共查询到20条相似文献,搜索用时 812 毫秒
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利用计算流体动力学软件FLUENT对旋风分离器内气固两相流动特性进行三维数值模拟,模拟气相流场采用雷诺应力模型,应用随机轨道模型模拟湍流流场中颗粒的运动轨迹,同时给出了不同抽气率下旋风分离器的速度、压力分布,计算出旋风器分级效率,模拟结果与文献实验数据吻合较好.结果表明,灰斗抽气可以提高锥体内旋转气流切向速度,轴向速度减少能够降低气流携带颗粒返混能力,并减小排气芯管下口短路流,提高旋风分离器分离效率.对于给定的旋风分离器,抽气率应有一最优值. 相似文献
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在研究发现旋风分离器减阻杆的基础上,研究了减阻杆对流场的影响,发现了减阻杆使切向速度分布趋于平缓、轴向速度上升峰值内移、径向上压力梯度减小、轴向上中心区从逆压梯度变为顺压梯度等重要规律,从而为分析旋风分离器减阻杆的减阻机理提供了依据。同时本文还首次发现旋风分离器入口附近有近24%的短路流量,提出设法减小这部分短路流量是提高分离效率的一个研究方向。 相似文献
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不同侧向入口旋风分离器流场数值分析 总被引:2,自引:0,他引:2
利用雷诺应力模型(RSM)对直切单入口、直切双入口、斜切单入口、斜切双入口、斜切螺旋面单入口、斜切螺旋面双入口6种不同侧向入口旋风分离器内部气相流场进行了计算分析。结果表明:双入口结构旋风分离器内部压力场和速度场具有更好的对称性与稳定性;仅改变入口斜切角度对旋风分离器内部速度场和压力场的分布影响不大;当本文中6种分离器内部具有相近的切向速度径向分布时,斜切螺旋面入口结构分离器压力损失减少约25%,入口所需总压降低17%,处理相同气体量的能耗约下降17%;斜切螺旋面双入口(XS-L型)分离器是一种综合性能比较优的旋风分离器。 相似文献
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旋风分离器减阻杆对流场的影响 总被引:1,自引:0,他引:1
在研究发现旋风分离器减阻杆的基础上,研究了减阻杆对流场的影响,发现了减阻杆使切向速度分布趋于平缓,轴向速度上升峰值内移,径向上压力梯度减小,轴处中心区从逆压梯度变为顺压梯度等重要规律,从而为分析旋风分离器减振阻杆的减阻机理提供了依据。同时本文还首次发现旋风分离器入口附近有近24%的短路流量,提出设法减小这部位短流流量是提高分离效率的一个研究方向。 相似文献
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Shuangcheng Fu Faqi Zhou Guogang Sun Huixin Yuan Jie Zhu 《Advanced Powder Technology》2021,32(3):931-939
This paper presents an experimental and numerical study on an industrial large-scale tangential-inlet cyclone separator with a novel and easy-to-implement vortex finder. The vortex finder was designed with slots on the side wall to improve cyclone performance. The collection efficiency, pressure drop, and interior flow field were analyzed. The proposed device provides an effective gas flow pathway and a coupled swirl-inertia separation mechanism, which eliminates short circuit flows under the bottom inlet of the slotted vortex finder to reduce the swirling intensity and minimize the flow instability in the separator. The pressure drop was reduced up to 27.9% compared to the conventional separator and the maximal increase in collection efficiency was 5.45%. The results presented here may provide a workable reference regarding the effects of vortex finders on improving flow fields and corresponding performance in industrial large-scale cyclone separators. 相似文献
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采用数值模拟方法,结合试验与理论分析,研究Shell型导叶式旋风管内短路流颗粒夹带问题。结果表明:Shell型旋风管直筒芯管下口存在短路流现象,计算得知短路流量占进口总流量的39.3%。理论分析发现,短路流主要夹带粒径小于9μm的颗粒,短路流夹带颗粒临界粒径为9μm。另外,数值模拟跟踪颗粒逃逸的轨迹证明,Shell型旋风管能将粒径大于9μm的颗粒全部除尽;粒径小于9μm的颗粒既有经排尘口返混逃逸,又有短路流夹带逃逸,其中短路流夹带逃逸占主要部分,且随着粒径的增加,经芯管下口短路夹带逃逸的数目减小。 相似文献
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In this study, aerocyclone separators, with five different vortex finder diameters are simulated using commercially available computational fluid dynamics code Fluent 6.3.26 to analyze flow field pattern and the collection efficiency. It is found that a decrease in vortex finder diameter results in an increase in pressure drop by 47.84% and an increase in the collection efficiency by 9.54%, whereas, the increase in vortex finder diameter leads to a reduction in pressure drop by 23.87% and a decrease in the collection efficiency by 7.70% as compared to the Stairmand high efficiency cyclone. It is also observed that a decrease in vortex finder diameter leads to about 33% increase in axial velocity and about 25% increase in tangential velocity, whereas, an increase in vortex finder diameter results in about 23% decrease in axial velocity and about 12% decrease in tangential velocity as compared to the Stairmand high efficiency cyclone. 相似文献
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Shuyan Wang Haolong Li Ruichen Wang Xu Wang Ruichao Tian Qiji Sun 《Advanced Powder Technology》2019,30(2):227-239
Hydrodynamic characteristics in a cyclone separator are simulated by means of DEM-CFD. Reynolds stress turbulence model (RSM) is used to capture gas turbulence. By changing the inlet angle, the distributions of pressure drop, tangential and axial velocity of gas phase are obtained within the cyclone. Simulated results indicate that the flow pattern consists of two regions: loss-free vortex region and forced vortex region. The negative inlet angle brings about a larger pressure drop comparing to positive inlet angle. The separation efficiency and trajectory of particles from simulation are obtained. The effects of inlet angle and particle size on separation efficiency are quantified. The separation efficiency is increased with an increase of particle size, while the separation efficiency firstly increases and then declined as inlet angle changes from negative to positive. An agreement between the numerical simulation and experimental results has been achieved in a cyclone separator. 相似文献
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Faqi Zhou Guogang Sun Xiaopeng Han Yong Zhang Wenqun Bi 《Advanced Powder Technology》2018,29(12):3394-3403
