Final answer:
The main difference between turbofan and turbojet engines is that turbofan engines have a large fan that creates a bypass airflow for increased efficiency and reduced noise. Turbofans are more fuel-efficient and preferable for commercial use compared to turbojets.
Step-by-step explanation:
The main difference between turbofan and turbojet engines lies in the presence of a large fan in the turbofan engine that bypasses air around the combustion chamber. This results in two distinct airflow paths inside the engine: one that goes through the core, where combustion occurs, and another that bypasses the core. The advantage of a turbofan engine over a turbojet is its efficiency at subsonic speeds, where the larger fan helps produce additional thrust without the need for an increase in fuel consumption. Turbofan engines are quieter and provide better fuel efficiency, making them suitable for commercial airliners.
Comparison Between Turbofan and Turbojet
Turbojet engines are simpler and were the first jet engines used in aircraft. They function by drawing in air, compressing it, mixing it with fuel, and igniting the mixture to create thrust. In contrast, the turbofan design adds a large fan at the front, which accelerates a considerable amount of air around the combustor, creating a bypass airflow that generates additional thrust. Turbofans also tend to run cooler and have lower exhaust velocities, contributing to noise reduction.
The development of turbofan engines represents a significant advancement in aviation technology, utilizing high-strength materials and sophisticated electronic controls to optimize performance and safety, including the GE90-110B1 turbofan engine powering Boeing 777 aircraft.