Surface-modified component and method of achieving high heat transfer during cooling

Abstract

A method of achieving high heat transfer during cooling includes providing an aluminum body having an inner surface enclosing a channel, where the inner surface comprises microscale roughness features and microcavities configured to enhance nucleation site density during flow boiling. A refrigerant is transported through the channel. During the transport, the refrigerant absorbs heat from a thermal load and undergoes flow boiling. The heat is transferred to the refrigerant at an average heat transfer coefficient of at least about 10 kW/(m2·K) at a mass flux of about 300 kg/(m2·s).

1 . A method of achieving high heat transfer during cooling, the method comprising:
 providing an aluminum body having an inner surface enclosing a channel, the inner surface comprising microscale roughness features and microcavities configured to enhance nucleation site density during flow boiling;   transporting a refrigerant through the channel, the refrigerant absorbing heat from a thermal load and undergoing flow boiling,   wherein the heat is transferred to the refrigerant at an average heat transfer coefficient of at least about 10 kW/(m 2 ·K) at a mass flux of about 300 kg/(m 2 ·s).   
     
     
         2 . The method of  claim 1 , wherein the microcavities have a linear size in a range from about 2 microns to about 30 microns. 
     
     
         3 . The method of  claim 1 , wherein the microscale roughness features have a height in a range from about 1 microns to about 15 microns. 
     
     
         4 . The method of  claim 1 , wherein the average heat transfer coefficient is stable within +/−5% for at least 28 days. 
     
     
         5 . The method of  claim 1 , wherein the channel has a diameter of at least about 3 mm and/or a length of at least about 1 m. 
     
     
         6 . The method of  claim 1 , wherein the refrigerant comprises a hydrochlorofluorocarbon, a hydrofluoro-olefin, a hydrofluorocarbon, and/or a zeotropic refrigerant blend. 
     
     
         7 . The method of  claim 1 , wherein the aluminum body comprises an enhancement factor Ø e.f.  of at least about 2 at the mass flux of about 300 kg/(m 2 ·s), where Ø e.f. =( h   structured / h   plain )/(ΔP structured /ΔP plain ). 
     
     
         8 . The method of  claim 1 , further comprising, prior to providing the aluminum body, forming the inner surface comprising the microscale roughness features and microcavities, the forming comprising:
 cleaning the inner surface with an organic solvent and/or deionized water;   after the cleaning, exposing the inner surface to a hydrochloric acid (HCl) solution comprising a HCl concentration of 2 M to 5 M; and   after the exposing, rinsing the inner surface with deionized water and then drying, thereby obtaining the inner surface comprising the microscale roughness features and microcavities.   
     
     
         9 . A surface-modified component for enhanced heat transfer during cooling, the surface-modified component comprising:
 an aluminum body having an inner surface enclosing a channel, the inner surface comprising microscale roughness features of about 1 microns to about 15 microns in height and microcavities of about 2 microns to about 30 microns in linear size,   wherein the inner surface comprises aluminum and native aluminum oxide, and wherein the aluminum body does not include an interface between the inner surface and a sub-surface region of the aluminum body.   
     
     
         10 . The surface-modified component of  claim 9 , wherein, during flow boiling of a refrigerant through the channel, an average heat transfer coefficient of at least about 10 kW/(m 2 ·K) is achieved at a mass flux of about 300 kg/(m 2 ·s). 
     
     
         11 . The surface-modified component of  claim 9 , wherein the aluminum body comprises an aluminum tube, and/or
 wherein the aluminum body comprises an aluminum alloy having an alloy designation in the 1000 through 7000 series.   
     
     
         12 . The surface-modified component of  claim 9 , wherein the channel has a diameter of at least about 3 mm and/or a length of at least about 1 m. 
     
     
         13 . The surface-modified component of  claim 9 , wherein the inner surface of the aluminum body further comprises micro-fins or grooves comprising the microscale roughness features. 
     
     
         14 . A method of modifying a surface of a component for enhanced heat transfer during cooling, the method comprising:
 providing an aluminum body having an inner surface enclosing a channel;   cleaning the inner surface with an organic solvent and/or deionized water;   after the cleaning, exposing the inner surface to a hydrochloric acid (HCl) solution comprising a HCl concentration of 2 M to 5 M; and   after the exposing, rinsing the inner surface with deionized water and then drying, thereby obtaining a surface-modified component comprising the aluminum body, wherein the inner surface comprises microscale roughness features and microcavities.   
     
     
         15 . The method of  claim 14 , wherein the exposure to the HCl solution takes place for a time duration from about 7 min to about 30 min. 
     
     
         16 . The method of  claim 14 , wherein the cleaning comprises immersing the aluminum body in acetone, ethanol, isopropanol, and the deionized water in succession. 
     
     
         17 . The method of  claim 14 , wherein the rinsing further comprises exposing the inner surface to isopropanol. 
     
     
         18 . The method of  claim 14 , wherein the microcavities have a linear size in a range from about 2 microns to about 30 microns. 
     
     
         19 . The method of  claim 14 , wherein the microscale roughness features have a height in a range from about 1 microns to about 15 microns. 
     
     
         20 . The method of  claim 14 , wherein the channel has a diameter of at least about 3 mm and/or a length of at least about 1 m.