Development of a benchmark for drag correlations of nonspherical particles based on settling experiments of super-ellipsoidal particles

In this study, a series of single-size super-ellipsoidal particles with a wide variety of shapes were generated and 3D printed. Two different drag coefficients (C-D and C-DA) were obtained by simultaneously measuring the windward surface area and the terminal velocity of printed particles in settling experiments. By use of power function, the influence of various shape factors introduced in previous drag correlations was analyzed and a new drag correlation suitable for both spherical and super-ellipsoidal particles was proposed. Comparative study showed that the present model allowed more effective prediction of the drag coefficient than the other 14 models. Furthermore, the approximate calculation formula of C-DA was constructed from C-D. Because the shape factors of super-ellipsoidal particles can be calculated accurately, the obtained experimental results in this work can be used as a benchmark database for calibrating drag correlations of nonspherical particles.