New Design Of Slotted Blade Impeller Of Electric Submersible Centrifugal Pump And Analysis Of Gas-Liquid Mixing Performance

At this stage,most of China’s oil fields enter a period of high water and high gas production.As a commonly used oil recovery equipment,electric submersible centrifugal pumps are suitable for high water-containing oil wells,but not for high-gas oil wells.When the traditional electric submersible centrifugal pump delivers gas-liquid two-phase flow,the gas will accumulate in the impeller flow channel.When the gas-liquid ratio is relatively high,air lock may occur,resulting in a drop in pump efficiency or even no work.Therefore,the pumped gas-liquid ratio is less than 10% of the well fluid.In order to improve the mixing performance of the electric submersible centrifugal pump and further broaden its application conditions,this paper designs the slot of the impeller blade of the Q10 electric submersible centrifugal pump,and disconnects the whole blade from the high gas content position to form the injection gap.The external characteristics and internal flow field law of the new electric submersible centrifugal pump when transporting two-phase flow are analyzed,which has important theoretical guiding significance for improving the efficiency of electric submersible centrifugal pump and increasing the output of oil and gas wells in the later stage of oil field exploitation.Taking the Q10 electric submersible centrifugal pump as the research object,the impeller blades are improved.Then,based on the fluid dynamics theory,the fluid domain of the new electric submersible centrifugal pump is established.The ICEM is used for mesh division to determine the fluid dynamics model and calculation method.The CFD fluid simulation software CFX simulates the single-phase flow and the gas-liquid two-phase flow of the prototype and the new electric submersible pump,and compares the external characteristics and internal flow characteristics of the new electric submersible centrifugal pump and the prototype electric submersible pump.Then,simulate the transient distribution of gas volume fraction,pressure field,velocity field and blade load in a variety of gas-bearing conditions and speed conditions,and set multiple monitoring points in the impeller flow channel to observe the variation of gas volume fraction,pressure and velocity in the channel region.By analyzing the simulation results,the following conclusions are obtained: under the design flow condition,the efficiency of the new electric submersible centrifugal pump is increased by 22.2%,and the average load of the impeller blades is reduced by 33.55%compared with the average load of the impeller of the prototype electric submersible centrifugal pump.The gas phase volume fraction of the new electric submersible centrifugalpump is more uniform under different gas content conditions and different speed conditions,and the gas phase volume fraction difference in the whole basin ranges from-0.005 to 0.005.Therefore,there is no serious gas-liquid separation phenomenon and gas accumulation in the flow channel.So,the new electric submersible pump with the slotted blade is more suitable for lifting the fluid with a gas-liquid ratio of more than 30%.The prototype electric submersible centrifugal pump has obvious gas accumulation in the impeller flow channel.The pressure values at the monitoring points in the impeller flow path are periodically oscillated.Under different speed conditions,at the same monitoring point at the same position,as the speed increases,a certain value around this point decreases,but the fluctuation amplitude increases.The speed value at each monitoring point in the impeller flow path of the new electric submersible centrifugal pump fluctuates periodically after 0.05 s.Under different gas content conditions,the velocity change trend of each monitoring point in the impeller flow channel does not change with the increase of the gas phase volume fraction at the same position.In the flow path of the stator,the gas volume fraction distribution,the pressure field distribution,the maximum velocity value,and the intensity of the eddy current phenomenon exhibit a certain periodicity,and the change of the gas phase volume fraction into the fluid only changes its period.In this paper,the impeller blades of the electric submersible centrifugal pump are designed to form the slotted blades.It provides a new idea for the modification of the centrifugal pump,not only limited to changing the number of blades and designing the long and short splitter blades,but also proves that the slotted blades with jetting gap can improve the mixing performance of the electric submersible pump.