Top 1000+ Solved Heat Transfer (HT) MCQ Questions Answer
Q. Which of the following is not used as a medium for high temperature heating ?
a. Dowtherm
b. Mercury
c. Liquid metal (e.g. molten sodium)
d. Fused salts (e.g., an eutectic mixture of 53% KNO3, 40% NaNO2and 7% NaNO3)
Q. In counter flow compared to parallel flow,
a. LMTD is greater
b. Less surface area is required for a given heat transfer rate
c. Both (A) and (B)
d. More surface area is required for a given heat transfer rate
Q. Heat exchangers operating, when the asymptotic range is reached,
a. Provide very large heat transfer co-efficient
b. Results in making part of the heating surface inactive
c. Results in abruptly increased velocity
d. None of these
Q. In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred
a. Through a metallic wall
b. By direct contact of hot flue gas with air
c. By heating an intermediate material (like chequor bricks) and then heating the air from this hot material
d. None of these
Q. In case of evaporators, liquid entrainment results primarily due to
a. High vacuum in the evaporator
b. High evaporation rate
c. Foaming of the solution
d. High heat transfer rate
Q. Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a longtube
a. Exit-fluid temperature > wall temperature
b. Exit fluid temperature < wall temperature
c. Exit fluid temperature = wall temperature
d. Graetz number > 100
Q. The Nusselt number for fully developed (both thermally and hydrodynamically) laminarflow through a circular pipe whose surface temperature remains constant is
a. 1.66
b. 88.66
c. 3.66
d. Dependent on NRe only
Q. Economy of a multiple effect evaporator is not influenced much by the
a. Boiling point elevations
b. Temperature of the feed
c. Rate of heat transfer
d. Ratio of the weight of the thin liquor to thick liquor
Q. For evaporation of viscous solution in a multiple effect evaporator, the preferred feedingscheme is
a. Forward
b. Backward
c. Parallel
d. None of these
Q. Multiple effect evaporators ar used to
a. Increase the steam economy & decrease the capacity
b. Increase the steam economy & the capacity
c. Decrease the steam economy & the capacity
d. Decrease the steam economy & increase the capacity
Q. Heat transfer co-efficient (h1) for liquids increases with
a. Increasing temperature
b. Decreasing temperature
c. Decreasing Reynolds number
d. None of these
Q. Which characteristic of a fluid is not important in deciding its route in a shell and tube heatexchanger?
a. Corrosiveness
b. Fouling characteristic
c. Viscosity
d. None of these