Turbine Engine Slideshow

Aircraft Engines Fundamentals

• Course: Aircraft Engines, AVIT 1540 at NORTHEAST STATE Aviation Technology

Aircraft Engine Types

Gas Turbine Engines

• Reciprocating Engine: Intake, compression, combustion, and exhaust occur in the same chamber, with each function requiring exclusive occupancy.

• Gas Turbine Engine: Separate sections for intake, compression, combustion, and exhaust; functions perform simultaneously without interruption.

Components of Gas Turbine Engines

• Comprises several key sections:

  • 1. Air Inlet

  • 2. Compressor Section

  • 3. Combustion Section

  • 4. Turbine Section

  • 5. Exhaust Section

  • 6. Accessory Section

  • 7. Systems for Starting, Lubrication, Fuel Supply, Anti-Icing, etc.

Engine Types and Features

Types of Gas Turbine Engines

• Types: Turbofan, turboprop, turboshaft, and turbojet.

• Turbofan Engines: Most common in airliner-type aircraft; quieter and better fuel consumption; produces around 80% of thrust from a large fan.

• Turboprop Engines: Efficient in low-speed ranges; uses a propeller driven through a reduction gearbox.

• Turboshaft Engines: Transfers power via shafts, mainly for helicopters and auxiliary power units.

Engine Components

Turbofan Engines

• Consists of both high-pressure and low-pressure spools; has separate turbines and shafts to manage pressure and speed.

• Bypass Ratio: Defines how much air bypasses the core of the engine, influencing noise and efficiency.

Operating Principles of Turbine Engines

• Air enters the engine through the inlet, is compressed in the compressor, heated in the combustion chamber, and then expanded to produce thrust through the turbine and exhaust.

• Basic Principles: Based on principles of physics, including Newton's Third Law and Bernoulli's Principle, influencing airflow through ducts.

Combustion and Turbine Sections

Combustion Section

• Houses combustion processes to convert fuel/air mixtures into energy driving the turbine.

• Must mix and burn efficiently while cooling the exhaust gases before they reach the turbine.

Turbine Section

• Transforms kinetic energy from exhaust gases into mechanical energy for driving the compressor and accessories.

• Components: Includes turbine inlet guide vanes and turbine disks that control gas flow.

Airflow Dynamics

• Airflow is affected by three variables: aircraft speed, altitude, and ambient temperature.

• The Brayton cycle explains the continuous combustion process essential for thrust generation.

Performance Factors

• Thermal Efficiency: The efficiency of converting fuel into work; significant factors include turbine inlet temperature and compressor efficiency.

• Net Thrust: Calculated based on airflow and gas velocity; certain parameters such as ram air effects influence thrust production.

Quiz Questions

• What three main sections comprise a gas turbine engine?

  • Choices: A. Compressor, diffuser, and stator; B. Turbine, combustion, and stator; C. Turbine, compressor, and combustion.

• The purpose of the inlet guide vane assembly on an axial flow compressor:

  • Choices: A. Direct air into the rotor; B. Convert pressure energy; C. Increase velocity.

• Three types of turbine blades: Impulse, reaction, impulse-reaction.

• The function of the nozzle diaphragm:

  • Directs the flow of gases to strike turbine blades efficiently.