エアレス噴霧塗装における非 Newton 流体の液膜分裂過程に関する定量解析

抄録

Laboratory experiments on atomization of shear thinning fluids (Xanthan gum solution in water) using airless sprayer were conducted in order to understand the hydrodynamic instability of the liquid sheet, which leads to droplet formation for ship hull coating. Flow visualization by backlight method reveals that the spatio-temporal behavior of the liquid sheet strongly depends on both the fluid rheology (concentration of the xanthan gum) and the spray pressure. The quantitative DFT analysis of the high speed video images shows that the high frequency modes of the liquid sheet instability are viscously damped for the high concentration fluids at low pressure atomization; the collapse distance of the liquid sheet at the spray axis increases with the concentration while it slightly depends on the angle from the axis. Our experimental results provide fruitful information to improve the efficiency and the quality in the spray painting for the ship hull.