Turbofans have revolutionized the aviation industry. Not to be confused with turbojets, turbofans now power nearly all commercial airliners.
Most commercial airliners feature one or more turbofans. Turbofans are airbreathing jet engines with an air intake, combustion chamber and an exhaust system. Air enters through the intake, at which point it mixes with fuel. A spark will then ignite the fuel-air mixture, resulting in combustion. As the hot exhaust gases are propelled out through the exhaust, the airplane is propelled forward. In addition to being powerful, however, modern turbofans are very fuel efficient. Here are several ways that modern turbofans improve fuel efficiency.
High Bypass Ratio
Modern turbofans can improve fuel efficiency with a high bypass ratio. All turbofans have a bypass ratio. It represents the amount of air that flows around the engine’s core relative to the amount of air that enters the combustion chamber.
In the past, turbofans typically featured a low bypass ratio, meaning more air entered the combustion chamber. Turbofans today, though, often feature a high bypass ratio. Some of them, in fact, have a bypass ratio of 10:1. This means for one unit of air that enters the combustion chamber, ten units of air will flow past the core. With a high bypass ratio, more thrust comes from the fan rather than the combustion process, which improves fuel efficiency.
Advanced Materials
Another way that modern turbofans improve fuel efficiency is through the use of advanced materials. Turbofans are no longer limited to traditional materials like steel and nickel alloys. While you can still find turbofans made of these materials, modern turbofans are often made of advanced materials that enhance their performance and fuel efficiency.
Some turbofans are made of Ceramic Matrix Composites (CMCs). Consisting of ceramic fibers within a ceramic matrix, CMCs are very heat resistant. They can withstand 20% hotter temperatures than traditional metal, which improves fuel efficiency.
Modern turbofans are also available in carbon fiber composites. Certain components of turbofans, such as the fan blades and casings, may be made of carbon fiber composites. Carbon fiber composites are very lightweight and, thus, promote greater fuel efficiency.
In Conclusion
Turbofans have come a long way in recent decades. Engineers have adjusted their bypass ratios and materials to achieve greater fuel efficiency. A high bypass ratio allows more air to go around the core, and materials like CMC and carbon fiber composites can improve heat resistance and reduce the weight of the engines. The end result is greater fuel efficiency with modern turbofans.
