Numerical identification of parameters for a flocculated suspension from concentration measurements during batch centrifugation

Abstract

This paper presents a new mathematical technique for the identification of two rheological model functions (namely, the hindered settling and effective solid stress functions) obtained from concentration profiles measured during the centrifugation of flocculated suspensions. We consider both a rotating tube and a basket centrifuge at a given angular velocity, and assume that the radius (i.e., the distance to the center of rotation) is the only spatial coordinate. The governing equation is a non-standard strongly degenerate parabolic partial differential equation for the solids volume fraction as a function of radius and time whose coefficients involve the model functions. We present a numerical technique for the parameter identification problem suitable for this type of equations, and apply it to determine the model functions in two numerical examples.