Systems and Methods to Control Combustion Dynamic Frequencies

Abstract

Systems and methods for frequency separation in a gas turbine engine are provided herein. The systems and methods for frequency separation in a gas turbine engine may include determining a hot gas path natural frequency, determining a combustion dynamic frequency, and modifying a compressor discharge temperature to separate the combustion dynamic frequency from the hot gas path natural frequency. Specifically, the compressor discharge temperature may be modified by adjusting the inlet guide vanes of the compressor or by adjusting a temperature of air entering the compressor.

We claim: 
     
         1 . A system for frequency separation in a gas turbine engine, the system comprising:
 a compressor;   a combustor in communication with the compressor, the combustor comprising a convective time;   a turbine in communication with the compressor and the combustor, the turbine comprising a hot gas path component; and   a computer controller in communication with at least one of the compressor, the combustor, or the turbine, the computer controller being configured to modify a compressor discharge temperature to separate a combustion dynamic frequency from a hot gas path component natural frequency and change the convective time of the combustor.   
     
     
         2 . The system of  claim 1 , further comprising at least one dynamic pressure sensor associated with the combustor and configured to monitor the combustion dynamic frequency. 
     
     
         3 . The system of  claim 1 , further comprising at least one temperature sensor associated with a compressor discharge and configured to monitor the compressor discharge temperature. 
     
     
         4 . The system of  claim 1 , further comprising one or more inlet guide vanes associated with the compressor, wherein the computer controller is configured to adjust the one or more inlet guide vanes to modify the compressor discharge temperature. 
     
     
         5 . The system of  claim 1 , wherein the computer controller is configured to adjust a temperature of air entering the compressor to modify the compressor discharge temperature. 
     
     
         6 . The system of  claim 1 , wherein the hot gas path component natural frequency comprises a single frequency or a range of frequencies. 
     
     
         7 . The system of  claim 1 , wherein the hot gas path component comprises a turbine bucket. 
     
     
         8 . The system of  claim 1 , wherein the combustion dynamic frequency comprises a single frequency or a range of frequencies. 
     
     
         9 . A system for frequency separation, comprising:
 a gas turbine engine comprising a compressor, a combustor in fluid communication with the compressor, and a turbine in fluid communication with the combustor, wherein the combustor comprises a convective time, and the turbine comprises a hot gas path component having a natural frequency; and   a computer controller in communication with the gas turbine engine, the computer controller comprising:
 at least one memory that stores computer-executable instructions; 
 at least one processor configured to access the at least one memory, wherein the at least one processor is configured to execute the computer-executable instructions to: 
 determine the natural frequency of the hot gas path component; 
 determine a combustion dynamic frequency; and 
 modify a compressor discharge temperature to separate the combustion dynamic frequency from the natural frequency of the hot gas path component and to change the convective time of the combustor. 
   
     
     
         10 . The system of  claim 9 , further comprising:
 at least one dynamic pressure sensor associated with the combustor and configured to monitor the combustion dynamic frequency; and   at least one temperature sensor associated with the compressor and configured to monitor the compressor discharge temperature.   
     
     
         11 . The system of  claim 9 , further comprising one or more inlet guide vanes associated with the compressor, wherein the computer controller is configured to adjust the one or more inlet guide vanes to modify the compressor discharge temperature. 
     
     
         12 . The system of  claim 9 , wherein the computer controller is further configured to adjust the temperature of air entering the compressor to modify the compressor discharge temperature. 
     
     
         13 . A method for frequency separation in a gas turbine engine having a compressor, a combustor having a convective time, and a turbine, the method comprising:
 determining a natural frequency of a hot gas path component located in the turbine;   determining a combustion dynamic frequency and, optionally, a combustion dynamic amplitude; and   modifying a compressor discharge temperature to separate the combustion dynamic frequency from the natural frequency of the hot gas path component.   
     
     
         14 . The method of  claim 13 , wherein determining the combustion dynamic frequency and, optionally, the combustion dynamic amplitude comprises monitoring the combustor with at least one dynamic pressure sensor. 
     
     
         15 . The method of  claim 13 , further comprising determining the compressor discharge temperature by monitoring the compressor with at least one temperature sensor. 
     
     
         16 . The method of  claim 13 , wherein modifying the compressor discharge temperature comprises adjusting one or more inlet guide vanes of the compressor. 
     
     
         17 . The method of  claim 13 , wherein modifying the compressor discharge temperature comprises adjusting the temperature of air entering the compressor.