Reduce Drag & Noise With Slots
NASA and BOEING TESTS CONFIRM USING SLOTS IN ACOUSTIC LINERS REDUCES DRAG AND NOISE
Tests are focused on industry demand for better fuel economy and less aircraft noise
NASA examined several thru-hole configurations and determined that slots instead of traditional round holes in the acoustic liner (with air passing perpendicular to the slots) had the greatest effect on reducing drag by as much as 50%.
Boeing completed a full scale test on a 737 CFM Leap 1B engine prototype using a slot pattern and results showed that “acoustic and drag benefits prove better than expected.”
IKONICS Precision Abrasive Machining can perforate slots in acoustic liners without the challenges associated with traditional machining. Changing from round holes to slotsin the acoustic liner makes a big difference. Results showed up to 50% less drag with acoustic benefits as well.
New Slot Geometry
This new geometry cut the penalty between a smooth wall and a conventional roundhole perforate ~50% without detrimental effect on the liner’s acoustic performance.Slots with flow running perpendicular reduced drag by up to 50% vs. standard round holes. Download the pdf in the link above for a detailed graph.
IKONICS Precision Abrasive Machining
IKONICS Technology can support a variety of precise features, shapes, and sizes in composite materials such as carbon fiber and fiberglass. IKONICS Advantages include no delamination, stress or pulled fibers like you would get with other processes such as CNC and Water Jet. With the PAM Abrasive Process you get a clean, smooth sidewall.
1. Howerton, B., Jones, M. “Acoustic Liner Drag: Measurements on Novel Facesheet Perforate Geometries”, 22nd AIAA/CEAS Aeroacoustics Conference, Aeroacoustics
Conferences. Lyon, France, 30 May – 1 June, 2016. AIAA 2016-2979. AIAA. Print.
2. Howerton, B., Jones, M., Jasinski, C. “Acoustic Liner Drag: Further Measurements on Novel Facesheet Perforate Geometries”, 2018 AIAA/CEAS Aeroacoustics Conference,
AIAA AVIATION Forum. Atlanta, Georgia, June 25-29, 2018. AIAA 2018-3605. AIAA. Print.
3. Norris, G. “Boeing-NASA Low-Drag, Low-Noise Engine Feature Beats Expectations”, Aviation Week & Space Technology. August 28, 2018. Online