Abstract
In the acoustic fatigue experiment for hypersonic vehicle in simulated
harsh service environment on ground, acoustic loads on the surface of test
pieces of the vehicle need to be measured. However, for the normal
microphones without high temperature resistance ability, the near field
sound measurement cannot be achieved. In this work, on the basis of
previous researches, an acoustic tubes array is designed to achieve the
near field measurement of acoustic loads on the surface of the test piece
in the supersonic airflow with high temperature achieved by coherent jet
oxygen lance. Firstly, the process of designing this acoustic tubes array
is introduced. Secondly, the equality of phase differences at the front
and at the end of the tubes is stated and proved using a phase differences
test with an acoustic tubes array whose design is presented in this text;
therefore, the phase differences of signals acquired by microphones can be
directly applied to beamforming algorithm to determine the acoustic load
source. Finally, using above mentioned acoustic tubes array, measurement
of acoustic load, with and without a test piece in the supersonic airflow
made by the coherent jet oxygen lance, is conducted respectively, and the
measurements results are analyzed.
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