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

      1. Compressor Section

      1. Combustion Section

      1. Turbine Section

      1. Exhaust Section

      1. Accessory Section

      1. 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.