ローラ上液膜のリングパターン挙動に関する研究 : 第1報,ニュートン流体による順回転の場合

概要

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When thin films of liquid are produced by roll coaters, it is commonly observed that the liquid film is not uniform but shows either regular or irregular patterns resulting from hydrodynamic instabilities. The appearance of the liquid film has been consiedred to be governed by the flow geometry and dynamics in a nip region between two rolls. This ribbing pattern on the roll is called "ring pattern" in the present paper. Experimental studies are carried out on measuring the ring pattern pitch, the height of the wave and the average liquid film thickness by using two rolls. It is found that the pitch for Ca > 3 does not depend upon the Gapillary number but is constant. The height of the wave increased with the Gapillary number. Simple empirical correlations for the pitch and the wave height of the ring pattern are proposed.
1990-04-25