Welcome to the von Karman Institute for Fluid Dynamics Store

Detailed Numerical Characterization of the Separation-Induced Transition, Including Bursting, in a Low-Pressure Turbine Environment

Be the first to review this product

Availability: In stock

€25.00
OR

Quick Overview

VKI PHDT 2014-01, Jason Babajee, Simulation, Detailed Numerical Characterization of the Separation-Induced Transition, Including Bursting, in a Low-Pressure Turbine Environment, ISBN 978-2-87516-068-3, 219 pgs

Detailed Numerical Characterization of the Separation-Induced Transition, Including Bursting, in a Low-Pressure Turbine Environment

Double click on above image to view full picture

Zoom Out
Zoom In

More Views

  • Detailed Numerical Characterization of the Separation-Induced Transition, Including Bursting, in a Low-Pressure Turbine Environment

Details

Detailed Numerical Characterization of the Separation-Induced Transition, Including Bursting, in a Low-Pressure Turbine Environment  
By Jason Babajee

PhD Thesis from the von Karman Institute/Ecole Centrale de Lyon, November2013, ISBN 978-2-87516-068-3, 219 pgs


Abstract

The Low-Pressure Turbine is a critical component of an Aero-Engine as it drives the Fan which produces most of the thrust in the current turbofan configuration. In order to increase the efficiency in terms of fuel consumption, there is a continuous research for blade count reduction (i.e. mass reduction) which entails a higher loading per rotor blade. It is well-known that this environment is characterised by a low Reynolds number flow condition associated with high diffusion along the aft region of the suction side. Consequently, the flow along this surface is prone to laminar separation which, depending on the status of the separation bubble, would lead to detrimental decrease in the aerodynamic performance (larger and deeper wake).

The present PhD thesis focuses on the investigation of the separation-induced transition phenomenon occurring in a Low-Pressure Turbine environment. The emphasis is put on the numerical predictions based on a CFD RANS approach using the innovative transition model based on transport equations for the numerical intermittency (γ) and the transition onset momentum thickness Reynolds number. Nine Low-Pressure Turbine rotor blades form a compre- hensive experimental reference database and cover a significant range of different isentropic outlet Reynolds numbers, isentropic outlet Mach numbers, inlet turbu- lence intensity levels, with or without incoming wakes and with two local roughness configurations. A first analysis of this database stresses the effect of the separa- tion on the transition onset and on the performance. A correlation definition is attempted and allows to link the diffusion rate of a blade to the isentropic outlet Reynolds number at bursting. A reliable and robust numerical methodology is established to predict the transition in the case of uniform upstream flow. The results are in good agreement with the experiments even though it was necessary to adapt the boundary conditions to predict the laminar separation numerically for highly-loaded and strong diffusion rate blades only. The resolution of the boundary layer velocity profiles allows to have an in-depth examination of the flow topology parameters. This gives proper information on the momentum thickness which is the main driving parameter of transition correlations. The Chimera technique for overlapping meshes is used to ease the modelling of passive control devices to trigger transition. It is a decent technique to implement standard geometries or more elaborate designs.

Additional Information

Manufacturer von Karman Institute for Fluid Dynamics

Product Tags

Use spaces to separate tags. Use single quotes (') for phrases.