Conjugate Heat Transfer Calculations on GT Rotor Blade for Industrial Applications: Part II—Improvement of External Flow Modeling

Abstract

Gas turbine design has been characterized over the years by a continuous increase of the maximum cycle temperature, justified by a corresponding increase of cycle efficiency and power output. In such way turbine components heat load management has become a compulsory activity and then, a reliable procedure to evaluate the blades and vanes metal temperatures, is, nowadays, a crucial aspect for a safe components design. This two part work presents a three-dimensional conjugate heat transfer procedure developed in the framework of an internal research project of GE Oil & Gas. The procedure, applied to the first rotor blade of the MS5002E gas turbine, consists in a decoupled analysis in which the internal cooling system was modeled by an in-house one dimensional thermo-fluid network solver, the external heat loads and pressure distribution have been evaluated through 3D CFD and the heat conduction in the solid is carried out through a 3D FEM solution. The second part of this work is focused on the improvement of external heat loads prediction through the use of a full featured geometry of the blade. In particular a detailed representation of the rim seal is accounted for as well as the actual geometry of the squealer tip. A new set of conjugate results is compared with temperature obtained by metallographic analysis, pointing out the relevant effect of the actual endwall contour on the metal temperature distribution at low spans of the blade.