Optimization of Kiel geometry for better recovery factor in high temperature measurement in aero gas turbine engine

Abstract

Abstract During gas turbine engine testing, steady-state gas-path stagnation temperatures and pressures are measured in order to calculate the adiabatic efficiencies of the major turbomachinery components. These measurements are carried out using fixed intrusive probes, which are installed at the inlet and outlet of each component. The overall uncertainty in calculated component efficiency depends on the accuracy of discrete point pressure and temperature measurement. High accuracy in measurement and prediction of measurement errors has become increasingly important if small gains in component performance needs to be achieved. The recent trend is to predict component efficiencies within ±1–2%. The present work covers different Kiel designs that have been developed in a response to this demand based on a MATLAB code and experimental evaluation. A parametric study has been carried out by varying the two most critical parameters viz. Ae/Ab ratio and L/D ratio to optimize the Kiel design. These design changes will allow measurements to be made with minimum possible errors and efficiencies to be calculated more accurately over a wider range of conditions inside a low bypass turbofan gas turbine engine.