Methods of determining variable element settings for a turbine engine

Abstract

Variable elements of a turbine engine such as variable inlet guide vanes, variable bleed valves and variable stator vanes can be adjusted to provide a desired level of power and/or efficiency for the turbine engine across a range of operating conditions. The variable element settings typically determined through experimentation when the engine is new. Unfortunately, over the life cycle of the turbine engine, as wear occurs, the original variable element settings may no longer provide a desired level of power and efficiency. To correct this problem, offsets to the original variable element settings are calculated based on observable operational conditions which provide a measure of the wear that has occurred. The offsets are applied to the original variable element settings to generate corrected variable element settings. These corrected variable element settings are then used to configure the turbine engine. The corrected variable element settings allow the turbine engine to continue to operate at a desired level of power and/or efficiency over the life of the turbine engine, despite any deterioration which may have occurred due to normal life cycle wear.

1 . A method of determining at least one variable element setting for a turbine engine, comprising:
 obtaining an original variable element setting from a setting schedule based on a sensed operational condition of the turbine engine;   determining at least one offset that is based on at least one sensed operational condition of the turbine engine; and   calculating a corrected variable element setting based on the obtained original variable element setting and the at least one offset.   
     
     
         2 . The method of  claim 1 , wherein the at least one offset is based on at least one sensed operational condition of the turbine engine that provides a measure of the amount of wear experienced by the turbine engine during its operational life. 
     
     
         3 . The method of  claim 1 , wherein the obtaining step comprises obtaining an original inlet guide vane setting, wherein the determining step comprises determining an inlet guide vane offset, and wherein the calculating step comprises calculating a corrected inlet guide vane setting based on the original inlet guide vane setting and the inlet guide vane offset. 
     
     
         4 . The method of  claim 3 , wherein the obtaining step comprises obtaining an original inlet guide vane setting that is based on a sensed compressor exit pressure. 
     
     
         5 . The method of  claim 3 , wherein the determining step comprises determining the inlet guide vane offset based on a sensed exit temperature of a turbine section of the turbine engine. 
     
     
         6 . The method of  claim 5 , wherein the inlet guide vane offset is also based on an exit temperature of a compressor section of the turbine engine. 
     
     
         7 . The method of  claim 6 , wherein the inlet guide vane offset is also based on an exit pressure of a compressor section of the turbine engine. 
     
     
         8 . The method of  claim 3 , wherein the determining step comprises determining the inlet guide vane offset based on an exit temperature of a compressor section of the turbine engine. 
     
     
         9 . The method of  claim 3 , wherein the determining step comprises determining the inlet guide vane offset based on an exit pressure of a compressor section of the turbine engine. 
     
     
         10 . The method of  claim 3 , wherein the determining step comprises determining the inlet guide vane offset based on an exit pressure of a turbine section of the turbine engine. 
     
     
         11 . The method of  claim 3 , wherein the determining step comprises determining the inlet guide vane offset based on a rotational speed of the turbine engine. 
     
     
         12 . The method of  claim 3 , wherein the determining step comprises determining the inlet guide vane offset based on a rotational speed of the turbine engine that has been corrected for the ambient temperature. 
     
     
         13 . The method of  claim 3 , further comprising:
 obtaining an original variable bleed valve setting that is based on a sensed operational condition of the turbine engine;   determining a variable bleed valve offset based on at least one sensed operational condition of the turbine engine; and   calculating a corrected variable bleed valve setting based on the original variable bleed valve setting and the variable bleed valve offset.   
     
     
         14 . The method of  claim 13 , wherein the at least one variable bleed valve offset is based on the determined inlet guide vane offset. 
     
     
         15 . The method of  claim 13 , further comprising:
 obtaining an original variable stator vane setting that is based on a sensed operational condition of the turbine engine;   determining a variable stator vane offset that is based on at least one sensed operational condition of the turbine engine; and   calculating a corrected variable stator vane setting based on the original stator vane setting and the variable stator vane offset.   
     
     
         16 . The method of  claim 3 , further comprising:
 obtaining an original variable stator vane setting that is based on a sensed operational condition of the turbine engine;   determining a variable stator vane offset that is based on at least one sensed operational condition of the turbine engine; and   calculating a corrected variable stator vane setting based on the original stator vane setting and the variable stator vane offset.   
     
     
         17 . The method of  claim 1 , wherein the obtaining step comprises obtaining an original variable bleed valve setting, wherein the determining step comprises determining a variable bleed valve offset, and wherein the calculating step comprises calculating a corrected variable bleed valve setting based on the original variable bleed valve setting and the variable bleed valve offset. 
     
     
         18 . The method of  claim 17 , further comprising:
 obtaining an original variable stator vane setting that is based on a sensed operational condition of the turbine engine;   determining a variable stator vane offset that is based on at least one sensed operational condition of the turbine engine; and   calculating a corrected variable stator vane setting based on the original variable stator vane setting and the variable stator vane offset.   
     
     
         19 . The method of  claim 1 , wherein the obtaining step comprises obtaining an original variable stator vane setting, wherein the determining step comprises determining a variable stator vane offset, and wherein the calculating step comprises calculating a corrected variable stator vane setting based on the original variable stator vane setting and the variable stator vane offset. 
     
     
         20 . A method of determining a variable element setting for a turbine engine, comprising:
 obtaining an original variable element setting from a schedule of settings that are experimentally determined when the turbine engine is new, wherein the original settings in the schedule are indexed to at least one operational condition of the turbine engine;   determining at least one variable element setting correction factor that is based on at least one sensed operational condition of the turbine engine, wherein the at least one sensed operational condition provides an indication of the amount of wear which the turbine engine has experienced during its lifecycle; and   calculating a corrected variable element setting based on the obtained original variable element setting and the determined at least one variable element correction factor.