A. Is always less than arithmetic average value
B. Is always more than arithmetic mean value and the geometric mean value
C. Is always less than arithmetic mean value, but more than geometric mean value
D. May be either more or less than geometric mean and arithmetic mean value depending upon
whether the flow of stream is co-current or counter-current
Related Mcqs:
- In case of a shell and tube heat exchanger, the minimum shell thickness for carbon steel (inclusive of corrosion allowance) depends on shell diameter and is in the range of ________________ mm?
A. 3-5
B. 5-11
C. 8-15
D. 12-18 - Log mean temperature difference in case of multi-pass shell and tube heat exchanger is always_________________?
A. Less than arithmetic mean value
B. More than arithmetic mean value
C. More than geometric mean value
D. Both B. & C. - 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 - 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 - 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 - 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. - 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 - 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 - 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 - In a shell and tube heat exchanger having triangular pitch, the shell side equivalent diameter is given by________________?
A. 4(0.86P2 – πd2/4)/πd
B. (P2 – πd2/4)/πd
C. 4(0.86P2 – πd2)/πd
D. (4P2 + πd2/4)/πd
