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El Hasadi, Yousef M.F. (author), Padding, J.T. (author)At the beginning of the second half of the twentieth century, Proudman and Pearson (J. Fluid. Mech.,2(3), 1956, pp.237–262) suggested that the functional form of the drag coefficient (C<sub>D</sub>) of a single sphere subjected to uniform fluid flow consists of a series of logarithmic and power terms of the Reynolds number (Re). In this paper...journal article 2023
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Nijssen, T.M.J. (author), Ottens, M. (author), Padding, J.T. (author)Lubrication forces play a major role in the behaviour of fluid–solid systems, where they affect the collisions between particles. Current implementations of lubrication forces in unresolved simulations often suffer from shortcomings, such as neglecting parts of the physics or relying on arbitrarily defined parameters. In this short...journal article 2023
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Butt, E.N. (author), Padding, J.T. (author), Hartkamp, R.M. (author)Electrochemical reduction of CO2 heavily depends on the reaction conditions found near the electrode surface. These local conditions are affected by phenomena such as electric double layer formation and steric effects of the solution species, which in turn impact the passage of CO2 molecules to the catalytic surface. Most models for CO2...journal article 2023
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Blake, J.W. (author), Konderla, V. (author), Baumgartner, L.M. (author), Vermaas, D.A. (author), Padding, J.T. (author), Haverkort, J.W. (author)The use of gas diffusion electrodes that supply gaseous CO<sub>2</sub> directly to the catalyst layer has greatly improved the performance of electrochemical CO<sub>2</sub> conversion. However, reports of high current densities and Faradaic efficiencies primarily come from small lab scale electrolysers. Such electrolysers typically have a...journal article 2023
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Fan, R. (author), Habibi, P. (author), Padding, J.T. (author), Hartkamp, R.M. (author)In heterogeneous catalysis, reactivity and selectivity are not only influenced by chemical processes occurring on catalytic surfaces but also by physical transport phenomena in the bulk fluid and fluid near the reactive surfaces. Because these processes take place at a large range of time and length scales, it is a challenge to model...journal article 2022
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Tsekos, C. (author), de Voogt, D. (author), de Jong, W. (author), Padding, J.T. (author)This work focuses on the numerical modelling and experimental validation of the hydrodynamic behaviour of a novel 50 kW<sub>th</sub> indirectly heated bubbling fluidized bed steam reformer. The hydrodynamic behaviour of fluidized beds with immersed vertical tubes and complex fluidized bed geometries in general have not been thoroughly...journal article 2022
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Sanjeevi, Sathish K.P. (author), Dietiker, Jean F. (author), Padding, J.T. (author)Detailed simulations of flow around various prolate spheroids are performed using multi-relaxation time lattice Boltzmann method (LBM). The simulations are performed in the Reynolds numbers range 0.1≤Re≤2000 at different incident angles 0<sup>∘</sup>≤ϕ≤90<sup>∘</sup> for various prolate spheroids of aspect ratios 1≤λ≤8. The Re is based on the...journal article 2022
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Fan, R. (author), Zachariah, Githin T. (author), Padding, J.T. (author), Hartkamp, R.M. (author)Many physical and chemical processes involve energy change with rates that depend sensitively on local temperature. Important examples include heterogeneously catalyzed reactions and activated desorption. Because of the multiscale nature of such systems, it is desirable to connect the macroscopic world of continuous hydrodynamic and...journal article 2021
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Blake, J.W. (author), Padding, J.T. (author), Haverkort, J.W. (author)The electrochemical reduction of CO<sub>2</sub> on planar electrodes is limited by its prohibitively low diffusivity and solubility in water. Gas-diffusion electrodes (GDEs) can be used to reduce these limitations, and facilitate current densities orders of magnitude higher than the limiting current densities of planar electrodes. These...journal article 2021
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Moghaddam, E.M.C. (author), Foumeny, E.A. (author), Stankiewicz, A.I. (author), Padding, J.T. (author)This paper investigates the validity of azimuthal averaging of 3D temperature fields in the analysis of lateral heat transfer in dense particle packings. This is conducted by synthetic generation of 3D packing surrogates of spheres, cylinders and Raschig rings with tube-to-pellet diameter ratio, 3 < N < 6, using an in-house Rigid Body...journal article 2021
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Kramer, O.J.I. (author), van Schaik, C. (author), Dacomba Torres, P.D.R. (author), de Moel, P.J. (author), Boek, E.S. (author), Baars, E.T. (author), Padding, J.T. (author), van der Hoek, J.P. (author)Granular activated carbon (GAC) filtration is an important unit operation in drinking water treatment. GAC filtration is widely used for its filtration and adsorption capabilities as a barrier for undesired organic macro- and micro-pollutants. GAC filtration consists of two successive phases: adsorption and filtration, capturing the impurities...journal article 2021
