Particle‐resolved turbulent flow in a packed bed: RANS, LES, and DNS simulations

Ambekar, Aniket S.; Schwarzmeier, Christoph; Rüde, Ulrich; Buwa, Vivek V.

doi:10.1002/aic.17615

Cited by 13 publications

(5 citation statements)

References 41 publications

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“…Although the computational cost of LES is lower than that of DNS, LES still requires more computational resources compared to RANS [42][43][44]. Considering the balance between accuracy and computational efficiency of the simulations in this study, the RANS model, which is widely used in engineering, was chosen.…”

Section: Numerical Methodology 221 Governing Equations and Turbulence...mentioning

confidence: 99%

Numerical investigation into turbulent drag reduction via the application of pufferfish spine-inspired cone microstructures in Suboff models

Zhao,

Zhu,

Feng

et al. 2024

Phys. Scr.

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The effective reduction of seawater drag is pivotal in enhancing the speed and minimizing the energy consumption of submarines, which has significant implications in the fields of energy and defense. Surface bionics has emerged as one of the leading techniques for drag reduction. Current research primarily focuses on replicating the groove-like structures observed on shark skins and the flexible properties of dolphin skins. However, the application of cone microstructures on submarine surfaces remains relatively underexplored. In this study, a novel arrangement of bionic drag-reducing microstructures is employed to modify the turbulence structure surrounding the submarine by incorporating bionic cone microstructures at both the front and rear ends of the submarine. Numerical simulations were performed using the SST k-ω turbulence model to evaluate the impact of these frontal microstructures on drag reduction under varying Reynolds numbers, spacings, and positions, as well as the tail microstructures' effect at different Reynolds numbers, heights, and circumferential separation angles. The findings reveal that positioning microstructures at the submarine's head increases the drag reduction rate proportionally with the distance from the apex, displaying an inverse relationship between spacing and drag reduction rate. Conversely, an increase in cone separation angle at the tail leads to a decrease in the overall drag reduction rate. At the same time, an inverse proportionality is observed between cone height and drag reduction rate. This suggests that cone microstructures play a dual role: mitigating friction drag greatly and augmenting pressure drag, thereby achieving overall drag reduction. Moreover, these cone microstructures disrupt eddy currents within the boundary layer surrounding the submarine, restraining the propagation of turbulent momentum transfer in both the head and tail regions. This research not only pioneers a novel drag reduction strategy for underwater vehicles but also sparks new avenues for their optimized surface design.

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Section: Numerical Methodology 221 Governing Equations and Turbulence...mentioning

confidence: 99%

Numerical investigation into turbulent drag reduction via the application of pufferfish spine-inspired cone microstructures in Suboff models

Zhao,

Zhu,

Feng

et al. 2024

Phys. Scr.

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“…In the present work, the particle-resolved VOF simulations were performed to simulate the gas–liquid (air–water) flow through a small portion of beds using the open-source flow solver OpenFOAM v6. All the simulations were performed at a particle Reynolds number [ Re p = ( ρ l d p V s / μ l , where V s is the superficial liquid velocity (m/s), ρ l and μ l is density (kg/m 3 ) and viscosity of liquid (Pa.s), respectively] of 31 corresponding to the laminar regime . The fluids were considered Newtonian and incompressible.…”

Section: Methodsmentioning

confidence: 99%

“…All the simulations were performed at a particle Reynolds number [Re p = (ρ l d p V s /μ l , where V s is the superficial liquid velocity (m/s), ρ l and μ l is density (kg/m 3 ) and viscosity of liquid (Pa.s), respectively] of 31 corresponding to the laminar regime. 22 The fluids were considered Newtonian and incompressible. In the VOF method, 23 a single set of continuity (eq 1) and momentum (eq 2) equation was solved…”

Section: Computational Modelmentioning

confidence: 99%

Effect of Particle Aspect Ratio and Shape on the Particle-Scale Dynamics of Gas–Liquid Flow through Packed Beds

Ambekar

Singh

Kumari

et al. 2023

Ind. Eng. Chem. Res.

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Packed beds are widely used to perform solid-catalyzed gas–liquid reactions and gas cleanup processes. In the present work, we simulated gas–liquid flow through realistic 3D particle-resolved domains consisting of cylindrical particles of varying aspect ratio (h = 1–5) and different particle shapes (Raschig ring, trilobe, daisy, and sphere) using the volume-of-fluid method. With an increase in h, we found that the number fraction of laterally oriented particles decreases and length of elongated void-throats increases. Further, we found that liquid preferentially flows over surface of laterally oriented particles and through elongated void-throats. The combined effect of h, orientation distribution, and elongated void-throats results in improved hydrodynamic performance (liquid holdup, wetting efficiency, interfacial area, and liquid distribution) with an increase in h. We also found that the hydrodynamic performance of trilobe- and daisy-shaped particles is better than cylindrical particles in terms of interfacial area due to preferential flow of liquid through the grooves on externally shaped particles.

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“…[19][20][21][22][23][24][25][26] Although such a mesh can represent the interface accurately, the mesh needs to be extremely fine at the contact point of the solid particles, which leads to high computational costs. 27 To solve these issues at the contact points, different approaches are proposed, for example, shrinking of the particle [28][29][30][31][32] and using a cylindrical bridge between the particles. 30,33 However, these methods change the particle size and thus the porosity of the bed.…”

Section: Simulationsmentioning

confidence: 99%

Hydrodynamics in a randomly packed bed of spheres: A comparison between PR‐CFD simulations and MRI experiments

Eghbalmanesh,

Romijn,

Baltussen

et al. 2024

AIChE Journal

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Multitubular reactors are commonly used in industry for processes involving highly exothermic chemical reactions. This reactor type consists of individual tubes, with a small diameter compared to the particle size. These slender beds facilitate heat management, but also give rise to flow maldistribution, which decreases the reactor efficiency. The aim of this article is to validate particle‐resolved simulations using Magnetic Resonance Imaging experiments while focusing on the flow maldistribution. The packing structure used in the simulations is reconstructed from the experimental images to facilitate a one‐to‐one comparison. A good match between experiments and simulations is found for the averaged flow profile, probability density function of the velocity in axial direction and even the local velocity distributions. However, a correction of the experimental results for magnetic susceptibility artifacts is necessary to obtain a similar match in the probability density functions and the local profiles.

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Particle‐resolved turbulent flow in a packed bed: RANS, LES, and DNS simulations

Cited by 13 publications

References 41 publications

Numerical investigation into turbulent drag reduction via the application of pufferfish spine-inspired cone microstructures in Suboff models

Numerical investigation into turbulent drag reduction via the application of pufferfish spine-inspired cone microstructures in Suboff models

Effect of Particle Aspect Ratio and Shape on the Particle-Scale Dynamics of Gas–Liquid Flow through Packed Beds

Hydrodynamics in a randomly packed bed of spheres: A comparison between PR‐CFD simulations and MRI experiments

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