Numerical Simulation of Sand Erosion Phenomena in Square-Section 90 Degree Bend With Linear/Nonlinear RANS Turbulence Models

2007 ◽  
Author(s):  
Masaya Suzuki ◽  
Kazuaki Inaba ◽  
Makoto Yamamoto
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Turbulence Models ◽  
Solid Particles ◽  
Two Phase ◽  
Streamline Curvature ◽  
Sand Erosion ◽  
Rans Turbulence Models ◽  
Wall Deformation ◽  
Bend Flow

Sand erosion is a phenomenon where solid particles impinging to a wall cause serious mechanical damages to the wall surface. This phenomenon is a typical gas-particle two-phase turbulent flow and a multi-physics problem where the flow field, particle trajectory and wall deformation interact with among others. On the other hand, the sand erosion is a serious problem to install pneumatic conveying systems for handling abrasive materials. Incidentally, the bend erosion is typical target of sand erosion experiments and is useful for verification of numerical simulations. Although, the secondary flow which occurs in such a flow field including streamline curvature cannot be reproduced by the standard k-ε model. To predict this flow field, a more universal model which can estimate anisotropic Reynolds stress is required. In the present study, we simulate sand erosion of 90 degree bend with a square cross-section. We use some linear/nonlinear turbulence models to predict the secondary flow of the bend. Besides, the performance of each model to predict clear/eroded bend flow field is studied.

Numerical Simulation of Sand Erosion Phenomena in Rotor/Stator Interaction of Compressor

2006 ◽  
Author(s):  
Masaya Suzuki ◽  
Kazuaki Inaba ◽  
Makoto Yamamoto
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Flow ◽  
Solid Particles ◽  
Aircraft Engines ◽  
Two Phase ◽  
Erosion Prediction ◽  
Sand Erosion ◽  
Wall Deformation ◽  
Rotor Stator Interaction

Sand erosion is a phenomenon where solid particles impinging to a wall cause serious mechanical damages to the wall surface. This phenomenon is a typical gas-particle two-phase turbulent flow and a multi-physics problem where the flow field, particle trajectory and wall deformation interact with among others. On the other hand, aircraft engines operating in a particulate environment are subjected to the performance and lifetime deterioration due to sand erosion. Especially, the compressor of the aircraft engines is severely damaged. The flow fields of the compressor have strongly three dimensional and unsteady characters. In order to estimate the deterioration due to sand erosion, the sand erosion simulation for the compressor is required under the consideration of the rotor-stator interaction. In the present study, we apply our three dimensional sand erosion prediction code to a single stage axial flow compressor. We numerically investigate the change of the flow field, the particle trajectories, and the eroded wall shape in the compressor, to clarify the effects of sand erosion.

Numerical Investigation on Wavy Streak Formation Due to Sand Erosion

2005 ◽  
Author(s):  
Masaya Suzuki ◽  
Kazuyuki Toda ◽  
Makoto Yamamoto
Keyword(s):  
Flow Field ◽  
Turbulent Flow ◽  
Stokes Equations ◽  
Numerical Procedure ◽  
Particle Collision ◽  
Navier Stokes ◽  
Two Phase ◽  
Sand Erosion ◽  
Wall Deformation ◽  
Turbulent Flow Field

It is well known that sand erosion is a typical multi-physic problem, that is, the interactions among flow field, particle motions and wall deformation are important. To simulate this phenomenon, turbulent flow field, particle trajectories and amount of erosion on an eroded wall are calculated repeatedly. In the computations of the flow field, compressible Navier-Stokes equations and low-Reynolds-number type k-ε turbulence model are adopted. Assuming that the concentration of suspended particles is dilute, particle-particle collision and the influence of particle motions on the flow field are neglected. The Neilson-Gilchrist erosion model is used to estimate the weight loss due to erosion. Based on this numerical procedure, the gas-particle two-phase turbulent flow field in 90-degree bend with a square cross-section is simulated, in order to clarify erosion pattern formation by fluid/particle/wall interaction.

