共查询到20条相似文献,搜索用时 15 毫秒
1.
《Advanced Powder Technology》2021,32(11):4295-4302
In this paper, numerical simulation of flow field in three types of standard new design cyclone separators namely 1D2Dn, 1D3Dn and 2D2Dn are investigated. In these standard cyclones, the length of cylindrical top part of the body is equal to 1, 1 and 2 times of the body diameter, respectively; and the length of the cylindrical bottom part is 2, 3 and 2 times of the body diameter. The new design cyclone is based on the idea of improving cyclone collection efficiency and pressure drop by increasing the vortex length. The Eulerian-Lagrangian computational procedure is used to predict particles tracking in the cyclones. The velocity fluctuations are simulated using the Discrete Random Walk (DRW). Results show that among the three standard new design cyclones, cyclone 2D2Dn has the highest efficiency followed by 1D3Dn one with about only 2% lower efficiency. Cyclone 1D2Dn possesses the lowest efficiency among all. Similarly, the highest pressure drop occurs in cyclone 2D2Dn. Cyclones 1D3Dn and 1D2Dn followed 2D2Dn one with a marked difference of about 20%. In result section, the details of the flow field including velocity, pressure contours, turbulence, velocity vectors and particle trajectory will be presented. 相似文献
2.
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
3.
《Advanced Powder Technology》2020,31(6):2541-2554
In this paper it is attempted to improve the performance of the gas–solid new design cyclones with imposing magnetic fields. First, Eulerian-Lagrangian method is used to model the flow and to track the solid particles within the new design cyclones. The Reynolds averaged Navier–Stokes equations with Reynolds stress turbulence model (RSM) are solved by use of the finite volume method based on the SIMPLE pressure correction algorithm in the computational domain. The velocity fluctuations are simulated using the Discrete Random Walk (DRW). Then, to investigate the possible influence of the magnetic field, horizontal and vertical distances of the magnetic source from the coordinate origin as influential parameters are investigated. Solid particles with three different diameters and with different materials including polystyrene, ferrous and nickel are used. Results show that applying a magnetic field can improve the collection efficiency for all different particles’ materials. Analysis of results proves that there is a strong correlation between cyclone performances. It is observed that the collection efficiency is very sensitive to vertical distance of the magnetic source from the origin. Moreover, providing higher efficiency without imposing pressure drop is the advantage of implication of a magnetic field. 相似文献
4.
采用CFD数值模拟方法对有柔性膜片的膜式燃气表内部流动进行数值模拟研究,解决了皮膜和旋转阀之间的联动关系以及旋转阀转动与皮膜运动的仿真实现等技术问题;运用滑移网格、动网格及用户自定义函数(UDF)技术实现了膜式燃气表内部流动的动态数值模拟,获得了旋转阀与阀座存在1mm间隙的情况下膜式燃气表内部流场和仪表压损数据.结果表明,数值模拟技术用于膜式燃气表这种复杂结构的内部流动研究是可行的. 相似文献
5.
6.
7.
8.
9.
《中国计量学院学报》2015,(4):406-410
利用控制体积法的SIMPLEC算法对气体涡轮流量计的内流场进行了数值模拟,给出了内流场信息,分析了内部几何结构对压力和速度分布的影响,及其与流量系数的关系.结果表明在湍流状态时的仪表系数K为常数,累计流量和瞬时流量的误差较小;而在层流以及转捩状态时,仪表系数总是在变化,累计流量和瞬时流量的误差较大.建议通过结构优化,促使层流向湍流状态的快速转捩,并保证叶轮动平衡,从而加大涡轮流量计的量程范围.该研究结果对涡轮流量计的结构优化设计具有一定的指导意义. 相似文献
10.
11.
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
12.
以大面积喷淋式平板电极甚高频等离子体增强化学气相沉积(VHF-PECVD)反应室为研究对象,利用FlexPDE和CFD-ACE+商业软件,对反应室电极间的电场和流场分布进行了数值模拟。根据数值模拟结果可知:对于大面积喷淋式平板电极VHF-PECVD反应室,电极间气体流速分布呈现管流特征,而气压分布和电场分布具有类似的分布规律,即在大面积电极中央区域电场较强气压较高,而电极边缘区域电场较弱气压较低;另外,反应室采用喷淋式平板电极进行反应气体馈入,气体总流量、工作气压和电极间距是调节电极间气压分布均匀性的重要参量,采用大电极间距、高工作气压,以及小的气体总流量有助于获得均匀的气压分布。 相似文献
13.
14.
