Multiple Particle Systems: Settling of a Suspension

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Questions and Answers

What is used to model the multiple particle system in a suspension of particles in a fluid?

  • Effective viscosity and average suspension density (correct)
  • Drag coefficient
  • Stokes' law
  • Fluid particle interaction

What does 'e' represent in the context of the suspension of particles in a fluid?

  • Fluid particle interaction
  • Voidage or volume fraction occupied by the fluid (correct)
  • Drag coefficient
  • Stokes' law

What is the drag coefficient for a single particle in the Stokes' law region?

  • R0/rave Urel
  • 24me
  • 24/Rep (correct)
  • (24me)/(Rep Urel rave)

What does 'Urel' represent in the context of the suspension of particles in a fluid?

<p>Relative velocity of the particle to the fluid (C)</p> Signup and view all the answers

What is used to calculate the effective average suspension density for a suspension of particles in a fluid?

<p>(erf + (1 - e)rp) (C)</p> Signup and view all the answers

Which law becomes modified when effective viscosity and average density are used to model a suspension of particles in a fluid?

<p>Stokes' Law (D)</p> Signup and view all the answers

In hindered settling under gravity, what is the relative velocity between the particles and the fluid?

<p>$UrelT - UT ef(e)$ (C)</p> Signup and view all the answers

What is the expression for the hindered settling velocity of particles relative to the vessel wall in batch settling?

<p>$UT / (e^2*f(e))$ (D)</p> Signup and view all the answers

What does the effective viscosity function, f(e), represent for uniform spheres forming a suspension of solid volume fraction less than 0.1?

<p>A function of the solid volume fraction (A)</p> Signup and view all the answers

What does Ufs represent in the context of a suspension of particles in a fluid?

<p>Superficial fluid velocity (D)</p> Signup and view all the answers

What are the actual velocities of the fluid and the particles, Uf and Up, given by?

<p>$Ufs * e$ and $Ups * (1 - e)$ (D)</p> Signup and view all the answers

What is the flow area occupied by the particles, Ap, in terms of the vessel cross-sectional area A and the solid volume fraction e?

<p>$(1 - e)A$ (A)</p> Signup and view all the answers

What does UrelT represent in the context of a particle in a suspension?

<p>$UT * ef(e)$ (A)</p> Signup and view all the answers

What is the expression for the terminal falling velocity for a particle in a suspension, UrelT, when considering average density, effective viscosity, particle density, gravitational acceleration, and solid volume fraction?

<p>$(rp - rf)<em>x^2</em>g<em>ef(e)/(18</em>m) (D)</p> Signup and view all the answers

What is the relation between flow area occupied by the fluid, Af, and vessel cross-sectional area A?

<p>$eA$ (C)</p> Signup and view all the answers

What is the expression for UrelT when comparing it with UT using effective viscosity function ef(e)?

<p>$UrelT = UT*ef(e)$ (A)</p> Signup and view all the answers

What is the effective viscosity of the suspension equal to?

<p>The fluid viscosity modified by a function of the fluid volume fraction (D)</p> Signup and view all the answers

What does the average suspension density (rave) represent?

<p>The voidage or volume fraction occupied by the fluid (D)</p> Signup and view all the answers

What does the drag coefficient (CD) represent in the context of a single particle in the Stokes' law region?

<p>The relative velocity of the particle to the fluid (C)</p> Signup and view all the answers

What is used to calculate the effective average suspension density for a suspension of particles in a fluid?

<p>Effective viscosity function f(e) (C)</p> Signup and view all the answers

What is the relation between CD, R0, and rave when using effective viscosity and average density to model a suspension of particles in a fluid?

<p>$CD = R0/rave$ (A)</p> Signup and view all the answers

What does the voidage or volume fraction occupied by the fluid represent in the context of a suspension of particles in a fluid?

<p>The relative velocity of the particle to the fluid (C)</p> Signup and view all the answers

What does the term UrelT represent in the context of a particle in a suspension?

<p>The particle settling velocity in the presence of other particles (A)</p> Signup and view all the answers

What is the relation between flow area occupied by the fluid, Af, and vessel cross-sectional area A?

<p>$Af = eA$ (D)</p> Signup and view all the answers

What is used to calculate the effective average suspension density for a suspension of particles in a fluid?

<p>Effective viscosity function (D)</p> Signup and view all the answers

What is the drag coefficient for a single particle in the Stokes' law region?

<p>$3.4$ (B)</p> Signup and view all the answers

What does 'Ufs' represent in the context of a suspension of particles in a fluid?

<p>Superficial fluid velocity (A)</p> Signup and view all the answers

What does 'e' represent in the context of the suspension of particles in a fluid?

<p>Solid volume fraction (D)</p> Signup and view all the answers

What are the actual velocities of the fluid and the particles, Uf and Up, given by?

<p>$Uf = Ufs/e$, $Up = Ups/(1 - e)$ (B)</p> Signup and view all the answers

Which law becomes modified when effective viscosity and average density are used to model a suspension of particles in a fluid?

<p>Stokes' law (D)</p> Signup and view all the answers

What does 'Up' represent in the context of batch settling?

<p>Superficial particle velocity (B)</p> Signup and view all the answers

What is used to model the multiple particle system in a suspension of particles in a fluid?

<p>Superficial velocities of the fluid and the particles (D)</p> Signup and view all the answers

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