Specific features in the transformation of liquid drops during their motion in a gas medium

Using high-speed video cameras (up to 10⁵ frames per second), a cross-correlation measuring system, and panoramic optical tracer visualization methods, some specific features have been revealed in the transformation of drops of liquids widely used in chemical technologies (kerosene, ethanol, water, acetone). The studies were performed for individual drops with characteristic sizes (radii) of 1–3 mm during their motion through a gas medium (air at a temperature of nearly 300 K) at velocities of 0.5–5 m/s. The ranges of change in the aerodynamic resistance coefficients c_d were determined for the studied liquid drops under the considered conditions. The effect of the sizes and velocities of drops on this parameter have been established. Real values of c_d for typical applications were shown to be much greater than for the corresponding droplike shapes.