1565. In a shell and tube heat exchanger, putting a longitudinal baffle across the shell, forces the shell side fluid to pass __________ through the heat exchanger.
Once
Twice
Thrice
Four times
✅ The correct answer is option B.
1568. A tank painted with which of the following coloured paints, would heat up maximum by radiation from sun?
Yellow paint
White paint
Black paint
Grey paint
✅ The correct answer is option C.
1571. 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?
35.5
43.75
81.25
48.25
✅ The correct answer is option C.
1574. The variation of thermal conductivity of a metal with temperature is often correlated using an expression of the form K = K₀ + at. where, K is the thermal conductivity and T is the temperature (in °K). The units of ‘a’ in SI system will be
W/m.k
W/m
W/m.k²
None, A is just a number
✅ The correct answer is option C.
1577. Intermittant tube cleaning is possible to be done in case of a __________ evaporator.
Basket type
Horizontal tube
Calendria
None of these
✅ The correct answer is option A.
1580. According to Reynolds analogy, Stanton number is equal to (where, f = Fanning friction factor)
2f
f
f/2
f/4
✅ The correct answer is option C.
1583. 1 BTU/hr.ft.°F is equal to __________ kcal/hr. m.°C.
1.49
1
4.88
None of these
✅ The correct answer is option A.
1586. Heat transfer rate per unit area is called
Thermal conductivity
Heat flux
Heat transfer co-efficient
Thermal diffusivity
✅ The correct answer is option B.
1588. Controlling heat transfer film co-efficient is the one, which offers __________ resistance to heat transfer.
No
The least
The largest
Lower
✅ The correct answer is option C.
1590. Maximum heat transfer rate is obtained in __________ flow.
Laminar
Turbulent
Creeping
Transition region
✅ The correct answer is option B.