DEVELOPMENT OF DIAGNOSTIC TOOLS FOR REAL TIME ASSESSMENT OF GAS TURBINE HOT GAS PATH COMPONENT TEMPERATURES. A PRELIMINARY STUDY

摘要

This paper outlines a part of the work under way at GE Oil and Gas -Nuovo Pignone to develop advanced diagnostic tools to evaluate gas turbine hot gas path components life on the basis of actual operating data continuously recorded by remote monitoring systems. The system aims at correlating component metal temperatures and stresses as a function of operating performance data measured through standard machine instrumentation. Monitored data is processed by a new inverse-cycle algorithm to evaluate gas-path temperatures and pressures. The generated gas path information needs then to be correlated to metal temperatures and stresses with precision suitable for input to algorithms evaluating creep, oxidation and hot corrosion Typically, calculations of gas path data to metal temperatures and stresses are performed at the design stage for a limited number of critical operating conditions by using complex and sophisticated CFD and structural/thermal analysis computer codes. For applications to diagnostic, direct use of such tools for any monitored sets of data would be impracticable. On the other hand, they represent the most effective means for assessing hot gas path component temperatures with adequate accuracy, particularly on last generation engines with substantial turbine blade and nozzle cooling. The approach chosen and described herein consists in extensively using high level design tools over a wide range of turbine operating conditions and use the results to produce equations and maps linking field monitored data to component temperatures suitable for easy implementation into a life evaluation system. In the paper major aspects of the above work are reviewed and synthesized, and significant steps in the first application to a turbine first stage cooled blade are illustrated.