Research On Gas-liquid Two-phase Flow Characteristics In Helical-axial Multiphase Pump

Helical-axial Gas-liquid two-phase flow is the most common flow pattern in engineering,According to the gas content and location of the two-phase flow patterns with the development of offshore and onshore oilfield,helical axial flow multiphase flow pump has become a research hotspot with its effective working mode and economic benefit Because of its complex structure types different and properties of the flowing media With the large-scale application of helical axial gas-liquid multiphase pump,the complex gas-liquid two-phase flow inside the pump has gradually become a hot and difficult issue,At this point,research on the Helical-axial flow oil-gas mixed transport pump is no longer limited to optimizing and improving efficiency and performance,and the deeper research is to study Research on Gasliquid two-phase flow characteristics on the Helical-axial Multiphase Pump under different GVF and speeds,and This thesis investigates the following topics,This thesis takes the single-stage Helical-axial flow oil-gas mixed pump jointly researched and designed by the research group as the research object,and uses ANSYS to conduct fluid simulation research on the research object.Among them,the gas-liquid two-phase flow model uses the Euler multiphase flow model,and the turbulence model uses SST6)- model,we have obtained the following:The performance of the multiphase pump has met the design requirements and the analysis of the rated head and efficiency of the Except for the low experimental efficiency at a large flow rate and small flow rate,the other working conditions don't change much,indicating that the hydraulic design has improved compared with the previous design.The Influence of GVF on the Pressure Distribution and the Velocity distribution of the compression stages under different inlet GVF has obtained to the pressure of the pump and Velocity will changes uniformly from the inlet to the outlet.From the first level from the impeller to the fourth-stage impeller,the pressure and velocity of the fluid are gradually increasing.The influence of the different GVF and input speeds on differential pressure,efficiency and input power to satisfy the demand for transmission,certain measuring instruments should be used while the pump is running on the oil field.When the GVF is lower,the differential pressure and efficiency do not decrease;but,when the GVF is higher,they will decline.They will,however,have no effect on the GVF changing when the flows to the termination reach their limit.However,as the GVF increases,the inlet power decreases.The multiphase pump must adjust the speed at any time to cope with the changing GVF to satisfy the outlet pressure demand.Based on the research in this thesis,it lays a foundation for the research group to study the evolution mechanism of the phenomenon of "cavitation and gas plugging" caused by gasliquid separation in the helical-axial flow oil-gas mixed transport pump.