Q. The value of N flux of A under steady state non-diffusing B with diffusing A is _________

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Q. If the value of N flux of A to the total N flux is 1 then it is a steady state diffusion of non-diffusing B.

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Q. In respect to free convection over a vertical flat plate, the Nusselt number for laminar and turbulent flows varies respectively with Grashoff number G ᵣ as

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Q. Experimental results indicate that the local heat transfer coefficient h g for flow over a flat plate with an extremely rough surface is approximated by the relation

hₓ = a x -0.12

Where a is a constant coefficient and x is distance from the leading edge of the plate. What is the relation between this local heat transfer coefficient and the average heat transfer coefficient for a plate of length x?

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Q. For the free convection circumstances, the following dimensionless numbers apply

(i) Grashof number
(ii) Prandtl number
(iii) Nusselt number

Identify the correct answer.

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Q. Two horizontal steam mains with diameters 5 cm and 15 cm are to be laid in a boiler house that any mutual heat effect is precluded. The mains are at the same surface temperature of 500 degree Celsius whilst the ambient air is at 50 degree Celsius. Workout the ratios of the heat transfer coefficients.

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Q. Two horizontal steam mains with diameters 5 cm and 15 cm are to be laid in a boiler house that any mutual heat effect is precluded. The mains are at the same surface temperature of 500 degree Celsius whilst the ambient air is at 50 degree Celsius. Workout the heat losses from one meter length of the mains

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Q. A spherical heater of 20 cm diameter and at 60 degree Celsius is immersed in a tank of water at 20 degree Celsius. Determine the value of convective heat transfer coefficient

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Q. A steam pipe 50 mm diameter and 2.5 m long has been placed horizontally and exposed to still air at 25 degree Celsius. If the pipe wall temperature is 295 degree Celsius, determine the rate of heat loss. At the mean temperature difference of 160 degree Celsius, the thermo-physical properties of air are

k =3.64 * 10⁻² W/m K
v =30.09 * 10⁻⁶ m²/s
P ᵣ =0.682
Β =1/160 + 273 = 2.31 * 10⁻³ per K

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Q. A steam pipe 50 mm diameter and 2.5 m long has been placed horizontally and exposed to still air at 25 degree Celsius. If the pipe wall temperature is 295 degree Celsius, find out the Grashof number. At the mean temperature difference of 160 degree Celsius, the thermo-physical properties of air are

k =3.64 * 10⁻² W/m K
v =30.09 * 10⁻⁶ m²/s
P ᵣ =0.682
Β =1/160 + 273 = 2.31 * 10⁻³ per K

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Q. Estimate the heat transfer from a 40 W incandescent bulb at 125 degree Celsius to 25 degree Celsius in quiescent air. Approximate the bulb as a 50 mm diameter sphere. The approximate correlation for the convection coefficient is
Nu = 0.60 (Gr Pr)^ 0.25

Where the different parameters are evaluated at the mean film temperature, and characteristics length is the diameter of the sphere.

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Q. A 40 W incandescent bulb at 125 degree Celsius to 25 degree Celsius in quiescent air. Approximate the bulb as a 50 mm diameter sphere. The approximate correlation for the convection coefficient is
Nu = 0.60 (Gr Pr)^ 0.25

Where the different parameters are evaluated at the mean film temperature, and characteristics length is the diameter of the sphere.

Find what percent of power is lost by free convection?

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Q. More than one tie line is represented in an equilibrium triangular system is known as

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Q. Find the slope of the operating line for the first stage if the dilutant in the feed is 5 kg and the solvent used for the second stage is 10 kg.

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Q. Plait point never occurs in the multistage operations.

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Q. A mixture undergoing multicomponent diffusion is analyzed through the Maxwell-Stefan approach. With regard to this approach which among the following statements are incorrect? The difference in the partial pressure of the Component A over a small distance ∆z (AB) is proportional to

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Q. If all the components except 1 of the multicomponent diffusing mixture are inert, then what will be the expression for Diffusivity of component 1 in the mixture?

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Q. A mixture of 60% hydrogen and 40% oxygen is blowing over a pan of water at 1atm pressure. The bulk gas temperature is 30°C and the water temperature is 20°C. The vapor pressure of water at this temperature is 17.53mm Hg. The concentration of moisture in the bulk gas is negligible and the diffusivity values are DO₂-H₂O=0.357cm²/s, DH₂-H₂O=0.972cm²/s at 34°C and DH₂-O₂=0.891cm²/s at 43°C.

Which of the following statements are correct?

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Q. A mixture of 60% hydrogen and 40% oxygen is blowing over a pan of water at 1atm pressure. The bulk gas temperature is 30°C and the water temperature is 20°C. The vapor pressure of water at this temperature is 17.53mm Hg. The concentration of moisture in the bulk gas is negligible and the diffusivity values are DO₂-H₂O=0.357cm²/s, DH₂-H₂O=0.972cm²/s at 34°C and DH₂-O₂=0.891cm²/s at 43°C.

What will be the values of the diffusivities (in cm²/s) at the mean gas-film temperature?

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Q. A mixture of 60% hydrogen and 40% oxygen is blowing over a pan of water at 1atm pressure. The bulk gas temperature is 30°C and the water temperature is 20°C. The vapor pressure of water at this temperature is 17.53mm Hg. The concentration of moisture in the bulk gas is negligible and the diffusivity values are DO₂-H₂O=0.357cm²/s, DH₂-H₂O=0.972cm²/s at 34°C and DH₂-O₂=0.891cm²/s at 43°C.

What is the value of the flux (kmol/m³.s) of water vapor through a stagnant film of estimated thickness 1.5mm on the water surface?

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