Numerical Simulation Study On The Effect Of Parameter Variation Of Viscoelastic Fene-p Model On Drag Reduction

Adding a small amount of polymer and surfactant fluid additives can realize fluid drag reduction of transport process,improve the efficiency of transport,the phenomenon is called additive drag reduction.The additive drag reduction phenomenon has been widely studied by scholars at home and abroad,and has been made great progress in the long distance oil pipeline transport and centralized heating and cooling cycle applications have a very big potential,because of its huge energy-saving value,since 1948 Toms published the additive drag reduction effect for the first time.Because the additive drag reducing fluid is viscoelastic,it is also called viscoelastic fluid.At present,viscoelastic fluid drag reduction research methods include theoretical research,experimental research and numerical simulation research in the world.However,due to the complexity of the drag reduction mechanism of viscoelastic fluid,the interpretation of the viscoelastic properties and the drag reduction mechanism is still obscure.There is also a lack of research on numerical simulation methods for engineering applications.Therefore,in this paper,based on viscoelastic FENE-P model,compiling UDF,applying CFD fluid calculation software is widely used in the field of FLUENT numerical simulation research.The main research contents of this paper are compared with numerical simulation and physical model test under the same conditions by comparing the experimental results verify the feasibility and accuracy of numerical simulation,and then the various conditions under different parameters are simulated to analyze the effects of viscoelastic FENE-P model parameters on the drag reduction effect,and the mechanism of drag reduction of the further study of viscoelastic fluid.Firstly,this paper introduces the theory of viscoelastic fluids,the main parameters and the constitutive equations and numerical methods.The governing equations of the viscoelastic FENE-P model are computed in terms of the tensor form and in the Cartesian coordinate system,and the FLUENT theory of UDF is described in detail,and a brief description of the FENE-P model in UDF is given.Secondly,the FLUENT software is used to simulate the turbulent flow in a flat plate channel,and the results are compared with the results of the physical model test under the same working condition using the phase Doppler measurement technique.The drag reduction effect,verify the average axial velocity analysis and the existing research results show that the viscoelastic FENE-P model,two times the development of FLUENT software based on the viscoelastic fluid test is scientific,accurate and feasible.Analysis of the results of numerical simulation of Newton fluid water and viscoelastic fluid 120 ppm CTAC surfactant solution postprocessing velocity contour and velocity vector field shows that the turbulent flow of viscoelastic fluid decreases,relative to the flow of water,a decrease in velocity near the wall bursting phenomenon,the turbulence was suppressed to a certain extent,the transverse velocity fluctuation attenuation the streamwise velocity fluctuation decreases slowly,and the vortex structure is stretched in the direction of flow of fluid,display from left to right flow,promote the energy transfer in the axial direction,the drag reduction is realized.Finally,the numerical simulation of 11 kinds of different parameters of viscoelastic fene model is carried out,and the numerical simulation results of four kinds of Weissenberg,four solvent viscosity ratio and four kinds of molecular stretch length are processed.Then,the drag reduction effect,average axial velocity distribution curve and turbulent kinetic energy of different groups are compared.The results show that the drag reduction effect of viscoelastic fluid under different working conditions are less than the maximum drag reduction asymptote proposed by Virk,the average curve of axial velocity of fluid turbulence with Newton laminar flow curve,further verified the simulation results with high reliability.Studying on parameters of viscoelastic FENE-P model about drag reduction effect shows that with the Weissenberg number(We)increases,the elastic viscoelastic fluid increases,enhanced turbulence of viscoelastic fluid in the inhibition effect of drag reduction effect is improved;with the solvent viscosity ratio(?)increases,the viscoelastic fluid turbulence suppression effect is reduced,reducing the effect of friction decreases;the molecular stretch length(L)increases,the coherent structure of reinforced viscoelastic fluid turbulent flow,the drag reduction effect is improved.