Membrane fouling is a complex phenomenon induced by various chemical or physical factors. Several models can be used in order to predict flux. In this paper, models extracted from the literature are compared with experimental data collected in our laboratory during ultrafiltration of bentonite suspensions for three different cell designs (a classical plane unit and two annular units, one fitted with a tangential inlet inducing a swirling decaying flow, the other generating a pseudo axial flow). Mass transfer coefficients are measured by means of an electrochemical method for the two axial cell designs and are further included in the gel model predicting the limiting ultrafiltration flux. In ultrafiltration, the particles retained by the membrane will accumulate in the immediate vicinity of its surface to form a layer of higher particle concentration involved in the gel model. This concentration is also determined experimentally. Nevertheless. the gel model is not able to predict the permeation flux during ultrafiltration of bentonite suspensions in different cell designs. A modification of the erosion model, which takes into account the cell configuration, is also presented.