Cold Model Experiment on Fluid Flow Phenomena in Hot Dip Plating Bath.

Abstract

Flow phenomena in a hot dip plating bath were investigated by using cold models with reduced scale of 1/5 and 1/10. The mean velocity components, root-mean-square value of turbulence components and Reynolds shear stress in the bath were measured using a hot-wire anemometer and a two-channel laser Doppler velocimeter (LDV). The flow in the bath had three dimensional components. Main flow induced by belt motion was directed from the entry region to the exit region, and this flow subsequently returned in the entry region along the side walls and the bottom wall. A part of the flow returning along the side walls entered the region enclosed with the belt. The flow in the region enclosed with the belt had also three dimensional components. The flow pattern in the whole bath was in good agreement with that suggested by mean velocity vectors measured with the LDV. Mean velocity components and the root-mean-square value of turbulence components were altogether low in the almost all part of the entry region except near the belt. As the value of Reynolds shear stress was very large in the vicinity of the belt in the exit region, the dross would be vigorously disturbed and dispersed there.