Sloped hierarchically-structured surface designs for enhanced condensation heat transfer

Abstract

An apparatus. The apparatus comprises a distribution of microstructures on an area of a surface, each of the microstructures having one or more sloping sides. The apparatus comprises a distribution of nanostructures being located on the one or more sloping sides. The distribution of microstructures on the area of the surface is configured to nucleate and grow droplets of liquid from a gas. The distribution of nanostructures forms a superhydrophobic surface for the liquid.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a distribution of microstructures on an area of a surface, each of the microstructures having one or more sloping sides;   a distribution of nanostructures being located on the one or more sloping sides; and   wherein the distribution of microstructures on the area of the surface is configured to nucleate and grow droplets of liquid from a gas; and   wherein the distribution of nanostructures forms a superhydrophobic surface for the liquid.   
     
     
         2 . The apparatus of  claim 1 , wherein the microstructures are configured to nucleate the droplets between the nanostructures. 
     
     
         3 . The apparatus of  claim 1 , wherein the microstructures are ridges. 
     
     
         4 . The apparatus of  claim 1 , wherein the microstructures are pointed structures. 
     
     
         5 . The apparatus of  claim 1 , wherein each of the microstructures are pyramidal-shaped structures. 
     
     
         6 . The apparatus of  claim 1 , further including:
 a heat pipe or a vapor chamber, the distribution of microstructures being located in a condenser portion of the heat pipe or the vapor chamber.   
     
     
         7 . The apparatus of  claim 1 , wherein the one or more sloping sides intersects with at least one side of the microstructure to form an apex shaped as a peak. 
     
     
         8 . The apparatus of  claim 1 , wherein the separation distance between apexes of adjacent ones of the microstructures is equal to or less than about  10  microns. 
     
     
         9 . The apparatus of  claim 1 , wherein at least one of the sloping sides intersects with at another side of an adjacent one of the microstructures at a base layer to form a valley. 
     
     
         10 . The apparatus of  claim 1 , wherein at least one of the sloping sides and another side of the one microstructure separately intersect with a third side of the one microstructure to form an apex shaped as a mesa. 
     
     
         11 . The apparatus of  claim 1 , wherein at least one of the sloping sides and another side of an adjacent one of the microstructures separately intersect with a horizontally oriented layer that is covered with the nanostructures and is adjacent to a base layer. 
     
     
         12 . The apparatus of  claim 1 , wherein at least one of the sloping sides intersects with another side which forms a right angle with respect to a base layer. 
     
     
         13 . The apparatus of  claim 15 , wherein at least one of the sloping sides intersects with another side of the one microstructure, and, the other side forms a different acute angle with respect to the line perpendicular to a base layer. 
     
     
         14 . The apparatus of  claim 1 , wherein for at least one of the sloping sides, there are sloped portions that have the acute angle interspersed horizontal portions that are parallel with a base layer. 
     
     
         15 . The apparatus of  claim 1 , wherein a distance between adjacent ones of the nanostructures is greater than a critical condensation radius for a nucleating one of the liquid droplet. 
     
     
         16 . A system, comprising:
 heat generating equipment; and   a heat transfer apparatus configured to remove heat generated by the electronic equipment, wherein the apparatus includes:   a distribution of microstructures on an area of a surface, each of the microstructures having one or more sloping sides;   a distribution of nanostructures being located on the one or more sloping sides; and   wherein the distribution of microstructures on the area of the surface is configured to nucleate and grow droplets of liquid from a gas; and   wherein the distribution of nanostructures forms a superhydrophobic surface for the liquid.   
     
     
         17 . The system of  claim 16 , wherein the distribution of microstructures is located on the surface of a condenser of the apparatus 
     
     
         18 . The system of  claim 16 , wherein the condenser is part of a heat pipe. 
     
     
         19 . The system of  claim 16 , wherein the condenser is part of a vapor chamber. 
     
     
         20 . A method, comprising:
 forming a distribution of microstructures on an area of a surface, each of the microstructures having one or more sloping sides, wherein the distribution of microstructures on the area of the surface is configured to nucleate and grow droplets of liquid from a gas; and   forming a distribution of nanostructures being located on the one or more sloping sides, wherein the distribution of nanostructures forms a superhydrophobic surface for the liquid.