 | ||
A hush house is an enclosed, noise-suppressed aircraft jet engine testing facility in which installed or uninstalled jet engines can be run under actual load conditions.
Jet engines, whether or not installed in aircraft, can be tested either indoors or outdoors.
The air intake and exhaust systems of indoor engine test cells and hush houses are designed to block the transmission of noise, whilst optimizing the engine air flows. The engine exhaust, after having been thoroughly mixed with cooling air, is generally discharged through a vertical stack. The gas path incorporates acoustic damping panels (often containing fibrous insulation protected from gas stream erosion by metal mesh) to reduce the sound energy of the gas stream and attenuate the noise transmitted to the surrounding outdoor area.
Because the engine exhaust flow is "augmented" with a relatively large flow of cooling air induced by a Venturi effect into the exhaust silencing system, the exhaust muffler of an indoor test facility is generally referred to as an augmenter tube, although the term "detuner" is commonly used in the UK.