Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Summer 5th Sem New 2151404 Food Engineering Operations I Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (NEW) EXAMINATION ? SUMMER 2019
Subject Code: 2151404 Date: 03/06/2019
Subject Name: Food Engineering Operations - I
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.
Q.1 (a) What is screening? Write the purpose of screen motion. 03
(b) Describe the different types of idlers used for belt conveyor. 04
(c) What is Fourier?s law of heat conduction? Derive an expression for heat conductance
when the walls are in series (composite wall).
07
Q.2 (a) State the principles of diffusion when two fluids are miscible. 03
(b) Define plane of rupture. How shallow and deep bins are differentiated on basis of
plane of rupture and angle of rupture?
04
(c) Enlist the traditional and improved storage structures used in India. Describe in detail
cover and plinth storage structure with suitable diagram.
07
OR
(c) Discuss the stepwise design procedure to calculate the convective heat transfer
coefficient.
A composite wall of a furnace has 2 layers of equal thickness having thermal
conductivities in the ratio of 3:2. What is the ratio of the temperature drop across the
two layers?
07
Q.3 (a) Show diagrammatically the vertical and lateral pressure variation in a bin. 03
(b) Define the followings
1. Open pore porosity and Closed pore porosity
2. Thermal diffusivity and Thermal conductivity
04
(c) Derive an expression of conduction heat transfer when the pipes of different materials
are in series.
07
OR
Q.3 (a) Calculate Prandtl Number when air at 100
0
C
ms / Kg
T 110
T . 1.46x10
2 / 3 -6
?
? ?
2 8 4
p
T 10 x 98 . 3 T 10 x 58 . 2 917 . 0 C
? ?
? ? ? kJ/kg K (where T is the absolute temperature
in Kelvin), k = 0.03186 w/mK
03
(b) Derive an expression of terminal velocity for spherical body.
04
(c) A steel pipe with 50 mm outer diameter is covered with a 6.4 mm asbestos insulation
(k = 0.166 W/mK) followed by a 25 mm layer of fiber glass insulation ( k = 0.0485
W/mK). The pipe wall temperature is 393K and outside insulation temperature is
311K. Calculate the interface temperature between the asbestos and the fiber glass.
07
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (NEW) EXAMINATION ? SUMMER 2019
Subject Code: 2151404 Date: 03/06/2019
Subject Name: Food Engineering Operations - I
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.
Q.1 (a) What is screening? Write the purpose of screen motion. 03
(b) Describe the different types of idlers used for belt conveyor. 04
(c) What is Fourier?s law of heat conduction? Derive an expression for heat conductance
when the walls are in series (composite wall).
07
Q.2 (a) State the principles of diffusion when two fluids are miscible. 03
(b) Define plane of rupture. How shallow and deep bins are differentiated on basis of
plane of rupture and angle of rupture?
04
(c) Enlist the traditional and improved storage structures used in India. Describe in detail
cover and plinth storage structure with suitable diagram.
07
OR
(c) Discuss the stepwise design procedure to calculate the convective heat transfer
coefficient.
A composite wall of a furnace has 2 layers of equal thickness having thermal
conductivities in the ratio of 3:2. What is the ratio of the temperature drop across the
two layers?
07
Q.3 (a) Show diagrammatically the vertical and lateral pressure variation in a bin. 03
(b) Define the followings
1. Open pore porosity and Closed pore porosity
2. Thermal diffusivity and Thermal conductivity
04
(c) Derive an expression of conduction heat transfer when the pipes of different materials
are in series.
07
OR
Q.3 (a) Calculate Prandtl Number when air at 100
0
C
ms / Kg
T 110
T . 1.46x10
2 / 3 -6
?
? ?
2 8 4
p
T 10 x 98 . 3 T 10 x 58 . 2 917 . 0 C
? ?
? ? ? kJ/kg K (where T is the absolute temperature
in Kelvin), k = 0.03186 w/mK
03
(b) Derive an expression of terminal velocity for spherical body.
04
(c) A steel pipe with 50 mm outer diameter is covered with a 6.4 mm asbestos insulation
(k = 0.166 W/mK) followed by a 25 mm layer of fiber glass insulation ( k = 0.0485
W/mK). The pipe wall temperature is 393K and outside insulation temperature is
311K. Calculate the interface temperature between the asbestos and the fiber glass.
07
2
Q.4 (a) What are the different sources of infestation for stored grain?
03
(b) Discuss variety of pores are available in food grains with diagram.
04
(c) (i) Write Bond?s law for size reduction.
(ii) In a wheat milling experiment, it was found that to grind 4 mm sized grains to IS
sieve 35 (0.351 mm opening), the power requirement was 10 kW. Calculate the power
requirement for milling wheat by the same mill to IS sieve 15(0.157 mm opening)
using (1) Rittingers? law (2) Kicks? law. Feed rate of milling is 180 kg/h.
07
OR
Q.4 (a) Write a procedure to measure angle of repose of a grain with help of a labeled diagram
and formula.
03
(b) Differentiate between continuous phase and dispersed phase. List out the application of
diffusion in food industry.
04
(c) (i) Define belt tension.
(ii) The capacity of toughened belt conveyor of 70 m length is 60 m
3
/hr. Width of the
belt is 61 cm and cross sectional area of the belt is 0.0309 m
2
. Calculate belt speed and
horse power for given belt conveyor. Given the constant A and B for the belt is 0.36
and 0.00298 respectively.
07
Q.5 (a) Describe the process of mass transfer in gas-liquid system with graph.
03
(b) Define the followings and represents with graph
1. Shear thinning
2. Shear thickening
3. Newtonian fluid
4. Non-Newtonian fluid
04
(c) List out the importance of engineering properties of food materials. Give the
description of following shapes with diagram
(a) Round, (b) Oblate, (c) Oblong, (d) Conic, (e) Ovate, (f) Truncate
07
OR
Q.5 (a) Draw the flow pattern of grain while emptying through a vertical silo.
03
(b) Discuss the importance of angle of repose, internal and external friction in design of
modern silo.
04
(c) (i) Define effectiveness of screen.
(ii) Wheat is milled in burr mill. The ground product was later on analysed in as set of
IS sieve. The screen analysis data is given below in table. Calculate the screen
effectiveness of (i) IS 40 mesh (ii) IS 20 mesh
IS screen number 100 70 50 40 30 20 15 Pan
%
material
retained
over
each
screen
Feed --
2 10 29 36 16 4 3
Overflow --
12 48 19 15 4 2
--
Underflow -- --
5 9 51 20 7 8
07
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This post was last modified on 20 February 2020