It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than _________________?

Related Mcqs:

1. LMTD correction factor is used in heat exchanger design for____________________?

   A. Double pipe heat exchanger
   B. Multipass shell and tube heat exchanger
   C. Fouling fluids
   D. Counter flow of hot and cold fluids

2. With increase in temperature drop (in a shell and tube heat exchanger), the LMTD correction factor, FT_________________?

   A. Decreases very rapidly
   B. Increases very rapidly
   C. Remains constant
   D. Increases linearly

3. The LMTD correction factor (FT) is defined as the __________________?

   A. Ratio of true temperature difference to the LMTD
   B. Ratio of LMTD to the true temperature difference
   C. Differenced of true temperature difference and the LMTD
   D. Geometric mean of the true temperature difference and the LMTD

4. The design stress, which is more than the damaging stress, is the least unit stress that will render a member unfit for service before the end of its normal life. The design stress factor or factor of safety indicates the margin between design stress and the _______________ stress?

   A. Working
   B. Damaging
   C. Allowable
   D. None of these

5. Factor of safety (i.e., overdesign factor) in heat transfer equipments is about _____________ percent more than the actual/theoretical design factor?

   A. 5-10
   B. 15-20
   C. 30-35
   D. 35-40

6. Tube side pressure drop in a 1-2 heat exchanger (for turbulent flow of fluids through the tubes) is about __________ times, that in a 1-1 heat exchanger having the same size & number of tubes and operated at the same liquid flow rate ?

   A. 2
   B. ½
   C. 4
   D. 8

7. The average velocity in the tubes of a 1-4 heat exchanger is ______________ times that in 1-1 heat exchanger having the same size & number of tubes and operated at same liquid flow rate ?

   A. 2
   B. 1/2
   C. 4
   D. 1/4

8. _____________ heat exchanger is also known as ‘hair pin type’ exchanger?

   A. Double pipe
   B. Finned
   C. Plate type
   D. Regenerative

9. In the design of a shell and tube heat exchanger, the corrosion allowance ____________________?

   A. Need not be provided for non-pressure parts like tie rods, spacers, baffles, supports etc.
   B. For carbon steel and cast iron pressure parts is 1.5 mm (except for tubes) and for severe
   conditions it is 3 mm
   C. For internal cover and tube sheet is provided on both the sides
   D. All A., B. & C.

10. The clearance between two tubes in a shell and tube heat exchanger is known as ‘ligament’, whose minimum value is _____________ the outside diameter of the tube, but in no case it should be less than 4.5 mm?

    A. Equal to
    B. Half
    C. One fourth
    D. Three fourth