Experimental study of sedimentation characteristics of spheroidal particles

The drag of non-spherical particles is a basic, important parameter for multi-phase flow. As the first step in research in this area, the terminal velocities, U_t, of hemispherical and spherical segment particles with maximal diameters of 6–21 mm were measured in static fluids by using a high-speed video camera. The drag coefficient, C_D, measured for Reynolds number, Re of 10¹–10⁵, has been obtained and compared with those for a sphere. The Re based on the terminal velocity has a logarithmic linear relationship with Ar number for both the facet facing upwards or downwards for the two experimental spheroidal particles, and their C_D values are greater than those of spheres. A shape function that depends on the initial orientation of the particle facet is presented to correct for the shape effects.