Manufacturing and testing of an active compressor blade for aeroelastic studies
Author(s)Sahoo, Debashis, 1976-
Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.
Carlos E.S. Cesnik.
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This thesis deals with the manufacture of a 26-bladed 'active' rotor that will be used for developing an experimental database on turbomachinery aeroservoelastic phenomena, such as flutter and its control. The active rotor has blades made of two stress-bearing composite spars, aerodynamically shaped foam, piezoelectric actuators attached to the spar base and a root which allows the blade to be inserted into the rotor. The thesis analyzed the models developed for the active rotor blade design from previous studies and made suitable refinements in them. The following parameters were obtained - spar dimensions, their location and material, piezoelectric dimensions and material, foam material, and root structure and material. Next, technologies were developed for manufacturing the root and the twisted spar, packaging the piezoelectric actuators using copper-Kapton and bonding them to the spars, and wiring the spars and actuators. However, further investigation is necessary with regards to the issues of foam shaping, spar-foam attachment, and development of accurate leading and trailing edges of the blade. The final step involved testing the blade before and after spar-foam bonding. This required testing on the benchtop to obtain the blade performance limitations, and then testing it in vacuum while spinning inside a spin pit, which was constructed for this purpose. The latter gives the blade performance under rotation. The scope of the thesis is limited to the benchtop tests conducted on the active wired spars. Some of the blade and spin pit wiring issues need to be resolved before conducting the spin tests in vacuum. Also a rotor frame incorporating 26 active blades needs to developed to test under vacuum and in a wind tunnel. The results of the preliminary benchtop tests as well as the blade finite element model predict that the blade performance would be lower than the initial target. Several ways of improving its actuation capability considered were: (a) applying higher voltage with DC offset to the actuators, (b) using multi-wafer actuators, and (c) using active fiber composites. However, these issues need further work. The active rotor, when completed, will serve as a robust tool for aeroservoelastic testing over a significantly larger operating range than is currently possible.
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2000.Also available online at the MIT Theses Online homepage <http://thesis.mit.edu>.Includes bibliographical references (p. 145-146).
DepartmentMassachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.
Massachusetts Institute of Technology
Aeronautics and Astronautics.