摘要
红枣悬浮速度是气力式收获、输送和清选除杂等装置设计与研究方面重要的物料特性参数,是风机选型与气力机械结构优化改进的理论依据。本文利用自制悬浮速度测定装置试验台,测定红枣在不同含水率及粒径下的悬浮速度数值,探究悬浮速度与两者之间变化关系,并获得气流速度下红枣悬浮高度变化范围,得出其悬浮的最佳气流速度。试验结果表明:红枣含水率在47.39%~72.35%变化时,其悬浮速度范围在27.13~34.28 m/s;红枣粒径在25.59~36.69 mm变化时,其悬浮速度范围在31.15~34.04 m/s,悬浮速度变化都呈上升趋势;响应面分析可知,相同含水率下,红枣悬浮速度数值随着粒径的增加而变大,当粒径确定时,随着含水率增加悬浮速度数值逐渐增加,但增加程度较小,可知红枣粒径变化对悬浮速度影响较大,含水率变化对悬浮速度影响较小;当含水率确定、气流速度在32 m/s时,不同粒径红枣,在锥管内不同高度悬浮,出现粒径较大在上端,粒径较小在下端的分层现象;对悬浮速度理论公式中形状修正系数进行计算,当红枣含水率72.35%、粒径25.59~36.69 mm时,其形状修正系数S在0.565~0.679之间。该试验测定结果为红枣气力式收获或分选等装置设计与研制提供理论依据。
The suspension speed of jujube is an important material characteristic parameter in the design and research of pneumatic harvesting,conveying,cleaning and impurity removal devices.It is also the theoretical basis for fan selection and optimization of pneumatic mechanical structure.In this paper,the suspension speed of jujube under different water content and particle size was measured by using the self-made suspension speed test-bed,and the relationship between the suspension speed and the two was explored.The range of suspension height under the air speed was obtained,and the best suspension speed was obtained.The results showed that when the moisture content of jujube varied from 47.39%to 72.35%,its suspension speed ranged from 27.13 to 34.28 m/s.When the particle size of jujube varied from 25.59 to 36.69 mm,its suspension speed ranged from 31.15 to 34.04 m/s,the influence was on the rise.The analysis of response surface showed that under the same moisture content,the suspension speed value of jujube increased with the increase of particle size.When the particle size was determined,the suspension speed value increased with the increase of moisture content,but the increase degree was small.It could be seen that the change of particle size of jujube had a greater impact on the suspension speed,and the change of moisture content had a smaller impact on the suspension speed.When the moisture content was determined,when the air velocity was 32 m/s,jujube with different particle size was suspended in different height in the cone tube,and the phenomenon that the larger particle size was at the upper end,and the smaller particle size was at the lower end was layered.The shape correction coefficient in the theoretical formula of suspension velocity was modified,when the moisture content of jujube was 72.35%,and the particle size was 25.59~36.69 mm,the shape correction coefficients was between 0.565~0.679.The test results provide theoretical basis for the design and development of the pneumatic harvesting or sorting device of jujube.
作者
于福锋
李平
张凤奎
李忠杰
张宏
范修文
Yu Fufeng;Li Ping;Zhang Fengkui;Li Zhongjie;Zhang Hong;Fan Xiuwen(College of Mechanical and Electrical Engineering,Tarim University,Alar,843300,China;Key Laboratory of Modern Agricultural Engineering in Colleges and Universities of Xinjiang Uighur Autonomous Region,Alar,843300,China)
出处
《中国农机化学报》
北大核心
2020年第6期99-105,共7页
Journal of Chinese Agricultural Mechanization
基金
国家重点研发计划项目(2016YFD0701504)
塔里木大学研究生科研创新项目(TDGRI201803)。
关键词
红枣
悬浮速度
物料特性
气力输送
测定分析
修正系数
red jujube
suspension velocity
material characteristics
pneumatic conveying
measurement analysis
correction factor
