Effect of Particle Concentration on the Pressure Signal of the Oil Pulsation Flow Based on the Wavelet Packet

The turbulence characteristics of the oil pulsation flow may be influenced by the concentration of particles. In this research, an NI PXI data acquisition system is utilized to experimentally analyze the flow pressure signal of the oil pulsation containing various concentrations of particles. To decompose the signal of the oil pressure, a wavelet basis function called sym8 was selected, and a 4-layer decomposition was performed. In this way, the wavelet coefficients of each node can be obtained. By utilizing wavelet packet decomposition, we investigated the impact of varying concentrations of particles on the energy distribution and values of the signal of the oil pressure. The findings indicate that the first three nodes of the signal of the oil pressure, regardless of the concentration of particles, play a significant influence on the signal of the oil pressure frequency band. The Euclidean distance between these nodes ranges from 0.6723 to 1.9786, showing considerable variability. As the concentration of particles increases, the Euclidean distance between these nodes decreases. Moreover, the primary frequency corresponding to nodes with even sequence numbers gradually decreases with increasing concentration of particles, while nodes with odd sequence numbers experience an opposite trend of gradual increase. Additionally, the primary frequency of the signal of the oil pressure gradually decreases with increasing the concentration of particles.