Question Set 33
What is a journal bearing?
Answer:
A journal bearing is a sliding contact bearing which gives lateral support to the rotating shaft.
Question No. 2
What are the types of journal bearings depending upon the nature of contact?
Answer: The types of journal bearings are
1. Full journal bearing
2. Partial bearing
1. Fitted bearing.
Question No. 3
What are the types of journal bearing depending upon the nature of lubrication?
Answer: The types are
1. Thick film type
2. Thin film type
3. Hydrostatic bearings
4. Hydrodynamic bearing.
Question No. 4
What is known as self – acting bearing?
Answer:
The pressure is created within the system due to rotation of the shaft; this type of bearing is known as self – acting bearing.
Question No. 5
What is flywheel?
Answer:
Flywheel is a machine elements used to minimize the fluctuation of speed in a engine.
Question No. 6
What is the function of flywheel?
Answer:
A flywheel used in machine serves as a reservoir which stores energy during the period when the supply of energy is more than the requirement and releases it dulling the period when the requirement of energy is more than the supply.
Question No. 7
Define the term ‘fluctuation of speed’ and ‘fluctuation of energy’.
Answer:
The ratio of maximum fluctuation of speed to the mean speed is called co efficient of fluctuation of speed. The ratio of fluctuation of energy to the mean energy is called coefficient of fluctuation of energy.
Question No. 8
State the type of stresses induced in a rim flywheel?
Answer:
The stresses induced in a rim flywheel are
1. Tensile stress due to centrifugal force
2. Tensile bending stress caused by the restraint of the arms and
3. The shrinkage stresses due to unequal rate of cooling of casting.
Question No. 9
What are the stresses induced in flywheel arms?
Answer:
The stresses induced in flywheel arms are
1. Tensile stress due to centrifugal force.
2. Bending stress due to torque.
3. Stress due to belt tension.
Question No. 10
How does the function of flywheel differ from that of governor?
Answer:
A governor regulates the mean speed of an engine when there are variations in the mean loads. It automatically controls the supply of working fluid to engine with the varying load condition & keeps the mean speed with contain limits. It does not control the speed variation caused by the varying load. A flywheel does not maintain constant speed.