A. Decreases the pressure drop
B. Decreases the outlet temperature of cooling medium
C. Increases the overall heat transfer coefficient
D. None of these
0
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 coefficient is „3k/l’. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade ?
0
A graph between _____________ is called Wilson plot?
A. 35.5
B. 43.75
C. 81.25
D. 48.25
0
For a laminar flow of fluid in a circular tube, ‘h1’ is the convective heat transfer co-efficient at velocity ‘V1’. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is________________?
A. (1/U) Vs. (1/v0.8)
B. (1/v0.8) Vs. U
C. v0.8 Vs . U
D. (1/U) Vs. (1/V)
0
Fouling factor for a heat exchanger is given by (where, U1 = heat transfer co-efficient of dirty surface U2 = heat transfer co-efficient of clean surface) ?
A. 1.26 h1
B. 0.794 h1
C. 0.574 h1
D. 1.741 h1
0
All analogy equations connecting friction factor and heat transfer co-efficient apply only to ___________________?
A. U1 – U2
B. 1/U1 – 1/U2
C. 1/U2 – 1/U1
D. U2 – U1
0
Reason for operating an evaporator in multiple effects is to secure ___________________?
A. Wall or skin friction
B. Form friction
C. Both A. and B.
D. Turbulent flow
0
Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the_________________?
A. Increased steam economy
B. Decreased steam consumption
C. Both A. and B.
D. Increased capacity
0
Critical value of the _____________ number governs the transition from laminar to turbulent flow in free convection heat transfer?
A. Existence of thermal boundary layer
B. Temperature gradient produced due to density difference
C. Buoyancy of the bubbles produced at active nucleation site
D. None of these