METHOD TO EVALUATE SERVICE BOUNDARY CONDITIONS FOR GAS TURBINE STATOR STRUCTURE BY USING INVERSE ANALYSIS

The service conditions and structures of gas turbines are so complex that it is very difficult to determine boundary conditions for thermal-mechanical analyses of these turbines. To improve the accuracy of the analyses, an analytical method for estimating the service boundary conditions for the whole gas turbine stator has been developed. This method consists of FEAs (finite element analyses), a DOE (design of experiments), and measured metal temperatures in an actual gas turbine. The FEAs, with varied boundary conditions, are analyzed using an orthogonal array. In each analysis, the differences between results of an FEA and the measured results are estimated. The model is modified to reduce the difference by using analyses of variance. The method was applied to a 150kW micro gas turbine stator and the good agreement between the analysis results and the measured data confirmed the validity of the method The modified model is applied to the clearance setting and life assessment of the gas turbine.