Heat Transfer - Study Mode

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[#256] In case of a multipass shell and tube heat exchanger, the temperature drop in the fluid

(A) Is inversely proportional to the resistance across which the drop occurs

(B) And the wall are proportional to individual resistances

(C) And the wall is not related

(D) None of these

Correct Answer

(B) And the wall are proportional to individual resistances

[#257] Three material A, B and C of equal thick-nes and of thermal conductivity of 20, 40 & 60 kcal/hr. m. °C respectively are joined together. The temperature outside of A and C are 30°C and 100°C respectively. The interface between B and C will be at a temperature of __________ °C.

(A) 40

(B) 95

(C) 70

(D) 50

Correct Answer

(C) 70

[#258] In a 1-1 cocurrent heat exchanger, if the tube side fluid outlet temperature is equal to the shell side fluid outlet temperature, then the LMTD is

(A) ∞

(B) 0

(C) Equal to the difference between hot and cold fluids inlet temperature

(D) Equal to the difference between hot fluid inlet temperature and cold fluid outlet temperature

Correct Answer

(B) 0

[#259] When vaporisation takes place through a blanketting film of gas, the phenomenon is termed as __________ boiling.

(A) Pool

(B) Nucleate

(C) Transition

(D) Film

Correct Answer

(D) Film

[#260] Boiling point elevation for a strong and concentrated solution is found by Duhring's rule, which states that at the same pressure, the boiling point of a solution is a linear function of the __________ of pure water.

(A) Boiling point

(B) Dynamic viscosity

(C) Kinematic viscosity

(D) Density

Correct Answer

(A) Boiling point