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
A tank is filled by three pipes with uniform flow. The first two pipes operating simultaneously fill the tank in the same time during which the tank is filled by the third pipe alone. The second pipe fills the tank 5 hours faster than the first pipe and 4 hours slower than the third pipe. The time required by the first pipe is:
A 6 hours
B 10 hours
C 15 hours
D 30 hours
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
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
Pipe A alone can fill a tankin 8 hours .Pipe B can fill it in 6 hours . If both the pipes are operated and after 2 hours pipe A is closed, then the other pipe will fill the tank in.
A 6 hours
B 3 1/2 hours
C 4 hours
D 1 1/2 hours
A pipe fills a tank in P minuties and another pipe fills the tank in Q minutes. A different pipe makes the tank empty in R minutes. If all these three pipe are opened then in how many minutes the tank will be full?
A p+q-qpqr
B pq+pr-pqpqr
C pq+qr-prpqr
D pqrqr+pr-pq
A water tank with 64-gallon capacity is filled by pipe A and emptied by pipe B. If the rate of water flow through pipe A is 2 gallons per hour, how many gallons per hour should flow through pipe B so that when both pipes are open, the initially empty tank shold be full in exactly 96 hours?
A 3/8
B 4/3
C 2/3
D 8/3
Pipe A can fill an empty cistern in 4 hours while along with Pipe B it can fill it up in 3 hours. Only Pipe A is turned on for an hour after which Pipe B is also turned on. How much total time will it take to fill up the cistern?
A 3 hrs 20 min
B 3 hrs 25 min
C 3 hrs 15 min
D 3 hrs
A concentric double pipe heat exchanger as compared to the shell and tube heat exchanger for the same heat load requires
A Less heating surface
B More space
C Lower maintenance cost
D None of these
The equivalent diameter for the annulus of a double pipe heat exchanger, whose inner pipe has fins on the outside is __________ compared to the same size pipes without fins.
A More
B Less
C Same
D Unpredictable

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