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

Abstract This paper presents the design of a transonic low-pressure turbine (LPT) for the next-generation fighter air-breathing engines. The study focuses on the design of a cascade profile representative of an LPT Nozzle Guide Vane (NGV), that follows conventional literature guidelines for transonic turbine airfoils. The paper reports on the numerical and experimental methods that will be employed for a detailed understanding of the flow physics for this baseline solution. 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 = 0.8–1.2). 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 cascade shock patterns 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 quantify the turbulence statistics and transport mechanisms through the transonic LPT passage. A detailed planning for high-fidelity flow simulations (LES and 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.