Validation of detailed CFD simulation of cascade flutter
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Throughout the years, some of the forces of nature within the gas turbine engines have been hidden due to the great amount of stiffness and low loading airfoils used as design drivers. Nowadays, these design key factors on the airfoils have been changing towards a less rigid and high loading blades to achieve a higher power to weight ratio and improve the performance. These new concepts have stimulated other physics that underlie the blades behavior. One example is flutter, which is a new challenge that engineers are facing today. The phenomenon it is still unclear in many aspects where the need of experimental test is always necessary for a better understanding.
The present work deals with the complex flutter phenomenon in an annular section turbine cascade located at KTH(Royal Institute of Technology). A detailed CFD (Computational Fluid Dynamics) simulation process with Volvo Aero’s software tool, Volsol, is used to understand and validate the results with experimental data taken from the KTH facility.
Four operating points are studied, where two of the cases represent an off-design condition. In addition, two different mesh grids will be used for different approaches. One approach is to compare the steady simulations of these four operating points by using Volsol against Ansys CFX. The other that implies an optimized mesh is to run the steady plus the unsteady aerodynamic simulations. For every case, the solutions of the steady state or mean flow will be taken as initial conditions for the unsteady simulations. The outcome of the latter analyses will be post-processed to address flutter with four different reduced frequencies. Another parameter to contemplate is the orthogonal rigid body modes of the blade, which could be axial, torsional and circumferential. The results from the unsteady are post-processed to obtain the complex unsteady pressure coefficients, the phase lag between the motion and complex unsteady pressures and assess flutter with the stability curve.
Place, publisher, year, edition, pages
2012. , 90 p.
Turbomachinery, cascade, flutter, aeroelasticity, validation, cfd, simulation, stability
IdentifiersURN: urn:nbn:se:kth:diva-106812OAI: oai:DiVA.org:kth-106812DiVA: diva2:574154
Master of Science - Turbomachinery Aeromechanic University Training
2012-11-02, M263, Brinellvägen 68, Stockholm, 13:15 (English)
Vogt, Damian, Dr
Vogt, Damian, Dr