Which of the following lengths of heat exchanger tubes are normally not used in practice ?

Related Mcqs:

1. 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

2. 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

3. In a shell and tube heat exchanger for a given heat transfer surface area, smaller diameter tubes are favoured as compared to larger diameter ones; because the smaller diameter tubes ______________?

   A. Are easier to clean
   B. Are less prone to fouling
   C. Can be fitted into a smaller shell diameter hence the cost of the heat exchanger would be less
   D. None of these

4. In a shell and tube heat exchanger, the shortest centre to centre distance between the adjacent tubes is__________________?

   A. Called tube pitch
   B. Called tube clearance
   C. Always less than the diameter of the tube
   D. None of these

5. 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

6. In case of 1.5″ heat exchanger tubes, the inside flow area _____________ with decrease in BWG?

   A. Increases
   B. Decreases
   C. Remains same
   D. None of these

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

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

8. Tubes are fixed to the tube sheet (a thick circular metallic plate) by the method of tube rolling and brazing (non-removable) or ferrule connection (removable). Thickness of the tube, sheet is normally ____________ the outside diameter of the tube but in no case it should be less than 22 mm (7/8″)?

   A. Half
   B. Three fourth
   C. Equal to
   D. 1.5 times

9. The thickness of heat transfer plates used in the plate type heat exchanger ranges from _____________ mm, pressed in a single piece provided with grooves & corrugations?

   A. 0.3 to 0.8
   B. 1.25 to 3.125
   C. 3.5 to 7.0
   D. 8 to12

10. In case of a shell and tube heat exchanger, the effect of L/D on inside film heat transfer coefficient (hi) vanishes after a Reynold number of_____________?

    A. 1000
    B. 3000
    C. 5000
    D. 10000