Electrohydrodynamic airflow across a heat sink using a non-planar ion emitter array

Abstract

A method of cooling a heat generating device includes positioning a base of an electronically conductive heat sink in thermal communication with a heat generating device, wherein the heat sink includes a plurality of fins extending in a longitudinal direction from a first end to a second end, and coupling the heat sink to ground. The method further includes emitting ions from a plurality of ion emitter elements disposed in a non-planar pattern along the first ends of the plurality of fins, wherein at least three ion emitter elements are equidistant from the first end of the nearest fin and are positioned in an arc having an axis that extends along the first end of the nearest fin.

What is claimed is: 
     
         1 . A method of cooling a heat generating device, comprising:
 positioning a base of an electronically conductive heat sink in thermal communication with a heat generating device, wherein the heat sink includes a plurality of fins extending in a longitudinal direction from a first end to a second end;   coupling the heat sink to ground; and   emitting ions from a plurality of ion emitter elements disposed in a non-planar pattern along the first ends of the plurality of fins, wherein at least three ion emitter elements are equidistant from the first end of the nearest fin and are positioned in an arc having an axis that extends along the first end of the nearest fin.   
     
     
         2 . The method of  claim 1 , wherein the arc is defined by a central angle of less than 30 degrees. 
     
     
         3 . The method of  claim 1 , wherein the distance between the three or more points and a nearest fin is from 10 to 25 millimeters. 
     
     
         4 . The method of  claim 3 , wherein the plurality of fins are spaced apart by a distance greater than 6 millimeters. 
     
     
         5 . The method of  claim 1 , further comprising:
 securing the plurality of ion emitter elements to the heat sink.   
     
     
         6 . The system of  claim 5 , wherein the plurality of ion emitter elements are secured to the heat sink by an electrically insulative member. 
     
     
         7 . The method of  claim 1 , further comprising:
 adjusting the distance between the ion emitter elements and the plurality of fins to optimize the efficient for generating airflow.   
     
     
         8 . The method of  claim 1 , further comprising:
 selectively applying electrical potential between the ion emitter elements and the plurality of fins to vary a rate of airflow through the heat sink.   
     
     
         9 . The method of  claim 8 , further comprising:
 sensing the temperature of the heat generating device, wherein the electrical potential is applied between the ion emitter elements and the plurality of fins in response to a temperature of the heat generating device exceeding a temperature set point.   
     
     
         10 . The method of  claim 9 , wherein the heat generating device includes one or more processors. 
     
     
         11 . The method of  claim 1 , further comprising:
 controlling an electrical potential between the ion emitter elements and the heat sink fins to vary a rate of airflow through the heat sink.   
     
     
         12 . The method of  claim 1 , wherein each ion emitter element is a wire or needle. 
     
     
         13 . The method of  claim 1 , wherein each ion emitter element is a needle that is unsupported at one end.