共查询到18条相似文献,搜索用时 171 毫秒
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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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三维旋转流场特征与压力损失关系的研究 总被引:4,自引:1,他引:3
本文以Stairmand高效旋风分离器为实验模型,利用五孔球形探针测试了典型三维旋转流动的速度和压力分布。并结合减阻杆的研究发现,测试了安装不同类型减阻杆后速度和压力分布的变化,从而在分析减阻杆减阻机理的同时,认识了三维旋转流场特征与压力损失的关系。 相似文献
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旋风分离器减阻杆减阻的PIV实验研究 总被引:2,自引:0,他引:2
采用先进的PIV实验技术对Stairmand型旋风分离器中安装减阻杆前后的强湍流场进行了测量。通过速度场、湍流强度、Reynolds应力等物理量的对比分析,表明减阻杆降低了中心涡核区的旋转动能和湍流强度。对减阻杆减阻机理进行了更深入的探讨。 相似文献
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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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旋风分离器是雾化焙烧制备稀土氧化物工艺中的常用分离设备之一。为了提高焙烧产物中超细颗粒的分离效率,采用Fluent数值模拟和实验验证相结合的方法,得到旋风分离器的优化构型,利用颗粒分离效率和流体压降2项指标进行评价,以探讨扩张结构旋风分离器的优化效果。结果表明:在锥筒高度为距旋风分离器顶板370 mm处,进行角度为10°的扩张改进后,分离器对粒径为1、 3、 5μm的颗粒分离效率分别提高13.25%、 42.33%、 44.02%,阻力系数减小3.6%;新改进结构旋风分离器在降低能耗的同时提高分离效率。 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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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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《Advanced Powder Technology》2023,34(1):103929
This study aimed to investigate the separation performance of a cyclone separator after reshaping its cylindrical body by installing the helical triangular fins. A numerical simulation based on Fluent was adopted to perform an orthogonal test to optimise the structure of the cyclone separator with helical triangular fins. Three structural parameters of the helical triangular fins were selected as optimisation variables: base width, fin size, and fin pitch, and their influences on the evaluation indices of the cut-off diameter were investigated. The optimal combination scheme was determined by range analysis, and the cyclone separator performances before and after optimisation were compared and analysed. The significant influence of the structural parameters on the cut-off diameter was in descending order as the fin pitch, fin size, and base width. For particles with diameter of 0.1, 0.5, 1, 2, and 3 μm, the separation efficiency of the cyclone separator with optimized helical triangular fins increased by 7.4 %, 15.9 %, 20.1 %, 10.9 % and 14.8 % respectively. Moreover, the cut-off diameter of the finned cyclone separator is reduced by 30.7 %, while the pressure drop is only increased by 6.6 %. The short circuit flow and back-mixing were alleviated, thereby considerably enhancing the stability of the flow field. Therefore, the finned cyclone separator was found to play a critical role in increasing the separation of fine particulate matter. 相似文献
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《Advanced Powder Technology》2022,33(8):103620
Here, an axial flow cyclone separator is design is proposed. The effects of varying the structural parameters and operating conditions on pressure drops and separation efficiency were investigated via a numerical simulation approach. The results show that of the three structural parameters considered, the distance between the diffuser and blade is the most significant factor impacting separation performance compared to the blade pitch and blade shaft diameter. Increasing the distance between conical outlet and blade can decrease its pressure drops and increase separation efficiency; while increasing the shaft diameter can increase pressure drops, and the increasing blade pitch can decrease both the pressure drop and the separation efficiency. The pressure drop of the optimized swirl tube was 102.1 Pa, with a corresponding separation efficiency of 95.04% for 100 μm particles at an extraction ratio of 10%. Further, the cut-off particle size can reach 3 μm, demonstrating that the swirl tube offers good separation performance and has the potential to be widely applied in industrial gas–solid separation applications. 相似文献
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In this paper, a comprehensive study is performed in order to demonstrate the effect of the flow and particle temperature on cyclone performance. Three main characteristics of the low-mass-loading gas-solid cyclone separators, including: pressure drop, particle separation efficiency and natural vortex length are investigated. Eulerian-Lagrangian approach is employed to solve the unsteady Navier-Stokes and energy equations to model the flow of particles. Because of the strong swirling flow in cyclone, Reynolds stress transport model (RSTM) is used to calculate the Reynolds stresses. Numerical simulation is accomplished at a temperature range of 293–700 K and four inlet velocities. Also, a comparison is conducted between two Stairmand high efficiency cyclones with the same dimensions, one with single inlet and the other with double inlets to declare the effect of the second inlet on cyclone performance. The analysis of results shows that the swirling flow becomes weaker for higher temperature cases and thus, flow pressure drop and particle separation efficiency is noticeably decreased. Increasing in temperature causes decrease in natural vortex length. Also, study of natural vortex length is performed for the studied range of temperature. 相似文献
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《Advanced Powder Technology》2022,33(11):103815
Low separation efficiency and large pressure drop are two common problems of cyclones. In this paper, a 3D printed guide vane cyclone separator was designed to study the separation efficiency, turbulent kinetic energy, and particle movement of particle group by experiment and simulation. The results shown that the tangential velocity was the major influence of separating. The bottom of the exhaust pipe was the main region of gas–solid separation and pressure drop. The separation efficiency and pressure drop were positively correlated with the inlet velocity and the particle radius of the fluid. The distribution of turbulent kinetic energy that leaded to the pressure drop loss was concentrated on the inlet of the exhaust pipe. The swirl has external and internal two directions. The optimized cyclone has a longer and narrower blade flow path to obtain higher separation efficiency, especially at low inlet velocity. 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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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