 . A device, comprising: 
 a boiling structure to convert a coolant from liquid to vapor and having a first thermal resistance; and    a wick structure adjacent the boiling structure to bring the coolant to the boiling structure and having a second thermal resistance that is higher than the first thermal resistance of the boiling structure.    
   
   
       2 . The device of  claim 1 , wherein boiling structure includes particles having an average diameter greater than about 50 μm.  
   
   
       3 . The device of  claim 2 , wherein the average diameter is less than about 500 μm.  
   
   
       4 . The device of  claim 1 , wherein the wick structure surrounds the boiling structure on all sides and does not extend over a top of the boiling structure.  
   
   
       5 . The device of  claim 1 , wherein a top surface of the wick structure extends above a top surface of the boiling structure by about 0.1 mm or greater.  
   
   
       6 . The device of  claim 1 , wherein the first thermal resistance is about 0.1° C./W for a 1 cm 2  area.  
   
   
       7 . The device of  claim 2 , wherein the particles include copper.  
   
   
       8 . The device of  claim 1 , wherein the wick structure includes a wire mesh, sintered particles, fibers, or axial grooves.  
   
   
       9 . A heat pipe, comprising: 
 a boiling structure;    a wick adjacent the boiling structure and having a lower capacity for heat transfer per unit area than the boiling structure; and    a casing enclosing the boiling structure and the wick.    
   
   
       10 . The heat pipe of  claim 9 , wherein the boiling structure has a mean feature size greater than about 50 μm.  
   
   
       11 . The heat pipe of  claim 9 , wherein a top surface of the wick extends beyond a top surface of the boiling structure.  
   
   
       12 . The heat pipe of  claim 9 , wherein a thermal resistivity of the boiling structure is less than about 0.1° C.-cm 2 /W.  
   
   
       13 . The heat pipe of  claim 9 , wherein a thermal resistivity of the wick is greater than about 0.1° C.-cm 2 /W.  
   
   
       14 . The heat pipe of  claim 9 , wherein the boiling structure, the wick, and the casing include copper.  
   
   
       15 . A device, comprising: 
 a coolant;    a first structure including particles having an average diameter greater than about 50 μm to convert some of the coolant from liquid to vapor;    a second structure around the first structure to wet the boiling structure with the coolant from multiple sides; and    a plurality of outer walls to enclose the coolant, the first structure, and the second structure in an air tight manner.    
   
   
       16 . The device of  claim 15 , wherein the average diameter of the particles is less than about 500 μm.  
   
   
       17 . The device of  claim 15 , wherein the second structure has a higher thermal resistance than the first structure.  
   
   
       18 . The device of  claim 15 , wherein the second structure includes a wire mesh, sintered particles, fibers, or axial grooves.  
   
   
       19 . The device of  claim 15 , wherein a top surface of the second structure extends beyond a top surface of the first structure by an amount sufficient to ensure pooling of the coolant on the top surface of the first structure.  
   
   
       20 . A system, comprising: 
 a heat pipe, including: 
 a boiling structure having a first thermal resistivity, and  
 a wick structure around the boiling structure and having a second thermal resistivity that is significantly greater than the first thermal resistivity; and  
   a fan to move air across at least a portion of the heat pipe.    
   
   
       21 . The system of  claim 20 , wherein the boiling structure includes particles having an average diameter of about 300 μm.