Study on Acoustic Detection of the Working State of Pulse Detonation Engine.

The experiment system of pulse detonation engine is set up to investigate the acoustic signature of detonation acoustic. The research on detonation acoustic characteristic of pulse detonation engine in three kinds of working states, deflagration stage, detonation stage and external detonation stage, is carried out. Results from the test show that the maximal P_Impact, P_Jet1, τ⁺ and τ_Interval are obtained in external detonation stage. In deflagration stage, the concentrate of PDE acoustic signal energy is obvious. The energy of impulsive rise of impact noise and jet noise is an important part of PDE acoustic in deflagration stage. In detonation stage, a concentration of energy distribution is appeared in low frequency, and the energy of medium-high frequency is decreased. In external detonation stage, energy distribution is more concentrated in low frequency. The value of η₁₁/η₅ can be used to detect the working state of pulse detonation engine. When η₁₁/η₅ is less than 5, pulse detonation engine is in deflagration stage, however, when η₁₁/η₅ is large than 5, pulse detonation engine is in detonation stage or external detonation stage. [ABSTRACT FROM AUTHOR]