Study On Flow Resistance And Heat Transfer Characteristics Of Non-Newtonian Fluid In Porous Media

The fluid flow in porous medium is a hot topic.Most of the present studies are concerned about the flow of Newtonian fluid in porous medium.However,most of the fluid in nature is non-Newtonian fluid,such as oil exploration,hydrogeology,polymer processing and so on,these problems are related to the flow of non-Newtonian fluid flow through porous medium.The study on the flow and heat transfer characteristics of non-Newtonian fluid in porous medium has a certain effect on the improvement of our life and production level.This paper mainly studies the flow resistance and convection heat transfer process for the non-Newtonian power-law fluid flow through porous media.The numerical simulation of fluid flow is carried out based on the theoretical analysis,the flow and convection heat transfer of power law fluid are studied deeply.The paper introduces the experimental data needed for the numerical simulation.The physical model and mathematical model are established by means of numerical simulation and some basic models are set up.Finally,the simulation results are compared with the experimental results,and the results will be verified by the classical formula.In this paper,CFD is used to simulate the flow of non-Newtonian power-law fluid with finite volume method.The simulation areas are partitioned by structured grids.The boundary conditions of porous media are set up by CFD,and the model is simplified.Some typical features are simplified into simple geometry and flow model,which is consistent with the experimental data.By setting the parameters in the pretreatment process of the numerical simulation,the influence of the rheological properties on the power-law fluid convective heat transfer in porous media with the finite difference method is studied.The paper ansyses the effect of the flow Reynolds number and power-law index n on power-law fluid velocity field,pressure field and temperature field,and obtains the velocity distribution,pressure distribution and friction coefficient;The influence of skeleton structure on the flow resistance of power-law fluid in porous media is studied.The Darcy flow and Forchheimer flow are introduced to analyze the influence of the structural parameters(such as particle,diameter and porosity)on the flow and heat transfer in porous media.It is found that the friction coefficient and the pressure loss decrease with the increase of the power-law index.After a careful study,we can get the point that it is related to the polymer network structure.The solution with high concentration has strong pseudoplastic property,and the stronger the pseudo plasticity of the solution has,the stronger the shear stress of the polymer structure is.For the porous media with different porosity,the friction coefficient of the fluid is different.For the skeleton with large porosity,the pore passage of the polymer solution is larger,so the pressure drop is smaller.The accuracy of the model is verified by comparing the results obtained by numerical simulation with the theoretical values and experimental data.Although there is a certain deviation between the experimental value and the simulated value on the strongly pseudoplastic fluid,it is basically consistent.It can be inferred that the simulation values may not consider the viscoelastic problem.In summary,the simulation value can reflect the flow of power-law fluid in porous media better.