Abstract：To establish a standard of determination method of particle Wadell spherity, standard geometry particles with known size and shape, and crop grains with known size but unknown shape were used, the particle Wadell spherity was determined based on the measurement of particle terminal settling velocity, that is,when a particle settled in laminar regime, particle settling velocity was related to particle shape. The results show that the relationship between particle terminal settling velocity and particle shape can be determined by the relationship between Stokes shape factor and particle Wadell spherity. For standard geometry particles with known size and shape, the relationship between Stokes shape factor and particle Wadell spherity as well as Stakes law are verified.For crop grains with known size but unknown shape, the particle Wadell spherity obtained is coincidence with that of crop grains.

Keywords: particle; Wadell spherity; terminal settling velocity; Stokes shape factor