【摘要】 本文分析了谷粒在垂直气流中的运动规律,并且在实验台上对各种谷粒的空气阻力系数进行了实验研究。测定了当气流与谷粒的相对速度为3～25米/秒时,谷粒空气阻力系数与相对速度之间的关系。空气阻力系数是用间接方法得到的,先用光电的方法测出谷粒在垂直气流中的运动时间,而后利用公式计算出阻力系数的值。共实验了大豆、玉米,高粱、小麦和水稻等五种谷粒。实验表明,当气流和谷粒的相对速度大干6米/秒左右时,阻力系数随相对速度的变化很小,在实验范围内差别不大于10％,即气流对谷粒的作用力大致正比于相对速度的平方。但相对速度小于6米/秒时,随相对速度的降低,阻力系数迅速增加。更多还原

【Abstract】 An analysis showing the motion law followed by grain moving in vertical air flow is developed in this article. Experiments on air drag coefficients of various grain have been carried out on a test bed. The relation between grain air drag coefficients and the relative velocity of grain has been determined when the relative velocity coefficients on air flow and graina ranges 3～25m/sec. The air drag coefficient is established indirectly: first measure out through photoelectronic method the grain moving timeon vertical air flow, then the calculat value of ding coefficient according to formula. Soybean, corn, rice, wheat and sorghum have undergone experiments.The experiment results show that when the relative velocity on air flow is higher than 6m/sec, the drag coefficient varies slowly with the relative velocity, and its difference would be no more than 10％ in mentioned experiment range. However, when the relative velocity is lower than 6 m/sec, the drag coefficient would increase remarkably with the decrease of relative velocity. It means the force exterted by air flow on grain would no longer be proportional to the square of the relative velocity.更多还原