Numerical Simulation and Experiment Research on Aerodynamic Characteristics of a Multi-Blade Centrifugal Fan

2011 ◽  
Vol 317-319 ◽  
pp. 2157-2161
Author(s):  
Yong Chao Zhang ◽  
Qing Guang Chen ◽  
Yong Jian Zhang ◽  
Xiang Xing Jia

The full flow field model of a widely used multi-blade centrifugal fan was built, and unstructured grids were used to discrete the computational domain. The moving reference frame is adopted to transfer data between the interfaces of the rotating field and the stationary field. Pressure boundary conditions are specified to the inlet and the outlet. The SIMPLE algorithm in conjunction with the RNG k-ε turbulent model was used to solve the three-dimensional Navier-Stokes equations. The steady and unsteady numerical simulations of the inner flow in the fan at different working conditions were presented using the CFD method. The numerical simulation results were validated by contrasting to the experiment results. The results displayed the characteristics of the velocity field, pressure field, pressure fluctuation at two monitoring points in the centrifugal fan. The results can provide basis for optimizing the fan design and the internal flow, and have important value of engineering applications in the increase of the overall performance in operation.

2012 ◽  
Vol 468-471 ◽  
pp. 2231-2234
Author(s):  
Feng Gao ◽  
Wei Yan Zhong

Numerical simulation of the three-dimensional steady and unsteady turbulent flow in the whole flow field of a multi-blade centrifugal fan is performed. Unstructured grids is used to discrete the computational domain. Pressure boundary conditions are specified to the inlet and the outlet. The SIMPLE algorithm in conjunction with the RNG k-ε turbulent model is used to solve the three-dimensional Navier-Stokes equations. The moving reference frame is adopted to transfer data between the interfaces of the rotating field and the stationary field. Based on the calculation of the inner-flow in the fan, the pressure pulsation of some important monitoring points and the aerodynamic noise distribution, banding together experiment data were farther analyzed The simulation results are of important significance to the optimal design and noise control of the fan.


Author(s):  
Mou-jin Zhang ◽  
Chuan-gang Gu ◽  
Yong-miao Miao

The complex three-dimensional flow field in a centrifugal impeller with low speed is studied in this paper. Coupled with high–Reynolds–number k–ε turbulence model, the fully three–dimensional Reynolds averaged Navier–Stokes equations are solved. The Semi–Implicit Method for Pressure–Linked Equations (SIMPLE) algorithm is used. And the non–staggered grid arrangement is also used. The computed results are compared with the available experimental data. The comparison shows good agreement.


2011 ◽  
Vol 233-235 ◽  
pp. 701-706
Author(s):  
Bing Tao Zhao ◽  
Yi Xin Zhang ◽  
Kai Bin Xiong

The numerical simulation of the fluid flow is presented by CFD technique to characterize the flow pattern of cyclone spray scrubber. In this process, the Reynolds-averaged Navier-Stokes equations with the Reynolds stress turbulence model (RSM) for fluid flow are solved by use of the finite volume method based on the SIMPLE pressure correction algorithm in the fluid computational domain. According to the computational results, the tangential velocity, axial velocity and turbulence intensity of the gas flow are addressed in the different flowrate. The results indicate that the CFD method can effectively reveal the mechanism of gas flow in the cyclone spray scrubber.


2013 ◽  
Vol 694-697 ◽  
pp. 56-60
Author(s):  
Yue Jun Ma ◽  
Ji Tao Zhao ◽  
Yu Min Yang

In the paper, on the basis of three-dimensional Reynolds-averaged Navier-Stokes equations and the RNG κ-ε turbulence model, adopting Three-dimensional unstructured grid and pressure connection the implicit correction SIMPLEC algorithm, and using MRF model which is supported by Fluent, this paper carries out numerical simulation of the internal flow of the centrifugal pump in different operation points. According to the results of numerical simulation, this paper analyzes the bad flow phenomena of the centrifugal pump, and puts forward suggests about configuration perfected of the centrifugal pump. In addition, this paper is also predicted the experimental value of the centrifugal pump performance, which is corresponding well with the measured value.


2013 ◽  
Vol 10 (05) ◽  
pp. 1350031 ◽  
Author(s):  
ALIREZA ARAB SOLGHAR ◽  
S. A. GANDJALIKHAN NASSAB

The three-dimensional steady state thermohydrodynamic (THD) analysis of an axial grooved oil journal bearing is obtained theoretically. Navier–Stokes equations are solved simultaneously along with turbulent kinetic energy and its dissipation rate equations coupled with the energy equation in the lubricant flow and the heat conduction equation in the bush. The AKN low-Re κ–ε turbulence model is used to simulate the mean turbulent flow field. Considering the complexity of the physical geometry, conformal mapping is used to generate an orthogonal grid and the governing equations are transformed into the computational domain. Discretized forms of the transformed equations are obtained by the control volume method and solved by the SIMPLE algorithm. The numerical results of this analysis can be used to investigate the pressure distribution, volumetric oil flow rate and the loci of shaft in the journal bearings. To validate the computational results, comparison with the experimental and theoretical data of other investigators is made, and reasonable agreement is found.


