共查询到18条相似文献,搜索用时 93 毫秒
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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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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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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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为探究供热管道压降测试环境下涂层对减阻效果的影响,本文以某市供热管网减阻测试项目为例,提出了实验测试方案,重点对测试数据以及压力模型进行分析。实验结果表明:供热管道压降测试环境下涂抹减阻涂层的管道减阻效果明显,并且减阻效果会随着管道流量的增加而增大,具有较高的减阻性能与防腐蚀性。 相似文献
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采用种子乳液聚合法和物理共混交联法制备了以水为溶剂的聚氨酯-聚丙烯酸乙酯(PU/PEA)乳液和聚氨酯-聚丙烯酸丁酯(PU/PBA)乳液柔性壁。该乳液不仅环保,而且强度高,弹性好,粘接性优良。小型水洞平板阻力测试结果表明,PU/PEA复合乳液有一定的减阻作用,水流速度高时减阻率也高,流速为3.0 m/s时达到8.8,PU/PEA(40/60)复合乳液涂层在0.5~3 m/s的速度范围内平均减阻率达到5%;粒子图像速度测试给出了在相同雷诺数下柔性壁与铝板的平均摩擦阻力系数的比较以及计算得到的减阻率。结果表明,PBA/PU和P(BA-EA)/PU的减阻效果差不多,平均约5.3%,而PBA/PU-MMA低速减阻,高速不减阻。PU/PBA混合乳液涂层在0.5 m/s和1 m/s的流速下减阻率分别为7%和4%。 相似文献
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针对某型轴流风机引起的气动噪声问题,建立该型轴流风机的三维模型,利用Lighthill声类比理论、FW-H声波波动方程和Fluent数值模拟,分析该轴流风机旋转叶片引起的气动噪声的噪声特性。数值模拟结果表明,旋转叶片上的静态压力主要集中在旋转方向前方的叶面上;而脉动压力则在叶片的两个面上均有分布,分布区域主要集中在叶片的外缘,这是由于叶片外缘脱落的旋涡引起的剧烈的气流震荡所导致。叶片上的气动噪声功率主要分布在叶片的外缘,其分布规律与脉动压力的分布规律有差异,表明旋转叶片的气动噪声并不完全由脉动压力产生。旋转叶片所诱发的气动噪声随着叶片转速和风机直径的增大而增大。 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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The steady and unsteady state simulations of Stairmand cyclone separator were carried out to investigate the performance of different interpolation schemes for discretization of pressure gradient and advection terms. The RSM turbulence model was revisited to explore its simulation capability of PVC phenomenon and fluctuating velocity profiles of cyclone separators. The combination of Presto, SO, standard and BFW schemes for discretization of pressure gradient and FOU, power law, SOU, QUICK and MUSCL schemes for discretization of advection terms were studied. The double precision solver of Fluent 6.3.26 and modified RSM turbulence model constants of Jiao et al. (Chem. Eng. Technol. 30 (2007) 15–20) were also verified for simulation of cyclone separators. The predicted mean and fluctuating velocity profiles and pressure drop inside the cyclone separator with steady and unsteady simulations have been compared to experimental results available in literature.The steady state simulation failed to predict velocity profiles and pressure drop inside cyclone separator accurately, whereas the unsteady state simulation predicted velocity profiles, pressure drop and PVC phenomenon close to experimental values. The prediction of fluctuating velocity profile was better than previously reported work in the core region compared to the off core region. The present study revealed that the SOU scheme for discretization of advection terms of momentum, kinetic energy and its dissipation rate equations and the FOU scheme for Reynolds stresses together with the Presto scheme for discretization of pressure gradient with unsteady simulation are the optimum choice for simulation of cyclone separators. 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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为了有效提高新型多效旋风分离器对粒径为0.1~3μm颗粒的分离效率,获取该设备的阻力性能,采用实验方法研究该新型多效旋风分离器压降与进口气速的关系,并与Lapple型旋风分离器进行比较。结果表明:进口风速为5~30m/s时,主体直径为0.25m的多效旋风分离器总阻力系数为7.29,其中,一级和二级预分离螺旋管的阻力系数分别为1.04和1.73;主体的阻力系数为4.52。直径为0.25m的Lapple型旋风分离器的阻力系数为7.21。 相似文献
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试验测定和对比页岩灰和流化催化裂化三旋灰(FCC三旋灰)的旋风分离器性能,考察入口气速、入口浓度对分离效率和分离器压降的影响.结果表明,在相同操作条件下,同一台旋风分离器上,粒度小于75 μm的页岩灰与FCC三旋灰的分离效率和分离器压降曲线差别显著;页岩灰的分离效率与分离器压降都明显低于FCC三旋灰,且入口浓度增大,页岩灰分离器压降的下降幅度高于FCC三旋灰;页岩灰分离效率最高的入口气流速度也低于FCC三旋灰.颗粒特性对旋风分离器的分离性能有明显影响,页岩灰和三旋灰的颗粒特性与形状差别是导致其旋风分离特性不同的一个基本原因;油页岩旋风分离器的设计应当考虑油页岩颗粒特性的影响. 相似文献
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Mofarrah Masoumeh Li Shuran Zheng Qinzhen Deng Guanle Liu Zhen Yan Keping 《Advanced Powder Technology》2019,30(6):1151-1159
The aim of this study was evaluating a micro gas cyclone performance with a body diameter of 10?mm to collect indoor fine particles. The design of a cyclone requires minimizing the pressure drop and maximizing the separation efficiency. Overall and grade efficiencies, pressure drops, and cut sizes have been investigated through a theoretical model, simulation, and experimental studies. The experimental part was conducted using an Electrical Low-Pressure Impactor (ELPI) device to measure particle concentration for flow rates of 10–13.3 (l/min). In order to study the pressure drop and velocity behavior for different flow rates, COMSOL software was utilized. The obtained results from experimental work have met the theoretical and simulation outcomes adequately. It has been confirmed by all the obtained results that by increasing the flow rate and subsequently inlet velocity, the particle collection efficiency and pressure drop increase while the cut size decreases. 相似文献
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A number of cyclones with different exit tube diameters have been simulated with CFD in this study. Results show that the exit tube diameter influences not only the velocity magnitude, but also the shape of the velocity profiles within cyclones. Depending on the diameter of the exit tube, the axial velocity profiles can exhibit a either maximum or a minimum on the axis. If the exit tube diameter is small, the central flow has a jet-like appearance. On the other hand, axial velocity dip in the profile can be observed near the center in a cyclone with a large gas exit tube. In addition, the well-known double vortexes, which commonly are present in a cyclone of practical design, do not exist in a cyclone with an excessively large exit tube. Quantitative comparison of velocity distribution shows that the tangential velocity increases as the exit tube diameter is reduced, giving rise to higher particle collection efficiency. Usually, the pressure drop decreases with increasing exit tube diameter. However, if the exit tube size is excessively large, the pressure drop may start to increase. Practically, cyclone with an excessively large exit tube should be avoided. 相似文献