Heat Transfer - Study Mode
[#306] For turbulent flow in a tube, the heat transfer co-efficient is obtained from the Dittus-Boelter correlation. If the tube diameter is halved and the flow rate is doubled, then the heat transfer co-efficient will change by a factor of
Correct Answer
(C) 6.1
[#307] A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day, when it is concentrating from 10% to 25% solids. The water evaporated in kg per day is
Correct Answer
(B) 24000
[#308] Harmonic mean temperature difference is given by
Correct Answer
(B) $$frac{{2 cdot Delta {{ ext{T}}_1} cdot Delta {{ ext{T}}_2}}}{{Delta {{ ext{T}}_1} + Delta {{ ext{T}}_2}}}$$
[#309] Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer co-efficient is 3k/l. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade?
Correct Answer
(C) 81.25
[#310] For a counter current heat exchanger with T i h = 80°C, T° c = 60°C, T° h = 50°C and T i c = 30°C, and the temperature difference between the two streams being the same everywhere along Z, the direction of flow of hot fluid. The temperature profile should satisfy
Correct Answer
(B) $$frac{{{{ ext{d}}^2}{ ext{T}}}}{{{ ext{d}}{{ ext{Z}}^2}}} = 0$$