Question-1

In a double pipe heat exchanger if the inner diameter of inner pipe is 6cms.and outer diameter is 8cms.respectively and pipe has a length of one metre. If the rate of heat transfer is 60w, over all heat transfer coefficient based on out side diameter is if temperature difference is 60C

Select one:

a. 1.56 W/mC

b. 0.000156 W/mC

c. 0.00156 W/mC

d. 0.156 W/mC

Question-2

For calculation of Reynolds number in case of fluid flowing in pipe, solid motion in fluid and in mixing respectively, the density and velocity of the following is taken into consideration

Select one:

a. Fluid in case of mixing and pipe flow, solid in case of solid motion in fluid

b. Viscosity with respect to fluid in all cases and density with respect to solid in motion in fluid

c. Viscosity with respect to fluid in all cases and density with respect to solid in solid motion in liquid and density of material of construction of impeller in case of mixing

d. Fluid into consideration in all cases

Question-3

An industry is being set up where one of the processes involves dispersing gas in liquid and other process involves viscous liquid which deposits on the wall and has to removed timely to promote heat transfer. Which of the following equipment you would suggest respectively for each of the purpose?

Select one:

a. helical ribbon agitator can be used in both cases

b. Paddle agitator, helical ribbon agitator

c. Turbine, helical ribbon agitator

d. Turbine, paddle agitator

Question-4

In a double pipe heat exchanger if the wall resistance can be neglected and the convective heat transfer coefficient on inner diameter basis of inner pipe is 1W/m2K and convective heat transfer coefficient on basis of outside diameter is 600W/m2K, then overall heat transfer coefficient is

Select one:

a. 601 W/mK

b. 600 W/mK

c. 599 W/mK

d. 1 W/mK

Question-5

In which of the following heat exchanger does the temperature profile remains constant for one fluid

Select one:

a. Both a and b

b. Boiler

c. Counter current flow

d. Condenser

Question-6

A flat blade turbine agitator with disk having six blades is installed in a tank. The tank diameter Dt is 2m, the turbine diameter Da is 0.81m, Dt = H, and the width W is 0.122 m. The tank contains four baffles, each having a width J of 0.15m. The turbine is operated at 1 revolutions per second and the liquid in the tank has a viscoscity of 10 cp and a density of 929 kg/m.If the power required is 2K watts. The power number, Reynold number is

Select one:

a. 10

b. 6.16

c. 100.5

d. 369.5

Question-7

The units of overall heat transfer coefficient U and convective heat transfer coefficient are

Select one:

a. None of the above

b. W/mk, W/mK

c. W/m K, W/mK

d. W/mK, W/mK

Question-8

In a double pipe heat exchanger if the inner diameter of inner pipe is 6cms.and outer diameter is 8cms.respectively and pipe has a length of one metre. The resistance to heat at wall if the thermal conductivity of the pipe is 8W/mk

Select one:

a. 0.011 units

b. -0.011 units

c. 8 units

d.0.00571 units

Question-9

A jacketed 1.83-m-diameter agitated vessel is being used to heat a liquid which is at 300K.Agitator is 0.61 m in diameter and is an anchor agitator with no baffles rotating at 200rpm.Hot water is in the heating jacket. The wall surface temperature is constant at 355.4K. The liquid has the following bulk physical properties: p= 961 kg/m , cp=2500 J/Kg. K, K = 0.173 W/m.k, and = 1.00 pa.s at 300 K and 0.084 pa.s at 355.4 K.

Select one:

a. 400-600 W/mK

b. 1000-1500 W/mK

c. 170-200 W/mK

d. 500-600 W/m K

Question-10

An agitation system a for a flat-blade turbine with a disk and six blades has the given conditions and sizes DT1=1.83m, Da1=0.61m, W1=0.122m, J1=0.15m, N1 = 90 rev/min, p = 929 kg/m and = 0.01 pa.s. It is desired to scale up these results for a vessel whose volume is 4 times as large. if it is designed for equal suspension solid ,the width of the turbine and speed of agitator for the scaled up vessel are

Select one:

a. 0.193, 1.175 rev/S

b. 0.176m, 1.06 rev/S

c. 0.193m, 2.04 rev/S

d. 0.193m, 1.06 rev/S