Akustika ◽  
2021 ◽  
pp. 25-29
Author(s):  
Igor Khramtsov ◽  
Vadim Palchikovskiy ◽  
Oleg Kustov

The article considers the determination of the impedance of the acoustic liner sample on the basis of numerical simulation of physical processes in a honeycomb resonator with a grazing incidence of sound waves. The computational domain is the test section of a grazing incidence impedance tube with an acoustic liner sample. The liner sample is a single honeycomb resonator with a depth of 14 mm and an open area percent of 4.2%. Numerical simulation is performed based on the direct solution of the non-stationary compressible Navier-Stokes equations in a three-dimensional formulation. The pressure-time and velocity-time signals are recorded in the numerical simulation and processed by Dean's method and the direct method (from the ratio of acoustic pressure to normal acoustic velocity). The comparison of impedances obtained by the two methods demonstrates a good agreement with each other.


Author(s):  
Man-Woong Heo ◽  
Jin-Hyuk Kim ◽  
Kwang-Yong Kim

AbstractMulti-objective optimization of a centrifugal fan with additionally installed splitter blades was performed to simultaneously maximize the efficiency and pressure rise using three-dimensional Reynolds-averaged Navier-Stokes equations and hybrid multi-objective evolutionary algorithm. Two design variables defining the location of splitter, and the height ratio between inlet and outlet of impeller were selected for the optimization. In addition, the aerodynamic characteristics of the centrifugal fan were investigated with the variation of design variables in the design space. Latin hypercube sampling was used to select the training points, and response surface approximation models were constructed as surrogate models of the objective functions. With the optimization, both the efficiency and pressure rise of the centrifugal fan with splitter blades were improved considerably compared to the reference model.


Author(s):  
Hyeon-Seok Shim ◽  
Hyo-Yeon Jung ◽  
Kwang-Yong Kim

Aerodynamic performance of a bobsleigh is one of the most important factors in reducing the race time. In this study, an investigation on the aerodynamic characteristics of a bobsleigh has been performed using three-dimensional Reynolds-averaged Navier-Stokes equations with the k-ε turbulence model. An unstructured tetrahedral grid system was constructed in the computational domain, and the optimal number of grids was selected through a grid-dependency test. The major axis length and thickness of ellipse-shaped front bumper, and the radii of the cowling on side and front views, were selected as four geometric parameters to be tested, and the drag coefficient was considered as an aerodynamic performance parameter. It was found that the drag coefficient was more sensitive to the thickness of the front bumper and the radius of the cowling on side view of the bobsleigh than on the other parameters.


A unique discrete form of the Navier-Stokes equations for unsteady, three-dimensional, incompressible flow has been used to study vortex breakdown numerically. A Burgers-type vortex was introduced along the central axis of the computational domain, and allowed to evolve in space and time. By varying the strength of the vortex and the free stream axial velocity distribution, using a previously developed Rossby number criterion as a guide, the location and size of the vortex breakdown region was controlled. While the boundaries of the vortex breakdown bubble appear to be nominally symmetric, the internal flow field is not. Consequently, the mechanisms for mixing and entrainment required to sustain the bubble region are different from those suggested by earlier axisymmetric models. Results presented in this study, for a Reynolds number of 200, are in good qualitative agreement with higher Reynolds number experimental observations, and a variety of plots have been presented to help illuminate the fluid physics.


Author(s):  
Jian-Cheng Cai ◽  
Da-Tong Qi ◽  
Fu-An Lu

This paper presents a method for predicting casing vibration and noise radiation of a centrifugal fan due to internal fluctuating pressure fields at the blade passing frequency (BPF). Using computational fluid dynamics (CFD) technique based on the finite volume method (FVM), a three-dimensional unsteady simulation of internal flow was carried out by solving the Reynolds averaged Navier-Stokes equations. The oscillating pressure distribution at the volute casing was taken as the excitation of the finite element analysis (FEA) model of the casing structure. Time-domain nodal forces on the casing were obtained by integrating the pressure and viscous stress over the element surfaces. Fast Fourier transform (FFT) was applied to these time series of nodal forces in order to extract the BPF components. Harmonic response analysis was carried out to the casing structure. Sound radiation was finally calculated by the indirect boundary element method (IBEM) with the vibration results as velocity boundary condition. This study shows that it is feasible to use fluid-structure weakly coupled simulations for the prediction of flow-induced casing vibration and noise radiation of centrifugal turbomachinary.


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