Heat Transfer

271. Mechanical recompression evaporation is used in the production of

1. Alcohol
2. Distilled water
3. Salt
4. Fruits jam

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272. Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter).

1. 0.2 D
2. 0.5 D
3. 0.66 D
4. 0.80 D

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273. Mode of heat transfer in which the fluid moves under the influence of changes in fluid pressure produced by external work is called

1. Radiation
2. Natural convection
3. Forced convection
4. Conduction

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274. Mode of heat transfer involved in the cooling of air cooled internal combustion engine is

1. Conduction
2. Natural convection
3. Forced convection
4. None of these

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275. Multipass heat exchangers are used

1. Because of simplicity of fabrication
2. For low heat load
3. To obtain higher heat transfer co-efficient and shorter tube
4. To reduce the pressure drop

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276. Multiple effect evaporation accounts for

1. Steam economy
2. Lower operating costs
3. Investment economy
4. None of these

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277. Multiple effect evaporation is generally recommended, when the

1. Large scale evaporation of liquor is needed
2. Corrosive liquids are to be concentrated
3. Fuel is cheaply available
4. Evaporation on small scale is to be done

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278. Multiple effect evaporators ar used to

1. Increase the steam economy & decrease the capacity
2. Increase the steam economy & the capacity
3. Decrease the steam economy & the capacity
4. Decrease the steam economy & increase the capacity

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279. Multiple effect evaporators are commonly used in the manufacture of
P. Paper
Q. Superphosphate
R. Sugar
S. Fats

1. P and Q
2. P and R
3. P and S
4. R and S

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280. Natural convection is characterised by

1. Grashoff number
2. Peclet number
3. Reynolds number
4. Prandtl number

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