共查询到20条相似文献,搜索用时 15 毫秒
1.
Experimental and theoretical analysis of stresses, noise and flow in centrifugal fan impeller 总被引:2,自引:0,他引:2
Stress analysis of fan impeller by experimental and finite element method has shown that, the stress pattern in impeller components is highly complex. The stresses in the impeller components can be reduced, by using the stiffening rings on the blades. In this paper, experimental and finite element approaches have been discussed to study the stresses in centrifugal fan impeller. The flow of centrifugal fan has been also determined by using the set-up as per AMCA and NAFM guidelines. The effect of the stiffening rings on the stresses, noise and fluid flow has been also investigated and discussed. 相似文献
2.
Sarhan Karray Zied Driss Hedi Kchaou Mohamed Salah Abid 《Journal of Mechanical Science and Technology》2011,25(7):1749-1760
A coupling algorithm is used to compute the equilibrium of a flexible anchor impeller in a stirred vessel. This coupling algorithm
is based on a partitioned approach, which consists of three relatively independent modules: the computational fluid dynamics
(CFD), the computational structure dynamics (CSD) and the interface. In the CFD module, the Euler formulation was used to
account for the moving boundary. In the CSD module, the updated Lagrangian formulation for solving the motion of non-linear
structure was used and a static study was adopted. In the interface module, an exchange of the forces and displacements was
allowed. The numerical results, such as the velocity field, the turbulent kinetic energy, its dissipation rate, the turbulent
viscosity and the mechanical deformation, have been presented. Particularly, we are interested in the study of the static
behavior of the anchor impeller and the evolution of the displacement field of the arms during various iterations of our coupling
algorithm. Accordingly, if the anchor impeller undergoes a deformation due to the flexion of the arms of the anchor impeller,
the numerical results changes slightly from iteration to another. At the end of certain iteration, the anchor impeller becomes
deformed and the velocity field is preserved. These results confirm that the fluid has a significant effect on the deformation
of the arms of the anchor impeller during mixing depending on the velocity of the anchor impeller and the fluid flow. The
numerical results were validated by a comparison with literature data. 相似文献
3.
双层直斜叶及其组合桨搅拌槽三维流场数值模拟 总被引:15,自引:1,他引:14
采用计算流体力学的方法,对双层六直叶涡轮桨、双层六斜叶涡轮桨以及双层六直斜叶交替涡轮桨搅拌槽流场进行研究。利用Laminar层流模型对其在甘油与水的混合物中产生的流场进行数值计算,得到三种不同结构形式的双层桨以恒转速200 r/min在搅拌槽内转动时所产生的流场结构,对比分析轴向、径向和周向的速度矢量图、速度云图以及速度分布曲线,为层流搅拌槽的设计和实际应用提供了理论依据。 相似文献
4.
WANG Yu HE Pingting YE Hong XIN Zhihong 《机械工程学报(英文版)》2007,20(5):42-45
Instantaneous flow field and temperature field of the two-phase fluid are measured by particle image velocimetry (PIV) and steady state method during the state of onflow. A turbulent two-phase fluid model of stirred bioreactor with punched impeller is established by the computational fluid dynamics (CFD), using a rotating coordinate system and sliding mesh to describe the relative motion between impeller and baffles. The simulation and experiment results of flow and temperature field prove their warps are less than 10% and the mathematic model can well simulate the fields, which will also provide the study on optimized-design and scale-up of bioreactors with reference value. 相似文献
5.
基于Workbench整体叶轮流固耦合强度分析 总被引:1,自引:0,他引:1
作为许多动力机械的核心部件的叶轮,其强度及可靠性的问题日渐突出。叶轮工作时,流体力和高速旋转时的离心力为其主要载荷。基于Workbench软件对整体叶轮的内部流场和工作压力分布进行数值模拟;使用ANSYS CFX进行复杂几何形状叶轮的流体动力分析,得到了整体叶轮的流场和工作压力场及流体载荷在叶轮内部产生的等效应力分布图,并耦合了旋转离心载荷等,研究了在高压工况情况下,叶轮的载荷组成和流固耦合下的叶轮强度。 相似文献
6.
