Determination of Saturation versus Centrifugal Dewatering for a Multilayer Porous Cotton Textile

Spin drying is the most commonly-used operation for laundry dehydration in domestic washing machines. In past decades, some parameters affecting residual water were investigated and semi-empirical models were given. However, they were only valid for test conditions because of incompatible unit analyses. In this study, a mathematical model with dimensionless numbers was developed by analogy between multilayer porous cotton textile and compressible porous media. Initially, textile porosity determined under compression and dewatering experiments were then determined at different drum speeds, water temperatures, and with test fabrics having various numbers of textile layers. Afterwards, all inputs and outputs were converted to dimensionless numbers, such as saturation ( S) and capillary number ( N _cap ). Finally, the mathematical model, including capillary effects for compressible porous media, was obtained to predict water content after spinning.