This paper presents an experimental and numerical study on a tangential inlet cyclone separator with a spiral guide vane which is not often researched. Numerical pressure drop results were in close agreement with the experimental data. The spiral guide vane was also found to considerably influence the velocity distribution, turbulence intensity, pressure drop and collection efficiency in the cyclone. A critical value of spiral guide vane turns appeared below or above which there was a marked increase in collection efficiency, pressure drop, and tangential velocity. Compared to a cyclone with zero spiral guide vane turn, the maximal decrease in collection efficiency in the cyclone with the critical spiral guide vane turns (one turn) was 2% approximately. The maximum-efficiency inlet velocity appeared to exist independent of spiral guide vane turns, as inlet velocity affected the radial distance traveled by the rebounded particles from the inner wall. The analysis of flow field in cyclones indicated that the flow field was improved with the spiral guide vanes employed to some extent. The results presented here may provide a workable reference for the effects of spiral guide vanes on the flow field and corresponding performance in cyclone separators. 相似文献
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Jianping Zhang Zhenting Zha Peng Che Honglei Ding Weiguo Pan 《Particulate Science and Technology》2019,37(6):665-672
Aiming at improving collection efficiency in the cyclone separator, the effects of inlet height and velocity on tangential velocity, static pressure and collection efficiency were studied. A three-dimensional model including gas-flow, and particle-dynamics fields was built by the Reynolds stress turbulence model, and the numerical simulation was achieved using the FLUENT software. The static pressure distribution, tangential velocity distribution, and particle trajectory of the cyclone were obtained, and the variation law of the collection efficiency with inlet height and velocity as well as particle diameter was analyzed. Numerical results indicate that both the static pressure and the tangential velocity in the cyclone basically present the axial symmetrical distribution, the static pressure shows a nonlinear increasing trend in the radius direction and the distribution of the tangential velocity is in the shape of a “hump.” The increase of inlet height in a certain range reduces the rotation numbers of particles in the cyclone and shortens the residence time, which results in the improvement of trapping performance. Furthermore, the appropriately increasing inlet velocity in a reasonable range can make the collection efficiency increased. 相似文献
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《Advanced Powder Technology》2020,31(10):4166-4179
This paper presents a study of gas-solid flow in a novel cyclone separator with inner cylinder, compared with that in a conventional cyclone. The Reynolds stress model (RSM) is used to simulate fluid flow, and the discrete phase model (DPM) is selected to describe the motion behavior of particles. The experimental data measured by particle image velocimetry (PIV) is used to verify the reliability of the numerical model. The results show that in the novel cyclone, the cleaned gas can be quickly discharged from the vortex finder, the movement distance and residence time of fine particles are prolonged, the short-circuit flow and vertical vortex under the vortex finder are eliminated, the mutual interference between upflow and downflow in the cylinder is eliminated, and the region of quasi-free vortex in the cone is enlarged. Compared with the conventional cyclone, the novel cyclone has higher collection efficiency and lower pressure drop. 相似文献
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《Advanced Powder Technology》2023,34(9):104149
The main purpose of present study is to comprehensively clarify the impact of cylinder vortex stabilizer on fluctuating turbulence structure of a Stairmand cyclone separator on basis of Large Eddy Simulation. The cylinder vortex stabilizer is easy and could be applied to any existing cyclone model without any major replacement. This novel modification in cyclone body is considered to alleviate the negative effect of entrainment of particles from the ash hopper and swing of the vortex end in swirling flow. The numerical simulations were conducted based on Stairmand cyclone separator and three new models with variation of vortex stabilizer length and diameter. The results showed that the cylinder vortex stabilizer could enhance flow instability and improve fluctuating turbulence structure to some extent. It is confirmed that cylinder vortex stabilizer could significantly reduce the tangential velocity in the inner quasi-forced vortex region of the cyclones. Comparing with Stairmand cyclone, the swirling first and second peak frequency of cyclone model with vortex stabilizer (Length L/D: 6.5, diameter d/D: 0.12) have been confirmed to get considerable reduction of 11.54% and 10.86%, respectively. This modified cyclone model is comparatively better for enhancement of flow stability, providing about 18.4% maximum reduction of normalized flow angle, 24.8% of rotational kinetic energy in dust collector and 14.2% in the main body of cyclone. 相似文献