# UPTU Previous Year Question Papers

## Transport Phenomena

Note : (1) Attempt all questions.

(2) Assume any data if found missing.

1. Attempt any four parts of the following :

(a) What are Analogies in different transport processes?

(b) What is Newton’s Second law of Motion? Discuss its significance in laminar flow.

(c) What is meant by Newtonian fluid and Non- Newtonian fluid? Explain with an examples.

(d) What is the science of “rheology”?

(e) What is diffusion? What factors may cause diffusion to occur?

(f)  What are the differential driving forces for momentum, heat and mass transports?

2. Attempt any four of the following :

(a) How are the thermal conductivities and viscosities of gases related?

(b) What are the units of viscosity and kinematic viscosity?

(c) How does the viscosity vary with temperature and pressure for (i) dilute gases (ii) liquids.

(d) Show that “momentum per unit area per unit time” has the same dimensions as “force per unit area”.

(e) What is Hagen – Poiseuille law and why is it important? Show that it is dimensionally consistent.

(f)  What is Fourier’s law of heat conduction in three-dimensional form?

3. Attempt any two of the following :

(a) Two immiscible liquids A and B are flowing in laminar flow between two parallel plates separated by distance ‘2b’. Let the viscosity of two liquids be nA and \^B respectively and \iA>YiB Derive the expression for velocity profiles and momentum flux.

(b) Obtain the shell balance equation for laminar flow of liquid in an annulus. Also derive the expression for velocity profile in it.

(c) A horizontal annulus is 27 ft long. The outside radius of the inner cylinder is 0.495 in, the inner radius of outer radius is 1.1 in. A 60% of aqueous soln. of sucrose (C12 H22 On) is to be pumped through the annulus at 20 °C. At this temperature the fluid density is 80.3 lb ft~s and its viscosity is 136.8 lbm ft_1 hr_1. What is the volume rate of flow when the impressed pressure drop is 5.39 psi ?

4. Attempt any two of the following :

(a) Derive the expression for the heat flow through composite wall of thickness t1? t2 and t3 having thermal conductivity kt, k2 and k3 respectively.

(b) Heat is flowing through an annular wall of inside radius r() and outside radius rr The thermal conductivity varies linearly with temperature from ko at T() to mkj at Tf. Develop an expression for the heat flow through the wall at r = r .

(c) What do you understand by cooling fin?

Explain. Also discuss various types of cooling fins.

5. Attempt any two of the following

(a) In a gas diffusion experiment chloropicrin (CCI3 no2) is kept in a cylindrical test tube. A gas is passed through the open end of the tube. What is the rate of evaporation (in g.hr1) in air at 25 °C? Total pressure = 770 mm Hg Diffusivity = 0.088 cm2 Sec-1 Vapor pressure = 23.81 mm Hg Distance from liq. Level to top of tube = 11.14 cm

Density of chloropicrin = 1.65 g cm-3 Surface area of liq. exposed to air = 2.29cm2

(b) A catalytic reaction 2A^.A2 is carried out in catalytic reaction. Show that where 5 —» Effective gas film thickness xAQ Gas stream composition at beginning,

(c) (i) Discuss the term “ Diffusion controlled chemical reactions”.

(ii) Define effectiveness factor for porous catalysts.