Experimental Study on Pressure Pulsation and Acceleration Response of Fluid Conveying Pipeline Under Multi-Excitation

The fluid conveying pipelines are often subjected to internal fluid fluctuation excitation in the hydraulic pump and external base excitation from the aircraft engine rotor. To investigate the acceleration response of the pipeline and pressure pulsation response of fluid, the vibration tests of the pipeline under base excitation, fluid fluctuation excitation, and multi-excitation are conducted. A set of test bench and test schemes of pipeline system under multi-excitation are designed. The test data are collected by a piezo-electric pressure sensor and a three-direction acceleration sensor. By analyzing the test data, the following results can be obtained: Under base excitation, the internal fluid still has a weak pressure pulsation response even without fluid fluctuation excitation. However, the pressure pulsation response remains unchanged with the increase of base excitation amplitude. Under fluid fluctuation excitation, the amplitudes of vibration responses at fluid fundamental frequency f_p increase with the increase of pump pressure except at 9 MPa and 15 MPa. The natural frequency of the pipeline is close to 3f_p when the pump pressure is 9 MPa and 15 MPa, respectively, and the pipeline system will have resonance. Under multi-excitation, the amplitudes of vibration responses are close to the superimposed amplitudes of two single source excitations at f_b = 175 Hz and f_p = 298 Hz. The vibration responses appear to beat vibration at f_b = 298 Hz and f_p = 297.6 Hz. The relevant test scheme and test data analysis adopted in this paper have important reference values for the in-depth study of pipeline vibration under multi-excitation and engineering practice.