Wall effect on pressure drop in packed beds

Cheng, Nian‐Sheng

doi:10.1016/j.powtec.2011.03.026

Cited by 85 publications

(36 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The remaining models derived for macroscale packed beds that include the bed-toparticle diameter ratio all deviate substantially, 160% to 344% median differences, from the SPH-derived results. As the SPH-derived results appear to match well the Ergun estimate at larger bed-to-particle diameter ratios, the larger deviations seen here for the Eisfeld & Schnitzlein [45], Raichura [60], Cheng [58], and Di Felice & Gibilaro [61] suggest these models are not appropriate for µPBs. The variation of the porosity and axial fluid velocity with position across the radius of the µPBs is shown in Figure 8 for the bed-to-particle diameter ratio of 15.1; the results are similar for all the other µPBs considered here.…”

Section: Micro-packed Bedsupporting

confidence: 46%

Explicit numerical simulation-based study of the hydrodynamics of micro-packed beds

Kashani

Elekaei

Živković

et al. 2016

Chemical Engineering Science

View full text Add to dashboard Cite

Knowledge of the hydrodynamic character of micro-packed beds (µPBs) is critical to understanding pumping power requirements and their performance in various applications, including those where heat and mass transfer are involved. The report here details use of smoothed particle hydrodynamics (SPH) based simulation of fluid flow on models of µPBs derived from X-ray microtomography to predict the hydrodynamic character of the beds as a function of the bed-to-particle diameter ratio over the range 5.2 ≤ ≤ 15.1 ⁄ . It is shown that the permeability of the µPBs decreases in a non-linear but monotonic manner with this ratio to a plateau beyond ⁄ ≈ 10 that corresponded to the value predicted by the Ergun equation. This permeability variation was best represented by the model of Reichelt (Chem.Ing. Technik, 44, 1068Technik, 44, , 1972 and also reasonably well-represented by that of Foumeny (Intnl. Transfer, 36, 536, 1993), both of which were developed using macroscale packed beds of varying bed-to-particle diameter ratios. Four other similarly determined correlations did not match well the permeability variation predicted by SPH. The flow field within the µPBs varied in an oscillatory manner with radial position (i.e. channelling occurred at multiple radial positions) due to a similar variation in the porosity. This suggests that use of performance models (e.g. for heat and mass transfer) derived for macroscale beds may not be suitable for µPBs. The SPH-based approach here may well form a suitable basis for predicting such behaviour, however. J. Heat Mass

show abstract

Section: Micro-packed Bedsupporting

confidence: 46%

Explicit numerical simulation-based study of the hydrodynamics of micro-packed beds

Kashani

Elekaei

Živković

et al. 2016

Chemical Engineering Science

View full text Add to dashboard Cite

show abstract

“…Classical hydrodynamic models neglect wall effects in packed beds when the bed diameter to particle‐size ratio is sufficiently large that its effect on the hydrodynamics is minimal. For large fixed beds, bed‐to‐particle diameter ratios larger than 13 are usually chosen to minimize bypass flow at the bed wall. Previously we established this ratio to be 10 in µPBRs, indicating the bed diameter‐to‐particle size ratio used in this study is sufficiently large that no obvious effect on the hydrodynamics due to column dimensions is expected, particularly with regard to pressure drop and liquid holdup.…”

Section: Resultsmentioning

confidence: 99%

Automated measurements of gas‐liquid mass transfer in micropacked bed reactors

2017

View full text Add to dashboard Cite

Gas-liquid mass transfer in micropacked bed reactors is characterized with an automated platform integrated with inline Fourier transform infrared spectroscopy. This setup enables screening of a multidimensional parameter space underlying absorption with chemical reaction. Volumetric gas-liquid mass-transfer coefficients (k L a) are determined for the model reaction of CO 2 absorption in a methyl diethanolamine/water solution. Parametric studies are conducted varying gas and liquid superficial velocities, packed bed dimensions and packing particle sizes. The results show that k L a values are in the range of 0.12$0.39 s 21 , which is about one-to-two orders of magnitude larger than those of conventional trickle beds. An empirical correlation predicts k L a in micropacked bed reactors in good agreement with experimental data.

show abstract

“…The applicable ranges of the Equations (1-4) have been summarised by Cheng [9] and Reddy et al [10].…”

Section: Montillet and Comiti Equationmentioning

confidence: 99%

“…These simulations have been carried out in air medium at different flow rate viz. (5) Calderbank and Pogorski (6) Dewasch and Froment (7) Klinzing, Shah and William A. Summers (8) Bruneel et al (9) Thermal conductivity [Wm (6) Dewasch and Froment (7) Klinzing, Shah and William A. Summers (8) Bruneel et al (9) Thermal conductivity [Wm …”

Section: Cfd Heat Transfer Study Of Alumina Pebble Bedmentioning

confidence: 99%

CFD Analysis for the Hydrodynamics and Heat Transfer in Packed Pebble Bed

Ghuge

Mandal

2015

Indian Chemical Engineer

View full text Add to dashboard Cite

Lithium titanate (Li 2 TiO 3 ) and lithium orthosilicate (Li 4 SiO 4 ) are the promising solid breeder materials for the fusion reactors. Packed bed of Li 2 TiO 3 or Li 4 SiO 4 pebbles is considered in the fusion reactor blanket for in situ production of tritium and for this a good effective thermal conductivity of the pebble bed is necessary. In recent past, Mandal et al.[26] studied the hydrodynamics and heat transfer properties of bed of lithium titanate pebbles at different operating conditions viz., gas flow rates, pebble sizes, bed wall temperatures, etc. In the present study laminar, k -ε and low Reynolds k -ε model have been used to simulate the hydrodynamics and heat transfer data of Li 2 TiO 3 pebble bed. The computational fluid dynamics (CFD)-simulated hydrodynamics results have been compared with hydrodynamics and heat transfer results of bed of Li 2 TiO 3 pebbles reported by Mandal et al.[26] and others. It was found that k -ε and low Reynolds number k -ε model shows better agreement with experimental results. The CFD study were carried out using low Reynolds k -ε model for pebble bed of different materials viz. Li 2 TiO 3 , Li 4 SiO 4 and alumina (Al 2 O 3 ). The effect of flow rate, pebble size, wall temperature, solid properties viz. thermal conductivity and specific heat on effective thermal conductivity and overall heat transfer coefficient has been discussed in this paper.

show abstract

Wall effect on pressure drop in packed beds

Cited by 85 publications

References 16 publications

Explicit numerical simulation-based study of the hydrodynamics of micro-packed beds

Explicit numerical simulation-based study of the hydrodynamics of micro-packed beds

Automated measurements of gas‐liquid mass transfer in micropacked bed reactors

CFD Analysis for the Hydrodynamics and Heat Transfer in Packed Pebble Bed

Contact Info

Product

Resources

About