Numerical study of hot and cold spheroidal particles in a viscous fluidShow others and affiliations
2020 (English)In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 149, article id 119206Article in journal (Refereed) Published
Abstract [en]
The gravity-driven motion of rigid particles with a temperature difference with respect to the surrounding viscous fluid is relevant in many natural and industrial processes, yet this has mainly been investigated for spherical particles. In this work we study the influence of the Grashof number (Gr) on the settling velocity and the drag coefficient CD of a single spheroidal particle of different aspect ratios (1/3, 1 and 3). The discrete forcing immersed boundary method (IBM) is employed to represent the fluid-solid interaction in both momentum and temperature equations, while the Boussinesq approximation is used for the coupling of momentum and temperature. The simulations show that the drag coefficient of any spheroidal particle below the onset of secondary motion can be predicted by the results of the settling spheres at the desired Grashof number as the main effect of the particle shape at low Galileo number (Ga) and sufficiently small Gr/Ga2 is found to be the change in the frontal area of the particle. Furthermore, we identify the regions of stable sedimentation (vertical path) in the Ga−Gr/Ga2 plane for the 3 particle shapes, investigated in this study. We show that the critical Ga beyond which the particle exhibits the zigzagging motion, is considerably smaller for oblate particles in comparison to prolate ones at low Gr/Ga2. However, both spheroidal shapes indicate a similar behavior as Gr/Ga2 increases beyond 0.5.
Place, publisher, year, edition, pages
Elsevier Ltd , 2020. Vol. 149, article id 119206
Keywords [en]
Direct simulation, Heat transfer, Non-spherical, Sedimentation, Aspect ratio, Drag, Drag coefficient, Grashof number, Turbulent flow, Viscosity, Viscous flow, Boussinesq approximations, Fluid solid interaction, Immersed boundary methods, Industrial processs, Spheroidal particles, Temperature differences, Spheres
National Category
Fluid Mechanics
Identifiers
URN: urn:nbn:se:kth:diva-272253DOI: 10.1016/j.ijheatmasstransfer.2019.119206ISI: 000538009600054Scopus ID: 2-s2.0-85077748676OAI: oai:DiVA.org:kth-272253DiVA, id: diva2:1425703
Note
QC 20200422
2020-04-222020-04-222025-02-09Bibliographically approved