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Noise from jet engine testing can cause deafness as well as non-auditory health effects such as hypertension and nervous disorders. This type of noise also disturbs the sleep of individuals in proximity to the test site, affects the performance of children in school, and decreases the value of real estate surrounding the test site. All of this makes noise from jet engine testing one of the most common sources of tension between surrounding communities and military air bases, and the military needs to aggressively pursue any and all available means to reduce its impact. Putting a muffler on an exhaust stream of 3800 degrees F is not simple. Engine heat is a limiting factor when thinking about noise abatement devices and strategies for jet engines.
Given the above, Navy scientists and engineers have developed a system to mix cold air with the exhaust plume immediately upon exiting the engine. This has the combined effect of decreasing the temperature to 1200 degrees F and reducing the velocity of the exhaust by a factor of four thereby lowering the acoustic power of the exhaust plume. The invention is embodied in a 50-foot cylinder which is between 6 and 14 feet in diameter and made of carbon-steel. Holes throughout the cylinder allow for the escape of exhaust which further reduces the power of the noise-producing flow turbulence. For additional slowing of the exhaust plume a cone is positioned at the end of the cylinder.
- Designed to be subjected to an operating environment for testing the General Electric F-414 jet engine at after burner conditions of 3900 degrees F
- Constructed to prevent structural resonance problems caused by the intense vibrational testing of the jet engine
- US patent 7,918,310 available for license