Hotspot spray cooling

Abstract

The present invention is a spray cooling thermal management device that cools an electronic component creating a varying amount of heat across its surfaces. Liquid coolant is dispensed upon the surface of the component. In areas of the chip that generate large heat fluxes, typically referred to as the core, the liquid coolant is dispensed as a continuous atomized droplet pattern. The atomized pattern creates a high heat flux evaporative cooling thin-film over the one or more core areas. Rather than optimize the atomized pattern and flow based upon complete thin-film vaporization, the present invention optimizes the atomized pattern for maximum heat removal rates. Any excess, non-vaporized, fluid flowing outward from the hotspot is used to cool the lower heat flux (non-core) areas of the component through the creation of a thick coolant film thereon.

1 . A spray cooling system comprising: 
 a cooling surface with a hotspot zone producing a high heat flux;    a sprayer in a spaced apart relationship to said hotspot zone and capable of transforming a supply of liquid coolant into a continuous pattern of droplets that impinge and create a thin coolant film generally within said hotspot zone; and    wherein said thin coolant film cools said hotspot zone primarily through evaporation.    
   
   
       2 . The spray cooling system of  claim 1 , wherein said high heat flux is greater than 300 watts per square centimeter.  
   
   
       3 . The spray cooling system of  claim 1 , wherein said hotspot zone includes an array of etched microchannels.  
   
   
       4 . The spray cooling system of  claim 1 , further including a vapor management protrusion surrounding said sprayer.  
   
   
       5 . The spray cooling system of  claim 1 , wherein said sprayer is an atomizer.  
   
   
       6 . The spray cooling system of  claim 1 , wherein said sprayer is at a non-perpendicular angle to said cooling surface.  
   
   
       7 . The spray cooling system of  claim 1 , wherein the mass flow rate of said impinging droplets is greater than the mass flow rate in which said thin coolant film is evaporated.  
   
   
       8 . A spray cooling system comprising: 
 a cooling surface with a hotspot zone producing a high heat flux;    a sprayer in a spaced apart relationship to said hotspot zone and capable of transforming a supply of liquid coolant into a continuous pattern of droplets that impinge and create a thin coolant film within said hotspot zone;    wherein said thin coolant film cools said hotspot zone primarily through evaporation; and    wherein non-evaporated amounts of said thin coolant film dispensed within said hotspot zone creates a thicker coolant film over the remaining areas of said cooling surface.    
   
   
       9 . The spray cooling system of  claim 8 , further comprising at least one secondary orifice for adding said coolant to said thick coolant film.  
   
   
       10 . The spray cooling system of  claim 9 , wherein said secondary orifice is a incremental drop ejector.  
   
   
       11 . The spray cooling system of  claim 8 , further comprising a vapor management protrusion surrounding said sprayer.  
   
   
       12 . The spray cooling system of  claim 8 , wherein at least a portion of said cooling surface includes a plurality of microchannels.  
   
   
       13 . The spray cooling system of  claim 8 , wherein said sprayer is at a non-perpendicular angle with said component.  
   
   
       14 . The spray cooling system of  claim 8 , wherein said sprayer is an atomizer.  
   
   
       15 . A spray cooling system comprising: 
 an electronic component with a cooling surface having a hotspot zone producing a high heat flux;    a sprayer in a spaced apart relationship to said hotspot zone and capable of transforming a supply of liquid coolant into a continuous pattern of droplets that impinge and create a thin coolant film within said high hotspot zone;    wherein said thin coolant film cools said hotspot zone primarily through evaporation; and    wherein non-evaporated amounts of said thin coolant film dispensed within said hotspot zone creates a thicker coolant film over the remaining areas of said cooling surface.    
   
   
       16 . The spray cooling system of  claim 15 , further comprising at least one secondary orifice for adding said liquid coolant to said thick coolant film.  
   
   
       17 . The spray cooling system of  claim 16 , wherein said secondary orifice is an incremental drop ejector.  
   
   
       19 . The spray cooling system of  claim 15 , further comprising a vapor management protrusion surrounding said sprayer.  
   
   
       20 . The spray cooling system of  claim 15 , wherein at least a portion of said cooling surface includes a plurality of microchannels.  
   
   
       21 . The spray cooling system of  claim 15 , wherein said sprayer is at a non-perpendicular angle with said component.  
   
   
       22 . The spray cooling system of  claim 15 , wherein said sprayer is an atomizer.  
   
