Chemical Heat Transfer

Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2.°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the_________________?

A. Higher condensing film co-efficient is desired
B. Condensate is corrosive in nature
C. Lower pressure drop through the exchanger is desired
D. Temperature of the incoming vapor is very high

Read More Details about this Mcq:

A cube, sphere & a thin circular plate (all having same mass and made of same material) are all heated to 300°C and allowed to cool in natural air. Which one will cool the slowest ?

A. Cube
B. Plate
C. Sphere
D. All will cool at the same rate

Read More Details about this Mcq:

A steel sphere of radius 0.1 m at 400°K is immersed in an oil at 300°K. If the centre of the sphere reaches 350°K in 20 minutes, how long will it take for a 0.05 m radius steel sphere to reach the same temperature (at the centre) under identical conditions? Assume that the conductive heat transfer co-efficient is infinitely large ?

A. 5 minutes
B. 10 minutes
C. 20 minutes
D. 40 minutes

Read More Details about this Mcq:

Presence of a non-condensing gas in a condensing vapour___________________?

A. Increases the rate of condensation
B. Decreases thermal resistance
C. Is desirable to increase the film co-efficient
D. None of these

Read More Details about this Mcq:

The critical radius of insulation for cylindrical pipe is (where, hi = heat transfer coefficient at inside of the pipe) ?

A. K/h0
B. 2K/h0
C. hi/K
D. 2hi/K

Read More Details about this Mcq:

A process stream of dilute aqueous solution flowing at the rate of10 Kg.s-1 is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 Kg.s-1. A 1 – 1 shell and tube heat exchanger is available. The best arrangement is_______________?

A. Counter flow with process stream on shell side
B. Counter flow with process stream on tube side
C. Parallel flow with process stream on shell side
D. Parallel flow with process stream on tube side

Read More Details about this Mcq:

Natural convection is characterised by__________________?

A. Grashoff number
B. Peclet number
C. Reynolds number
D. Prandtl number

Read More Details about this Mcq:

The unit of heat transfer co-efficient is_________________?

A. BTU/hr. ft2°F
B. BTU/hr. °F. ft
C. BTU/hr. °F
D. BTU/hr. ft

Read More Details about this Mcq:

In Joule’s experiment, an insulated container contains 20 kg of water initially at 25°C. It is stirred by an agitator, which is made to turn by a slowly falling body weighing 40 kg through a height of 4 m. The process is repeated 500 times. The acceleration due to gravity is 9.8 ms-2. Neglecting the heat capacity of agitator, the temperature of water (in °C) is________________?

A. 40.5
B. 34.4
C. 26.8
D. 25

Read More Details about this Mcq:

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

A. P and Q
B. P and R
C. P and S
D. R and S

Read More Details about this Mcq: