Experimental analysis of a confined bluff body flow laden with solid particles

An experimental study of the two-phase flow downstream a confined bluff body is presented in this paper. This situation is particularly interesting for the development of gas-solid flow turbulence closures. Measurements are made with a phase Doppler anemometer. Glass beads are added to the inner jet. The initial particle size distribution covers a wide range of size classes from 20 mu m to 110 mu m with a mean value of 60 mu m. The single phase configuration is chosen to establish a stagnation point in the recirculating region. This configuration emphasises the role of the inertia of the particles. This study shows that no local equilibrium with the fluid turbulence can be assumed and that one has to write and solve transport equations for the fluctuating velocity of the particles. In particular, production and transport effects are clearly observed. Contrasted mass-loading ratio of the inner jet ranging from 22 % to 110 % are selected in order to show the two-way coupling between continuous and discrete phases. We show that it has a noticeable effect on the structure of the flow downstream the bluff body and on the spatial distribution of the particulate phase.