58103-mt----advanced Transport Phenomena

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Code No: 58103/MT M.Tech. – I Semester Supplementary Examinations, September, 2008 ADVANCED TRANSPORT PHENOMENA (Chemical Engineering) Time: 3hours

Max. Marks:60 Answer any FIVE questions All questions carry equal marks ---

1.

An isothermal Newtonian fluid is made to move under laminar flow in a long circular tube of length ‘L’ and radius ‘R’. Arrive at the velocity distribution relation for fully established flow using the shell balance approach. Find the relation between average and maximum velocities and also the Hagen poiseuille law stating the assumptions implied.

2.

Discuss the applications of Navier-stokes equation and Euler equation for laminar flow problems and explain their significance.

3.

Explain briefly the analogies between heat, momentum and mass transfer, with their importance. Derive prandtl an anology between momentum and heat transfer.

4.

A wetted wall column is created in which liquid flows down the column in a form of a film in a laminar flow and the gases flow up the column. A simple absorption takes place. Assuming the system to be a simple binary mixture, setup the necessary balance relation and from this relation, show how you can obtain a relation in terms of dimensionless numbers. State clearly the assumptions made.

5.

Dittus and Boelter proposed the following equation for correlating the heat-transfer coefficient for turbulent flow in a pipe: 1 hD Nu = = 0.023Re0.8 Pr 3 K What should be the corresponding equation for the mass-transfer coefficient when the transfer is to a turbulent fluid flowing in a pipe. Contd…2.,

Code No: 58103/MT

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6.

A solid body occuping the space from y=0 to y= ∞ is initially at temperature T0. At time t=0, the surface at y=0 is suddenly raised to temperature T1 and maintained at that temperature for t>0. ∂T = α∇ 2T can Find the time dependent temperature profiles T(y, t). ∂t be used.

7.a)

Define concentrations; velocities and fluxes in mass and molar units in a multi component system. Find the time smoothed velocity distribution for turbulent flow in a long tube, using prandtl mixing length.

b) 8.

Write short notes on the following: a) Dimensional analysis b) Equations of change for power law fluids. *****