Conjugate Heat Transfer Analysis of a Rib-Cooled High-Pressure Turbine Vane under Pulsating Conditions

Numerical simulations play a pivotal role in the development and optimization of turbomachinery components. While experimental methods remain the gold standard for performance and flow analyses, their application is often constrained by factors such as fluid compressibility, elevated temperatures, diversified range of Reynolds numbers, probe intrusion into the flow field, and the difficulty of instrumentation in certain regions of the machine. In light of these limitationsand with the growing availability of computational resourcesthere is a strong incentive to refine computational models and validate their predictions against empirical data, establishing a complementary relationship between the two investigative approaches. High-fidelity simulations, in particular, enable a detailed investigation of fluid dynamic phenomena induced by structural modifications, including in regions inaccessible to direct measurement. This thesis presents a numerical investigation into cooling strategies for a high-pressure turbine vane. The focus is on a first-stage vane subjected to unsteady thermal and pressure loads originating from a Rotating Detonation Combustor (RDC). The study begins with a comprehensive literature review, emphasizing established cooling techniques for high-pressure stator vanes. For the applied component, the selected geometry is a highpressure vane designed at Politecnico di Torino as part of the EnaTech-RDE PRIN 2022 project. This vane, previously optimized for obtainign elevated performances in transonic operation, had been the subject of earlier studies. An unstructured computational grid was created using Ansys Meshing, with targeted refinements in regions of high gradients. This mesh was used for two distinct computational fluid dynamics (CFD) analysis types: the initial phase included a mesh sensitivity study focused on the external flow around the vane. After achieving convergence in the key variables, three Reynolds-Averaged Navier-Stokes (RANS) simulations were conducted using the k −ω SST turbulence model: the first simulation modeled thermal interaction between the main gas path and the vane body and the next two included internal cooling channels, first in a smooth configuration, and then with inclined rib turbulators. A comparative analysis was then conducted between the two internally cooled configurations using the Transitional k − ω SST model with a γ − Reθ transition formulation. This model is particularly effective in capturing separated flow phenomena, such as those occurring between individual cooling ribs. The final stage of the work involved a set of Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations using the same transition model. Results from these were compared against steady-state counterparts to assess the thermal response of the solid domain relative to the transient characteristics of the fluid flow.