Drop coalescence in pipe flows tropfenkoagulation in rohrströmungen

Abstract

The object of the work was to demonstrate clearly the turbulence-dependent coalescence of water droplets in a relatively short pipe section using a modern, high-resolution, non-intrusive light-scattering measuring method. The investigation was carried out excluding condensation processes. The polydisperse droplets were produced by mixing two air streams of different temperature and saturated with water vapor. The effect of drop size and the shape of the drop size distribution on the coalescence was investigated. The deposition of particles which occurred at the pipe inner wall was measured. The measured values were compared with the results of various model calculations, the conservation equations for a drop system being solved numerically. The theoretical simulation of the turbulence-dependent drop coalescence also made allowances for the effects of turbulent cross-mixing and wall deposition of the drops in the pipe.