RANS Simulation Of Dilute Polymer Solution Drag Reduction In Turbulent Pipe Flows

Slickwater fracturing fluid plays an important role in the development of shale gas,lickwater fracturing fluid flow in the fracture pipeline in essence belongs to the turbulent drag reduction in the field of fluid mechanics.At present,numerical simulation research of polymer turbulent drag reduction problem for engineering applications is less,developed suitable RANS methods for engineering analysis of practicality and economy not only has important guiding significance for shale gas fracturing process design hydraulic parameters and crude oil drag reduction in the pipe but also can promote the application and development of turbulence simulation methods.In this paper,by introducing a wall function function to describe the viscoelastic of drag reducing fluid,combined with the effective viscosity model and damping function that reflecting the drag reduction effection,put forward a kind of RANS methods of polymer dilute solution turbulent drag reduction in pipe flow.Using the proposed drag reduction method to simulate pipe flow drag reduction solution and compared with experimental results of LDV,finally analyzes factors which influence drag reduction of polymer dilute solution turbulent in pipe flows.The results show that using Dou Guoren wall function and Li Zhaomin wall function which reflects the characteristics of the drag reduction fluids for simulating dilute polymer solution drag reduction in turbulent pipe flows,the results of simulated are very close with LDV experimental results.Drag reduction parameter D* and drag reduction parameter c increase,friction coefficient decreases,and drag reduction rate increase.The results show that the velocity profile of standard k-epsilon model is flat than drag reduction simulation method,the velocity is less than the drag simulation method.Turbulent kinetic energy of turbulent drag reduction fluid decreases gradually as the distance from the wall,the turbulent kinetic energy of the drag reducing fluid is lower than Newtonian fluid.With the increase of wall function,the simulation results show that friction coefficient decreases,drag reduction effect become better;The increase of ?/?m the lead to the decrease of friction coefficient decreases;Drag reduction rate decreased with the increase of dynamic viscosity;when buffer layer become thicker,the friction coefficient is less,drag reduction rate increases.In this paper,the drag reduction simulation method do a pretty good job of simulating polymer dilute solution pipe turbulent drag reduction phenomenon and flow characteristics under the condition of engineering,provided a reference for flow simulation of slickwater fracturing fluid flow in the pipeline,also has a guiding significance for drag reduction simulation in other types of fluid flow,this method get some economical benefit.