Which of the following is the best tube material from thermal conductivity point of view alone ?

Related Mcqs:

1. 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

2. In most of the shell and tube heat exchangers, the tube pitch is generally ______________ the tube diameter?

   A. Less than
   B. 1.25-1.50 times
   C. 2.5 times
   D. one-fourth of

3. In a shell and tube heat exchanger, the overall heat transfer co-efficient is proportional to the tube side (volumetric flow rate)0.8. This is valid, only when the ratio of the tube side film resistance to the total resistance is almost equal to____________________?

   A. ∞
   B. 1
   C. 20.8
   D. 2

4. Minimum tube pitch recommended for shell and tube heat exchangers is about _______________ times the outside diameter of the tube?

   A. 1.25
   B. 1.75
   C. 2.5
   D. 3.5

5. In which of the following evaporators, steam is fed inside the tube while the liquor is outside the tube ?

   A. Long tube vertical evaporator
   B. Short tube vertical evaporator
   C. Horizontal tube evaporator
   D. None of these

6. Tube wall thickness depends on the corrosiveness of the fluids and their operating pressure & temperature and is specified by Birmingham wire gauge (B.W.G)-a number which varies from 8 to 18 with the numbers 14 and 16 being more commonly used. Outside diameter of tubes varies from about 15 to 50 mm; however a tube of less than _____________ mm outside diameter is generally not recommended for fouling fluids ?

   A. 16
   B. 19
   C. 28
   D. 38

7. In a shell and tube heat exchanger having square pitch, the shell side equivalent diameter is given by (where, P = pitch, d = outside diameter of the tube) ?

   A. 4(P2 – πd2/4)/πd
   B. (P2 – rd2/4)/rd
   C. 4P2/πd
   D. πd/4P2

8. The ratio of tube length to shell diameter in case of liquid shell and tube heat exchanger ranges from__________________?

   A. 2 to 3
   B. 3 to 5
   C. 4 to 8
   D. 6 to 12

9. In a shell and tube heat exchanger, the ‘tube pitch’ is defined as the _____________________?

   A. O.D. of the tube for square pitch
   B. Shortest distance between two adjacent tube holes
   C. Shortest centre to centre distance between adjacent tubes
   D. None of these

10. Ratio of tube length to shell diameter for a shell and tube heat exchanger is________________?

    A. 8 : 1 to 12 : 1 for both liquid-liquid and gas-gas heat exchangers
    B. 4 : 1 to 8 : 1 for liquid-liquid exchanger
    C. < 4 : 1 for gas-gas exchangers
    D. Both B. & C.