Influence of fluid viscosity and flow transition over non-linear filtration through porous media

The present study investigates two important though relatively unexplored aspects of non-linear filtration through porous media. The first aspect is the influence of viscosity variation over the coefficients of the governing equations used for modelling non-linear filtration through porous media. Velocity and hydraulic gradient data obtained for a wide range of fluid viscosities (8.03E-07 to 3.72E-05 N/m(2)) were studied. An increase in fluid viscosity resulted in an increased pressure loss through packing which can be quantified using the coefficients of the governing equations. Coefficients of Forchheimer equation represent linearly increasing trend with the kinematic viscosity. On the other hand, coefficient of Wilkins equation represents similar values for different fluid viscosities and remained unaffected by the variation in packing properties. Obtained data were utilized to understand the nature of flow transition in porous media. Behaviour of polynomial and Power-law coefficient with variation in flow velocity were also examined. Critical Reynolds number corresponding to the deviation of flow from Darcy regime varies with the porous packing and was observed to be in the range of 0-100. Coefficients of polynomial (Forchheimer) model were observed to be independent of the range of flow velocity, whereas the Power law coefficients are extremely sensitive to the data.