A model is presented for the dewatering of a saturated two-phase medium in a screw press. The model accounts for the detailed two-phase rheological behaviour of the pressed material and splits the press into two zones, an initial well-mixed constant-pressure region followed by an axial transport region in which the total pressure steadily increases. In this latter region, a slowly varying helical coordinate transformation is introduced to help reduce the dynamics to an annular bi-axial compression of the two-phase medium. Unlike previous modelling, the transition point between the two zones is determined self-consistently, rather than set a priori, and the pressure along the length of the press is deduced from the rheology of the two-phase flow rather than averaging the two-phase dynamics over a cross section of the press. The model is compared to experimental observations of the dewatering of a paper-making fibre suspension and of a clay slurry, and is shown to reproduce operational data.
- Screw press
- Two-phase flow
Eaves, T. S., Paterson, D. T., Hewitt, D. R., Balmforth, N. J., & Martinez, D. M. (2020). Dewatering saturated, networked suspensions with a screw press. Journal of Engineering Mathematics, 120(1). https://doi.org/10.1007/s10665-019-10029-3