共查询到18条相似文献,搜索用时 671 毫秒
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《化学反应工程与工艺》2018,(4)
为了探究入口结构对旋风分离器内涡核摆动的影响,采用雷诺应力模型(Reynolds stress model,RSM)对两种不同入口结构旋风分离器内旋转流动进行了气相流场的数值模拟。结果表明,切向速度在截面上呈现明显的非轴对称现象,主要表现为等值线分布不对称,零值所在位置与几何中心不重合,零值靠近壁面的一侧,切向速度较大,零值远离壁面的一侧切向速度较小。直切式旋风分离器内部偏心比(|Δr|/D)多在0.025~0.050,而蜗壳式旋风分离器内部偏心比则多在0.000~0.025,偏心程度明显下降。蜗壳式旋风分离器在90~270°截面和180~360°截面上的旋转中心偏移轴线值(|Δx|和|Δy|)的平均值均减小,蜗壳式旋风分离器偏心距(|Δr|)的平均值相对于直切式减小23.5%。 相似文献
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轴对称进口回转通道对旋风分离器分离特性影响的研究 总被引:7,自引:1,他引:6
针对单进口旋风分离器内气流轴不对称问题,将单进口旋风分离器入口方式改造为轴对称型回转通道形式(即采用双进口与单进口等长通道长度的新型切向进气方式),从旋风分离器的进风量、入口含尘量及阻力损失等方面,分析了轴对称型进口回转通道对旋风分离器分离特性的影响。分级分离效率的试验与计算结果表明,新型旋风分离器的分离性能不仅优于单进口,而且稍优于Stairmand高效旋风分离器 相似文献
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本文给出一种简易的新的压降计算式,但比以前发表过的方程更精确。它适用于进口或出口导管不呈蜗壳状的旋风分离器。 相似文献
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《中国石油和化工标准与质量》2017,(19)
本文通过ANSYS有限元软件,建立了带切向矩形入口的旋风分离器的三维有限元模型,通过分析计算切向矩形入口结构的强度,得出了应力分布,并按照《钢制压力容器分析设计标准》进行强度评定,结果表明目前设计的旋风分离器结构强度能够满足安全要求。 相似文献
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以XLPB-5.0和XCX-5.0两种旋风分离器为原型,采用CFD软件对这两种旋风分离器进行了流场与分离效率的数值模拟,初步探讨了入口蜗壳形式与芯管结构对分离效率的影响。模拟结果显示:旋风分离器内流场呈各向异性分布特点,切向速度是影响分离效率的首要因素,径向速度的存在会造成"流场短路"现象,使轴向速度呈不对称分布,导致分离效率的降低。轴向速度与径向速度的共同作用促使颗粒在旋风分离器内做螺旋运动;XLPB-5.0和XCX-5.0的分离效率分别为92.55%和94.96%,与实验结果基本吻合,且不同芯管参数下XCX型的分离效率比XLPB型高;螺旋式入口蜗壳(XCX-5.0型)对旋风分离器上部流场的影响相比直流式入口蜗壳(XLPB-5.0型)复杂;对于两种旋风分离器,随着芯管直径的增大,分离效率逐渐变小;随着芯管深度的增大,分离效率先增大后减小。 相似文献
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综述了近年来关于入口结构包括入口结构类型、入口截面形状以及入口下倾角度等对旋风分离器性能影响的研究。认为不同的入口结构参数设计对旋风分离器的性能及能耗有较大影响;随着入口数量增多,分离器压降降低,分离效率先升高后减少,双进口分离器的性能较优。入口截面形状采用倒三角形有利于提高分离效率,但压力损失增加;对于矩形入口旋风分离器,增大高宽比有利于提高分离效率,但也会增大压力损失。随着入口截面角的增加,压力损失降低,分离效率先升高后减小,存在有最优的入口截面角;螺旋下倾角能够改善旋风分离器的分离性能,降低压力损失并有效减少上灰环现象的发生。 相似文献
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基于计算流体力学(CFD)软件Fluent中的颗粒随机轨道模型(DPM),对两种入口形式的固液分离旋流器的壁面磨损进行数值模拟的比较,结果表明:单入口式固液分离旋流器顶板的最大磨损位于方位角140°~210°,环形空间壁面最大磨损位于方位角120°和190°,底流口附近壁面最大磨损在周向方向180°的底流口上方1~2mm位置;双入口式旋流器的壁面磨损呈对称分布,最大磨损在底流口位置,顶板壁面最大磨损在两个入口区域,顶板外层最大磨损位于方位角80°~110°和260°~290°,环形空间壁面最大磨损位于方位角120°和300°;相同条件下,双入口式旋流器顶板和环形空间的壁面磨损小于单入口式旋流器顶板和环形空间的壁面磨损;而对于底流口附近的壁面磨损,双入口式固液分离旋流器底流口附近的壁面磨损略大。 相似文献
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Three cyclone separators with different inlet geometry were designed, which include a conventional tangential single inlet (CTSI), a direct symmetrical spiral inlet (DSSI), and a converging symmetrical spiral inlet (CSSI). The effects of inlet type on cyclone performance characteristics, including the collection efficiency and pressure drop, were investigated and compared as a function of particle size and flow rate in this paper. Experimental result indicated that the symmetrical spiral inlet (SSI), especially CSSI inlet geometry, has effect on significantly increasing collection efficiency with insignificantly increasing pressure drop. In addition, the results of collection efficiency and pressure drop comparison between the experimental data and the theoretical model were also involved. 相似文献
