Which of the following best describes bulk granular materials?
A
Liquids that flow like water
B
Gases with random motion
C
Discrete solid particles that can flow under gravity
D
Magnetic particles suspended in air
Analysis & Theory
Bulk granular materials are made of discrete solid particles that can behave like fluids under certain conditions.
Which equipment is commonly used to store and discharge bulk granular materials?
Analysis & Theory
Silos and hoppers are designed for the storage and controlled flow of granular materials.
The angle of repose of a granular material represents:
A
Angle at which the material melts
B
Maximum angle without flow
D
Angle at which material self-combusts
Analysis & Theory
The angle of repose is the steepest angle at which granular material remains stable without sliding.
Which factor increases the flowability of bulk granular materials?
B
Irregular particle shape
Analysis & Theory
Vibration helps break internal friction and improves the flow of granular materials.
What is rat-holing in granular flow?
A
Material compaction under pressure
B
Formation of tunnels due to air flow
C
Flow of material only in the center while sides remain stagnant
D
Uniform flow from all sides
Analysis & Theory
Rat-holing occurs when material flows through a central narrow path, leaving material stagnant at the sides.
Which flow pattern is more desirable in silos for granular materials?
Analysis & Theory
Mass flow ensures uniform movement of all material in the silo, reducing segregation and blockages.
Segregation in granular materials refers to:
B
Separation based on size or density
Analysis & Theory
Segregation occurs when particles separate due to differences in size, shape, or density during handling or flow.
What is arching in a hopper or silo?
A
Formation of a stable bridge that blocks flow
B
Expansion of material due to heat
Analysis & Theory
Arching occurs when particles interlock and form a bridge over the outlet, blocking flow.
Which of the following materials is likely to have poor flowability?
Analysis & Theory
Wet flour tends to clump and has cohesive properties, making it flow poorly.
Flow aids are used in granular handling systems to:
A
Reduce friction between hopper walls
D
Improve material discharge and avoid blockages
Analysis & Theory
Flow aids like vibrators or air pads are used to enhance flow and prevent bridging or rat-holing.