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Kramer, O.J.I. (author), de Moel, P.J. (author), Padding, J.T. (author), Baars, Eric T. (author), Rutten, Sam B. (author), Elarbab, Awad H.E. (author), Hooft, Jos F.M. (author), Boek, Edo S. (author), van der Hoek, J.P. (author)Fluid flow through a bed of solid particles is an important process that occurs in full-scale water treatment operations. The Carman–Kozeny model remains highly popular for estimating the resistance across the bed. It is common practice to use particle shape factors in fixed bed state to match the predicted drag coefficient with experimentally...journal article 2021
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Mohammadzadeh Moghaddam, E. (author), Foumeny, Esmail A. (author), Stankiewicz, A.I. (author), Padding, J.T. (author)We investigate forced convective heat transfer in packings of spheres, cylinders and Raschig rings, made of glass, steel and alumina, in relatively narrow tubes. A detailed comparison is made between resolved pellet-scale, azimuthally-averaged temperature profiles, and 2D-axially-dispersed pseudo-homogenous plug flow (2D-ADPF) predictions....journal article 2021
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Kramer, O.J.I. (author), de Moel, Peter J. (author), Kaveripuram Ramasamy, S.R. (author), Baars, Eric T. (author), van Vught, Wim H. (author), Breugem, W.P. (author), Padding, J.T. (author), van der Hoek, J.P. (author)Natural particles are frequently applied in drinking water treatment processes in fixed bed reactors, fluidised bed reactors, and sedimentation processes to clarify water and to concentrate solids. When particles settle, it has been found that, in terms of hydraulics, natural particles behave differently when compared to perfectly round spheres....journal article 2021
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Mema, I. (author), Padding, J.T. (author)Having proper correlations for hydrodynamic forces is essential for successful CFD-DEM simulations of a fluidized bed. For spherical particles in a fluidized bed, efficient correlations for predicting the drag force, including the crowding effect caused by surrounding particles, are already available and well tested. However, for elongated...journal article 2021
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Nijssen, T.M.J. (author), Kramer, O.J.I. (author), de Moel, P.J. (author), Rahman, J. (author), Kroon, J.P. (author), Berhanu, P. (author), Boek, E.S. (author), van der Hoek, J.P. (author), Padding, J.T. (author)Liquid-solid fluidisation is frequently encountered in drinking water treatment processes, for instance in seeded crystallisation softening processes. For modest superficial fluid velocities, liquid–solid fluidisation systems are generally considered to be homogeneous, as reported in literature. However, during fluidisation experiments with...journal article 2021
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Kramer, O.J.I. (author), van Schaik, C. (author), Hangelbroek, J.J. (author), de Moel, P.J. (author), Colin, M.G. (author), Amsing, M. (author), Boek, E.S. (author), Breugem, W.P. (author), Padding, J.T. (author), van der Hoek, J.P. (author)Liquid-solid fluidisation is frequently encountered in drinking water treatment processes, often to obtain a large liquid-solid interfacial surface area. A large surface area is crucial for optimal seeded crystallisation in full-scale softening reactors. Due to crystallisation, particles grow and migrate to a lower zone in the reactor which...journal article 2021
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Jagirdar, Mrinal (author), Lee, Poh Seng (author), Padding, J.T. (author)Internally cooled and heated desiccant-coated heat and mass exchangers (ICHDHMX) driven by low-grade heat are very attractive owing to their energy-saving potential, especially for applications where substantial moisture removal (such as air-conditioning) is a necessity. In this paper, we derive equations for the performance of an ideal...journal article 2021
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Vikrant, V. (author), Padding, J.T. (author)A novel approach to Multiphase-Particle-in-Cell (MP-PIC), called Continuum Particle Model (CPM), is developed for dense gas-particle flows. CPM has high computational speed, comparable to that of MP-PIC, but a robustness and accuracy closer to that of a Discrete Element Model (DEM). The gas phase is treated as a continuum phase and particles...journal article 2020
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Mohammadzadeh Moghaddam, E. (author), Foumeny, E. A. (author), Stankiewicz, A.I. (author), Padding, J.T. (author)The local flow structure and pressure drop in random packings of Raschig rings are analyzed using sequential Rigid Body Dynamics (RBD) method and Computational Fluid Dynamics (CFD) simulation. Tube-to-pellet diameter ratios, N, between 3 and 6 are investigated for laminar, transitional and turbulent flow regimes (5 ≤ Re<sub>p</sub> ≤ 3,000)....journal article 2020