Impact of the flow on an acoustic excitation system for aeroelastic studies
2012 (English)In: Proceedings of the ASME Turbo Expo, 2012, no PARTS A AND B, 1609-1620 p.Conference paper (Refereed)
The flow in turbomachines is highly unsteady. Effects like vortices, flow separation, and shocks are an inevitable part of the turbomachinery flow. Furthermore, high blade aspect ratios, aerodynamically highly loaded and thin profiles increase the blade sensitivity to vibrations. According to the importance of aeroelasticity in turbomachines, new strategies for experimental studies in rotating machines must be developed. A basic requirement for aeroelastic research in rotating machines is to be able to excite the rotor blades in a defined manner. Approaches for active blade excitation in running machines may be piezoelectric elements, magnetism, or acoustics. Contact-free excitation methods are preferred, since additional mistuning is brought into the investigated system otherwise. A very promising method for aeroelastic research is the non-contact acoustic excitation method. In this paper investigations on the influence of an annular cascade flow on the blade vibration, excited by an acoustic excitation system, are presented for the first time. These investigations are carried out at the Aeroelastic Test Rig (AETR) of the Royal Institute of Technology in Stockholm. By varying the excitation angle, the outlet Mach number, and the relative position of the excited blade to the excitation system, the influence of the flow on the acoustic excitation is quantified. The results show that there is a strong dependency of the excited vibration amplitude on the excitation angle if the outlet Mach number is increased, which implies that preferable excitation directions exist. Furthermore, it is shown that a benefit up to 23% in terms of excited vibration amplitude can be reached if the flow velocity is raised.
Place, publisher, year, edition, pages
2012. no PARTS A AND B, 1609-1620 p.
, Proceedings of the ASME Turbo Expo, 7
Acoustic excitation, Excitation methods, Excited vibrations, Experimental studies, Piezoelectric elements, Relative positions, Royal Institute of Technology, Turbomachinery flows, Acoustic wave transmission, Aerodynamics, Aspect ratio, Eddy current testing, Exhibitions, Gas turbines, Mach number, Rotating machinery, Aeroelasticity
IdentifiersURN: urn:nbn:se:kth:diva-129679DOI: 10.1115/GT2012-69966ScopusID: 2-s2.0-84881124277ISBN: 9780791844731OAI: oai:DiVA.org:kth-129679DiVA: diva2:655123
ASME Turbo Expo 2012: Turbine Technical Conference and Exposition, GT 2012; Copenhagen; Denmark
QC 201310102013-10-102013-10-032013-10-10Bibliographically approved