Experimentally determining the sizes of water flow droplets entrained by high-temperature gases

Abstract

Regularities pertinent to counter mixing of the flows of high-temperature (1000 K) gases and water (with the characteristic droplet sizes from 0.05 to 0.5 mm) are experimentally investigated using high-speed (105 snapshots per second) cross-correlation video recording equipment and panoramic optic digital “tracer” visualization methods (called the Particle Image Velocimetry and Interferometric Particle Imaging techniiques). The sizes of droplets entrained by high-temperature gases and their motion velocities acquired after having been mixed with gases (with the gas motion velocities varied in the range of 0.1–2.5 m/s) are established. The initial droplet motion velocities were varied from 0.5 to 5.0 m/s. Two characteristic water droplet motion modes in the counter flow of high-temperature gases under the conditions of intense phase transformations were established. It is demonstrated that the droplet motion pattern in the counter flow of high-temperature gases, as well as the droplet evaporation intensity depend in the main on the initial sizes of liquid droplets. The integral dependence Redr = f(Reg) using which it is possible to predict the droplet motion modes and trajectories, as well as phase transformation intensity with the a priori known droplet sizes and steam-droplet and gas flow velocities is obtained.