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A novel cyclone design, named converging symmetrical spiral inlet (CSSI) cyclone, is developed by improving the inlet geometry of conventional tangential single inlet (CTSI) cyclone for enhancing the physical performance of the cyclone. The collection efficiency of the CSSI cyclone is experimentally compared with the widely used CTSI cyclone. The results indicate that the CSSI cyclone provides higher collection efficiency by 5%~20% than that of the CTSI cyclone for a tested inlet velocity range of 11.99~23.85 m/s. In addition, the results of collection efficiency comparison between experimental data and theoretical model are also discussed. 相似文献
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《Journal of aerosol science》2003,34(8):1085-1095
Two single inlet cyclones and a double inlet cyclone were designed and fabricated to evaluate, and compare, their collection efficiencies. Two single inlet cyclones had different inlet sizes and vortex finder diameters. The double inlet cyclone had two inlet parts that divided the cyclone inlet in two. Clean air was introduced to the inlet near the cyclone wall, and particle-laden air was introduced to the inlet away from the cyclone wall. This double inlet made the clean air swirl in the region near the vortex finder, and the particle-laden air swirl in the region close to cyclone wall. The performance of the double inlet cyclone was evaluated at various clean air flow rates, keeping the particle-laden air flow rate constant.The collection efficiency of the double inlet cyclone was found to be 5–15% greater than that of the single inlet cyclone with the same inlet size and vortex finder diameter. As the flow rate of clean air was increased, the collection efficiency increased. This result indicates the possibility of achieving higher collection efficiencies with a double inlet cyclone. 相似文献
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3-D computational fluid dynamics for gas and gas-particle flows in a cyclone with different inlet section angles 总被引:2,自引:0,他引:2
A three-dimensional computational fluid dynamics (CFD) Reynolds stress model (RSM) was used to describe the gas and gas-solid flow in a cyclone with a scroll inlet duct at three different inlet section angles in relation to the cyclone body. The effects of the inlet section angles on the fluid dynamics inside the cyclone and on the performance parameters (collection efficiency and pressure drop) were analyzed by means of the finite volume method using a computational code and an industrial-sized cyclone for separation of gas-particle phases operated by Votorantim Cimentos Company. The numerical results show that the value for overall collection efficiency in this work increased to 77.2% for the 45° inlet section angle, while that for the normal inlet duct was 54.4% under the same operating conditions. 相似文献
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为探究颗粒负荷对小型旋风器内气固两相流动的影响,基于雷诺应力模型(RSM)和欧拉-欧拉方法的混合流模型(Mixture)进行气体-颗粒、颗粒-颗粒的相间耦合计算。采用粒径为0.5~5μm的颗粒组在40L/min、60L/min和80L/min的入口流量下模拟0~3kg/m3的5种不同颗粒浓度工况,通过对比旋风器内纯气相流场和颗粒负荷流场的不同,研究了颗粒的存在对流场的影响;探究了入口流量和浓度变化对旋风器内分离效率和压降特性的影响。基于模型有效性验证的数值模拟结果表明:较高颗粒浓度负荷使旋风器内的气相流场发生显著变化。随着入口流量的增大,旋风器的分离效率先增大后减小,压降呈非线性增大。随着颗粒浓度的增大,旋风器的分离效率逐渐增大,压降先减小后增大。 相似文献
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常规切向进口旋风分离器的气流进入旋风分离器后必定要经过排气芯管外壁和筒体内壁之间,因此不可避免会使得相当一部分气流没有经过分离空间而直接从排气芯管底部排出(短路流量),这也是影响旋风分离器分离效率的重要因素之一。在前人工作的基础上,对旋风分离器的进口结构进行了改进:使得旋风分离器的入口具有一定截面角,并借助数值计算技术,分别对传统的和具有一定入口截面角旋风分离器内的三维流场进行了数值模拟,计算了芯管底部的"短路流量",结果表明:进口具有一定截面角可以明显减小芯管底部的"短路流量",这对改善旋风分离器的分离效率具有重要的实际意义。 相似文献