Cooling System for High Power Vacuum Tubes

Abstract

According to one embodiment, a two-phase cooling system includes a condensing heat exchanger fluidly coupled to an evaporator assembly and a pressure controller. The condensing heat exchanger condenses a coolant from a vapor phase to a liquid phase by removing heat from the coolant. The evaporator assembly is thermally coupled to a vacuum tube and operable to receive liquid coolant from the condensing heat exchanger, cool the vacuum tube by evaporating the coolant from the liquid phase to the vapor phase, and transporting the evaporated coolant to the condensing heat exchanger. The pressure controller maintains the pressure of the coolant in the evaporator assembly at a sub-ambient pressure to lower the boiling point of the coolant for reducing the operating temperature of the vacuum tube.

1 . A two-phase cooling system for a vacuum tube comprising:
 a condensing heat exchanger that is operable to condense water from a vapor phase to a liquid phase by removing thermal energy from the water;   an evaporator assembly having an inlet and an outlet that are fluidly coupled to the condensing heat exchanger, the evaporator assembly in thermal communication with a vacuum tube and operable to:
 receive, through the inlet, the water in the liquid phase from the condensing heat exchanger; 
 cool the vacuum tube by transferring thermal energy from the vacuum tube to the water, the transfer of thermal energy causing the water in the liquid phase to boil and vaporize; and 
 transport, using a pump, the vaporized water to the condensing heat exchanger through the outlet; and 
   a pressure controller operable to maintain the pressure of the water in the evaporator assembly and the condensing heat exchanger at a sub-ambient pressure of less than three pounds-per-square-inch-absolute.   
   
   
       2 . A two-phase cooling system for a vacuum tube comprising:
 a condensing heat exchanger that is operable to condense a coolant from a vapor phase to a liquid phase by removing thermal energy from the coolant;   an evaporator assembly having an inlet and an outlet that are fluidly coupled to the condensing heat exchanger, the evaporator assembly in thermal communication with a vacuum tube and operable to:
 receive, through the inlet, the coolant in the liquid phase from the condensing heat exchanger; 
 cool the vacuum tube by transferring thermal energy from the vacuum tube to the coolant, the transfer of thermal energy causing the coolant in the liquid phase to boil and vaporize; and 
 moving the vaporized coolant to the condensing heat exchanger through the outlet; and 
   a pressure controller operable to maintain the pressure of the coolant in the evaporator assembly at a sub-ambient pressure.   
   
   
       3 . The two-phase cooling system of  claim 2 , wherein the evaporator assembly is operable to cool the vacuum tube using a pool boiling technique. 
   
   
       4 . The two-phase cooling system of  claim 2 , wherein the evaporator assembly is operable to cool the vacuum tube using a spray/jet impingement cooling technique. 
   
   
       5 . The two-phase cooling system of  claim 2 , wherein the coolant comprises water. 
   
   
       6 . The two-phase cooling system of  claim 2 , wherein the coolant comprises water and one or more antifreeze agents. 
   
   
       7 . The two-phase cooling system of  claim 2 , wherein the coolant comprises a perfluorocarbon. 
   
   
       8 . The two-phase cooling system of  claim 2 , further comprising a pump fluidly coupled between the condensing heat exchanger and the evaporator assembly, the pump operable to transport the coolant from the condensing heat exchanger to the inlet of the evaporator assembly. 
   
   
       9 . The two-phase cooling system of  claim 2 , further comprising an air removal system coupled to the condensing heat exchanger, the air removal system operable to remove air from the condensing heat exchanger and the evaporator assembly. 
   
   
       10 . The two-phase cooling system of  claim 2 , wherein the coolant comprises water and the sub-ambient pressure is less than three pounds-per-square-inch-absolute. 
   
   
       11 . The two-phase cooling system of  claim 2 , wherein the pressure controller is operable to maintain the pressure of the coolant in the condensing heat exchanger at the sub-ambient pressure. 
   
   
       12 . A method for cooling a vacuum tube comprising:
 receiving a coolant in a liquid phase from a condensing heat exchanger, the condensing heat exchanger operable to condense the coolant from a vapor phase to the liquid phase by removing thermal energy from the coolant;   cooling the vacuum tube by transferring thermal energy from the vacuum tube to the coolant, the transfer of thermal energy causing the coolant in the liquid phase to boil and vaporize;   moving the vaporized coolant to the condensing heat exchanger; and   maintaining the coolant at a sub-ambient pressure.   
   
   
       13 . The method of  claim 12 , wherein receiving the coolant in the liquid phase comprises receiving water in the liquid phase. 
   
   
       14 . The method of  claim 12 , wherein receiving the coolant in the liquid phase comprises receiving water and one or more antifreeze agents in the liquid phase. 
   
   
       15 . The method of  claim 12 , receiving the coolant in the liquid phase comprises receiving perfluorocarbon in the liquid phase. 
   
   
       16 . The method of  claim 12 , wherein receiving the coolant from the condensing heat exchanger comprises pumping the coolant from the condensing heat exchanger using a pump. 
   
   
       17 . The method of  claim 12 , further comprising removing air from the condensing heat exchanger and the evaporator assembly using an air removal system. 
   
   
       18 . The method of  claim 12 , wherein cooling the vacuum tube by boiling and vaporizing the coolant from the liquid phase to the vapor phase comprises cooling the vacuum tube by boiling and vaporizing the coolant from the liquid phase to the vapor phase using a pool boiling technique. 
   
   
       19 . The method of  claim 12 , wherein cooling the vacuum tube by boiling and vaporizing the coolant from the liquid phase to the vapor phase comprises cooling the vacuum tube by boiling and vaporizing the coolant from the liquid phase to the vapor phase using a spray/jet impingement cooling technique. 
   
   
       20 . The method of  claim 12 , wherein maintaining the coolant at the sub-ambient pressure comprises maintaining the coolant at less than three pounds-per-square-inch-absolute. 
   
   
       21 . The method of  claim 12 , further comprising maintaining the pressure of the coolant in the condensing heat exchanger at the sub-ambient pressure.