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Overview of CFM56-7B Turbofan Engine

Sep 22, 2024

CFM56-7B Turbofan Engine Overview

Introduction

  • Purpose: Create thrust for aircraft movement by accelerating air from front to back of the engine.

Key Components of the CFM56-7B

  1. Fan

    • Large diameter propeller that accelerates air.
  2. Compressors

    • Low Pressure Compressor:
      • Step-by-step pressure increase, consisting of 12 stages.
    • High Pressure Compressor:
      • Works in tandem with low pressure compressor to further increase air pressure.
  3. Combustion Chamber

    • Location where jet fuel is mixed with compressed air and ignited.
  4. Turbines

    • High Pressure Turbine:
      • 1 stage, helps drive the high-pressure compressor.
    • Low Pressure Turbines:
      • 4 stages, help drive the low-pressure compressor and fan.
  5. Exhaust Assembly

    • Final component where exhaust gases exit the engine.

Engine Functionality

  • High Bypass Ratio Engine:
    • 80% of airflow goes through the bypass duct, providing 80% of the engine thrust.
    • Primary flow passes through compressors, combustor, and turbines; secondary flow is directed by the fan.

Airflow Process

  1. Compression:

    • Air is compressed in both low and high-pressure compressors.
    • Temperature can reach up to 450°C.
  2. Combustion:

    • Heated air enters combustor where fuel is injected and ignited, raising temperature to 1700°C.
  3. Energy Extraction:

    • Hot gases pass through five turbine stages, extracting energy and reducing pressure.
    • Turbines drive the compressors and fan.
  4. Exhaust:

    • Air expelled through primary duct, combining with air from the fan stream.

Summary

  • A turbofan engine operates on a flow cycle:
    • Air is compressed → Heated by burning fuel → Passed through turbines → Drives compressors and fan.