Session: 32-04 Low Pressure Turbines 1

Paper Number: 123820

123820 - A Collaborative Framework for Design and Validation of Next-Generation Transonic Low-Pressure Turbines 

In the context of the European EDF project Neumann, Task 4.5 aims to advance low-pressure turbine (LPT) designs for the next-generation of fighter air-breathing engines by developing and validating innovative technologies and design solutions through cutting-edge numerical and experimental methods. The project is led by AvioAero and is based on a collaborative effort by the Von Karman Institute, Morfo, KTH, Dream Innovation and UNIGE.

The first part of the project entails the design of an LPT vane airfoil operated in the low-transonic regime. The vane design is based on conventional literature guidelines and will serve as a baseline against numerically optimized airfoils featuring shock-mitigation technologies for profile loss minimization. This paper presents the design of the baseline case and describes the numerical and experimental methods employed to deeply investigate the flow field physics.

The experimental setup includes a high-speed linear cascade that can be operated at a wide range of inlet turbulence levels (Tu =  5% - 8%) and outlet Mach numbers ( M = 0.8 - 1.3). The test section inlet is equipped for hot-wire anemometry measurements, while a purposely designed multi-hole probe is traversed to measure the aerodynamic flow quantities at the cascade outlet. The central passage airfoils feature arrays of pneumatic pressure taps to evaluate the blade loading and hot films to study the status of the boundary layer. Optical sidewalls enable full-field Schlieren and Background-Oriented Schlieren imagery to study shock patterns within the cascade and unsteady shock-boundary layer interactions. The test section is designed with provision for time-resolved stereo-PIV measurements to cross-validate the cascade velocity field and to quantify the turbulence statistics and transport mechanisms from the inlet to the outlet of the transonic turbine passage.

A detailed planning for high-fidelity flow simulations (LES/DNS) is presented in the second part of the paper. State-of-the-art computational methodologies will be employed along with advanced post-processing techniques including mode decomposition to enhance the understanding of the flow physics, assess the limitations of traditional numerical methods and complement the experimental findings.

The paper elaborates on the best design practices for transonic LPT airfoils, while presenting a purposely designed experimental setup and outlining a comprehensive plan for high-fidelity computational studies.

Presenting Author: Bogdan Cernat von Karman Institute for Fluid Dynamics

Presenting Author Biography: Research Engineer

Authors:

Bogdan Cernat von Karman Institute for Fluid Dynamics
Alexandre Halby von Karman Institute for Fluid Dynamics
Sergio Lavagnoli von Karman Institute for Fluid Dynamics
Filippo Rubechini Morfo Design
Stefano Guidolotti Morfo Design
Ardeshir Hanifi KTH
Mihai Mihaescu KTH
Davide Lengani University of Genova
Francesco Bertini GE Avio Aero