Momentum Transfer - Food Engineering - Life Sciences Previous Year Questions

1

2007 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2007

Main functions of baffles in a bioreactor are (P) to prevent a vortex (Q) to increase aeration (R) to reduce interfacial area of oxygen transfer (S) to reduce aeration rate

A

P, Q

B

Q, R

C

R, S

D

P, S

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2

2011 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2011

A sugar syrup (density = 1040 kg/m³ and viscosity = 1600 × 10⁻³ Pa.s) is required to be pumped into a tank (1.5 m diameter and 3 m height) by a 3 cm inside diameter pipe. If the liquid is required to flow under laminar conditions the minimum time to fill the tank with the syrup will be

A

192.9 h

B

19.3 h

C

38.6 h

D

57.9 h

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3

2013 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2013

In the extruder barrel, the compression is achieved by back pressure created by the die and by

A

increasing pitch and decreasing diameter of the screw

B

using the tapered barrel with constant pitch

C

increase in the clearance between barrel surface and screw

D

opening of the die

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4

2014 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2014

Fruit juice is flowing in a circular pipe (inner diameter 2 cm) at a mass flow rate of 2 kg s⁻¹ and at a temperature of 25°C. The density and viscosity of the juice at 25°C are 1045 kg m⁻³ and 0.5 Pa s, respectively. Take π = 22/7. The Reynolds number for this flow will be ______.

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5

2014 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2014

Shear stress (τ, Pa) and shear rate (γ, s⁻¹) relationship of a pseudoplastic fluid follows the Power law equation given by, τ = kγⁿ = 2.6 γ⁰.⁴⁵, where 'n' and 'k' are flow behavior index and consistency index respectively. The apparent viscosity (μₐ) of the fluid at a shear rate of 5 s⁻¹ is ______ Pa s.

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6

2014 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2014

Water enters a cylindrical tank at a steady uniform rate of 0.1 m³ s⁻¹; simultaneously water is discharged from the tank through an orifice (area 0.05 m²) located at the bottom of the tank. Initial level of water in the tank from the bottom is 5 m. If the acceleration due to gravity = 9.81 m s⁻² and coefficient of discharge = 0.30, the final value of the steady-state height of water level from the bottom of tank is ______ m.

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7

2014 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2014

A chocolate mix at 100°C is flowing through a 2 cm diameter and 4 m long stainless steel tube at 13.2 kg per minute. The density of the mix is 1750 kg m⁻³ and its viscosity at 100°C is 2 Pa s. Take π = 22/7. The pressure drop for this flow will be ______ Pa.

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8

2016 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2016

Fluid is flowing inside a pipe of radius ‘R’ in fully developed laminar flow. If the velocity of the fluid at the centre at a distance ‘L’ is v_max, velocity at radial distance of ¾ (R) will be __ times v_max

A

9/16

B

7/16

C

16/9

D

16/7

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9

2017 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2017

A 50% sucrose solution at 20 °C is flowing at a rate of 3.5 m³/h through a pipe with an inside diameter of 0.0475 m and length of 12 m. The viscosity and the density of the solution are 15.43 cp and 1232 kg/m³, respectively. The Reynolds number of the flow is ______ .

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10

2017 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2017

Power consumption in liquid mixing is proportional to ______ .

A

Power number × liquid density × (rotational speed)³ × (impeller diameter)⁵

B

Power number × liquid density × (rotational speed)² × (impeller diameter)³

C

Liquid density × viscosity of the liquid × (rotational speed)² × (impeller diameter)³

D

Acceleration due to gravity × liquid density × (rotational speed)³ × (impeller diameter)⁵

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11

2017 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2017

Refer to the shear stress – shear rate plot shown in the figure below. Match the lines (Column I) with appropriate rheological behavior (Column II).

A

P-2, Q-3, R-4, S-1

B

P-1, Q-3, R-4, S-2

C

P-2, Q-4, R-3, S-1

D

P-4, Q-3, R-2, S-1

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12

2018 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2018

Identify the correct statement related to the viscosity of Newtonian fluids from the following.

A

It is not influenced by temperature

B

It increases with shearing rate

C

It decreases with shearing rate

D

It is not influenced by shearing rate

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13

2019 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2019

Impeller in a fruit juice mixing tank is rotating at 200 rpm with a Reynolds number >10⁴. Density of juice is 1045 kg m^-3. If diameter of the impeller is doubled and other conditions remained constant, the power requirement of mixing will increase by a factor of ________.

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14

2019 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2019

Buffalo milk having density of 1030 kg m^-3 is homogenized with a pressure of 30 MPa. Given, acceleration due to gravity as 9.81 m s^-2 and assuming no pressure loss, the velocity (m s^-1) of the milk flowing through the homogenizer valve will be ________ (round off to 2 decimal places).

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15

2020 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2020

A fluid with flow behaviour index less than one (n < 1) is

A

Dilatant

B

Pseudoplastic

C

Bingham plastic

D

Newtonian

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16

2021 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2021

Which of the following expressions represent the Reynolds number of a fluid flowing through a uniform circular cross section pipe?

A

\(\frac{(\text{density of the fluid}) \times (\text{average velocity of the fluid}) \times (\text{internal diameter of the pipe})}{(\text{dynamic viscosity of the fluid})}\)

B

\(\frac{(\text{average velocity of the fluid}) \times (\text{internal diameter of the pipe})}{(\text{kinematic viscosity of the fluid})}\)

C

\(\frac{(\text{dynamic viscosity of the fluid})}{(\text{average velocity of the fluid}) \times (\text{density of the fluid}) \times (\text{internal diameter of the pipe})}\)

D

\(\frac{(\text{kinematic viscosity of the fluid})}{(\text{average velocity of the fluid}) \times (\text{internal diameter of the pipe})}\)

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17

2026 · Life Sciences · Food Engineering · Momentum Transfer

Life Sciences (XL) 2026

Water is flowing at 100 litres/min through a pipe with a diameter of 5 cm. Assume the coefficient of viscosity of water to be 0.001 Pa.s and the density to be 1000 kg/m³. The Reynolds number for this flow is ______ (Round off to nearest integer)

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