Mass Transfer - Transport Phenomena and Rate Processes - Metallurgical Engineering Previous Year Questions

1

2007 · Metallurgical Engineering · Transport Phenomena and Rate Processes · Mass Transfer

Metallurgical Engineering (MT) 2007

The number of boundary conditions required to solve a steady-state two-dimensional diffusion equation \(\nabla^2 C = 0\) is

A

1

B

2

C

3

D

4

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2

2007 · Metallurgical Engineering · Transport Phenomena and Rate Processes · Mass Transfer

Metallurgical Engineering (MT) 2007

In a RH degasser, the hydrogen mass balance is governed by the following equation: \(-W \frac{dC_H}{dt} = R (C_H - C_{H,eq})\), where \(W\) is the capacity of the degasser in tons, \(C_H\) is the hydrogen concentration at any time \(t\), and \(C_{H,eq}\) is the equilibrium hydrogen concentration in liquid steel, \(R\) is the circulation rate in tons per minute. In order to bring down the hydrogen content from 5 ppm to 1 ppm in 20 minutes, the circulation rate, \(R\), should be (Given: \(C_{H,eq} = 0.5\) ppm, \(W = 150\) tons)

A

10.05 tons/min

B

12.51 tons/min

C

14.73 tons/min

D

16.48 tons/min

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3

2008 · Metallurgical Engineering · Transport Phenomena and Rate Processes · Mass Transfer

Metallurgical Engineering (MT) 2008

During the carburization of a steel, a case depth of d has been obtained in 40 hours at 1173 K. For achieving a case depth of d/2 at 1273 K, the time required in hours is

A

1

B

2

C

3

D

4

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4

2010 · Metallurgical Engineering · Transport Phenomena and Rate Processes · Mass Transfer

Metallurgical Engineering (MT) 2010

The composition at a distance x = 2 mm is approximately (assuming erf(x) ≈ x for small x)

A

0.3

B

0.474

C

0.524

D

0.7

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5

2017 · Metallurgical Engineering · Transport Phenomena and Rate Processes · Mass Transfer

Metallurgical Engineering (MT) 2017

The rate of dissolution of Al particles in liquid steel is proportional to concentration difference (\(\Delta C\)). \(\Delta C\) is defined by: \n(Given: (i) \(C_b\) = bulk concentration of dissolved Al in liquid steel, (ii) \(C^*\) = saturation concentration of Al in liquid steel at the given temperature, (iii) \(C_m\) = Density of Al/Atomic weight of Al.)

A

\(C^* - C_b\)

B

\(C_b - C_m\)

C

\(C^* - C_m\)

D

\(\sqrt{C^*C_m} - C_b\)

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6

2019 · Metallurgical Engineering · Transport Phenomena and Rate Processes · Mass Transfer

Metallurgical Engineering (MT) 2019

Consider electrodeposition of copper on a copper electrode from an aqueous solution containing \(0.5 \times 10^{-3} \text{ mol.cm}^{-3}\) \(\text{CuSO}_4\). Given: Faraday constant, \(F = 96500 \text{ Coulomb per gram equivalent}.\) Assume transport of reactant is rate limiting, and mass transfer coefficient is \(10^{-4} \text{ cm.s}^{-1}\). The limiting current density (in \(mA.cm^{-2}\)) is ____________.

A

4.83

B

9.65

C

19.30

D

38.60

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7

2019 · Metallurgical Engineering · Transport Phenomena and Rate Processes · Mass Transfer

Metallurgical Engineering (MT) 2019

A 50 mm (diameter) sphere of solid nickel is oxidized in a gas mixture containing 60% argon and 40% oxygen by volume. The rate of oxidation of nickel is controlled by the rate of transport of oxygen through the concentration boundary layer. The rate of oxidation (in moles of nickel per minute (mol/min), rounded off to two decimal places) is ______.
Given: Total pressure = 1atm.; Temperature = 1173 K; Concentration of oxygen at the surface of the solid = 0; Boundary layer mass transfer coefficient = 0.03 m.s\(^{-1}\); Universal gas constant, R = \(8.205 \times 10^{-5} m^3.atm.K^{-1}.mol^{-1}\). Assume ideal gas behavior.

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8

2020 · Metallurgical Engineering · Transport Phenomena and Rate Processes · Mass Transfer

Metallurgical Engineering (MT) 2020

Iron is corroding in fresh water which has dissolved oxygen concentration of 15 mM. The anodic current density at an overpotential of 120 mV is ________ A.cm^-2 (round off to three decimal places).
Given:
1. Anodic Tafel slope is 0.06 V.
2. Diffusion coefficient of oxygen is \( 2.42 \times 10^{-5} \text{ cm}^2\text{s}^{-1} \).
3. Diffusion layer thickness is 0.06 cm.

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9

2022 · Metallurgical Engineering · Transport Phenomena and Rate Processes · Mass Transfer

Metallurgical Engineering (MT) 2022

The concentration \( C \) of a solute (in units of atoms·mm⁻³) in a solid along \( x \) direction (for \( x > 0 \)) follows the expression
\[ C = a_1 x^2 + a_2 x \]
where \( x \) is in mm, \( a_1 \) and \( a_2 \) are in units of atoms·mm⁻⁵ and atoms·mm⁻⁴, respectively. Assuming \( a_1 = a_2 = 1 \), the magnitude of flux at \( x = 2 \) mm is ______ × 10⁻³ atoms·mm⁻²·s⁻¹ (answer rounded off to the nearest integer).
Given: diffusion coefficient of the solute in the solid is \( 3 \times 10^{-3} \; \text{mm}^2\text{·s}^{-1} \).

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10

2026 · Metallurgical Engineering · Transport Phenomena and Rate Processes · Mass Transfer

Metallurgical Engineering (MT) 2026

Which one of the following options is correct?
In a convective heat transfer for laminar flow over a flat plate, Nusselt number is a function of Reynolds number and Prandtl number. Similarly, in a convective mass transfer for laminar flow over a flat plate, Sherwood number is a function of:

A

Schmidt number and Reynolds number

B

Weber number and Reynolds number

C

Schmidt number and Weber number

D

Weber number and Prandtl number

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