Experimental and Numerical Study of Controlled Flutter Testing in a Linear Turbine Blade Cascade

Abstract

In this paper, experimental testing of flutter and numerical simulations using a commercial code ANSYS CFX and an in-house code TRAF are performed on an oscillating linear cascade of turbine blades installed in a subsonic test rig. Bending and torsional motions of the blades are investigated in a travelling wave mode approach. In each numerical approach, a rig geometry model with a different level of complexity is used. Good agreement between the numerical simulations and experiments is achieved using both approaches and benefits and drawbacks of each technique are commented in this paper. It is demonstrated that both used computational techniques are adequate to predict turbine blade flutter. It is concluded that validated numerical tools can provide a better insight of flutter phenomena of operationally flexible steam turbine last stage blades.

Enhanced Flutter Test Rig for a Transonic Flow in a Linear Turbine Blade Cascade and Numerical Data Validation

“…6. All solver setups are defined according to simulations in [12][13][14][15]; the flow field is modelled as viscous and fully turbulent. The ideal gas law is used to describe the thermodynamic properties of the flow.…”

“…One of the major advantages of this setup over the available testing facilities is that coupled bending-torsion modes can be easily achieved [10,11]. Before the test rig enhancement, measurements in the controlled flutter test rig were carried out on subsonic flow field cases, and datasets were exploited for CFD validations [12][13][14][15], where a close match between the experimental data and the numerical results was achieved. In addition, a calculating procedure for a flutter prediction based on the commercial code ANSYS CFX was also developed to be used during the preliminary design phase in Doosan Skoda Power [16].…”