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您的检索式：作者名="M.A. van der Hoef"
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| 1 | Two-fluid modeling of Geldart A particles in gas-fluidized beds显示文摘We have investigated the effect of cohesion and drag models on the bed hydrodynamics of Geldart A particles based on the two-fluid (TF) model. For a high gas velocity U0 = 0.03 m/s, we found a transition from the homogeneous fluidization to bubbling fluidization with an increase of the coefficient C1, which is used to account for the contribution of cohesion to the excess compressibility. Thus cohesion can play a role in the bed expansion of Geldart A particles. Apart from cohesion, we have also investigated the influence of the drag models. When using the Wen and Yu drag correlation with an exponent n = 4.65, we find an under-prediction of the bed expansion at low gas velocities (U0 = 0.009 m/s). When using a larger exponent (n = 9.6), as reported in experimental studies of gas-fluidization, a much better agreement with the experimental bed expansion is obtained. These findings suggest that at low gas velocity, a scale-down of the commonly used drag model is required. On the other hand, a scale-up of the commonly used drag model is necessary at high gas velocity (U0 = 0.2 and 0.06 m/s). We therefore conclude that scaling the drag force represent only an ad hoc way of repairing the deficiencies of the TF model, and that a far more detailed study is required into the origin of the failure of the TF model for simulating fluidized beds of fine powders. | M.A. van der Hoef J.A.M. Kuipers | 2008 | Particuology2008，6，6： | 16 |
| 2 | Gas–solid interaction force from direct numerical simulation (DNS) of binary systems with extreme diameter ratios显示文摘Fluid-particle systems as commonly encountered in chemical, metallurgical and petroleum industries are mostly polydisperse in nature. However, the relations used to describe fluid-particle interactions are originally derived from monodisperse systems, with ad hoc modifications to account for polydispersity. In previous work it was shown that for bidisperse systems with moderate diameter ratios of 1:2 to 1:4, this approach leads to discrepancies, and a correction factor is needed. In this work we demonstrate that this correction factor also holds for more extreme diameter ratios of 1:5, 1:7 and 1:10, although the force on the large particles is slightly overestimated when using the correction factor. The main origin of the correction is that the void surrounding the large particles becomes less in case of a bidisperse mixture, as compared to a monodisperse system with the same volume fraction. We further investigated this discrepancy by calculating the volume per particle by means of Voronoi tessellation. | S. Sarkar S.H.L. Kriebitzsch M.A. van der Hoef J.A.M. Kuipers | 2009 | Particuology2009，7，4： | 2 |
| 3 | From bubbling to turbulent fluidization: Advanced onset of regime transition in micro-fluidized beds显示文摘 | Junwu Wang Lianghui Tan M.A. van der Hoef M. van Sint Annaland J.A.M. Kuipers | 2011 | Chemical Engineering Science2011，，9： | 1 |
| 4 | Fluidization with hot compressed water in micro-reactors显示文摘 | B. Potic S.R.A. Kersten M. Ye M.A. van der Hoef J.A.M. Kuipers W.P.M. van Swaaij | 2005 | Chemical Engineering Science2005，，22： | 1 |
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