Pulse properties in gas–liquid flow through randomly packed beds under microgravity conditions

Salgi, Paul; Balakotaiah, Vemuri; Ramé, Enrique; Motil, Brian J.

doi:10.1016/j.ijmultiphaseflow.2015.02.020

Cited by 4 publications

(5 citation statements)

References 18 publications

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“…Lastly, we predict that pulses formed just beyond the transition from bubbly ow may not be stable. Future work will focus on a more detailed comparison with available experimental data from both 0 g and 1 g down-ow data [8][9][10]. We will also continue exploring the feasibility of time-dependent simulations in the nearpulsing regime.…”

Section: Discussionmentioning

confidence: 97%

“…Temporal growth rate (s −1 ) v l, g : Average mesoscale velocity in liquid or gas phase (m/s) p l, g : Average mesoscale pressure in liquid or gas phase (Pa) Data Availability e data on average pulse properties used for comparison with the predictions made in this article may be found in the studies cited within the text as references [8][9][10].…”

Section: Symbols ε Lmentioning

confidence: 99%

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Modeling Pulse Properties near the Bubble-to-Pulse Transition in Randomly Packed Beds

Salgi

Krayem

2019

International Journal of Chemical Engineering

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Traveling wave analysis of a recently developed two-fluid model for bubbly flow in lab-size packed beds is used to propose a constitutive closure for the effective viscosity, a nonzero parameter that is needed in the liquid momentum balance to avoid the prediction of disturbances with an infinite growth rate. Near-solitary wave profiles are predicted over a range of velocity parameters consistent with linear stability analysis. Centimeter-scale periodic disturbances are predicted in the near-pulsing regime. Preliminary estimates of average pulse properties compare well with typically reported experimental values. Initial comparison with time integration subject to periodic boundary conditions shows agreement of the liquid saturation profiles but differences in the liquid velocity profiles.

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Section: Discussionmentioning

confidence: 97%

Section: Symbols ε Lmentioning

confidence: 99%

Modeling Pulse Properties near the Bubble-to-Pulse Transition in Randomly Packed Beds

Salgi

Krayem

2019

International Journal of Chemical Engineering

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“…[This approximate frequency was determined from observation of the pressure traces of the few long-duration experiments]. In contrast, the pulse frequency in both the aircraft and ISS experiments was of the order of 4 Hz, see Salgi et al 31 .…”

Section: Discussionmentioning

confidence: 99%

The international space station packed bed reactor experiment: capillary effects in gas-liquid two-phase flows

et al. 2023

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Experimental data on flow patterns and pressure drop in two-phase gas-liquid flows through a packed bed obtained aboard the International Space Station (ISS) are analyzed in the limit of low flow rates. Four distinct flow regimes (dispersed bubble, pulse, elongated or large bubble, and gas continuous) are observed and the transition boundaries are identified by a change in the slope of the pressure gradient versus flow rate. It is found that the pressure drop is a function of flow history with the relative magnitude of the hysteresis decreasing with increasing gas or liquid flow rates. Pressure drop (or friction factor) correlations are presented for each of the flow regimes. The capillary or interfacial contribution to the pressure gradient is found to be dominant in the gas channeling regime but comparable to the viscous contribution in the large bubble regime. Preliminary data indicating the slow accumulation of the gas in the bed in the large bubble regime over a longer time period and the intermittent nature of this regime are also presented.

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“…Nevertheless, the wall-clock computational times of our CFD simulations were on the order of 2 weeks. Thus, there is still room for improvement and a demonstrated need for reduced-order models (either data-driven or otherwise), such as one-dimensional two-fluid models, 12,[14][15][16][17] to quantitatively investigate the pulse flow regimes and pressure drop correlations. This direction is left for future work.…”

Section: Discussionmentioning

confidence: 99%

“…Two‐phase flow through a PBR under microgravity conditions has been of particular interest because, in these conditions, gravity is no longer a dominant force in setting the displacement behavior. Based on experimental characterizations 9–14 previous work developed empirical models for the streamwise pressure drop, liquid holdup, and flow regime diagram 12,15–17 for gas‐liquid flow through PBRs in microgravity conditions.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamics of bubble flow through a porous medium with applications to packed bed reactors

Nagrani,

Marconnet,

Christov

2023

AIChE Journal

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Gas‐liquid flows through packed bed reactors (PBRs) are challenging to predict due to the tortuous flow paths that fluid interfaces must traverse. Experiments at the International Space Station showed that bubble and pulse flows are predominately observed under microgravity conditions, while the trickle and spray flows observed under terrestrial conditions are not present in microgravity. To understand the physics behind the former experiments, we simulate bubble flow through a PBR for different packing‐particle‐diameter‐based Weber numbers and under different gravity conditions. We demonstrate different pore‐scale mechanisms, such as capillary entrapment, buoyancy entrapment, and inertia‐induced bubble displacement. Then, we perform a quantitative analysis by introducing new dynamic scales, dependent upon the evolving gas‐liquid interfacial area, to understand the dynamic trade‐offs between the inertia, capillary, and buoyancy forces on a bubble passing through a PBR. This analysis leads us to define new dimensionless Weber‐like numbers that delineate bubble entrapment from bubble displacement.

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Pulse properties in gas–liquid flow through randomly packed beds under microgravity conditions

Cited by 4 publications

References 18 publications

Modeling Pulse Properties near the Bubble-to-Pulse Transition in Randomly Packed Beds

Modeling Pulse Properties near the Bubble-to-Pulse Transition in Randomly Packed Beds

The international space station packed bed reactor experiment: capillary effects in gas-liquid two-phase flows

Hydrodynamics of bubble flow through a porous medium with applications to packed bed reactors

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