断齿式挤压脱水流道内流场数值模拟

发布时间：2018-04-29 04:08

  本文选题：断齿式螺旋 + 间断距离　； 参考：《农业机械学报》2017年10期

【摘要】：为了探讨在间断距离影响下断齿式螺旋流道的脱水性能,采用双流体模型对断齿螺旋在20、35、50 mm 3种间断距离下的流场进行数值模拟,对比分析了3种结构参数模型下断齿式螺旋脱水装置工作性能、流道内颗粒浓度分布、颗粒速度分布及多孔介质区域内外压差分布情况。研究表明,数值模拟结果能够较为准确地推测断齿式螺旋挤压脱水装置的内部流动特性。50 mm间断距离下断齿式螺旋挤压脱水装置工作效率最大下降了7.9%,20 mm间断距离下出渣口颗粒体积分数下降3.2%;流道内颗粒体积分数变化分3个阶段,整体呈波浪型递增式趋势,间断长度对腔体内部流态影响较大。间断区对颗粒运动具有一定的缓冲作用,间断距离长短能够控制颗粒在腔体内的滞留时间。多孔介质区域内外侧压差在脱水后期增幅最大,相同工况下间断距离越小压差越大。本次模拟计算下最优间断距离为35 mm、出渣口压力为5 000 Pa、转速为50 r/min。该研究可为断齿式螺旋挤压脱水装置的设计提供参考。
[Abstract]:In order to investigate the dewatering performance of broken tooth helical runner under the influence of discontinuous distance, a two-fluid model was used to simulate the flow field of broken tooth helix at three discontinuous distances of 205mm. The working performance, particle concentration distribution, particle velocity distribution and pressure difference distribution inside and outside the porous media region of the helical dewatering device with broken teeth under three structural parameter models were compared and analyzed. Research shows that The numerical simulation results can accurately predict the internal flow characteristics of the broken tooth screw extrusion dehydration device. The working efficiency of the broken tooth screw extrusion dehydration device under the discontinuous distance of 50 mm decreases the maximum working efficiency of the broken tooth screw extrusion dehydration device and decreases the slag outlet at the discontinuous distance of 7.9 mm to 20 mm. The particle volume fraction decreased by 3.2 and the change of particle volume fraction in the channel was divided into three stages. The whole body shows a wave-type increasing trend, and the length of discontinuity has a great influence on the internal flow state of the cavity. The discontinuous region has a certain buffer effect on the particle movement, and the length of the discontinuous distance can control the retention time of the particle in the cavity. The pressure difference between the inner and outer side of porous media is the largest in the later stage of dehydration, and the smaller the discontinuous distance is under the same working condition, the greater the pressure difference is. The optimal discontinuous distance is 35 mm, the slag outlet pressure is 5 000 Paand the rotational speed is 50 r / min. This study can be used as a reference for the design of screw extrusion dehydration device with broken teeth.
【作者单位】： 农业部南京农业机械化研究所;安徽农业大学工学院;
【基金】：农业部公益性行业科研专项(201403019) 江苏省自然科学基金项目(BK20151073)
【分类号】：TH69
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本文编号：1818309