ASSESSMENT OF TWO COMMERCIAL SOFTWARE FOR FELXIBLE FLUTTER PREDICTION IN GAS TURBINE
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
By recent advancement in gas turbine design for smaller, lighter and more powerful engines with higher efficiency and reliable operation in one side and limited material strengths from fatigue point of view on the other side lead to occurring undesirable vibration behavior for high loaded engines in some slim and long mechanical components such as blades; consequently, catastrophic engine failure will caused by distortion in flow. Most challenging excitement is flexible flutter where blades and disk are operating on their natural modes within engine’s operating range and surrounding flow cause to increase or decrease the amplitude of oscillation. Investigation of this phenomenon is covered by aeroelastic instability this requires studying structural and surrounding flow behavior simultaneously.
Parallel to progression of aeroelasticity knowledge and test facilities, numeric computational code developers try to overtake each other for faster and more robust solver in CFD and FE. Behind of all, solution methods are developing in order to make virtual reality closer to actual in less computation time. For instance in FE solvers cyclic symmetric method uses instead of full model simulation and in CFD solvers Frequency-based methods try to fill time-marching method place. On the other side, modeling strategies such as INFluenece Coefficient (INFC) or phase-lagged method in CFD codes are employed to boost the solution determination up.
In this project is tried to simulate flexible flutter with ANSYS Workbench for structural analysis and ANSYS CFX and NUMECA software as CFD solvers. The results of these two software could show capabilities and consistence of each software in steady and unsteady simulation in time-marching method with INFC strategy and Non-Linear Harmonic (NLH) method based on travelling wave mode scheme. In addition, optimum configurations for flexible flutter simulation in both software are provided which include optimum settings for y+ value, turbulence model, and convergence criterion and mesh number for steady simulation and for unsteady analysis, number of periods and passages, time steps, coefficient loops and method of excitation in CFD code is discussed. All conclusions in this research can be useful to opt appropriate software with optimum configurations for aeroelasticity application in future flexible flutter simulations.
Place, publisher, year, edition, pages
2012. , 6 p.
aero/gas turbine, flexible flutter, aeroelasticity, CFD, FE, Non-Linear Harmonic (NLH) Method, ANSYS, NUMECA
Energy Engineering Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-124022OAI: oai:DiVA.org:kth-124022DiVA: diva2:632392
Master of Science - Turbomachinery Aeromechanic University Training
2012-12-13, M263, Brinelvagan 68, Stockholm, 12:30 (English)
Vogt, Damian, Docent
Vogt, Damian, Docent
Results of this project is under confidential rights of FUTURE concersium and is not allowed to published to third-part.2013-06-282013-06-242013-06-28Bibliographically approved