Numerical aspects of flow computation through orifices

Erdal, Abidin; Andersson, Helge I.

doi:10.1016/s0955-5986(97)00017-4

Cited by 60 publications

(22 citation statements)

References 9 publications

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“…Due to the flow symmetry along the x-axis, a 2-D axisymmetric simulation was used to calculate the flow field. To properly resolve regions with large velocity gradients, in all simulations the position of the first element in axial as well as in radial direction was approximately at 5.10 À4 Â d nozzle from the nozzle edge (Erdal and Andersson, 1997). Depending on the applied Re nozzle it was necessary to use 50-100 nodes over the nozzle radius and 200-300 nodes within the capillary.…”

Section: Evaluation Of the Fluid Dynamic Fieldmentioning

confidence: 99%

Induction of mammalian cell death by simple shear and extensional flows

Tanzeglock

Šoóš

Stephanopoulos

et al. 2009

Biotech & Bioengineering

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In this work we investigated whether the type of shear flow, to which cells are exposed, influences the initiation of cell death. It is shown that mammalian cells, indeed, distinguish between discrete types of flow and respond differently. Two flow devices were employed to impose accurate hydrodynamic flow fields: uniform steady simple shear flow and oscillating extensional flow. To distinguish between necrotic and apoptotic cell death, fluorescence activated cell sorting and the release of DNA in the culture supernatant was used. Results show that Chinese Hamster Ovaries and Human Embryonic Kidney cells will enter the apoptotic pathway when subjected to low levels of hydrodynamic stress (around 2.0 Pa) in oscillating, extensional flow. In contrast, necrotic death prevails when the cells are exposed to hydrodynamic stresses around 1.0 Pa in simple shear flow or around 500 Pa in extensional flow. These threshold values at which cells enter the respective death pathway should be avoided when culturing cells for recombinant protein production to enhance culture longevity and productivity.

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Section: Evaluation Of the Fluid Dynamic Fieldmentioning

confidence: 99%

Induction of mammalian cell death by simple shear and extensional flows

Tanzeglock

Šoóš

Stephanopoulos

et al. 2009

Biotech & Bioengineering

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“…Although RANS simulations could reasonably predict the discharge coefficient in certain simulations, first and second order statistics downstream of the orifice plate diverge significantly from experimental data. Erdal and Andersson (1997) demonstrate that the standard k-ε turbulence model does not accurately capture the physics of the flow especially around the region where the fluid accelerates across the pipe. A review of the literature has not found a simulation technique that can reasonably predict both the pressure drop and first and second order statistics downstream of the plate.…”

Section: Introductionmentioning

confidence: 91%

“…Erdal and Andersson (1997), in a two-dimensional axisymmetric simulation of an orifice plate with a standard and modified k-ε model, show that the pressure drop across the orifice plate is highly dependent on the grid refinement around the orifice plate and the turbulence model used. Shah et al (2012) model the orifice flow meter with a standard k-ε model and show that the pressure recovery downstream of the orifice plate is not well predicted.…”

Section: Introductionmentioning

confidence: 98%

Wall-resolved Large Eddy Simulation of a flow through a square-edged orifice in a round pipe at Re = 25,000

Benhamadouche

Arenas

Malouf

2017

Nuclear Engineering and Design

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The orifice plate is a pressure differential device frequently used for flow measurements in pipes across different industries. The present study demonstrates the accuracy obtainable using a wallresolved Large Eddy Simulation (LES) approach to predict the velocity, the Reynolds stresses, the pressure loss and the discharge coefficient for a flow through a square-edged orifice in a round pipe at a Reynolds number of 25000. The ratio of the orifice diameter to the pipe diameter is = 0.62, and the ratio of the orifice thickness to the pipe diameter is 0.11. The mesh is sized using refinement criteria at the wall and preliminary RANS results to ensure that the solution is resolved beyond an estimated Taylor micro-scale. The inlet condition is simulated using a recycling method, and the LES is run with a dynamic Smagorinsky sub-grid scale (SGS) model. The sensitivity to the SGS model and to the pressure-velocity coupling is shown to be small in the present study. The LES is compared with the available experimental data and ISO 5167-2. In general, the LES shows good agreement with the velocity from the experimental data. The profiles of the Reynolds stresses are similar, but an offset is observed in the diagonal stresses. The pressure loss and discharge coefficients are shown to be in very good agreement with the predictions of ISO 5167-2. Therefore, the wall-resolved LES is shown to be highly accurate in simulating the flow across a square-edged orifice.

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“…Turbulence is assumed to be a property of the carrier fluid phase, and turbulent flow is modeled using the k-ε RNG model, which, taking care of the effect of rapid strain in complex flow, it capable of predicting the gross flow behaviour in recirculating region (Pathak, 2011). The same choice was made by other authors who investigated similar kind of flows (Erdal and Anderssont, 1997;Frawley et al, 2010;Pathak, 2011). …”

Section: By the Following Correlation Attributed Tomentioning

confidence: 99%

Numerical investigation of solid-liquid slurry flow through an upward-facing step

Messa¹,

Malavasi²

2013

Journal of Hydrology and Hydromechanics

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Abstract:The flow of a solid-water mixture through an upward-facing step in a channel is numerically investigated. The effect of expansion ratio, mean solids volume fraction and particle diameter on the velocity field, pressure distribution and solid volume fraction field is studied. Expansion ratios of 0.50 and 0.67, particle diameter of 125 µm and 440 µm and mean solid volume fraction between 0.05 and 0.20 are considered. Particle density is 2465 kg m -3 . An Eulerian twofluid model is used to simulate the flow. Due to the lack of experimental data, the model was validated by comparison to other numerical investigations and to experimental data about the horizontal pipe case. Afterwards, it is studied the effect of the above mentioned parameters upon the degree of coupling between the phases and the extension of the disturbance region in the pressure and solid volume fraction fields downstream the step. Parameters of engineering interest, such as the reattachment length and the pressure recovery downstream the enlargement, are investigated.

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Numerical aspects of flow computation through orifices

Cited by 60 publications

References 9 publications

Induction of mammalian cell death by simple shear and extensional flows

Induction of mammalian cell death by simple shear and extensional flows

Wall-resolved Large Eddy Simulation of a flow through a square-edged orifice in a round pipe at Re = 25,000

Numerical investigation of solid-liquid slurry flow through an upward-facing step

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