Impinging jet cleaning of tank walls: Effect of jet length, wall curvature and related phenomena

Abstract

The effect of jet length and wall curvature on the flow patterns generated by an impinging water jet were quantified and the effect on cleaning investigated in a brief study. The length of time taken to establish steady flow was characterised. Jet impingement on a flat vertical wall was investigated for jets of diameter 2-4 mm for lengths, L, up to 1 m. The amount of liquid lost to splatter was measured and found to be insensitive to L for short L (< 300 mm for these nozzles) and strongly related to L for longer values. The shape of the radial flow zone on flat walls agreed with existing models once the fraction of liquid lost to splatter was accounted for. Tests on horizontal and vertical cylinders with curvatures in the range 6.9 to 20 m-1 showed that the curvature of the impinged wall did not affect the shape of the radial flow zone until higher flow rates (> 1.5 dm 3 min-1). The cleaning of two viscoplastic model food soils was studied briefly: a hydrophobic petroleum jelly and Carbopol ® , a water-soluble gel. The splatter correction was not able to account for all the differences observed in cleaning at different jet lengths. There was no appreciable effect of curvature on cleaning behaviour. Soaking of the Carbopol ® increased its cleaning rate.

Cleaning insoluble viscoplastic soil layers using static and moving coherent impinging water jets

“…Carbopol, Chee et al, 2018;egg yolk, Yang et al, 2019, Murcek et al, 2019. Layers of uniform thickness 0 were prepared using the spreader tool described by Cuckston et al (2019) on the smaller plates, and using the tool described by Glover et al (2016) on the larger plates.…”

Heat Transfer During Pulsating Liquid Jet Impingement onto a Vertical Wall

“…7b, the wall flow spreads out far beyond the border of the heater. For higher nozzle distances (a higher rate of splattering) or lower Reynolds numbers, the extent of the RFZ reduces considerably (compare, [11,24]). Assume that the mass of water accumulated in the rope is approximately similar for all cases.…”

Heat transfer during pulsating liquid jet impingement onto a vertical wall

“…7b, the wall flow spreads out far beyond the border of the heater. For higher nozzle distances (a higher rate of splattering) or lower Reynolds numbers, the extent of the RFZ reduces considerably (compare, [11,24]).…”