Experimental evaluation and transient simulation of detergent transport in household vertical axis washing machines

Detergent transport between the compartments and through the garments during the washing process in household top-load washing machines is investigated. An experimental methodology was put forward for evaluating the time evolution of the detergent concentration in each compartment, and also in a probe enveloped by a cotton-linen that emulates the garments. The experiments were carried out following a full factorial experiment, pointing out the detergent insertion location and the agitation speed as the rate-determining factors. A lumped transient model was put forward for the convective transport of detergent. The set of ODEs was solved numerically through an adaptive time-step algorithm. The closing parameters required by the model were reduced from the experimental data, thus providing the model with a semi-empirical character. The model predictions for the time evolution of the detergent concentration and the experimental data agreed to within the range of the measurement uncertainties (∼15%).