Mass transfer from small spheroids suspended in a turbulent fluid
Mass transfer from small spheroids suspended in a turbulent fluid
By coupling direct numerical simulation of homogeneous isotropic turbulence with a localised solution of the convection-diffusion equation, we model the rate of transfer of a solute (mass transfer) from the surface of small, neutrally buoyant, axisymmetric, ellipsoidal particles (spheroids) in dilute suspension within a turbulent fluid at large Péclet number,. We observe that, at, the average transfer rate for prolate spheroids is larger than that of spheres with equivalent surface area, whereas oblate spheroids experience a lower average transfer rate. However, as the Péclet number is increased, oblate spheroids can experience an enhancement in mass transfer relative to spheres near an optimal aspect ratio. Furthermore, we observe that, for spherical particles, the Sherwood number scales approximately as over to, which is below the scaling observed for inertial particles but consistent with available experimental data for tracer-like particles. The discrepancy is attributed to the diffusion-limited temporal response of the concentration boundary layer to turbulent strain fluctuations. A simple model, the quasi-steady flux model, captures both of these phenomena and shows good quantitative agreement with our numerical simulations.
coupled diffusion and flow, homogeneous turbulence, particle/fluid flow
Lawson, John M.
4e0b1895-51c5-41e6-9322-7f79e76e0e4c
Ganapathisubramani, Bharathram
5e69099f-2f39-4fdd-8a85-3ac906827052
21 October 2021
Lawson, John M.
4e0b1895-51c5-41e6-9322-7f79e76e0e4c
Ganapathisubramani, Bharathram
5e69099f-2f39-4fdd-8a85-3ac906827052
Lawson, John M. and Ganapathisubramani, Bharathram
(2021)
Mass transfer from small spheroids suspended in a turbulent fluid.
Journal of Fluid Mechanics, 929 (A19), [A19].
(doi:10.1017/jfm.2021.867).
Abstract
By coupling direct numerical simulation of homogeneous isotropic turbulence with a localised solution of the convection-diffusion equation, we model the rate of transfer of a solute (mass transfer) from the surface of small, neutrally buoyant, axisymmetric, ellipsoidal particles (spheroids) in dilute suspension within a turbulent fluid at large Péclet number,. We observe that, at, the average transfer rate for prolate spheroids is larger than that of spheres with equivalent surface area, whereas oblate spheroids experience a lower average transfer rate. However, as the Péclet number is increased, oblate spheroids can experience an enhancement in mass transfer relative to spheres near an optimal aspect ratio. Furthermore, we observe that, for spherical particles, the Sherwood number scales approximately as over to, which is below the scaling observed for inertial particles but consistent with available experimental data for tracer-like particles. The discrepancy is attributed to the diffusion-limited temporal response of the concentration boundary layer to turbulent strain fluctuations. A simple model, the quasi-steady flux model, captures both of these phenomena and shows good quantitative agreement with our numerical simulations.
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mass-transfer-from-small-spheroids-suspended-in-a-turbulent-fluid
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Published date: 21 October 2021
Additional Information:
Funding Information:
This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 846648. Declaration of interests
Publisher Copyright:
© 2021 Cambridge University Press. All rights reserved.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
Keywords:
coupled diffusion and flow, homogeneous turbulence, particle/fluid flow
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Local EPrints ID: 453671
URI: http://eprints.soton.ac.uk/id/eprint/453671
ISSN: 0022-1120
PURE UUID: 1d13d07c-15fd-4a15-95bc-2c5d37696cdc
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Date deposited: 20 Jan 2022 17:45
Last modified: 10 Oct 2024 01:56
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