Adaptive Flow Field Thermal Modeling Techniques for Turbine Rotor-Stator Cavities

Abstract

At preliminary design stages of the turbine discs design process, reducing uncertainty in the thermal prediction of critical parts models is decisive to bid a competitive technology in the aerospace industry. This paper describes a novel approach to develop adaptive thermal modeling methods for non-gaspath turbine components. The proposed techniques allow automated scaling of disc cavities during preliminary design assessment of turbine architectures. The research undertaken in this work begins with an overview of the past investigations on the flow field in cavities of the air system surrounding the turbine discs. A theoretical approach is followed to identify the impact of the design geometry and operation parameters of a simplistic rotor-stator cavity, with special focus on swirl and windage effects. Then, a parametric CFD process is set up to conduct sensitivity analysis of the flow field properties. The CFD sensitivity analysis confirmed the parameter influences concluded from the theoretical study. The findings from the CFD automated studies are used to enhance the boundary conditions of a thermal FE-model of an actual high pressure turbine. The new set of thermal boundary conditions adapts the flow field to changes in the cavity parameters. It was found that the deviation to experimental data of the traditional preliminary modeling technique is about 4 times higher as the deviation of the CFD-enhanced technique. When running the FE-model through a transient cycle, the results from the CFD-enhanced method are significantly closer to the test data than those from the traditional method, which suggests there is high potential for using these adaptive thermal techniques during turbine preliminary design stages.

Whole Engine Thermal Analysis for Calculation of Clearances in a Heavy-Duty Gas Turbine

“…The models are restricted to the range of data being measured and therefore not adaptable to new conditions. Optimization of individual components has been carried out in some investigations based on coupled thermo-structural studies (Toal et al, 2008) and (Rey Villazón et al, 2013). Recently, integrated approaches are being used in order to attack the problem of thermo-mechanical modelling with more sophisticated boundaries (Contreras et al, 2011) and(Peschiulli et al, 2009).…”