Objective:
Noise emanating from military operations increasingly is a concern as urban areas encroach on once-remote installations. The military is aggressively pursuing means to reduce the impact of noise on adjacent communities. The objective of this project is to demonstrate the capabilities of a noise attenuation device (NAD) to significantly reduce (greater than 20 dBA) the noise produced by jet engines during stationary testing and aircraft run-up.
Technology Description:
The NAD to be demonstrated is a large muffler that reduces jet engine noise by intercepting the exhaust plume, mixing it in a confined region with approximately three times the quantity of aspirated air, slowing the plume down, and reducing the intensity of the noise produced. It is a cylindrically shaped device made of carbon steel, about 50 feet in length, 8 feet in diameter, and weighing 19 tons. Portable and low-cost, the NAD is built to withstand the rigors of jet engines operating at after-burner power and provides at least 20 dBA attenuation of jet noise over a frequency range greater than that of the human ear (6.25 to 20,000 Hz) as demonstrated by both near- and far-field measurements. The NAD has been developed via bench-scale, small-scale, and full-scale engine testing of the J-52 and F-404 engines. This demonstration will target the F-414 engine. Based on the results, tests with other engines may be undertaken (e.g., the F-119 or F-135). Expected Benefits:
The NAD can be used for engine test purposes for which enclosed Jet Engine Test Cells (JETC) are not feasible. Being transportable, the NAD can be moved to different locations at an activity as needed (e.g., an engine test pad or an aircraft high power run-up pad) to facilitate the run-up of engines. The cost of fabricating an NAD is approximately $200 thousand, as compared to $12-15 million for the construction of a new JETC. (Anticipated Project Completion - 2008) Principal Investigator: Dr. Norman Helgeson Naval Facilities Engineering Service Center 1100 23rd Avenue Port Hueneme, CA 93043-4370 Telephone: (805) 982-1335 Fax: (805) 982-4832 E-mail: norman.helgeson@navy.mil
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