Turbofan engine assembly and method of assembling same

Abstract

A method for assembling a gas turbine engine includes providing a core gas turbine engine including a high-pressure compressor, a combustor, and a turbine, coupling a counter-rotating fan assembly to the core gas turbine engine such that air discharged from the counter-rotating fan assembly is channeled directly into an inlet of the gas turbine engine compressor, and coupling a counter-rotating low-pressure turbine assembly to the counter-rotating fan assembly.

1 . A method of assembling a turbofan engine assembly comprises: 
 providing a core gas turbine engine including a high-pressure compressor, a combustor, and a turbine;    coupling a counter-rotating fan assembly to the core gas turbine engine such that air discharged from the counter-rotating fan assembly is channeled directly into an inlet of the gas turbine engine compressor; and    coupling a counter-rotating low-pressure turbine assembly to the counter-rotating fan assembly.    
   
   
       2 . A method in accordance with  claim 1  wherein coupling further comprises coupling a counter-rotating fan assembly to the core gas turbine engine such that compressed air is discharged from the counter-rotating fan assembly at a first operating pressure and received at the core gas turbine high-pressure compressor at approximately the first operational pressure.  
   
   
       3 . A method in accordance with  claim 1  wherein coupling further comprises coupling a counter-rotating fan assembly including a first fan assembly and a second fan assembly to the core gas turbine engine such that the first fan assembly rotates in a first direction and the second fan assembly rotates in an opposite second direction.  
   
   
       4 . A method in accordance with  claim 3  further comprising: 
 coupling a first shaft between the first fan assembly and a first turbine rotor that is configured to rotate in a first rotational direction; and    coupling a second shaft between the second fan assembly and a second turbine rotor that is configured to rotate in a second rotational direction that is opposite the first rotational direction.    
   
   
       5 . A method in accordance with  claim 1  wherein coupling further comprises coupling a counter-rotating fan assembly that discharges a predetermined quantity of air based on the gas turbine engine compression ratio to the core gas turbine engine.  
   
   
       6 . A method in accordance with  claim 1  wherein providing a core gas turbine engine comprises providing a core gas turbine engine that includes a predetermined quantity of compressor stages based on the quantity of compressed air discharged from the counter-rotating fan assembly.  
   
   
       7 . A method in accordance with  claim 1  further comprising coupling a gooseneck between the counter-rotating fan assembly and the core gas turbine engine to facilitate channeling air discharged from the counter-rotating fan assembly to the core gas turbine engine.  
   
   
       8 . A method in accordance with  claim 7  further comprising orienting the gooseneck within the turbofan engine assembly to facilitate preventing particles having a predetermined mass from being channeled in a radially inward direction into the core gas turbine engine.  
   
   
       9 . A turbofan engine assembly comprising: 
 a core gas turbine engine including a high-pressure compressor, a combustor, and a high-pressure turbine;    a counter-rotating fan assembly coupled to said core gas turbine engine such that air discharged from said counter-rotating fan assembly is channeled directly into an inlet of said gas turbine engine compressor; and    a counter-rotating low-pressure turbine assembly coupled to said counter-rotating fan assembly.    
   
   
       10 . A turbofan engine assembly in accordance with  claim 9  wherein said counter-rotating fan assembly is selectively sized to discharge compressed air at a first operating pressure, said core gas turbine engine is configured to receive the compressed air at approximately the first operational pressure.  
   
   
       11 . A turbofan engine assembly in accordance with  claim 9  wherein said counter-rotating fan assembly comprises a first fan assembly that rotates in a first direction and a second fan assembly rotates that rotates in an opposite second direction.  
   
   
       12 . A turbofan engine assembly in accordance with  claim 9  wherein said core gas turbine engine comprises a predetermined quantity of compressor stages based on the compression ratio of said counter-rotating fan assembly and the overall compression ratio of the gas turbofan engine assembly.  
   
   
       13 . A turbofan engine assembly in accordance with  claim 11  further comprising: 
 a first shaft coupled between said first fan assembly and a first turbine rotor that is configured to rotate in a first rotational direction; and    a second shaft coupled between said second fan assembly and a second turbine rotor that is configured to rotate in a second rotational direction that is opposite the first rotational direction.    
   
   
       14 . A turbofan engine assembly in accordance with  claim 9  wherein said core gas turbine engine comprises a predetermined quantity of high-pressure turbine stages based on the compression ratio of said counter-rotating fan assembly and the overall compression ratio of the gas turbofan engine assembly.  
   
   
       15 . A turbofan engine assembly in accordance with  claim 9  further comprising a gooseneck coupled between the counter-rotating fan assembly and the core gas turbine engine to facilitate channeling air discharged from the counter-rotating fan assembly to the core gas turbine engine.  
   
   
       16 . A turbofan engine assembly in accordance with  claim 16  wherein said gooseneck is configured to prevent particles having a predetermined mass from being channeled in a radially inward direction into said core gas turbine engine.