| The study of grain flow characteristics is practically a problem on gas-solid two phase flow of big particle. At the present stage, two main aspects of gas-solid two phase flow are fluidized bed and pneumatic conveying. Besides, suspending velocity is an important parameter in design of pneumatic conveying. Based on researching grain suspending velocity, this paper studied the grain flow characteristics in vertical tube. Grain particles, filling amount, diameter of conveying tube were the influencing factors in the experiment and the grain flow characteristic in vertical tube was the test indicator. Filling amount was investigated with a single factor and orthogonal experiment. Significances of various factors'impact on suspending velocity were obtained by analysis of variance. Do orthogonal experiment with three kinds of grain particles, the results show that when the test particles are mung bean, filling amount is 600g and diameter of conveying tube is 120mm, the experimental conditions were the most appropriate, to be a companion to minimum suspending velocity of 11.35m/s, in the same conditions, soybean's suspension velocity is 14.10m/s, string bean's suspension velocity is 13.90m/s. By researching on three factors'influence, results indicated that the main parameter of suspending velocity were their own physical properties of grain. The suspending velocity varies directly with the diameter of particles and tubes and it varies inversely with the filling amount. |
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