Aeronautics – NASA-MIT Collaboration Could Transform Aircraft Design as We Know it
Think about this: With just a 1% improvement in the fuel efficiency of commercial aircraft, the airline industry could save millions of dollars and dramatically reduce human-produced greenhouse gas emissions. Researchers at NASA and the Massachusetts Institute of Technology (MIT) have joined forces to test a revolutionary airplane design that challenges conventional wisdom. MIT's unique D8 "double-bubble" configuration, so-called for its fuselage—which is double the width of current aircraft fuselages—relies on a technology called boundary layer ingestion (BLI) to redirect slower air (boundary layer) that hugs the surface of the aircraft into its engines—mounted on top of the rear fuselage. By combining advanced modeling and simulations run on high-performance computers with wind tunnel test results, and then comparing the D8 configuration with a conventional business jet-type configuration (with engines mounted on pylons on the sides of the rear fuselage), the NASA-MIT team found that the D8 burns 5 – 9% less fuel than a conventional configuration.
Bottom line: If researchers can show that the benefits of BLI engine technology can work at higher speeds, then future aircraft may be able to fly using 60% of the fuel used during each flight by today's aircraft.
If the fuel savings predicted for this cool new airplane design pan out at higher speeds, then tomorrow's aircraft could use 60% of the fuel used by aircraft flown today. Less fuel means lower costs for the airlines, and—hopefully—cheaper ticket prices for the rest of us.
Shishir Pandya, aerospace engineer, NASA Advanced Supercomputing Facility, NASA Ames Research Center
Quick Facts
- Accurate simulations capturing the complex physics of airflow on the surface of the D8 aircraft and surrounding air used 166 million grid points and approximately 70 overlapping grids. Each airflow simulation required hundreds of nodes, about 25,000 processor-hours, and almost 7 terabytes of memory on Pleiades over 3 to 4 days.
- The resulting airflow was analyzed to assess the power required to fly at cruise condition. Computational results show that at low speeds (70 – 120 mph), the BLI configuration requires less power compared to a conventional configuration.
- The NASA-MIT team, including Aurora Flight Sciences and Pratt & Whitney, conducted an experiment in a 14- by 22-foot wind tunnel at NASA's Langley Research Center using a 1/11th scale model of the D8 to measure the power required to achieve cruise condition.
- The team's next step is to redesign the aircraft so that it is efficient at higher speeds, and then assess the BLI benefit at Mach 0.7 to Mach 0.85 in order to do trade studies of fuel efficiency versus speed.
Key Image
Image Caption
Depiction of the computed pressure field on the surface of an MIT D8 aircraft. The innovative integration of the engine on the top rear of the fuselage makes it possible to take advantage of the slower air flowing next to the fuselage surface, to gain fuel efficiency. The shape of the rear fuselage is designed to maximize slower fluid entering the engine fan. Shishir Pandya, NASA/AmesDownload High-Res Image
Contacts
Shishir Pandya, NASA Ames Research Centershishir.pandya@nasa.gov