chemical engineering heat transfer chemical engineering MCQs – Page 18

Practise multiple-choice questions from chemical engineering heat transfer chemical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering heat transfer chemical engineering Mcqs
341. If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is________________?
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A. Always higher than h2

B. Always between h1 and h2

C. Always less than h1

D. Dependent on metal resistance

342. The equivalent diameter for pressure drop is ________________ that for heat transfer?
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A. Smaller than

B. Greater than

C. Equal to

D. Not related with

343. Low thermal conductivity of heat insulating materials is due to its_________________?
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A. High specific heat

B. Dense structure

C. High proportion of air space

D. None of these

344. Steady state one dimensional heat flow by conduction as given by Fouriers low does not assume that_______________?
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A. Constant temperature gradient exists

B. Boundary surfaces are isothermal

C. There is no internal heat generation

D. Material is anisotropic
345. Mechanical recompression evaporation is used in the production of____________________?
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A. Distilled water

B. Fruits jam

C. Alcohol

D. Salt

346. Heat exchangers operating, when the asymptotic range is reached, ?
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A. None of these

B. Results in making part of the heating surface inactive

C. Provide very large heat transfer co-efficient

D. Results in abruptly increased velocity

347. In a multipass shell and tube heat exchanger, tube side return pressure loss is equal to _____________ the velocity head?
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A. Square root of

B. Twice

C. Square of

D. Four times
348. A backward feed multiple effect evaporator is better than forward feed for concentrating cold feed, because it provides __________________?
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A. Higher economy

B. Lower capacity

C. Both A. & B.

D. Lower economy

349. Which of the following is concerned with both heat and mass transfer ?
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A. Froude number

B. Kutateladze number

C. Nusselt number

D. Lewis relationship
350. 1000 Kg of liquid at 30C in a well stirred vessel has to be heated to 120C, using immersed coils carrying condensing steam at 150C. The area of the steam coils is 1.2 m2 and the overall heat transfer co-efficient to the liquid is 1500 W/m2.C. Assuming negligible heat loss to the surrounding and specific heat capacity of the liquid to be 4 kJ/kg.C, the time taken for the liquid to reach desired temperature will be__________________?
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A. 44 min

B. 15 min

C. 51 min

D. 22 min

351. A body is called grey if the monochromatic emissivity of the body is___________________?
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A. Unity

B. Different for all wavelengths

C. Zero

D. Same for all wavelengths
352. For evaporation of viscous solution in a multiple effect evaporator, the preferred feeding scheme is _________________?
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A. Forward

B. Backward

C. None of these

D. Parallel

353. In natural convection heat transfer, the correlating parameter is the_______________________?
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A. Eckert number

B. Grashoff number

C. Bond number

D. Graetz number

354. Prandtl number is the ratio of________________?
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A. Thermal diffusivity to mass diffusivity

B. Momentum diffusivity to thermal diffusivity

C. Mass diffusivity to thermal diffusivity

D. Thermal diffusivity to momentum diffusivity

355. Which of the following is not concerned with the heat transfer ?
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A. Peclet number

B. Stanton number

C. Brinkman number

D. Schmidt number
356. In case of a multipass shell and tube heat exchanger, providing a baffle on the shell side ______________ the heat transfer rate?
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A. Decreases

B. Does not affect

C. Increases

D. May increase or decrease, depends on the type of baffle

357. Heat transfer efficiency leading of energy conservation in a heat exchanger can be achieved by____________________?
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A. Enhancing the fluid pumping rate

B. Keeping the heat transfer surface clean

C. Increasing the tube length

D. None of these

358. In a multiple effect evaporator, the effect of boiling point elevation is to______________________?
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A. Increase the economy

B. Reduce the economy

C. Reduce the capacity

D. None of these

359. The separation of liquid droplets from the vapor is done by a/an _____________ in the evaporators?
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A. Entrainment separator

B. Vacuum pump

C. Steam ejector

D. Compressor

360. Fouling factor used in the design of a multipass shell and tube heat exchanger is a_____________________?
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A. None of these

B. Conversion factor for individual film heat transfer co-efficient to overall heat transfer coefficient

C. Factor of safety

D. Non-dimensional factor