TWLQ系列涡轮气体流量计是一款用于天然气等气体介质瞬时流量和累积流量测量的仪表。TWLQ-100型涡轮气体流量计的核心部件是D100叶轮,其工作原理是将叶轮置于被测流体中,当介质流经流量计时,由于叶轮叶片与流过的介质之间存在一定夹角,流体对叶轮产生转动力矩,使叶轮克服机械摩擦阻力矩和流动阻力矩而旋转,以叶轮的旋转速度来反映流量的大小。因此,叶轮的几何形状、尺寸及动平衡将直接影响涡轮气体流量计的性能和使用寿命。 相似文献
7.
为研究前弯型叶轮外径对液力透平水力性能的影响,进行试验,获得了液力透平外特性数据,与计算流体动力学(Computational fluid dynamics, CFD)的结果进行对比分析,发现两者结果十分接近,验证了CFD模拟的准确性。利用CFD技术获得了215 mm、235 mm和255 mm叶轮外径液力透平的外特性曲线,发现随叶轮外径的增加,高效点向大流量区域偏移,在大流量区域,扬程大幅下降,轴功率小幅提升,效率有较明显提升,在小流量区域,扬程上升,轴功率略微下降,效率下降明显。对215 mm、235 mm和255 mm外径叶轮的速度场分析,发现随叶轮外径的增加,叶轮与蜗壳基圆之间的循环流量逐渐减小,流动状态得到明显改善,叶轮内水力损失也有较为明显的减小。利用理论公式推测改变了叶轮外径后的液力透平的高效点参数,发现普遍高于CFD模拟结果,分析产生差值的可能原因。对液力透平的轴功率、扬程进行理论分析,探讨其随叶轮外径增加的变化趋势。 相似文献
8.
叶轮曲率半径与离心泵性能关系的研究 总被引:1,自引:0,他引:1
对离心泵的性能和消耗功率与叶轮曲率半径的关系进行了实验分析。采用了两种实验方法(常温流体和高温流体)对5种不同半径和角度的叶轮模型进行了试验。结果表明,叶轮的曲率半径和总出口面积对离心泵性能有明显的影响。 相似文献
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Weng Kong Chan S. C. M Yu L. P. Chua Y. W. Wong 《Journal of Mechanical Science and Technology》2001,15(12):1869-1875
This paper presents computational and flow visualization results on a centrifugal blood pump. 4 impeller designs were tested at a rotational speed of 2000 rpm using blood analog as working fluid. All impellers have seven blades but of different geometry (Impellers A3, A4, B2 and R7). Flow visualization within the impeller passages was conducted using an image de-rotation system. A pair of large scale vortices was found within the blades of impeller R7 while a single vortex was found in most of the passages of backward facing impellers (Impellers A3, A4 and B2). To establish the effects of blade geometry on blood cells, CFD was used to simulate the blade to blade flow to provide an estimate of the maximum shear stress. The results showed that though most of the stresses within the blade passages are below a threshold level of 150 N/m2 for extensive erythrocyte damage to occur, there are some regions near to the leading edge of the pressure side where the shear stresses are above threshold level. 相似文献
11.
Numerical simulation and analysis of flow characteristics in the front chamber of a centrifugal pump
Yang Wu Xiaoping Chen Hua-Shu Dou Lulu Zheng Zuchao Zhu Baoling Cui Boo Cheong Khoo 《Journal of Mechanical Science and Technology》2017,31(11):5131-5140
We performed numerical simulations to study the flow characteristic in a centrifugal pump based on the RANS equations and the RNG k-ε turbulent model. The flow field, including the front and back pump chambers, the impeller wear-ring, the impeller passage, the volute casing, the inlet section and outlet section was calculated to obtain accurate numerical results of fluid flow in a centrifugal pump. The flow characteristic was studied from the internal flow structure in pump chambers, the radial velocity at impeller outlet as well as the pressure inside of the pump, the circumferential velocity and the radial velocity in front pump chamber. The variation of flow parameters in internal flow versus flow rate in the centrifugal pump was analyzed. The results show that the overall performance of the pump is in good agreement with the experimental data. The simulation results show that the distribution of flow field in the front pump chamber is axial asymmetry. The energy dissipation at the impeller outlet is larger than other areas. The distribution of the circumferential velocity and that of radial velocity are similar along the axial direction in the front pump chamber, but the distribution of flow is different along the circumferential and the radial directions. It was also found that the vorticity is large at the impeller inlet compared with other areas. 相似文献
12.
