1464. The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe, where the wall heat flux is constant, is
2.36
4.36
120.36
Dependent on NRe only
✅ The correct answer is option B.
1467. In a backward feed multiple effect evaporator
Feed is introduced in the first effect
Feed flows from low pressure to high pressure
No pumps are required between successive effects
None of these
✅ The correct answer is option B.
1470. Heat produced when a steady state current, I passes through an electrical conductor having resistance, ‘R’ is
IR
I²R
IR²
I²R²
✅ The correct answer is option B.
1473. If air (a non-condensing gas) is present in a condensing vapor stream, it will __________ the condensation rate of vapor.
Increase
Decrease
Not affect
Increase the condensing film co-efficient as well as
✅ The correct answer is option B.
1475. Extremely large or small volumes of fluids are generally best routed through the shell side of a shell and tube heat exchanger, because of the
Less corrosion problems
Flexibility possible in the baffle arrangement
Low pressure drop
High heat transfer co-efficient
✅ The correct answer is option B.
1477. In case of __________ boiling, the bubbles formed on a submerged hot surface get absorbed in the mass of the liquid.
Nucleate
Pool
Low pressure
None of these
✅ The correct answer is option B.
1479. (NRe.NPr)(D/L) is called the __________ number
Peclet
Stanton
Graetz
None of these
✅ The correct answer is option C.
1481. Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a long tube
Exit-fluid temperature > wall temperature
Exit fluid temperature < wall temperature
Exit fluid temperature = wall temperature
Graetz number > 100
✅ The correct answer is option C.
1483. An evaporator while concentrating an aqueous solution from 10 to 40% solids evaporates 30000 kg of water. The amount of solids handled by the system in kg is
4000
9000
4600
3000
✅ The correct answer is option A.
1485. For a multipass shell and tube heat exchanger, the LMTD correction factor is always
1
> 1
< 1
Between 1 & 2
✅ The correct answer is option C.