Flow Of The Second-order Fluid Having Variable Coefficients In Annulus With The Inner Cylinder Having Annular Solid And Rotating

Under the production condition of screw pump well of polymer flooding, oil well produced liquid with high polymer is viscoelastic fluid. The flow of the produced liquid in the annulus, formed by pump rod and tubing, with the pumping rod having centralizer can be regarded as the flow of the viscoelastic fluid in the annulus with the inner cylinder having annular solid and rotating. It can provide the necessary theoretical basis for the working parameter optimization of the screw pump production well of the polymer flooding engineering in the oil field to study the flow of the viscoelastic fluid in the annulus with the inner cylinder having annular solid and rotating.In this paper, the viscoelastic rheological properties of the produced liquid in screw pump production well are described by the model of the second-order fluid having variable coefficients. The governing equations and the computational formula of the pressure drop and the stability parameter H of the flow of the second-order fluid having variable coefficients in annulus with the rotating inner cylinder having annular solid under the cylindrical coordinate system are established, and the relative numerical solution and calculation methods were given. Taking HPAM aqueous solution for examples, the governing equations and the computational formula of the pressure drop and the stability parameter H of the flow are numerically solved and calculated. The influences of the flow and the geometry parameters of annular solid on the distribution of stream function and velocity and the pressure drop as well as stability parameter H were analyzed.Through the experiments of the flow of HPAM aqueous solution of the mass percentage concentration 0.050%,0.100% and 0.125%, regarded as the second-order fluid having variable coefficients, in the annulus with the inner cylinder having annular solid and rotating, and based on the governing equations, computational formula of the pressure drop and the stability parameter H as well as the corresponding numerical methods established and presented, the values of the pressure drop numerically calculated are compared with those experimentally measured, and the critical maximum value of the stability parameter H of the flow was determined. The results show that the maximum average relative errors between the values of the pressure drop numerically calculated and those experimentally measured were 4.20%, so that the governing equations, the computational formula of the pressure drop and the corresponding numerical methods established and presented in this paper are correct, and the critical maximum value of the stability parameter//of the flow of the second-order fluid having variable coefficients in the annulus with the inner cylinder having annular solid and rotating is 396.3.