   
       23 . A thermal management system comprising: 
 a cooling surface with a hotspot having a first heat flux;    an at least one sprayer in a spaced apart relationship to said hotspot and capable of transforming a supply of liquid cooling into a continuous pattern of droplets that impinge and create a thin coolant film on said hotspot;    wherein said thin coolant film absorbs said first heat flux;    wherein a radial flow of said thin coolant film creates a thicker coolant film over a second zone of said electronic component, said second zone producing a second heat flux that is less than one-third the magnitude of said first heat flux; and    wherein said thicker coolant film absorbs said second heat flux.    
   
   
       24 . The thermal management system of  claim 23 , further comprising at least one secondary orifice for adding said coolant to said thicker coolant film.  
   
   
       25 . The thermal management system of  claim 24 , wherein said at least one secondary orifice is an incremental drop ejector.  
   
   
       26 . The thermal management system of  claim 23 , further comprising a vapor management protrusion surrounding said at least one sprayer.  
   
   
       27 . The thermal management system of  claim 24 , wherein at least a portion of said cooling surface includes a plurality of etched microchannels.  
   
   
       28 . The thermal management system of  claim 24 , wherein said sprayer is at a substantial angle with said component.  
   
   
       29 . The thermal management system of  claim 24 , wherein said second heat flux is less than 100 watts per square centimeter.  
   
   
       30 . The thermal management system of  claim 24 , wherein said sprayer is an atomizer.  
   
   
       31 . The thermal management system of  claim 24 , wherein a hydraulic jump exists between said thin coolant film and said thicker coolant film.  
   
   
       32 . A method of cooling an electronic component with at least one high heat flux hotspot, said method comprising: 
 dispensing an at least one stream of liquid droplets with the momentum necessary to result in high heat flux evaporative cooling of said at least one hotspot, said dispensing also resulting in a thick film that cools the non-hotspot areas of said electronic component.    
   
   
       33 . The method of  claim 32 , wherein said at least one stream of liquid droplets are dispensed at a non-perpendicular angle to said hotspot.  
   
   
       34 . The method of  claim 32 , wherein said at least one hotspot includes an array of etched microchannels.  
   
   
       35 . A liquid cooling system comprising: 
 an electronic component to be cooled having a cooling surface with a hotspot producing a first heat flux, wherein the non-hotspot portion of said cooing surface produces a second heat flux;    wherein said first heat flux is at least three times greater in magnitude than said second heat flux; and    an at least one sprayer in a spaced apart relationship and at a non-perpendicular angle to said hotspot, wherein said at least one sprayer dispenses droplets onto said hotspot in a fashion that creates a thin coolant film on said hotspot and a thick film on said non-hotspot portion of said cooling surface, said thin coolant film capable of cooling said hotspot and said thick film capable of cooling said non-hotspot portion of said cooling surface.    
   
   
       36 . The liquid cooling system of  claim 35 , wherein said hotspot includes an array of etched microchannels.  
   
   
       37 . The liquid cooling system of  claim 35 , wherein said first heat flux is at least three times greater in magnitude than said second heat flux.  
   
   
       38 . The liquid cooling system of  claim 35 , further including at least one secondary nozzle for adding a supply of liquid coolant to said thick film.  
   
   
       39 . The liquid cooling system of  claim 38 , wherein said at least one secondary nozzle is an incremental drop ejector.  
   
   
       40 . A continuously replenished evaporative cooling film created upon a surface to be cooled, said cooling film comprising: 
 a thin-film zone generally located over and capable of cooling a high heat flux portion of said cooling surface; and    said thin-film zone flowing radially into a thicker-film zone located over and capable of cooling a low heat flux portion of said cooling surface.    
   
   
       41 . The continuously replenished evaporative cooling film of  claim 40 , wherein said thicker-film zone is separated from said thin-film zone by a hydraulic jump.  
   
   
       42 . A cooling film for continuously absorbing heat from a surface to be cooled, said surface having a first zone with a first heat flux and second zone having a second heat flux, said cooling film comprising: 
 means for said cooling film to absorb heat from said first zone at a greater rate than said second zone.    
   
   
       43 . A cooling film for continuously cooing a surface of an electronic component: 
 said electronic component having a first component zone generating a first heat flux and a second component zone generating a second heat flux;    said cooling film having a thin-film evaporative zone located over said first component zone and having a thickness capable of absorbing said first heat flux in the general proximity of said first component zone; and    said cooling film having a thick-film cooling zone located over said second component zone and having a thickness capable of absorbing said second heat flux.    
   
   
       44 . The cooling film of  claim 43 , wherein said first heat flux is at least three times greater than said second heat flux.