Engine for an aircraft

Abstract

An engine includes an inlet tube introducing air to a combustion process and a first plurality of fuel injectors disposed in the inlet tube and used for scram-jet engine operation. The engine includes a second plurality of fuel injectors used for ram-jet engine operation. The second plurality of fuel injectors is upstream from the first plurality of fuel injectors and is disposed in the inlet tube. The engine includes a combustor swirl zone downstream of and adjacent to the first plurality of fuel injectors.

1 . An engine comprising:
 an inlet tube, the inlet tube introducing air to a combustion process;   
       a first plurality of fuel injectors, the first plurality of fuel injectors for scramjet engine operation and disposed in the inlet tube;
 a second plurality of fuel injectors, the second plurality of fuel injectors for ramjet engine operation, the second plurality of fuel injectors upstream from the first plurality of fuel injectors, the second plurality of fuel injectors disposed in the inlet tube; and 
 a combustor swirl zone, the combustor swirl zone downstream of and adjacent to the first plurality of fuel injectors. 
 
     
     
         2 . The engine of  claim 1 , the combustor swirl zone further comprising an outer radius, wherein the outer radius of the combustor swirl zone is greater than an inlet tube outer radius. 
     
     
         3 . The engine of  claim 1 , further comprising at least one plasma stabilizer. 
     
     
         4 . The engine of  claim 3 , wherein the at least one plasma stabilizer is downstream of the second plurality of fuel injectors. 
     
     
         5 . The engine of  claim 4 , wherein the at least one plasma stabilizer is upstream of the first plurality of fuel injectors. 
     
     
         6 . The engine of  claim 4 , wherein the at least one plasma stabilizer is downstream of the first plurality of fuel injectors. 
     
     
         7 . The engine of  claim 6 , wherein the at least one plasma stabilizer is disposed within the combustor swirl zone. 
     
     
         8 . The engine of  claim 7 , wherein the combustor swirl zone comprises a backward facing step portion, and
 where the at least one plasma stabilizer is disposed within the backward facing step portion of the combustor swirl zone.   
     
     
         9 . The engine of  claim 7 , wherein the combustor swirl zone comprises an axially extending portion, and
 wherein the at least one plasma stabilizer is disposed within the axially extending portion of the combustor swirl zone.   
     
     
         10 . The engine of  claim 7 , wherein the combustor swirl zone comprises a tapered portion, and
 wherein the at least one plasma stabilizer is disposed within the tapered portion of the combustor swirl zone.   
     
     
         11 . The engine of  claim 6 , wherein the at least one plasma stabilizer is disposed downstream of the combustor swirl zone. 
     
     
         12 . The engine of  claim 11 , wherein the engine further comprises a downstream portion, and
 wherein the at least one plasma stabilizer is disposed within the downstream portion of the engine adjacent a tapered portion of the combustor swirl zone.   
     
     
         13 . The engine of  claim 3 , wherein the plasma stabilizer further comprises:
 a cylindrical dielectric sleeve;   a high voltage center rod within the cylindrical dielectric sleeve; and   a converging flow area, the converging flow area concentrically surrounding the cylindrical dielectric sleeve,   wherein the cylindrical dielectric sleeve electrically isolates the high voltage center rod from the converging flow area.   
     
     
         14 . The engine of  claim 13 , further comprising:
 a turbine section; and   a voltage source, the voltage source electrically coupled to the high voltage center rod, wherein the voltage source provides a voltage to the high voltage center rod.   
     
     
         15 . The engine of  claim 14 , wherein the high voltage center rod is at least partially composed of one of niobium, molybdenum, tungsten, nickel, and an alloy. 
     
     
         16 . The engine of  claim 14 , wherein the cylindrical dielectric sleeve is at least partially composed of a ceramic. 
     
     
         17 . The engine of  claim 3 , wherein the engine is configured such that (i) under a ramjet condition, only the second plurality of fuel injectors and the at least one plasma stabilizer are in operation, and (ii) under a scramjet condition, only the first plurality of fuel injectors is in operation. 
     
     
         18 . The engine of  claim 17 , wherein the engine is configured such that, in a transition condition between the ramjet condition and the scramjet condition, at least the second plurality of fuel injectors and the first plurality of fuel injectors are in operation. 
     
     
         19 . The engine of  claim 10 , wherein the tapered portion extends to a downstream portion that extends downstream along each side of the inlet tube from the combustion swirl zone, the downstream portion extending downstream from the combustion swirl zone at an angle that gradually increases to a diverging exhaust portion. 
     
     
         20 . The engine of  claim 19 , wherein the diverging exhaust portion extends downstream along each side of the inlet tube from the downstream portion and diverges radially outward at a steeper angle than that of the downstream portion.