颗粒Wadell球形度的测量方法标准的编制

Standard Establishment of Determination Method of Wadell Spherity of Particles

为了编制颗粒Wadell球形度的测量方法标准,采用已知形状和粒径的标准几何体颗粒、已知粒径而未知形状的农作物颗粒,通过测量颗粒的自由沉降速度来测量颗粒Wadell球形度,即当颗粒在层流状态下自由沉降时,颗粒的自由沉降速度与颗粒的形状有关。结果表明:颗粒的自由沉降速度与颗粒形状的关系可由Stokes形状系数与颗粒的Wadell球形度的关联确定;对已知形状和尺寸的标准几何体颗粒,实验验证了Stokes形状系数与Wadell球形度的关系以及Stokes定律;对已知粒径而未知形状的农作物颗粒,测量的Wadell球形度与农作物颗粒的球形度吻合。

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.