22562 Power Engineering and Refrigeration Unit 4 Notes PDF

Gas Turbines:

Components and Process:

1. Compressor: Draws in and compresses ambient air.
2. Combustion Chamber: Where compressed air is mixed with fuel and ignited.
3. Turbine: Expanding gases from the combustion chamber turn the turbine. The turbine, in turn, drives the compressor.
4. Power Turbine (in some configurations): Extracts energy from the remaining jet and provides power for external work.

Types:

1. Single Shaft Turbine: Compressor and turbine are mounted on a single shaft.
2. Twin Shaft Turbine: A power turbine is mounted on a separate shaft, allowing it to rotate independently of the main turbine.

Applications:

1. Jet Engines for aircraft.
2. Power Generation in combined cycle plants.
3. Mechanical Drive for pumps and compressors.
4. Marine Propulsion for ships.

Jet Propulsion:

Types of Jet Engines:

1. Turbojet: Simplest form where air is sucked in, compressed, mixed with fuel, ignited, and then expelled at high speeds.
2. Turbofan: Has an additional fan at the front which helps in increasing thrust by accelerating more air than what goes through the main engine.
3. Turboprop: Uses a turbine to drive a propeller, commonly used in regional and smaller aircraft.
4. Turbo shaft: Similar to turboprop but the output shaft is used to drive something other than a propeller, like a helicopter rotor.
5. Ramjet: Has no moving parts and can operate at very high speeds but needs to be moving to function.
6. Scramjet: A variation of ramjets that can operate at hypersonic speeds.

Applications:

1. Aviation: Powers most modern aircraft.
2. Spacecraft Propulsion: Rocket engines operate on the same principle but use stored oxidizers.
3. Missile Propulsion: For guided missiles.

Advantages of Gas Turbines:

1. High Power-to-Weight Ratio: Especially beneficial for aviation.
2. Smooth Operation: Due to continuous combustion.
3. Reliability: Fewer moving parts than reciprocating engines.

Challenges:

1. Efficiency: Gas turbines are generally less efficient than diesel engines at partial loads.
2. Cost: High initial cost.
3. Noise: Especially in aviation applications.

Recent Advancements:

1. Materials: Development in materials like ceramics that can withstand higher temperatures, thus improving efficiency.
2. Computational Fluid Dynamics (CFD): Helps in designing more efficient blades and components.
3. Noise Reduction Technologies: Important for commercial aviation.

Gas turbines and jet propulsion have revolutionized air travel, space exploration, and even power generation. As the technology continues to evolve, these engines will become even more efficient and eco-friendly.