Numerical modelling of the flow in a swelling preform during LCM mould filling

Composite industry increasingly uses natural fibres because of their environment-friendly advantages. These natural fibres may swell during the mould filling process when they absorb resin, and this swelling reduces the porosity and permeability of the preform. Hence, computational modelling of the flow in swelling porous media would be useful to model the different mould filling processes with the swelling effect. This paper demonstrates the possibility of using computational fluid dynamics to study the effect of swelling on liquid composite moulding mould filling in isotropic and orthotropic porous media. An empirical relation for local permeability changes is used to model the flow of resin under constant volume flow rate and constant injection pressure conditions. The flow front locations and inlet pressure predicted by the computational fluid dynamics simulations are in good agreement with the experimental data for 1D rectilinear flow case. Further, to capture the flow patterns, two different arrangements employing point injection are considered. It was observed that the volume fraction of resin in swelling porous medium is 6% less than rigid porous medium at any given time. It was also observed that the location of the inlet and outlet has a considerable effect on the flow front advancement.

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Porous Media Computational Fluid Dynamics and the Role of the First Coil in the Embolization of Ruptured Intracranial Aneurysms

Journal of Clinical Medicine ◽

10.3390/jcm10071348 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1348

Author(s):

Karol Wiśniewski ◽

Bartłomiej Tomasik ◽

Zbigniew Tyfa ◽

Piotr Reorowicz ◽

Ernest Bobeff ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Porous Media ◽

Packing Density ◽

Coil Embolization ◽

Intracranial Aneurysms ◽

Patient Specific ◽

Computational Fluid Dynamics Analysis ◽

Ruptured Intracranial Aneurysms ◽

Statistical Results

Background: The objective of our project was to identify a late recanalization predictor in ruptured intracranial aneurysms treated with coil embolization. This goal was achieved by means of a statistical analysis followed by a computational fluid dynamics (CFD) with porous media modelling approach. Porous media CFD simulated the hemodynamics within the aneurysmal dome after coiling. Methods: Firstly, a retrospective single center analysis of 66 aneurysmal subarachnoid hemorrhage patients was conducted. The authors assessed morphometric parameters, packing density, first coil volume packing density (1st VPD) and recanalization rate on digital subtraction angiograms (DSA). The effectiveness of initial endovascular treatment was visually determined using the modified Raymond–Roy classification directly after the embolization and in a 6- and 12-month follow-up DSA. In the next step, a comparison between porous media CFD analyses and our statistical results was performed. A geometry used during numerical simulations based on a patient-specific anatomy, where the aneurysm dome was modelled as a separate, porous domain. To evaluate hemodynamic changes, CFD was utilized for a control case (without any porosity) and for a wide range of porosities that resembled 1–30% of VPD. Numerical analyses were performed in Ansys CFX solver. Results: A multivariate analysis showed that 1st VPD affected the late recanalization rate (p < 0.001). Its value was significantly greater in all patients without recanalization (p < 0.001). Receiver operating characteristic curves governed by the univariate analysis showed that the model for late recanalization prediction based on 1st VPD (AUC 0.94 (95%CI: 0.86–1.00) is the most important predictor of late recanalization (p < 0.001). A cut-off point of 10.56% (sensitivity—0.722; specificity—0.979) was confirmed as optimal in a computational fluid dynamics analysis. The CFD results indicate that pressure at the aneurysm wall and residual flow volume (blood volume with mean fluid velocity > 0.01 m/s) within the aneurysmal dome tended to asymptotically decrease when VPD exceeded 10%. Conclusions: High 1st VPD decreases the late recanalization rate in ruptured intracranial aneurysms treated with coil embolization (according to our statistical results > 10.56%). We present an easy intraoperatively calculable predictor which has the potential to be used in clinical practice as a tip to improve clinical outcomes.

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Permeability prediction of porous media using a combination of computational fluid dynamics and hybrid machine learning methods

Engineering With Computers ◽

10.1007/s00366-020-01012-z ◽

2020 ◽

Cited By ~ 4

Author(s):

Jianwei Tian ◽

Chongchong Qi ◽

Yingfeng Sun ◽

Zaher Mundher Yaseen ◽

Binh Thai Pham

Keyword(s):

Machine Learning ◽

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Porous Media ◽

Learning Methods ◽

Machine Learning Methods ◽

Permeability Prediction ◽

Hybrid Machine

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Porous Medium Model in Computational Fluid Dynamics Simulation of a Honeycombed SCR DeNOx Catalyst

Chemical Engineering & Technology ◽

10.1002/ceat.201400127 ◽

2015 ◽

Vol 38 (2) ◽

pp. 283-290 ◽

Cited By ~ 8

Author(s):