Numerical Simulation of Flow in a Horizontal Sedimentation Tank

2011 ◽  
Vol 130-134 ◽  
pp. 3624-3627
Author(s):  
W.L. Wei ◽  
Zhang Pei ◽  
Y.L. Liu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Secondary Flow ◽  
Mixture Model ◽  
Turbulence Model ◽  
Two Phase ◽  
Sedimentation Tank ◽  
Phase Mixture ◽  
Good Agreement

In this paper, we use two-phase mixture model and the Realizable k-ε turbulence model to numerically simulate the advection secondary flow in a sedimentation tank. The PISO algorithm is used to decouple velocity and pressure. The comparisons between the measured and computed data are in good agreement, which indicates that the model can fully simulate the flow field in a sedimentation tank.

Modelling of a Turbulent Jet in a Gas Crossflow

2013 ◽  
Author(s):  
Dominic L. Moffat ◽  
Alexey A. Burluka
Keyword(s):  
Turbulence Models ◽  
Computation Time ◽  
Flow Region ◽  
Average Density ◽  
Combustion Model ◽  
Main Stream ◽  
Complex Flow ◽  
Two Phase ◽  
Rans Turbulence Models ◽  
Average Surface Area

The first part of this work presents a comparison of predictions obtained with several two-equation type RANS turbulence models commonly used in industry against experimental data obtained by Whitelaw et al [1]. All examined models yield a relatively poor match in the flow region very close to the wall; agreement with the measurements improves significantly when moving further away from the wall. This concerns both the internal normal stress profiles and the average velocity profiles, the latter show improved prediction of the recirculation zone area when moving further into the main stream. Downstream behaviour for both models shows an excellent match more than 6 diameters away from the jet inlet, defined as the region after which the flow essentially resumes its normal duct behaviour[1]. Expanding upon these RANS results, another series of simulations using LES modelling with the standard Smagorinsky SGS model was conducted using the same grid and compared to the RANS-based results. Although performance in the most complex flow areas was slightly improved over RANS, this was at the cost of an increase of computation time by almost a factor of 6. The next stage involved developing a code based on the model for two-phase flow described in [2] to predict the atomisation pattern for a non-vaporising (or “cold”) flow based on the parameters of the previous simulations. This model implements transport equations for the liquid mass fraction and the average surface area per unit mass along with an equation for average density; resulting in an entirely Eulerian model which can be used to predict atomisation from first principles. Current work consists in development of additional source terms describing vaporisation in a strongly turbulent environment and further coupling with a combustion model applicable to the combustion chamber of an industrial gas turbine.

scholarly journals Assessment of RANS Turbulence Models for Straight Cooling Ducts: Secondary Flow and Strong Property Variation Effects

2020 ◽  
pp. 309-321
Author(s):  
Thomas Kaller ◽  
Alexander Doehring ◽  
Stefan Hickel ◽  
Steffen J. Schmidt ◽  
Nikolaus A. Adams
Keyword(s):  
Heat Transfer ◽  
Secondary Flow ◽  
Turbulence Models ◽  
Turbulent Heat Flux ◽  
Special Focus ◽  
Turbulent Heat ◽  
Property Variation ◽  
Rans Turbulence Models ◽  
Rans Simulations ◽  
Scale Turbulence

Abstract We present well-resolved RANS simulations of two generic asymmetrically heated cooling channel configurations, a high aspect ratio cooling duct operated with liquid water at $$Re_b = 110 \times 10^3$$ and a cryogenic transcritical channel operated with methane at $$Re_b = 16 \times 10^3$$. The former setup serves to investigate the interaction of turbulence-induced secondary flow and heat transfer, and the latter to investigate the influence of strong non-linear thermodynamic property variations in the vicinity of the critical point on the flow field and heat transfer. To assess the accuracy of the RANS simulations for both setups, well-resolved implicit LES simulations using the adaptive local deconvolution method as subgrid-scale turbulence model serve as comparison databases. The investigation focuses on the prediction capabilities of RANS turbulence models for the flow as well as the temperature field and turbulent heat transfer with a special focus on the turbulent heat flux closure influence.

scholarly journals PIV test of the flow field of a centrifugal pump with four types of impeller blades

