Related Questions

Indirect contact heat exchangers are preferred over direct contact heat exchangers, because
A Heat transfer co-efficient are high
B There is no risk of contamination
C There is no mist formation
D Cost of equipment is lower
Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a long tube
A Exit-fluid temperature > wall temperature
B Exit fluid temperature
C Exit fluid temperature = wall temperature
D Graetz number > 100
Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is
A Finned tube heat exchanger with air inside and steam outside
B Finned tube heat exchanger with air outside and steam inside
C Shell and tube heat exchanger with air inside tubes and steam on shell side
D Shell and tube heat exchanger with air on shell side and steam inside tubes
How are the efficiencies of any heat engine (miu) and reversible heat engine (miuR) compared, when both are operating between same heat source and same heat sink?
A miu = miuR
B miu>miuR
C miu
D none of these
In most of the shell and tube heat exchangers, the tube pitch is generally __________ the tube diameter.
A Less than
B 1.25-1.50 times
C 2.5 times
D One-fourth of
In heat exchangers, degree of approach is defined as the difference between temperatures of
A Cold water inlet and outlet
B Hot medium inlet and outlet
C Hot medium outlet and cold water inlet
D Hot medium outlet and cold water outlet
The use of heat exchangers is made in
A Radiators in automobile
B Condensers and boilers in steam plants
C Condensers and evaporators in refrigeration and air conditioning units
D All of the above
Multipass heat exchangers are used
A Because of simplicity of fabrication
B For low heat load
C To obtain higher heat transfer co-efficient and shorter tube
D To reduce the pressure drop
Double pipe heat exchangers are used
A When heat transfer area required is very high
B When heat transfer area required is very low, i.e (100 - 200 ft2)
C Because it occupies less floor area
D Because it is less costly
Minimum tube pitch recommended for shell and tube heat exchangers is about __________ times the outside diameter of the tube.
A 1.25
B 1.75
C 2.5
D 3.5

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