Research on the characteristic of noise and pressure fluctuation in the oil-gas mixing transportation of screw-axial pump

Abstract

In order to study the spiral gas-liquid mixing loss and noise characteristics of the oil-gas mixing transportation of screw-axial pump, with the oil-gas mixing transportation of screw-axial pump as the research object, based on the RNG k–ε psilon internal unsteady flow model to simulate the pump parameter change of gas and liquid delivery information, extract the unsteady gas-liquid transfer information parameters and pressure fluctuation signals, using acoustic software LMS Virtual Lab IBEM indirect boundary element method is used to solve the helical axial multiphase mixture pumps in dipole source caused by noise. The distribution law of pressure field, pressure pulsation and sound pressure level in the pump and outlet of the helical axial flow multiphase flow pump is analyzed. The results show that the gas-liquid mixing in the helical-axial-flow oil-gas mixing pump, from impeller inlet to impeller outlet, is aggravated, the pressure increases and the flow is turbulent. From the inlet of the guide vane to the exit of the guide vane, the bubbles gradually move from the hub to the middle of the runner, then the pressure gradually decreases, and the low voltage area leads to the vortex phenomenon; for the internal pressure fluctuation of helical axial flow type oil-gas mixing pump, the pressure gradient in the static and static interference area between the impeller and the guide blade is large, which is an important area affecting hydraulic performance. The pressure pulsation in the cascade is affected by the blade passing frequency and the mutual interference between the rotor and stator blades. The pressure pulsation maximum value is mainly corresponding to the blade frequency and its doubling frequency, and under the interaction of rotor - stator cascade, the pressure pulsation of the monitoring point near the static and static interface is superimposed, and the main frequency is the blade’s triple leaf frequency. For screw axial flow noise in the oil-gas mixture pumps, screw axial multiphase flow pump hydrodynamic noise exports more than imports, sound pressure level frequency in low frequency band is evident, for impeller pressure impulses and its frequency doubling, after three times the pressure impulses, sound pressure level decline slows, the distribution of sound pressure level along with the increase of flow rate, shows the tendency of increase after decreases first. The research results are of great theoretical value and practical significance for the unsteady turbulent gas-liquid mixed transport, pressure fluctuation and noise characteristics in the oil-gas mixed transport pump.