Posted on October 24, 2024 Jacob Luiz
Modern jet engines have revolutionized the aviation industry since their debut on the market, enabling faster and more efficient travel on a global scale. However, one of the longstanding challenges of their operation has been the immense amount of noise they generate during combustion, an issue that is particularly prevalent during takeoff and landing phases. Noise pollution is a concern for both environmental and community safety, as well as the comfort of onboard passengers. As a result, the aviation industry continues to pursue innovative solutions to minimize noise levels, with engineers leveraging advanced soundproofing technologies and measures to create quieter aircraft.
Jet engine noise can originate from multiple sources, including the combustion of fuel-and-air mixtures, the expulsion of high-speed exhaust gasses for thrust, and general mechanical vibrations that travel throughout the assembly. Reducing this noise involves addressing all sources through design improvements and the implementation of certain technologies. Below are some of the most effective design techniques and features used in modern aircraft to reduce engine noise.
Chevrons: One common feature added to modern engines to reduce noise is chevrons, which are sawtooth-shaped patterns located at the exhaust section. Their presence smooths out the mixing process of hot air expelled from the engine with cool atmospheric air, mitigating turbulent noise.
High Bypass Ratio Turbofan: In turbofan engines specifically, a significant portion of the air taken in from the atmosphere bypasses the combustion chamber to instead be directed around the engine core. The presence of a high bypass ratio turbofan reduces the amount of high-speed exhaust gasses exiting the engine during operations, thereby lowering overall noise pollution.
Acoustic Liner Technology: Acoustic liners are materials that are known to optimally absorb sound waves, regularly being installed inside engine nacelles for the most effective use.
Active Structural-Acoustic Control (ASAC): ASAC technology involves having sensors and actuators embedded in an aircraft’s engine structure to detect noise-producing vibrations. When this occurs, the technology will create anti-vibration forces that counter undesirable noise emissions with stabilization.
Engine Systems with Soundproofing: Soundproofing methods are diverse, with one of the most common options being to add insulation to key systems that are known to vibrate or create audible noise. This helps to stop issues at the source, ensuring that nothing escapes into the aircraft cabin or the surrounding atmosphere.
In addition to innovations in engine design, modifications to aircraft operations are also being explored and adopted to reduce noise pollution. For instance, many airlines have implemented noise abatement procedures that include determining optimal flight paths, takeoff, and landing techniques that are designed to reduce overall noise impact on surrounding communities during operations. An example of this is using continuous descent approaches, where pilots can minimize the amount of engine thrust needed during descent to be quieter.
Before being deployed on aircraft, all powerplants are tested in specialized engine test facilities that measure noise levels and assess the effectiveness of reduction technologies. While this allows for current fleets to better meet regulatory requirements, it also enables engineers and manufacturers to test cutting-edge technologies for further noise mitigation.
If you are looking to secure an engine for an aircraft with the specific goal of minimizing noise, there are a few factors that one can consider to make the most sound investment. Oftentimes, a large and powerful jet engine with many moving parts will produce more noise than a more simplistic option, though the presence of acoustic liners, chevron exhaust nozzles, and other previously mentioned features can make a major difference. If an engine does not have such features, be sure to research upgrade capabilities or if modifications can be made to reduce noise energy. It is also important to consider the regulations imposed by local jurisdictions and aviation bodies to ensure compliance when choosing an engine.
With a better understanding of how to soundproof against aircraft noise, you can ensure that you make informed purchasing decisions. Once you are ready to begin procurement for reliable jet engine components and various parts that contribute to aircraft noise reduction, ASAP Semiconductor has you covered. Here, we offer competitive pricing and on-time delivery for a plethora of new, used, obsolete, and hard-to-find aerospace items that trace back to leading manufacturers from across the globe. Take the time to explore our selection with the curated catalogs and search engine featured on our website, and you are always welcome to take the first step of purchasing with our online Request for Quote (RFQ) service. You can also call or email directly for consultation, so never hesitate to reach out to our staff.
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