Transition from quasi-periodic to chaotic pressure pulsations in gas‒liquid multiphase pumps: A nonlinear dynamics perspective

With advancements in computational intelligence, data-driven analysis of model characteristics from vast datasets has become pivotal. This paper focuses on data from gas–liquid multiphase pump simulations, analyzing pressure pulsation dynamics via modal decomposition. Under pure-liquid conditions, pressure pulsation manifests as stretching transport mode and rotor-stator interaction mode, while under gas‒liquid two-phase conditions, it manifests as turbulent mode, stretching mode and transport mode. Due to the influence of gas, leakage vortex contains more energy, which causes the turbulent pulsation of the leakage vortex to emerge as a unique motion mode, which greatly impacts the stable operation. Further, the modal energy is sorted and the trajectory of the three-dimensional nonlinear dynamic system of pressure pulsation is constructed. An analysis of the dynamics of the phase space trajectories, utilizing results from multivariate entropy and multidimensional relational dimension, indicates that the gas phase introduces more multiscale transient events, causing the dynamic system of pressure fluctuations to transition from a quasi-periodic state to a chaotic state. In contrast, pure-liquid conditions constrain the system, showing low-dimensional characteristics, allowing for the establishment of a low-dimensional phase space trajectory model.