粉体连续降压排放装置实验研究

发布时间：2018-02-09 03:27

本文关键词： 粉体排料流率压降　出处：《中国科学院大学(中国科学院工程热物理研究所)》2017年硕士论文　论文类型：学位论文

【摘要】：本文在粉体连续排料降压装置上,开展了竖管压降特性研究、筛网压降特性研究以及排料流率实验研究,得到以下结论:1.竖管压降特性实验1)当料仓压力一定时,颗粒移动速度对竖管段压降影响很小,可以忽略,而随着表观气速的增大,竖管段压降呈线性增大;当表观气速一定时,竖管段压降随着料仓压力的升高而增大。2)表观气速Ug0在0～0.2m/s范围内时,空隙率ε基本不随表观颗粒速度Us0和表观气速Ug0变化,而随入口压力Pin的增大而减小。提出了适用于竖管移动床的空隙率-压力拟合计算公式:ε = 0.32+ 0.04067/Pm。通过该拟合公式以及Ergun方程可以较为准确的预测竖管段压降,在本实验范围内,压降预测的最大误差小于20%。2.筛网卸压特性实验1)对于同一种物料,随着筛网排气流量的增大,筛网压降逐渐升高;2)在排气流量一定时,随着颗粒粒径的增大,筛网段压降逐渐降低;3)在料仓压力PA一定的情况下,随着筛网排气量的增大,筛网段压降占总压降的百分比逐渐升高。3.排料流率特性实验1)随着L段入口压力的升高,排料流率先缓慢增大,处于稳定排料状态,当入口压力增大到一定值后,排料流率迅速增大,且L段入口压力会自发下降,进入流动失稳状态。2)对于管径较大的L段弯管而言,其排料启动压力更低,排料流率更大,排料曲线的斜率更大。3)对平均粒径较大的物料而言,其排料过程中的启动压力更低,且在相同入口压力下排料流率更大。
[Abstract]:In this paper, the characteristics of vertical tube pressure drop, sieve net pressure drop characteristic and discharge flow rate are studied on the powder continuous discharge pressure lowering device. The following conclusions are obtained: 1) when the silo pressure is constant, the pressure drop characteristic of vertical tube is tested. The effect of particle moving velocity on the pressure drop of vertical pipe is very small and can be ignored. However, with the increase of apparent gas velocity, the pressure drop of vertical pipe increases linearly, and when the apparent gas velocity is constant, the pressure drop of vertical pipe increases linearly with the increase of apparent gas velocity. The pressure drop of vertical pipe increases with the increase of silo pressure. 2) when the apparent gas velocity (Ug0) is in the range of 0 ~ 0.2 m / s, the porosity 蔚 basically does not change with the apparent particle velocity Us0 and the apparent gas velocity Ug0. However, with the increase of inlet pressure Pin, the porosity pressure fitting formula for vertical tube moving bed is proposed: 蔚 = 0.32 0.04067% Pm. Through this fitting formula and Ergun equation, the vertical pipe pressure drop can be predicted more accurately. The maximum error of pressure drop prediction is less than 20. 2. Experiment 1) for the same material, the pressure drop of the screen increases gradually with the increase of the exhaust flow rate of the screen)) with the increase of the particle size, the pressure drop of the screen increases gradually when the exhaust flow rate is fixed. The pressure drop of sieve mesh section gradually decreases.) under the condition of constant pressure PA of sieve, the percentage of pressure drop of screen net segment to total pressure drop gradually increases with the increase of screen net exhaust volume. Experiment 1) with the increase of inlet pressure of L section, the pressure drop of sieve mesh section increases gradually. When the inlet pressure increases to a certain value, the discharge flow rate increases rapidly, and the inlet pressure of L section will decrease spontaneously, and enter the flow instability state. 2) for the L section elbow with larger diameter, the discharge flow increases slowly and stably, and the discharge rate increases rapidly when the inlet pressure increases to a certain value. The starting pressure is lower, the discharge flow rate is larger, and the slope of discharge curve is larger. 3) for the material with larger average particle size, the starting pressure is lower and the discharge flow rate is larger under the same inlet pressure.
【学位授予单位】：中国科学院大学(中国科学院工程热物理研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ545

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