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avec la fraction d'huile, tandis qu'il diminue à des vitesses élevées. Comparativement à l'écoulement horizontal, la rétention d'eau est plus élevée et le gradient de pression frictionnel plus bas.

The fluid dynamics in the jet region has been investigated numerically and experimentally by using a gas-solid jetting fluidized-bed cold model. A hydrodynamic model of gas-solid flow characteristics is based on the volume-averaged mass conversion and Navier-Stokes equations. The model was tested in the two-dimensional bed with a central jet and a cone-shaped distributor. The experimental data were obtained from the frame-by-frame analysis of films. The jet penetration height increases with an increase of the jet gas velocity and nozzle diameter. The jet frequency decreases with an increase in the jet gas velocity. Furthermore, a simple model to estimate the initial bubble diameter is presented using the assumption that the gas leakage velocity is equal to the minimum fluidization velocity. It has been verified that the hydrodynamic model shows a good agreement with experimental data, which makes this model a useful tool to study the jet characteristics in gas-solid fluidized beds.