Investigation of the State and Transport of Particulate Phases in a Turbulent Tube Flow

Abstract

A comprehensive description of gas-particle flows requires the knowledge of the distribution states of the particulate phase. To determine these distribution states in the first instance, optical methods are suitable, in particular double pulse holography. It yields a maximum amount of information, because as an imaging method it allows the determination of position, size and velocity of each individual particle of a collective simultaneously. The consequence is that the spatial distribution of the particles can be determined, as well as the frequency distributions of all the relevant quantities, such as diameter, velocity, momentum and energy as well as their local dependence and correlation. In the present case double pulse holography was employed to study different gas-particle flows at the outlet of a vertical tube (length 1 m, diameter 50 mm, mean gas velocity 3 m/s, Re = 10000). The dispersed phases consisted of water droplets with a broad size spectrum from 3 to 100 m̈m, and of glass spheres ranging from 20 to 35 μm. The most important results which are discussed in this paper are: 1 the local dependence of concentration, mean size and mean particle velocity, 2 the frequency distributions of particle size and velocity, 3 the distributions of energy and momentum as function of particle size, 4 the correlation of particle velocity with particle size. The results reflect the different behaviour of the two particulate phases used.