Premixer with diluent fluid and fuel tubes having chevron outlets

Abstract

A premixer includes an air tube formed in a burner tube defining a longitudinal axis, and a coaxially disposed fuel tube with a turbulence enhancing chevron outlet. The fuel tube may include an exterior tube and an interior tube with the interior tube, the exterior tube or both having chevron outlets. The chevron outlets may be tapered and notched.

What is claimed: 
     
         1 . A premixer, comprising:
 a fuel plenum;   a burner tube;   an air tube formed in the burner tube;   a first tube disposed coaxially inside the air tube;   a second tube disposed coaxially inside the first tube   at least one of the first tube and second tube having a chevron outlet,   at least one of the first tube and second tube coupled to the fuel plenum, and disposed coaxially inside the air tube;   an air source coupled to the air tube; and   a bell mouth disposed at least partially about the burner tube and coupled to the air source, the bell mouth adapted to direct air into the air tube.   
     
     
         2 . The premixer of  claim 1 , wherein the chevron outlet comprises a notch at a downstream end of the second tube. 
     
     
         3 . The premixer of  claim 2  wherein the notch comprises a notch selected from among a group consisting of a V shaped notch, a U shaped notch and a straight notch. 
     
     
         4 . The premixer of  claim 1 , wherein at least one of the first tube and second tube having a tapered downstream end. 
     
     
         5 . The premixer of  claim 1 , wherein the first tube has a chevron outlet and the second tube does not have a chevron outlet. 
     
     
         6 . The premixer of  claim 1 , wherein the second tube has a chevron outlet and the first tube does not have a chevron outlet. 
     
     
         7 . The premixer of  claim 5 , further comprising a source of diluent fluid coupled to one of the first tube and second tube. 
     
     
         8 . A combustor, comprising:
 a fuel source;   an air source; and   a plurality of premixers comprising:
 a burner tube; 
 an air tube formed in the burner tube and coupled to the air source; 
 a first tube disposed coaxially inside the air tube; 
 a second tube disposed coaxially inside the first tube; 
 at least one of the first tube and second tube having a turbulence enhancing chevron outlet; and 
 at least one of the first tube and second tube coupled to the fuel source. 
   
     
     
         9 . The combustor of  claim 8  each premixer further comprises a bell mouth disposed at least partially about the burner tube and coupled to the air source the bell mouth adapted to direct air into the air tube. 
     
     
         10 . The combustor of  claim 8 , wherein the turbulence enhancing chevron outlet comprises a notch at a downstream end of the first tube. 
     
     
         11 . The combustor of  claim 8 , wherein the turbulence enhancing chevron outlet comprises a notch at a downstream end of the second tube. 
     
     
         12 . The combustor of  claim 8  wherein the first tube comprises a tube with a tapered downstream end and a notch on the tapered downstream end. 
     
     
         13 . The combustor of  claim 8  wherein the second tube comprises a tube with a tapered downstream end and a notch on the tapered downstream end. 
     
     
         14 . The combustor of  claim 12 , wherein at least one of the first tube or the second tube is tapered. 
     
     
         15 . The combustor of  claim 12 , further comprising a source of diluent fluid coupled to the first tube and wherein the fuel source is coupled to the second tube. 
     
     
         16 . The combustor of  claim 12 , further comprising a source of diluent fluid coupled to the second tube and wherein the fuel source is coupled to the first tube. 
     
     
         17 . An apparatus, comprising:
 a fuel source;   a first tube;   a second tube disposed within the first tube;   wherein one of the first tube or second tube is coupled to the fuel source and at least one of the first tube or second tube has a chevron outlet for enhancing turbulence;   an air tube surrounding the first tube;   an air source; and   an air directing component coupled to the air source and adapted to direct air into the air tube.   
     
     
         18 . The apparatus of  claim 17 , wherein the chevron outlet comprises one selected from among a group consisting of a V-shaped notch on the first tube, a U shaped notch on the first tube, and a straight notch on the first tube. 
     
     
         19 . The apparatus of  claim 17 , wherein at least one of the first tube or second tube is tapered. 
     
     
         20 . The apparatus of  claim 17 , further comprising:
 a diluent source; and   wherein the first tube is coupled to the fuel source and the second tube is coupled to the diluent source.   
     
     
         21 . The apparatus of  claim 17 , further comprising:
 a diluent source; and   wherein the second tube is coupled to the fuel source and the first tube is coupled to the diluent source.