Research On Hydrodynamic Characteristics Of Airfoil Turbine And Performance Of Filter Backwashing

With the in-depth development of oil fields in the direction of refinement,increasingly complex oily wastewater and rising water injection standards pose new challenges to existing water treatment technologies.Existing technologies often fail to meet requirements,and axial dynamic backwash technology emerges as a result.The core of technology is to build a airfoil turbine under the action of backwashing compound field.Turbine characteristics determine the flow field,so studying turbine characteristics is critical to further reveal the backwashing mechanism.By referring to the formation method of the orthogonal straight busbar blades,two types of turbines with straight and twisted blades were constructed.Based on the moment of momentum theorem,considering the velocity slip,the circumferential velocity equation and theoretical head equation were deduced to provide a basis for predicting turbine performance.Turbine efficiency was divided into cascade transmission efficiency and eddy current loss efficiency,and the relationship between the distortion characteristics and hydraulic efficiency was studied.The turbine blade cascade efficiency was 41%~47%,while the curved plate turbine was stable at about 41%.The plate turbine was slightly better,and the twisting characteristics had little effect on the cascade efficiency.Flat turbine cascade efficiency was 41%~47%,while curved plate turbine was stable at about 41%.Flat turbine showed a slight advantage,and the distortion characteristics had little effect on the cascade efficiency.Fluent software was used to simulate two kinds of turbine flow fields,it was found that the velocity and pressure distribution of the curved turbine flow field were evener than those of the flat turbine,and the hydraulic efficiency and eddy current loss efficiency of the curved plate turbine were all higher than those of the flat turbine,which showed that the uniform flow field distribution caused by blade distortion was a key factor in hydraulic efficiency and eddy current loss.The backwashing performance of the three turbines was evaluated based on the value of G.The Fluent software was used to calculate the shaft work and useful work of the three turbines,and the simulation was verified by experiments.Studying the turbine speed gradient based on the simulation data,the results show that airfoil turbine is the most suitable of these three types of turbines.Considering the turbine head comprehensively,the airfoil turbine can generate a local G value of 35-45 times that of the air-water backwashing in the range of 1420r/min to 1810r/min.Taking energy as a bridge,the geometric characteristics of the turbine were analyzed,and the internal relationship between backwash efficiency was studied,which point out the way for future development.