2021 ◽  
Vol 37 ◽  
pp. 192-204
Author(s):  
Baocheng Shi ◽  
Kaili Zhou ◽  
Jianpeng Pan ◽  
XingKai Zhang ◽  
Ruomeng Ying ◽  
...  
Keyword(s):  
Flow Field ◽  
Relative Velocity ◽  
Solid Particles ◽  
Particle Image Velocimetry System ◽  
Pump Efficiency ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Solid Mixture ◽  
Pressure Surface ◽  
Single Arc

Abstract Flow fields for various impellers were measured using water and a two-phase liquid–solid mixture with a particle image velocimetry system in a centrifugal rotating frame in controlled conditions. After measuring absolute velocity vectors in impeller passages, the vectors were decomposed based on the triangle speed principle and the distribution of relative velocity vectors within the impeller was obtained. Then, the distribution of particles and their influence on the performance of different impellers were analyzed. The following conclusions were made from the comparison of relative velocity vector field: first, the wear on the outlet of blades can be mitigated effectively by reducing the outlet angle of impeller blades; second, the pump with a double-arc-shaped profile had a more uniform and stable flow field distribution and higher performance than that with a single-arc profile; and finally, the “jet–wake” structure can be improved significantly by using impellers with long and short blades, resulting in a remarkable reduction in energy loss and improvement in pump efficiency. We also found that solid particles were mainly distributed at the outlet of the impeller and volute wall, while the concentration distribution of large particles tended to match the pressure surface. This research can provide some theoretical guidance for the design and optimization of two-phase flow centrifugal pumps.

scholarly journals Liquid/solid flow field in a centrifugal pump with different impeller blade types by PIV

2021 ◽  
pp. 002029402110223
Author(s):  
Baocheng Shi ◽  
Kun Xue ◽  
Jianpeng Pan ◽  
XingKai Zhang ◽  
Ruomeng Ying ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Vector Fields ◽  
Solid Particles ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Impeller Blade ◽  
Rotating Speed ◽  
Pressure Surface ◽  
Solid Liquid

In this study, a non-stirred Particle Image Velocimetry (PIV) testing device is developed to measure the flow field in a solid–liquid two-phase centrifugal pump. The pump casing and impeller are made of an organic glass material. Two types of impellers are designed considering different structure parameters. The performance curves of the pump are obtained for the different impellers at a rotating speed of 900 rpm with particle concentrations of 0%, 3%, 5%, and 10%. The flow fields for water and a solid–liquid two-phase mixture for the two impellers are measured utilizing the PIV system in a centrifugal rotating frame at the designed condition. The distribution of the particles, together with its influence on the performance of the different impellers, is analyzed. From a comparison of the relative velocity vector fields, the following can be concluded. First, the pump with a double arc-shaped profile demonstrated a more uniform and stable flow field distribution and higher performance than that with a single arc profile. Secondly, the solid particles were distributed mainly at the outlet of the impeller and volute wall, whereas the concentration distribution of the larger particles tended to match the pressure surface. This research can provide theoretical guidance for the design and optimization of two-phase flow centrifugal pumps.

Numerical Analysis on Two-Phase Integration of Sludge Thickening and Digestion Reactor Flow Field

2013 ◽  
Vol 392 ◽  
pp. 131-137
Author(s):  
Hong Xiang Chai ◽  
Wei Jie Wang ◽  
Xue Bin Hu
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Flow Field ◽  
Turbulence Models ◽  
Reaction Chamber ◽  
Design Parameters ◽  
Utilization Rate ◽  
Two Phase ◽  
Improve Design ◽  
Sludge Thickening

A numerical simulation has been carried out to study the flow field in the two-phase integration of sludge thickening and digestion reactor. The study is based on the solution of the complete NavierStokes equations and RNG k-ε turbulence models using a finite volume technique. The analysis results show that the two-phase integration of sludge thickening and digestion reactor exists some problems such as inlet sludge short flow in the connecting pipe, the lower utilization rate of higher part of outer chamber and uneven recycle in the inner reaction chamber. It is valuable to provide basis and improve design parameters, the two-phase integration of sludge thickening and digestion reactor will get a more ideal flow to improve sludge thickening and digestion effect.

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