Heat transfer device and an associated method of fabrication

Abstract

A heat transfer device includes a casing and a wick disposed within the casing. The wick includes a first sintered layer and a second sintered layer. The first sintered layer includes a plurality of first sintered particles, having a first porosity and a plurality of first pores. The first sintered layer is disposed proximate to an inner surface of the casing. The second sintered layer includes a plurality of second sintered particles, having a second porosity and a plurality of second pores. The second sintered layer is disposed on the first sintered layer. The heat transfer device includes at least one first sintered particle smaller than at least one second pore and the first porosity is smaller than the second porosity.

1 . A heat transfer device comprising:
 a casing having an inner surface and an outer surface; and   a wick disposed within the casing; wherein the wick comprises:
 a first sintered layer comprising a plurality of first sintered particles, having a first porosity and a plurality of first pores, disposed proximate to the inner surface of the casing; and 
 a second sintered layer comprising a plurality of second sintered particles, having a second porosity and a plurality of second pores, disposed on the first sintered layer; wherein at least one first sintered particle is smaller than at least one second pore and the first porosity is smaller than the second porosity. 
   
     
     
         2 . The heat transfer device of  claim 1 , wherein each first pore has a size in a range of ten nanometers to ten micrometers. 
     
     
         3 . The heat transfer device of  claim 1 , wherein each second pore has a size in a range of one micrometer to fifty micrometers. 
     
     
         4 . The heat transfer device of  claim 1 , wherein each first sintered particle has a size in a range of hundred nanometers to fifty micrometers. 
     
     
         5 . The heat transfer device of  claim 1 , wherein each second sintered particle has a size in a range of ten micrometers to hundred micrometers. 
     
     
         6 . The heat transfer device of  claim 1 , wherein the first porosity is in a range of five percent to forty percent. 
     
     
         7 . The heat transfer device of  claim 1 , wherein the second porosity is in a range of eight percent to twenty percent. 
     
     
         8 . The heat transfer device of  claim 1 , wherein the wick further comprises a third sintered layer including a plurality of third sintered particles, having a third porosity and a plurality of third pores, disposed on the second sintered layer 
     
     
         9 . The heat transfer device of  claim 8 , wherein each third pore has a size in a range of one nanometer to ten micrometers. 
     
     
         10 . The heat transfer device of  claim 8 , wherein the third porosity is in a range of twenty percent to eighty percent. 
     
     
         11 . The heat transfer device of  claim 8 , wherein each third sintered particle has a size in a range of hundred nanometers to ten micrometers. 
     
     
         12 . The heat transfer device of  claim 8 , wherein a size of each third sintered particle is less than or equal to a size of each second sintered particle. 
     
     
         13 . The heat transfer device of  claim 8 , wherein the casing, the plurality of first sintered particles, the plurality of second sintered particles, and the plurality of third sintered particles comprise a same material. 
     
     
         14 . The heat transfer device of  claim 1 , wherein the first sintered layer is disposed contacting the inner surface of the casing. 
     
     
         15 . The heat transfer device of  claim 1 , further comprising a coating disposed between the first sintered layer and the inner surface of the casing. 
     
     
         16 . The heat transfer device of  claim 15 , wherein the casing comprises a first material and the first sintered layer, the second sintered layer, and the coating comprises a second material different from the first material. 
     
     
         17 . The heat transfer device of  claim 1 , further comprising an evaporator section, a transport section, and a condenser section within the casing, wherein the wick has a uniform thickness extending along the evaporator section, the transport section, and the condenser section. 
     
     
         18 . The heat transfer device of  claim 1 , further comprising an evaporator section, a transport section, and a condenser section within the casing, wherein the wick has a non-uniform thickness extending along the evaporator section, the transport section, and the condenser section. 
     
     
         19 . A method comprising:
 filling a plurality of particles within a first half casing portion, wherein the plurality of particles comprises a plurality of first particles and a plurality of second particles;   leveling the plurality of first and second particles within the first half casing portion;   vibrating the first half casing portion to segregate the plurality of first particles from the plurality of second particles such that a first layer portion having the plurality of first particles, is disposed proximate to an inner surface of the first half casing portion and a second layer portion having the plurality of second particles is disposed on the first layer portion;   sintering the first layer portion and the second layer portion to generate a first sintered layer portion including a plurality of first sintered particles, having a first porosity and a plurality of first pores, and a second sintered layer portion including a plurality of second sintered particles, having a plurality of second pores and a second porosity greater than the first porosity, wherein at least one first sintered particle is smaller than at least one second pore, and the first sintered layer portion and the second sintered layer portion together form a first wick portion;   repeating the filling, the leveling, the vibrating, and the sintering process in a second half casing portion to form a second wick portion within the second half casing portion; and   coupling the first half casing portion to the second half casing portion such that the first wick portion is coupled to the second wick portion to form a heat transfer device.   
     
     
         20 . The method of  claim 19 , wherein the leveling further comprises forming a uniform thickness of the plurality of first and second particles along an evaporator section, a transport section, and a condenser section of the first half casing portion. 
     
     
         21 . The method of  claim 19 , wherein the leveling further comprises forming a non-uniform thickness of the plurality of first and second particles along an evaporator section, a transport section, and a condenser section of the first half casing portion. 
     
     
         22 . The method of  claim 19 , wherein the sintering further comprises disposing a sintering spacer having a non-uniform contact surface on the second layer portion. 
     
     
         23 . The method of  claim 19 , wherein the sintering further comprises:
 disposing a first sintering spacer having a uniform contact surface on the second layer portion; and   disposing at least one second sintering spacer between the uniform contact surface of the first sintering spacer and the second layer portion.   
     
     
         24 . The method of  claim 19 , further comprises performing filling, leveling, and sintering of a third layer portion having a plurality of third particles disposed on the second sintered layer portion to generate a third sintered layer portion including a plurality of third sintered particles, having a plurality of third pores, and a third porosity, on the second sintered layer portion, wherein a size of each third sintered particle is less than or equal to a size of each second sintered particle. 
     
     
         25 . The method of  claim 19 , further comprising applying a coating on the inner surface of the first half casing portion before filling the plurality of first and second particles in the first half casing portion, wherein the first half casing portion comprises a first material and the plurality of first and second particles and the coating comprise a second material different from the first material.