Numerical simulation of electroosmotic flow 总被引:1,自引:0,他引:1
We have developed a numerical scheme to simulate electroosmotic flows in complicated geometries. We studied the electroosmotic injection characteristics of a cross-channel device for capillary electrophoresis. We found that the desired rectangular shape of the sample plug at the intersection of the cross-channel can be obtained when the injection is carried out at high electric field intensities. The shape of the sample plug can also be controlled by applying an electric potential or a pressure at the side reservoirs. Flow induced from the side channels into the injection channel squeezes the streamlines at the intersection, thus giving a less distorted sample plug. Results of our simulations agree qualitatively with experimental observations. 相似文献
15.
应用基于有限体积法的FLUENT6.1计算软件对管道中单钝体的燃气绕流现象进行了仿真研究,即对实现管道燃气流量计量的DN200mm新型宽量程流量计的流场进行了数值模拟,就燃气计量管道中漩涡发生体的漩涡脱落频率与实测数据进行了比较。结果表明,数值计算结果与实测结果具有很好的一致性,从而提出了在新型燃气流量计的研制中可以应用数值模拟方法来优化流量计结构设计的结论。 相似文献
16.
为研究不同管道条件对涡街流量计测量结果及内部流场产生的影响,该文针对2种不同直管段长度时涡街流量计的旋涡脱落频率进行仿真计算与实验测试,结果显示仿真计算与实验测试结果具有较好的一致性,验证数值仿真用于涡街流量计流场分析的可行性。在此基础上,对上下游直管段长度不足、上游有单个90°弯头、下游有单个90°弯头这3种管道条件下共13种不同长度情况对应的涡街流量计的流场特性进行了仿真计算,结果表明,前端直管段长度的减少对测量结果的影响较后直管段更为明显;信号强度与直管段长度没有直接关系;前端有弯头时,频率值大幅降低,最大误差达-60.62%,弯头离旋涡发生体越近,降幅越大;后端有弯头对测量结果影响相对较小,最大误差为-13.23%。 相似文献
17.
18.
The numerical simulation of time-dependent, 2-D compressible boundary-layer flow containing a region of separation is studied. The separation is generated by the introduction of an adverse pressure gradient along the freestream boundary. In order to validate the numerical method, a low Mach-number laminar separation bubble flow is considered, which enables an extensive comparison with incompressible results. The generation of an adverse pressure gradient along the freestream boundary can be realized in various ways. An imposed decelerating flow boundary is compared with a suction technique. The effects of the strength of the pressure gradient and the presence of small upstream perturbations on the separation bubble are also investigated. The time-averaged characteristics of the flow are in good quantitative agreement with incompressible approximate theories predicting the condition for separation. The appearance of self-excited vortex shedding in unperturbed flows under a sufficiently strong adverse pressure gradient is consistent with incompressible flow simulations reported in the literature. The satisfactory result achieved in the calculation of the low-Mach-number flow encourages the application of the numerical method to flows with strong compressibility effects. 相似文献
19.
随着航空噪声越来越受到关注,计算声传播的算法成为研究热点。高阶间断伽辽金(Discontinuous Galerkin,DG)方法具有高精度、对网格质量要求低、适合自适应和并行计算等优点,可以以较高的效率对声场进行计算。文章运用高阶DG方法对线性化欧拉方程(Linearized Euler Equations, LEE)进行空间离散,并且基于离散后的线性化欧拉方程对带有背景流场的NACA0012翼型和30P30N多段翼型的声场进行数值计算。采用有限体积法计算得出流场信息后,通过插值将流场数据导入声场网格,并运用高阶DG方法进行声场计算。计算结果与参考文献中FW-H(Ffowcs Williams-Hawkings)算法对比一致性较好,验证了高阶DG算法的可行性。 相似文献
20.
Numerical simulation of gas flow in pneumatic components 总被引:1,自引:0,他引:1
Dr. rer. nat. Harald Berger 《Forschung im Ingenieurwesen》1992,58(3):67-74
The flow through pneumatic components is characterized by very complex flow phenomina. In general the flow is viscous, transonic
(0≦M≦4) and turbulent. Small geometrical dimensions of pneumatic components make flow measurement difficult or sometimes impossible.
Hence the accurate numerical prediction of the flow field becomes of great importance. In this paper we present the theoretical
framework and the numerical capabicities of the commercial Navier-Stokes CFD code TASC flow. We solve some test problems which
reflect many features of the numerical flow simulation in pneumatic components. For the test cases considered here, TASC flow
was found to be an excellent tool for fast and accurate flow simulation. 相似文献