Variable area turbine vane arrangement

Abstract

A turbine section of a gas turbine engine includes a ring of turbine nozzle segments each having paired turbine vanes. Turbine throat area is modulated by rotating each rotational turbine vanes about an axis of rotation which is located such that rotation changes the turbine throat area concurrently between one rotational stator vane and two adjacent fixed turbine vanes. Each paired turbine vane doublet includes at least one rotational turbine vane between two fixed turbine vanes.

1 . A turbine nozzle segment for a gas turbine engine comprising:
 a fixed turbine vane; and   a rotational turbine vane adjacent said fixed turbine vane, said rotational turbine vane rotatable about an axis of rotation relative said fixed turbine vane.   
   
   
       2 . The turbine nozzle segment as recited in  claim 1 , wherein said fixed turbine vane and said rotational turbine vane are located between an outer vane platform segment and an inner vane platform segment. 
   
   
       3 . The turbine nozzle segment as recited in  claim 2 , wherein said fixed turbine vane is fixed to said outer vane platform segment and said inner vane platform segment. 
   
   
       4 . The turbine nozzle segment as recited in  claim 1 , further comprising an actuator system having an actuator rod mounted through said rotational turbine vane at said axis of rotation. 
   
   
       5 . The turbine nozzle segment as recited in  claim 4 , wherein said rotational turbine vane is rotated by a unison ring driven linkage. 
   
   
       6 . The turbine nozzle segment as recited in  claim 1 , wherein said axis of rotation is aft of a geometric center of gravity of a cross section of said rotational turbine vane. 
   
   
       7 . The turbine nozzle segment as recited in  claim 1 , wherein said axis of rotation is located approximately midway between a trailing edge of said fixed turbine vane and a trailing edge of said rotational turbine vane. 
   
   
       8 . A turbine section of a gas turbine engine comprising:
 an annular outer vane platform;   an annular inner vane platform;   a fixed turbine vane fixed to said annular outer vane platform and said annular inner vane platform; and   a rotational turbine vane between said annular outer vane platform and said annular inner vane platform, said rotational turbine vane rotatable about an axis of rotation aft of a geometric center of gravity of a cross section of said rotational turbine vane.   
   
   
       9 . The turbine section as recited in  claim 8 , wherein said annular outer vane platform and said annular inner vane platform are formed from a respective multiple of outer vane platform segments and a multiple of inner vane platform segments, wherein each of said multiple of outer vane platform segments and said multiple of inner vane platform segments include at least one of said fixed turbine vanes. 
   
   
       10 . The turbine section as recited in  claim 9 , wherein each of said multiple of outer vane platform segments and said multiple of inner vane platform segments include at least one of said rotational turbine vane between a first fixed turbine vane and a second fixed turbine vane. 
   
   
       11 . The turbine section as recited in  claim 8 , wherein said fixed turbine vane alternates with said rotational turbine vane. 
   
   
       12 . The turbine section as recited in  claim 8 , wherein said axis of rotation is located approximately midway between a trailing edge of said fixed turbine vane and a trailing edge of said rotational turbine vane 
   
   
       13 . A method of varying a turbine nozzle throat area of a gas turbine engine comprising the steps of:
 (A) locating a rotational turbine vane between a first fixed turbine vane and a second fixed turbine vane; and   (B) rotating the rotational turbine vane about an axis of rotation to vary a throat area concurrently between the rotational stator vane and both the first fixed turbine vane and the second fixed turbine vane.   
   
   
       14 . A method as recited in  claim 13 , wherein said step (A) further comprises:
 (a) alternating each of a multiple of rotational turbine vanes with a multiple of fixed turbine vanes about a turbine section of the gas turbine engine.   
   
   
       15 . A method as recited in  claim 14 , wherein said step (B) further comprises:
 (a) rotating a unison ring to simultaneously rotate each of the multiple of rotational turbine vanes.   
   
   
       16 . A method as recited in  claim 13 , wherein said step (B) further comprises:
 (a) locating the axis of rotation aft of a geometric center of gravity of a cross section of the rotational turbine vane.