Abstract
A linear stability analysis for a sedimenting bidisperse gas-solid suspension (or gas flu-idized bed) is performed. Mass, momentum and energy conservation equations for each of the two species are derived using constitutive equations that are valid at high Stokes numbers, (St1 ≫ 1). The homogeneous suspension becomes unstable at sufficiently large St1 to waves of particle volume fraction with the wave number in the vertical direction. Numerical calculations of the growth rate in an unbounded suspension indicate that the marginal stability limits are controlled by the small wave number (k ≪ 1) behavior. Depending on the Stokes number and the volume fractions ø1 and ø2 of the two species, the suspension becomes unstable due to 0(k) or 0(k 2) contributions to the growth rate. The O (k) term corresponds to an instability due to kinematic waves similar to that predicted for bidisperse suspensions of particles in viscous liquids [22]. The 0(k 2) contribution represents an instability to dynamic waves similar to that obtained from an analysis of averaged equations for monodisperse fluidized beds [4].
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Valiveti, P., Koch, D.L. (1998). Instability of Sedimenting Bidisperse Particle Gas Suspensions. In: Biesheuvel, A., van Heijst, G.F. (eds) In Fascination of Fluid Dynamics. Fluid Mechanics and its Applications, vol 45. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-4986-0_16
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DOI: https://doi.org/10.1007/978-94-011-4986-0_16
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