Short Answer:
The main function of a flywheel is to store energy in the form of rotational motion and to maintain a constant speed of the engine or machine. It absorbs extra energy when the energy supply is high and releases it when the supply is low. This helps in reducing speed fluctuations and provides uniform motion to the rotating parts of a machine.
In simple words, the flywheel ensures smooth and stable operation by balancing the uneven torque produced during the working of engines or other mechanical systems. It also helps in reducing vibration and increasing efficiency.
Detailed Explanation:
Function of a Flywheel
A flywheel performs the important task of maintaining uniform motion and controlling energy variations in engines and machines. It is a rotating mechanical device that stores energy when the supply is more than required and releases it when the supply is less. This process ensures that the speed of the machine remains steady even when the input power or load changes during operation.
In mechanical systems like internal combustion engines, reciprocating compressors, and presses, the power generated or required is not constant throughout the working cycle. This uneven power results in speed variations. The flywheel acts as an energy balancing device to minimize these speed changes by using its property of inertia.
The flywheel’s function is based on the principle of conservation of energy. When the machine produces more energy than required, the excess energy is stored as kinetic energy in the flywheel by increasing its rotational speed. During periods when energy supply decreases or load increases, the flywheel releases the stored energy by reducing its speed slightly. This way, the energy remains balanced throughout the operation cycle.
Main Functions of a Flywheel
- Maintaining Constant Speed:
One of the most important functions of a flywheel is to keep the rotational speed of a machine or engine constant. In engines, power is produced in pulses, such as during the power stroke in an internal combustion engine. The flywheel stores energy during the power stroke and releases it during other strokes like suction, compression, and exhaust to ensure smooth motion. - Energy Storage and Release:
The flywheel works as an energy reservoir. It stores kinetic energy during high torque conditions and supplies it during low torque periods. This energy exchange helps in maintaining the balance between energy input and energy output. - Reduction of Speed Fluctuations:
Machines that work with variable loads or uneven torque tend to fluctuate in speed. The flywheel minimizes these speed variations by controlling the rotational motion, thereby keeping the operation uniform and stable. - Improving Machine Efficiency:
A flywheel ensures smoother power transmission and prevents mechanical shocks caused by irregular energy flow. This increases the overall efficiency and life of the machine. - Assisting in Power Stroke Completion:
In multi-cylinder engines or reciprocating machines, not all parts of the cycle generate power. The flywheel helps to carry the machine through the non-power strokes by supplying the necessary energy from its stored reserve. - Reducing Vibrations and Jerks:
Because of its large moment of inertia, the flywheel resists sudden changes in rotational speed. This helps reduce vibrations, jerks, and mechanical stress in the components of the machine. - Providing Power During Peak Load:
In some machines like punching presses or rolling mills, a high amount of energy is required for a short duration. The flywheel supplies this energy instantly, allowing the motor to run smoothly without being overloaded.
Working of the Flywheel Function
During the operation of an engine or machine, the torque produced by the power source changes continuously.
- When the torque is higher than the average required, the flywheel absorbs energy and rotates faster.
- When the torque is lower than the average, the flywheel releases energy and rotates slower.
This alternate storing and releasing of energy keeps the speed of the machine within a small range, known as the coefficient of speed fluctuation. The effectiveness of a flywheel depends on its moment of inertia (I) and angular velocity (ω). The energy stored in a flywheel can be expressed as:
This equation shows that both mass and speed influence how much energy a flywheel can store or supply.
Examples of Flywheel Functions
- In Internal Combustion Engines:
The flywheel stores energy during the power stroke and releases it during other strokes to keep the crankshaft rotating smoothly. Without the flywheel, the engine speed would vary widely between strokes. - In Power Press Machines:
Flywheels store energy when the press is idle and release it during the punching or pressing operation, where a high amount of energy is needed in a short time. - In Electric Power Plants:
Flywheels are used to balance the supply and demand of mechanical energy. They help regulate the speed of generators and turbines. - In Automobiles:
The flywheel connects the engine to the clutch and helps in starting the engine. It also maintains engine speed during gear shifting and prevents sudden jerks. - In Reciprocating Compressors:
It helps to overcome the energy variations caused by the reciprocating motion of pistons and ensures smoother operation.
Importance of the Flywheel Function
The function of a flywheel is essential for the stable and efficient performance of any rotating machinery. By preventing large fluctuations in speed, it reduces mechanical stress, improves balance, and ensures that energy is used efficiently. Without a flywheel, machines would operate irregularly, causing vibrations, increased wear, and poor performance.
The flywheel thus acts as both an energy stabilizer and a performance enhancer in any system involving rotational motion.
Conclusion:
The function of a flywheel is to regulate speed, store and release energy, and maintain smooth operation in engines and machines. It ensures that energy flow remains steady even when input power or load changes. By minimizing speed variations and providing balance, the flywheel improves machine efficiency, reduces wear, and enhances reliability. Therefore, it is a vital component in most mechanical and power systems.