Heat Transfer Operations Practice Test 2

1. When using ΔT_LM for a shell and tube heat exchanger, we cannot use the conventional formula for LMTD.

False

True

2. What are the types of pitch arrangements are available for the baffles to be used in Shell and Tube HE?

Square pitch and Rectangular pitch

Hexagonal pitch & Triangular pitch

Rectangular pitch and Hexagonal pitch

Square pitch and Triangular pitch

3. What is the flow area if the pitch of a shell and tube HE is 40mm, the inner diameter of the tubes is 20mm, clearance is 10mm and baffle space is 10mm?

55 sq mm

60 sq mm

50 sq mm

53 sq mm

4. When phase change occurs in one of the fluids, it is preferred to be kept at the shell side.

True

False

5. Which one of the following fluid cannot be placed in the shell side?

Fluid with very high pressure

Condensing Vapour

Fluid with very high temperature

Fluid with high viscosity

6. To calculate the temperature difference in a Shell and tube heat exchanger, we use _____

LMTD

Square mean of the temperature difference

Mean temperature difference

Median of the temperature difference

7. Consider we have a Double Pipe Heat Exchanger, with the inner tube of diameter 20mm (neglect thickness) and outer tube of diameter 30mm. We have two fluids A & B (both with viscosity 2.5×10^-5Pa-s), we desire to have their flow rates as 15 Kg/s and 21 Kg/s respectively. What is the Reynolds number for this setup for the inner pipe?

15000

13000

12000

14000

8. In a 2-4 Shell and Tube heat exchanger, how many concurrent and counter current flow regimes are observed?

4 concurrent and 0 counter current

1 concurrent and 1 counter current

0 concurrent and 4 counter current

2 concurrent and 2 counter current

9. Use of baffles in shell and tube Heat exchangers increases pressure drop.

False

True

10. We can use mean temperature difference too in place of LMTD if we can calculate it.

False

True