THE VISUALIZATION OF GAS-ASSISTED INJECTION LONG BUBBLE IN A TUBE

摘要

A long bubble-driven fluid flow in a circular tube is visualized by an optical method. A pressurized airflow was injected into an 8 mm I.D. and 1,500 mm long horizontally placed glass tube filled with silicon oil to produce a long bubble in the tube. The images were analyzed by two-value calculation and a thinning process to extract the contour of the bubble front. Data points on the contour were then deduced to undergo a regression curve fitting. The results show a good verification of the theoretically derived non-dimensional contour equation. The deduced penetration speed indicates that the speed is increasing downstream due to the decreasing fluid slug in the tube. The experimental results shows the theoretical bubble profile can be introduced to the simulation study to reduce the calculating time. The theoretical bubble profile is more precise in a lower λ value than in a higher one.