Jie Yao ◽

Zhaoping Zhong ◽

Lin Zhu

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Porous Medium ◽

Dynamics Simulation ◽

Computational Fluid Dynamics Simulation ◽

Medium Model ◽

Denox Catalyst ◽

Porous Medium Model

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Non-Darcy buoyancy driven flows in a fluid saturated porous medium: the use of asymptotic computational fluid dynamics (ACFD) approach

Heat and Mass Transfer ◽

10.1007/s00231-007-0348-2 ◽

2007 ◽

Vol 44 (9) ◽

pp. 1117-1125 ◽

Cited By ~ 2

Author(s):

D. Jaya Krishna ◽

Tanmay Basak ◽

Sarit K. Das

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Porous Medium ◽

Saturated Porous Medium ◽

Buoyancy Driven Flows ◽

Fluid Saturated Porous Medium

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Computational Modelling of Self-Excited Combustion Instabilities

Volume 2: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations ◽

10.1115/2000-gt-0104 ◽

2000 ◽

Cited By ~ 4

Author(s):

Steve J. Brookes ◽

R. Stewart Cant ◽

Iain D. J. Dupere ◽

Ann P. Dowling

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Heat Release ◽

Large Scale ◽

Computational Modelling ◽

Combustion Efficiency ◽

Design Tool ◽

Premixed Combustion ◽

Combustion Instabilities ◽

Combustion Systems

It is well known that lean premixed combustion systems potentially offer better emissions performance than conventional non-premixed designs. However, premixed combustion systems are more susceptible to combustion instabilities than non-premixed systems. Combustion instabilities (large-scale oscillations in heat release and pressure) have a deleterious effect on equipment, and also tend to decrease combustion efficiency. Designing out combustion instabilities is a difficult process and, particularly if many large-scale experiments are required, also very costly. Computational fluid dynamics (CFD) is now an established design tool in many areas of gas turbine design. However, its accuracy in the prediction of combustion instabilities is not yet proven. Unsteady heat release will generally be coupled to unsteady flow conditions within the combustor. In principle, computational fluid dynamics should be capable of modelling this coupled process. The present work assesses the ability of CFD to model self-excited combustion instabilities occurring within a model combustor. The accuracy of CFD in predicting both the onset and the nature of the instability is reported.

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Double porous media modeling in computational fluid dynamics for hemodynamics of stent-assisted coiling of intracranial aneurysms: A technical case report

Hemorrhagic Stroke ◽

10.1016/j.hest.2020.01.004 ◽

2020 ◽

Vol 1 (1) ◽

pp. 85-88

Author(s):

Masanori Tsuji ◽

Fujimaro Ishida ◽

Tomoyuki Kishimoto ◽

Kazuhiro Furukawa ◽

Yoichi Miura ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Porous Media ◽

Case Report ◽

Intracranial Aneurysms ◽

Double Porous Media

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Computational Fluid Dynamics Using a Porous Media Setting Predicts Outcome after Flow-Diverter Treatment

American Journal of Neuroradiology ◽

10.3174/ajnr.a6766 ◽

2020 ◽

Vol 41 (11) ◽

pp. 2107-2113

Author(s):

M. Beppu ◽

M. Tsuji ◽

F. Ishida ◽

M. Shirakawa ◽

H. Suzuki ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Porous Media ◽

Flow Diverter

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The Effect of Vertical Throughflow on Thermal Instability in a Porous Medium Layer Saturated by a Nanofluid: A Revised Model

Journal of Heat Transfer ◽

10.1115/1.4029773 ◽

2015 ◽

Vol 137 (5) ◽

Cited By ~ 7

Author(s):

D. A. Nield ◽

A. V. Kuznetsov

Keyword(s):

Boundary Condition ◽

Porous Medium ◽

Porous Media ◽

Thermal Instability ◽

Volume Fraction ◽

Critical Rayleigh Number ◽

Nanoparticle Volume Fraction ◽

Governing Equations ◽

Medium Layer ◽

Vertical Throughflow

The model developed in our previous paper (Nield and Kuznetsov, 2011, “The Effect of Vertical Throughflow on Thermal Instability in a Porous Medium Layer Saturated by a Nanofluid,” Transp. Porous Media, 87(3), pp. 765–775) is now revised to accommodate a more realistic boundary condition on the nanoparticle volume fraction. The new boundary condition postulates zero nanoparticle flux through the boundaries. We established that in the new model, oscillatory instability is impossible. We also established that the critical Rayleigh number depends on three dimensionless parameters, and we derived these three parameters from the governing equations. We also briefly investigated the major trends.

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