| As a forward-looking key technology for the development and utilization of deep-sea oil and gas fields,the mixed transportation of oil and gas has important research significance and value.The strong adaptability of the helical axial flow multiphase mixed pump in harsh environments and the operation stability under high gas content conditions have made its research value widely recognized.Special problems such as liquid separation make the research progress of mixed infusion pump more resistant.In this paper,the YQH-100 helical axial flow oil and gas mixing pump is taken as the research object,aiming at improving its hydraulic performance,and optimizing the design of the structure parameters of the moving impeller of the compression unit of the mixing pump.The influence of the performance of the compression unit of the mixed pump is analyzed,and the variation law of the internal flow characteristics of different design schemes is analyzed.The main research contents and conclusions include:On the basis of the original model design,five axial inclination angle schemes were designed for different directions on both sides of the blade,and numerical simulations were carried out for each scheme under different working conditions.The results show that the blades are inclined to the pressure surface along the axis,the supercharging effect of the moving impeller is reduced,and the efficiency and head of the compression unit are reduced to different degrees.When the blade is inclined to the back direction along the axis,with the change of the inclination angle,the pressurization effect of the compression unit first increases and then weakens,the gas-liquid separation phenomenon on the hub side is gradually improved,and the efficiency and head of the compression unit first increase and then decrease.The optimal inclination angle is around-4°.When the blade is inclined along the axial direction of-4°,the turbulent kinetic energy of the blade inlet area is reduced,and the high gas content area on the hub side is reduced,and the supercharging effect of the moving impeller is better.Obviously,the efficiency of this scheme is increased by 6.26% and the head is increased by 5.88 m under the design flow condition.when the inclination angle continues to increase,the degree of uneven distribution of gas-liquid two-phase in the flow channel increases,and the hydraulic pressure of the compression unit increases.Performance starts to degrade.A design method of adding auxiliary wings to the back of the rotor blade is proposed,and three different placement schemes are designed.The simulation results under different working conditions show that the efficiency of the compression unit after the auxiliary wing is added on the back of the blade is improved under different working conditions,the static pressure value in the flow channel of the moving impeller has a downward trend,and the compression unit under low flow conditions the pressurization effect is poor,and the head has a small drop.The head of the compression unit tends to be stable under medium and large flow conditions,and is higher than the original model under large flow conditions.The optimal conditions of the three schemes have a trend of larger flow condition deviation.the auxiliary wing reduces the degree of gas-liquid separation in the flow channel of the moving impeller,and reduces the degree of gas-phase accumulation on the hub side,but there is still a small-scale gas-liquid separation phenomenon in the flow channels on both sides,and a small amount of gas-phase medium gathers on the back of the auxiliary wing.The changes of turbulent kinetic energy at the impeller inlet of the three schemes are different,and the difference of the placement position of the auxiliary wing has little effect on the external characteristics of the compression unit.Combining the above two design methods,the combination optimization of different design schemes is carried out.Through the comparison and analysis of the numerical simulation calculation results under different conditions,it is concluded that the pressure distribution of the combined optimization model is more uniform,and the hub side in the flow channel of the moving impeller is more uniform.Compared with the original model,the volume fraction of the gas is significantly reduced,the degree of gas-liquid separation is reduced,the vorticity and vortex intensity in the impeller inlet area are relatively reduced,and the flow loss is reduced compared with the original model.The optimized model not only improves the disadvantages of the drop in lift when the auxiliary wing is added alone,but also reduces the flow loss.The efficiency of the compression unit of the mixed pump is further improved,so that the lift and efficiency are significantly improved,and the optimal condition tends to shift to the large flow condition;the overall performance is better than th e original model,which only adopts blade inclination and separate Add a wing effect.Among them,the combined design of the blade axially inclined at-4° and the auxiliary wing added at 1/3 of the height of the back of the blade has the best hydraulic performance.Under the design conditions,its efficiency and head are increased by 11.14% and 27.99%,respectively,compared with the original model.And the efficiency and lift of the optimized model are greatly affected by the axial inclination of the blades,and the shaft power is greatly affected by the ailerons. |
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