Research On The Influence Of Blade Thickness And Quantity On The Performance Of Multiphase Pump

Crude oil mined in nature is usually a multiphase mixture composed of oil,gas and various impurities.How to efficiently transmit crude oil is an important technology in crude oil mining and processing.Due to the lack of the theoretical basis and effective design method of multiphase fluid motion,the traditional transmission pump has low efficiency and short life in the process of oil and gas multiphase transportation.In recent years,the multiphase mixed transportation technology with oil and gas mixed transportation as the main feature has attracted wide attention.This paper takes a kind of oil and gas multiphase pump as the research object,three-dimensional modeling of the calculation domain of the multiphase pump,uses Fluent flow field analysis software for numerical simulation,and selects the Navier-Stokes equation describing the conservation of the momentum of the viscous incompressible fluid(Abbreviated as N-S equation),Mixture model and SIMPLEC algorithm for velocity and pressure coupling calculation to solve the flow field inside the multiphase transportation pump.The effect of the combination of the blade thickening parameters of the multiphase transportation pump and the number of dynamic and static blades on the fluid motion in the flow channel was systematically studied.By analyzing the external characteristics of the multiphase pump,the pressure distribution on the surface of the dynamic and static blades,the speed distribution of the multiphase pump,and the phase distribution of the meridian surface of the stationary blade,the flow characteristics of the multiphase pump were studied.1.Effect of the blade thickening parameters on the performance of the multiphase pumpThe geometric parameter ? of the static vane of the multiphase transportpump is defined to represent the thickness of the static vane.Under the conditions of different gas content,the internal pressure distribution,velocity distribution and gas phase distribution of the multiphase pump are calculated.The results show that: When the ? value is between 1.0 and 5.0,the boosting and efficiency of the multiphase pump will increase first and then decrease with the static ? value.When ? = 3.5,the multiphase pump has the highest boost and efficiency,respectively 75 kpa and 34.6%,compared with ? = 1.0,the gas phase distribution and velocity distribution of the stationary impeller are more uniform,and the high-pressure area at the tail of the stationary blade moves toward the middle of the blade.As the value of ? increases,the smaller the flow cross section at the tip of the blade,the pressure at the stationary blade increases,the displacement and resistance to the fluid increase,the transport capacity is improved,and the efficiency is higher.However,when the flow area at the tip of the blade is too small,the stationary blade hinders the smooth flow of fluid,causing the multiphase pump to increase pressure and reduce efficiency simultaneously.Under the design conditions,for different values of the static vane ?,the effect of the gas content of the fluid on the boosting and efficiency of the multiphase pump is basically the same,showing a linear decrease,the slope of the straight line is almost equal,and the intercept different.As the gas content increases,the density of the fluid decreases,the pressurization in the pump decreases,and the efficiency decreases.When the gas content of the fluid is 70%,? = 3.5 is more than ? = 1.0,the pressure increase is about 2.9%,and the efficiency is about 1.5%.2.Effect of Dynamic and Static Blade Number Combination on Performance of multiphase PumpUsing the two-factor analysis of variance,the effect of the combination of dynamic and static blade numbers on the performance of the multiphase pump was studied.The pressure increase and efficiency of the multiphase pump under different gas content conditions were calculated.Distribution of gas content.The results show that:The number of stationary blades has asignificant effect on the boosting and efficiency of the multiphase pump,and the number of moving blades has no significant effect on the boosting and efficiency of the multiphase pump.The stationary blade is the main component that converts kinetic energy into pressure energy,and plays a leading role in the fluid transportation efficiency.When the air content is zero,the boost pressure of the multiphase pump at the design flow rate decreases with the increase of the number of stationary blades,and increases with the increase of the number of moving blades.When the air content is zero,the efficiency of the multiphase pump at the design flow rate increases with the increase in the number of stationary blades and decreases with the increase in the number of moving blades.For different combinations of dynamic and static vane numbers,the change law of air content rate on supercharging and efficiency is basically the same.With the increase of air content rate,the pump supercharging and efficiency show a nonlinear monotonous decrease.Under the condition of high gas content,the fluid medium in the flow channel flows complicatedly,and the gas-liquid separation phenomenon is more serious,so that the pressure increase and efficiency are seriously reduced,and finally close to a point.Choosing the proper combination of static vane thickening parameters and the number of dynamic and static vanes has a significant impact on improving the boost pressure and efficiency of the multiphase pump,and has practical significance for the development and design of an efficient multiphase pump.