Virtual Robustness Evaluation of Turbine Structure Assemblies Using 3D Scanner Data

In this paper, the functional robustness of a jet engine component is investigated. Located at the rear part of the engine, the Turbine Rear Structure (TRS) provides a support structure for the low-pressure shaft, while redirecting the exhaust flow from the low-pressure turbine to the exit nozzle. For larger engines, TRSs are fabricated assemblies consisting of cast, wrought and sheet metal parts. In a case study, virtual tools are used to examine how geometrical variation in cast parts of the TRS assembly affects performance. Variation data are obtained by scanning cast parts in a 3D laser scanner. The resulting data are fed into a CAD model as surface point parameters. The parts are then assembled virtually using CAT software. The assemblies are subsequently fed into a simulation platform where they are meshed, and CFD and FEM are used to evaluate the structural and aerodynamic effects of the variation. To quantitatively analyze the effects of variation, five cast parts with different geometrical variations are virtually assembled into 25 geometries and analyzed with respect to sixteen functional properties. Results show that geometric variation has a noticeable effect on performance. We believe this approach to be a useful tool in engine design. Being able to virtually examine the geometrical robustness of a design in early phases reduces the need for redesign loops. This leads not only to faster and less expensive product development, but also to better and more reliable engine designs.