ISBN 9783843956192

978-3-8439-5619-2, Reihe Thermodynamik

Simon Köhler
Experimental Investigation of the Aerothermal Behavior in a Turbine Center Frame

203 Seiten, Dissertation Universität Stuttgart (2025), Softcover, A5

Zusammenfassung / Abstract

The present work is focused on the internal aerothermal behavior of structural engine parts. An experimental investigation of a generic design establishes a comprehensive understanding of the internal flow and heat transfer processes. The modular design features different geometric options, motivated by potential variations of the engine.

To ensure efficient use of coolant, precise knowledge of the internal heat transfer characteristic is obtained by the transient TLC method. However, this method assumes time-independent convective heat transfer, which sets the flow's time-mean and unsteady stability as a prerequisite. Time-mean velocity distributions determined by Particle Image Velocimetry (PIV) reveal an initial view into the complex internal flow dynamics. Moreover, strong fluctuations are determined. To temporally resolve these perturbations, a high-speed PIV approach is applied and a modification to the Spectral Proper Orthogonal Decomposition (SPOD) approach is developed. It reveals stable unsteadiness within the observed flow. Additionally, a multi-TLC experiment exposes congruent heat transfer patterns, which underscores the applicability of the transient TLC method.

In interaction with comprehensive evaluation of the time-mean flow structure, the heat transfer characteristics are disclosed. Three geometries are evaluated at different operating points to gain a comprehensive view onto the flow and heat transfer behavior. Across all geometries, the flow field and heat transfer patterns are shown to be congruent within the observed operating range for each geometry respectively. In detail, the flow structure comprises complex 3D flow paths dominated by interactions of an inlet jet and large-scale vortices. Ultimately, these discussions exhibit valuable information about the flow and heat transfer response to certain geometric variations, which guide future structural turbine part designs.