Investigations of gas-powder two phase flow in packed bed

Gas-powder two-phase flow in packed beds was investigated and the results are presented in this paper. The experimental system, in which the glass powder and air gas were injected into the lower part of the packed bed allowed the estimation of the influence of gas velocity, powder feed rate, powder and packed particles diameter on pressure loss and total hold up of powder in the packed bed. On the base of the experimental results, a one-dimensional mathematical model for gas-powder two-phase flow in the packed bed was developed. This model allows satisfactory prediction of the pressure loss and the hold ups of powders. The maximum deviation between calculated and measured values was less than ±15%. Furthermore, the conditions when the blockade of the flow occurs were defined. The additional pressure loss (expressed by F_k) due to the gravitational force of powders and the collision and the friction between powders and packed particles, was correlated with Froude number as: F_k = 1.8462/F_r(2)+74.13/F_r^(0.7309) for the void fraction in the packed bed ε₀ of between 0.36 to 0.41 or F_k = 1.1670/F_r(2)+8181.10 for ε₀ = 0.42.