The collisions of droplets and particles at the different initial temperatures

Abstract

This paper presents the experimental research findings of the behavior of water droplets (with the radii from 0.2 to 1 mm) when interacting with metal particles (with the radii from 2 to 4 mm) and substrate (a cylindrical disk with a radius of 30 mm and a height of 10 mm). The initial temperature of the liquid was varied in the range of 20–90 °C, and the initial temperature of metal particles and the substrate ranged from 20 to 250 °C. The conditions for the consistent realization of two regimes of interaction between droplets and particles were determined: agglomeration and stretching separation. Maps of collision regimes were built in a coordinate system that takes into account the influence of inertia forces, surface tension, and the ratio of energies in the collision zone. Conditions under which a rather large and limited number of satellite droplets are formed by collisions were determined. The variables of the collisions of liquid droplets with each other and with solid particles were compared. The conditions under which the regimes are similar or, conversely, have significant differences were identified. Mathematical expressions were formulated to describe the boundaries of transitions between droplet-particle interaction regimes on the respective maps. Differences in the limiting conditions of intense secondary atomization of liquid droplets when they collide with solid particles of various sizes and a massive substrate were determined.