Angled baffles are preferred in the agitation tank to control the swirling action; if the viscosity of the liquid to be mixed is about 200 poise. However, the baffle may be completely eliminated for mixing liquids having viscosity above ____________________ poise?

Related Mcqs:

1. The centre to centre distance between two consecutive baffles in a shell and tube heat exchanger is called the baffle pitch or baffle spacing, which is more than 1/5th the I.D. of the shell. Which of the following is not a function of the baffles ?

   A. To increase the residence time of shell side fluid
   B. To provide support to the tube bundle
   C. To reduce the induced vibration in the tubes
   D. To increase the tube side heat transfer co-efficient by inducing turbulence

2. Multiple blade paddle agitator is used for mixing high viscosity liquids/paste in which the paddle diameter is commonly 0.8 times the tank diameter. However, the width of the blade is in the range of ______________ times the paddle diameter?

   A. 0.1 to 0.25
   B. 0.3 to 0.5
   C. 0.5 to 0.6
   D. 0.65 to 0.80

3. Baffles are provided in a shell and tube heat exchanger to increase the turbulence and velocity of the shell side fluid. Which of the following shaped baffles does not fall in the category of transverse baffle ?

   A. Segmental baffle
   B. Flat plate extending across the wall
   C. Disk type baffle
   D. Helical type baffle

4. The approximate liquid depth in an agitation tank is equal to (where, d = tank diameter)_________________?

   A. 0.5 d
   B. 0.75 d
   C. d
   D. 2 d

5. The diameter of a propeller agitator used in agitation tank ranges from ____________ percent of the tank diameter and its peripheral speed is normally 300 to 500 metres/minute ?

   A. 5 to 10
   B. 15 to 30
   C. 40 to 50
   D. 55 to 75

6. Baffles may be eliminated for_________________?

   A. Low viscosity liquids (< 200 poise)
   B. High viscosity liquids (> 600 poise)
   C. Large diameter tanks
   D. None of these

7. Baffle width is normally taken as ______________ times the tank diameter?

   A. 0.1-0.12
   B. 0.4-0.5
   C. 0.45-0.6
   D. 0.2-0.45

8. For turbulent flow (NRe > 2100) of low viscosity fluid (μ > 20cp) in steel pipes, the optimum inside pipe diameter is given by(where, Q = fluid flow rate, ft3/sec, ρ = fluid density, lb/ft3 μ = fluid viscosity, centipoise Di = optimum inside pipe diameter, inches) ?

   A. Di, opt = 3.9 Q0.45 ρ0.13
   B. Di, opt = 3.9 Q0.45. μ0.95
   C. Di, opt = 4.7 Q0.36. μ3.2ρ0.13
   D. Di, opt = 3 Q0.36. μ0.88

9. Power required for agitation depends upon the______________________?

   A. Height & properties of the liquid
   B. Agitator type & speed of agitation
   C. Size of agitator & the tank
   D. All A., B. and C.

10. The thickness of segmental baffles (25 -35% cut truncated plates usually) is generally _____________ the tube wall thickness?

    A. Equal to
    B. Twice
    C. Four times
    D. Half