| Due to the exhaustion of onshore oil resources,the exploitation of resources has been extended to the depths of the sea.The multi-phase mixed transport technology with gas-liquid mixed transport pump as the key equipment has saved the investment cost to a large extent,so it has been widely concerned by researchers.Gas-liquid mixed transport pump is widely used in the field of petroleum development based on its advantages of high speed,large flow and high applicability to conveying mixed media with different gas rates.In the process of its work,gas-liquid separation is easy to occur and air mass is blocked in the flow channel,resulting in low work efficiency has been concerned by the academic community.Therefore,it is necessary to study such issues.To meet the needs of mixed pump in the oil market.Based on the Euler multiphase flow model and SST k-ω turbulence model,the basic model of the gas-liquid mixed transport pump was numerically calculated with air and water as the mixed medium under different gas content,and the external and internal flow characteristics of the mixed transport pump were analyzed.It is found that gas-liquid separation and gas phase agglomeration are the fundamental reasons for the degradation of the conveying performance of the mixed transport pump.Therefore,the modification scheme of changing blade sweep angle and airfoil attack angle is proposed to explore its influence on the performance of gas-liquid mixed transport pump.The main conclusions are as follows:(1)By comparing the external characteristics of the mixed transport pump with different blade sweep angles,it is found that the transmission performance of the mixed transport pump with blade sweep is better,and the occurrence of gas-liquid separation can be effectively slowed down.(2)Blade sweep can effectively reduce the degree of gas phase agglomeration in the impeller passage and inhibit the formation of vortices at the impeller outlet.The head coefficient,efficiency and the two variables show a quadratic and cubic surface function relationship for different inlet gas content rates and different blade sweep angles,respectively.Under the design flow,compared with the basic model,the head coefficient and efficiency of the mixed-transport pump are the highest when the sweep angle is-25°.When the inlet gas content is 60%,the head coefficient and efficiency increase by 2.93% and 2.94%,respectively.(3)Appropriate airfoil attack angle can reduce the energy dissipation in the impeller runner and improve the hydraulic performance of the mixed pump.Changing the flanking stroke angle of the wheel flange,the head coefficient and the efficiency are quadratic and cubic functions,respectively,between the two variables at different inlet gas content rates.When the flanking angle coefficient of the wheel edge δchanges from-0.214 to 0.214,the head coefficient and efficiency decrease to different degrees,and the highest performance improvement of the hybrid pump is achieved at δ =-0.214,with the head coefficient and efficiency increasing by 6.32%and 2.05%,respectively,compared with the base model.(4)Varying the hub flanking stroke angle,the head coefficients and efficiencies are related to the two variables as cubic and primary functions,respectively,at different inlet gas content rates.When the wheel flanking type stroke angle coefficient δ increases from-0.214 to 0.214,the head coefficient and efficiency both tend to increase,and the hydraulic performance of the hybrid pump improves most significantly when δ =0.214,and the head coefficient and efficiency increase by2.48% and 1.94%,respectively,compared with the base model. |
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