Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Summer 8th Sem 2180507 Transport Phenomena Previous Question Paper

Enrolment No.___________

**GUJARAT TECHNOLOGICAL UNIVERSITY**

**BE ?SEMESTER-VIII EXAMINATION- SUMMER 2020**

Subject Code: 2180507

Subject Code: 2180507

**Date:**

**28/10/2020**

**Subject Name: Transport Phenomena**

Time: 02:30 PM TO 05:00 PM

Time: 02:30 PM TO 05:00 PM

**Total Marks: 70**

**Instructions:**

**1. Attempt all questions.**

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

**MARKS**

**Q.1 (a)**State the relevance of transport phenomena in chemical

**03**

Engineering.

**(b)**State and explain the laws of Conservation.

**04**

**(c)**State and discuss various levels of transport phenomena.

**07**

**Q.2 (a)**Estimate the viscosity of N2 at 50 OC and 854 atm, given the

**03**

molecular weight 28 g/g-mole, p

*c*= 33.5 atm, and

*T*c = 126.2 K

**(b)**State the shell momentum balance equation and its boundary

**04**

conditions.

**(c)**State and discuss the Newton's law of viscosity along with

**07**

supporting equations and schematic diagram.

**OR**

**(c)**Glycerin at 26.5 OC is flowing through a horizontal tube 1 ft long

**07**

and with 0.1 inch inside diameter. For a pressure drop of 40 psi,

the volume flow rate (w/) is 0.00398 ft3/min. The density of

glycerin at 26.5 OC is 1.261 g/cm3. Find the viscosity of the

glycerin and subsequent Reynolds no.

**Q.3 (a)**Give the physical significance of the three kinds of time derivatives

**03**

used in the equation of change for momentum transport.

**(b)**Discuss the general trends of viscosity with temperature and

**04**

pressure for ordinary fluids.

**(c)**Write a brief note on molecular theory of the viscosity of gases at

**07**

low density.

**OR**

**Q.3 (a)**A plastic panel of area 1 ft2 and thickness 0.252 inch was found

**03**

to conduct heat at a rate of 3 W at steady state with temperature

T1 = 24 OC and T2 = 26 OC imposed on the two main surfaces.

What is the thermal conductivity of the plastic in cal/cm.s.K at 25

OC.

**(b)**State the boundary conditions associated with shell energy

**04**

balance.

**(c)**State and discuss various kinds of Navier-Stokes equation initiated

**07**

from molecular arguments.

1

**Q.4 (a)**Discuss the significance of momentum, thermal and mass

**03**

diffusivities

**(b)**A copper wire has a radius of 2 mm and a length of 5 m. For what

**04**

voltage drop what the temperature rise at the wire axis be 10 OC, if

the surface temperature of wire is 20 OC?

**(c)**Explain with appropriate equations the Fourier's law of

**07**

molecular energy transport

**OR**

**Q.4 (a)**Write in short about Molecular Mass Transport.

**03**

**(b)**Show that only one diffusivity is needed to describe the

**04**

diffusional behavior of a binary mixture.

**(c)**Derive the equation for temperature and heat flux distribution

**07**

through cylindrical shell with an electric heat source.

**Q.5 (a)**Define thermal conductivity and thermal diffusivity. What are its

**03**

units?

**(b)**Using the equation of combination of kinetic theory and

**04**

corresponding states arguments estimate DAB for the system of

CO-CO2 at 296.1 K and 1 atm total pressure. The data is given as

follows

**Species**

**Tc (k)**

**Pc (atm)**

CO

133

34.5

CO2

304.2

72.9

The values for constants are a = 2.745 ? 10-4 & b = 1.823

**(c)**Derive the relation for diffusion with a heterogeneous chemical

**07**

reaction with suitable assumptions and notations.

**OR**

**Q.5 (a)**Compare convective and molecular molar fluxes.

**03**

**(b)**State the various equations of diffusivities for temperature and

**04**

pressure dependence.

**(c)**Deduce the expression for diffusion through a stagnant gas film

**07**

with appropriate schematic diagram.

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This post was last modified on 04 March 2021