In this work, gas–liquid distributions in an industrial centrifugal pump operated at various steady state conditions have been quantitatively determined. Therefore, high-resolution gamma-ray computed tomography (HireCT) has been applied, operated in time-averaging rotation-synchronized CT scanning mode. Detailed studies have been performed on a hydraulic test facility providing authentic operating conditions for industrial centrifugal pumps. The gas phase distribution in the centrifugal pump has been studied for swirling gas–liquid two-phase flow as an inlet flow regime and at defined inlet gas volumetric flow rates between 0% and 5%. In this way, the influence of the inlet flow boundary conditions on the performance of the centrifugal pump as well as the gas holdup distribution within the impeller region could be successfully determined. 相似文献
13.
Jong-Soo Choi 《Journal of Mechanical Science and Technology》1994,8(2):161-174
The objective of this research was to identify which aspects of the fluid dynamics are associated with noise generation in centrifugal turbomachinery. Research emphasis was placed on the generation of noise at frequencies other than the blade passage tones. In order to avoid noise generated by the interaction of the discharged flow and stationary objects outside of the impeller, experiments are performed on a centrifugal impeller without diffuser and casing. With this discharge configuration, the radiated noise spectra are shown to be dominated by harmonically related broad humps at low frequency. These were proven to be generated by the interaction of a coherent unsteady flow structure rotating around the impeller discharge and the trailing edges of the impeller blades. 相似文献
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叶轮是流体机械中进行直接能量转换的核心部件,其结构参数会严重影响轴流式管道发电机能量转化效率及性能。为了使叶轮获得更好的水力性能、空蚀性能、工作稳定性能,采用Wilson法设计轴流式管道发电机叶轮的结构,优化叶轮的结构参数,获得性能优异的叶形结构。通过CFD仿真,结果表明:优化结构参数后的叶片能显著改善叶轮的水力性能、空蚀性能、工作稳定性能。通过实验对仿真进行验证,结果证明了本文设计方法的有效性以及改进后叶轮性能的优越性。对轴流式管道发电机的叶轮结构设计与优化有一定的指导意义。 相似文献
16.
The impeller blade structure is one of the important factors affecting the performance of the turbine flow sensor. However, the underlying fluid dynamics mechanism is still not fully understood. The DN10 turbine flow sensor's internal flow field was analyzed based on computational fluid dynamics (CFD) simulations to explain the influence mechanism of blade structure on its performance. The experiment proves that the simulation method is reliable. The structural parameter η, which characterizes the shape of the impeller blade, was defined, and four turbine flow sensor structures were studied. The results suggested that the value of η affects the stability of the impeller's fluid dynamics characteristics, the velocity distribution at the impeller inlet, and the acting position and time of the wake flow behind the upstream flow conditioner. Therefore, the structural parameter influents the performance of the turbine flow sensor. With the increase of η, the characteristic curve gradually moves down, the average meter factor decreases, and the linearity error increases. 相似文献
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Sung Kim Ung-Been Jeong Kyoung-Yong Lee Jin-Hyuk Kim Joon-Yong Yoon Young-Seok Choi 《Journal of Mechanical Science and Technology》2017,31(11):5099-5106
During design optimization, the impeller and diffuser of a mixed-flow pump are generally optimized separately. In such cases, the total head can be overdesigned. In this study, the designs of the impeller and diffuser were optimized simultaneously by using computational fluid dynamics and the Response surface method (RSM). Design variables were defined according to the vane plane development of the impeller and diffuser. Three-dimensional Reynolds-averaged Navier–Stokes equations for the shear stress transport turbulence model were discretized by finite volume approximations and solved on hexahedral grids to analyze the flow in the pump. The total head and total efficiency were selected as objective functions, with four design variables related to the impeller outlet angles and diffuser inlet angles used for optimization. The RSM was constructed based on the objective functions with design points generated from the central composite method. The hydraulic performance of the optimum model was analyzed. 相似文献