Effect Of Composite Airfoil On Performance Of Helical Axial Flow Gas-liquid Mixed Pump

As national strategic resources,petroleum and natural gas have been favored by the world.The mixed transportation technology of petroleum and gas determines the exploitation,storage and transportation of energy.It has been widely concerned by scholars from all over the world.In this paper,the helical axial flow gas-liquid mixed transport pump was used as the original model for the modified design.Based on the Fluent solver under the Euler multiphase flow model and the SST k-ω turbulence model,the numerical calculation of the calculation domain of the mixed transport pump was carried out,and the accuracy of the numerical calculation method was verified by comparing with the experimental data.By combining the design theory of aviation airfoil and wind airfoil,the design scheme of the composite airfoil of the helical axial flow gas-liquid mixed pump is determined.In order to study the effect of the composite airfoil on the performance of the helical axial flow gas-liquid mixed pump,this paper defines the energy dissipate and the gas aggregate to characterize the dynamic energy loss of the fluid in the impeller channel and the gas phase accumulation state in the channel.The composite position of the new airfoil on the suction surface of the main airfoil was initially obtained.The composite airfoil scheme was obtained by comparing the changes in the external characteristics of the mixed pump in different schemes to determine the composite position of the airfoil.Secondly,the composite airfoil of maximum thickness composite scheme was determined.On the basis of the optimal composite position,by changing the maximum thickness of the composite airfoil.The mathematical equations of the relative thickness about the head coefficient and efficiency of the hybrid pump are established,analyzing the external and internal flow characteristics of the modified hybrid pump,and exploring the maximum thickness of the composite airfoil.The influence of the thickness changing law on the performance of the mixed pump,the final airfoil composite scheme is determined,and the results show that:(1)Comparing the external characteristics of the mixed pump with three kinds of airfoil composite positions,it is found that when the airfoil composite position with different maximum thickness is in the middle of the main airfoil suction surface,the head coefficient and efficiency are the highest,the degree of gas separation in the impeller channel are also improved.By defining the degree of gas aggregation and energy dissipate and combining the internal flow field analysis of the mixed pump,it is concluded that the airfoil has the best effect when compositing in the middle of the suction surface of the main airfoil;(2)The change of the maximum thickness of the composite airfoil makes the external characteristic curve of the hybrid pump as a "hump" characteristic,which is manifested as the head coefficient and efficiency increase first and then decrease with the increase of the maximum thickness of the composite airfoil.When the airfoil composite position is in the middle,the maximum thickness is 1.25 mm and the gas phase volume fraction is 70%,the head coefficient and efficiency of the mixed pump are both at the maximum point and the head coefficient and efficiency compared to the basic model are increased by 2.4% and 1.16%.(3)The gas aggregate area is similar to the turbulent kinetic energy change area.The gas accumulation causes the internal resistance of the fluid in this area to increase and the stability of the fluid decreases.The ratio of mechanical energy change to heat energy in the flow process is increased,which is manifested as turbulent kinetic energy sharply increased.So,we can consider that gas aggregate area leads to the dissipation of fluid kinetic energy and reduces the efficiency of the mixed pump.The innovation of this paper: Combining the design theory of aviation airfoil and fan airfoil,the design method of axial flow pump composite airfoil is proposed for the first time.By adopting the method of impeller airfoil composite new airfoil,the purpose of retrofitting the impeller blade is achieved.The head coefficient and efficiency of the pump determine the influence of the composite position and maximum thickness of the composite airfoil on the performance of the mixed pump;the introduction of energy dissipate to characterize the kinetic energy dissipate of the fluid in the flow channel,and more intuitively describe the mixed pumps’ relationship between internal flow and external characteristics.