Heat exchanger tube with enhanced heat transfer co-efficient and related method

Abstract

A method of enhancing the heat transfer coefficient of a tube flowing a fluid in the tube in heat exchange relation with a second fluid external to the tube includes applying metal particles to an interior surface of the tube to thereby create an increased wetted area for interaction with fluid flowing through the tube; wherein the particles are applied by: providing an applicator head including an electric arc and at least one metal wire; displacing the head along the interior of the tube; feeding the wire into the electric arc as the head is displaced along the interior of the tube; melting the wire to form molten metal particles; and applying the molten metal particles about and along the length of the interior wall surface of the tube as the head is displaced along the interior of the tube.

1 . A method of enhancing the heat transfer coefficient of a tube flowing a fluid in the tube in heat exchange relation with a second fluid external to the tube comprising applying metal particles to an interior surface of the tube to thereby create an increased wetted area for interaction with fluid flowing through the tube. 
   
   
       2 . The method of  claim 1  wherein the particles are applied by:
 providing an applicator head including an electric arc and at least one metal wire;   displacing the head along the interior of the tube;   feeding the wire into the electric arc as the head is displaced along the interior of the tube;   melting the wire to form molten metal particles; and   applying the molten metal particles about and along the length of the interior wall surface of the tube as the head is displaced along the interior of the tube.   
   
   
       3 . The method of  claim 1  including providing a second wire, melting the second wire together with the first mentioned wire to form the molten metal particles, and applying the metal particles of said first and second wires along the length of the interior wall surface of the tube. 
   
   
       4 . The method of  claim 1  including mixing the molten particles with atomized gas to facilitate applying the molten metal particles to the interior wall surface of the tube. 
   
   
       5 . A heat exchanger tube comprising a hollow tube having an interior surface substantially covered with metal particles for enhancing heat exchanger properties of the tube, said metal particles in molten form when applied to said interior surface and metalurgically bonded thereto. 
   
   
       6 . A method of enhancing heat transfer characteristics of a heat exchanger tube adapted to carry a fluid there through, the method comprising:
 locating a MIG welding torch nozzle within the heat exchanger tube;   moving the torch nozzle axially relative to the tube while applying welding material to and along the interior surface of the tube to thereby enhance heat transfer between the tube and the fluid flowing through the tube.   
   
   
       7 . The method of  claim 6  wherein the welding material is applied in discrete amounts to increase surface roughness of said interior surface. 
   
   
       8 . The method of  claim 6  including rotating the welding torch such that material is added to the interior surface of the tube in the form of a continuous spiral rib.