Modelling the cleaning of viscoplastic layers by impinging coherent turbulent water jets

Comparison of models for predicting cleaning of viscoplastic soil layers by impinging coherent turbulent water jets

“…For the thin layer case, the liquid film is deflected away from the substrate at the cleaning front (see Figure 1(b)), so a momentum-driven cleaning mechanism is expected. The derivation of the momentum-driven cleaning model is summarised here: a detailed account is given by Fernandes and Wilson (2020). The soil layer has initial thickness 𝛿 o .…”

“…Fernandes et al (2019) showed that the ratio of the thickness of the liquid film, ℎ, and of the initial thickness of the soil layer, 𝛿 o , is an important parameter determining the cleaning dynamics for hydrophobic, viscoplastic soils. Fernandes and Wilson (2020) proposed three different scenarios, shown schematically in Figure 1: (a) Very thin soil layers, where 𝛿 o < ℎ. The liquid film flows over the soil layer, promoting shear at the interface between the liquid film and the soil.…”

“…The liquid film is deflected by the soil layer, and removal is governed by the growth of a cleaning front that expands from the impinging point. This scenario was considered by Glover et al (2016), Fernandes et al (2019) and Fernandes and Wilson (2020).…”

“…The first formulation, the shear driven model, is similar to that of Yeckel and Middleman (1987) and considers the progressive relocation and accumulation of soil at a given radial location as a result of a shear driven flow in the soil layer. The second formulation, termed the momentum-driven model extends the approach of Fernandes and Wilson (2020) to consider the effect of a growing berm of dislodged material.…”

Application of a water jet for cleaning grease and improving the surface adhesion properties of galvanized steel wire ropes

“…Köhler et al 17 reported the removal of soil layers from model food by a vertical water jet generated by a solid stream nozzle that moves across a plate, impinging normally on the plate. Fernandes et al 18 presented a first-order model for cleaning thin layers of soil materials based on the rate of viscous dissipation in a shallow wedge of material at the cleaning front. Takeuchi et al 19 cleaned electrostatic accelerator tubes by applying a high-pressure water jet and examined their high-voltage performances.…”