Gaseous fluidization of short fibers and powders, influence of temperature and pressure

[Display omitted] •Fluidization of a mixture of short fibers and SiC powder.•Calculation of the minimum fluidization velocity (Umf) for rarefied/laminar flows.•Validation of the calculated Umf values by measurements at various pressures and temperatures.•Optimization of the fluidization conditions for a short fiber/powder mixture.•PyC ex-ethanol CVD coating deposition on short fiber/powder mixtures. The fluidization of short Hi Nicalon S fibers was investigated before considering CVD coatings with controlled composition and thicknesses. The fluidization of a short fiber batch alone being delicate and not reproducible, the study consisted in comparing the hydrodynamic behavior of a powder alone, to that of a short fiber/powder mixture. The fluidization behavior of the particle beds was studied by following their pressure drop as a function of pressure and temperature. The minimum fluidization velocity (Umf) was evaluated at room temperature (Tamb) at different reduced pressures, and at 200 mbar as a function of temperature. The results are in good agreement with the theoretical equations. At low pressures and Tamb, Umf increases rapidly. In contrast, Umf varies only slightly with temperature. While the pressure does not seem to affect the fluidization behavior of the powder alone, it displays a clear optimum at 200 mbar for the short fiber/powder mixture.