logo

CuriousTab

CuriousTab

Discussion


Home Biochemical Engineering Agitation and Aeration Comments

  • Question
  • Transient flow range of mixing speed is obtained for


  • Options
  • A. Rei<10
  • B. 10<Rei<104
  • C. Rei&gt104
  • D. None of these

  • Correct Answer
  • 10<Rei<104 


  • Agitation and Aeration problems


    Search Results


    • 1. Henry's law relates

    • Options
    • A. the partial pressure of oxygen and the saturation concentration of oxygen in the liquid
    • B. the oxygen transfer rate and the bubble size
    • C. the oxygen transfer rate and the temperature
    • D. the oxygen transfer rate to the partial pressure of oxygen in the liquid
    • Discuss
    • 2. Which of the following is not considered among the three best-known theories of interphase mass transfer?

    • Options
    • A. two-film theory
    • B. penetration theory
    • C. surface renewal theory
    • D. Calderbank and Moo-Young theory
    • Discuss
    • 3. A typical ceiling fan would be best described as a(n)

    • Options
    • A. radial flow impeller
    • B. axial flow impeller
    • C. intermig impeller
    • D. Rushton turbine
    • Discuss
    • 4. Vortexing in stirred tank reactors can be prevented by

    • Options
    • A. installing baffles in the reactor
    • B. shifting the impeller to an off-centre position
    • C. Both (a) and (b)
    • D. using axial flow impellers
    • Discuss
    • 5. The average fractional gas hold up (H) can be given as (where Zf and Zl are the level of aerated and clear liquid respectively)

    • Options
    • A. H = (Zf-Zl)/Zf
    • B. H = Zf/Zl
    • C. H = Zf/ZfZl
    • D. H =(Zf+Zl)/Zf
    • Discuss
    • 6. A flooded impeller will lead to poor oxygen transfer rates because

    • Options
    • A. bubbles tend to coalesce under the impeller
    • B. bubbles tend to break down too rapidly under high shear conditions
    • C. bubbles tend to move too quickly through the bulk liquid
    • D. the cells clog up the surface of the bubble
    • Discuss
    • 7. Turbine impeller consists of flat impeller blades with

    • Options
    • A. a vertical pitch welded directly to the shaft
    • B. a angled pitch welded directly to the shaft
    • C. a vertical pitch welded to a horizontal disk
    • D. a angled pitch welded to a horizontal disk
    • Discuss
    • 8. The power consumption in a stirring vessel can be assessed by using a

    • Options
    • A. dynamometer
    • B. strain gauge attached to agitator shaft
    • C. watt meter attached to agitator motor
    • D. all of these
    • Discuss
    • 9. The rate limiting step in the movement of oxygen from the gas phase in a bubble to the cell is the movement of oxygen molecules through

    • Options
    • A. gas-liquid interface
    • B. bubble boundary layer
    • C. bulk liquid
    • D. gas phase
    • Discuss
    • 10. Swirling and vortex formation can be prevented by

    • Options
    • A. using baffles
    • B. using diffusion ring with turbines
    • C. both (a) and (b)
    • D. none of these
    • Discuss


    Comments

    There are no comments.

Enter a new Comment