## 1000 degC to -150degC in 0.01s

Scientific discovery and discussion
kiloran
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### 1000 degC to -150degC in 0.01s

http://www.bbc.co.uk/news/science-environment-43732035

That reduction in temperature in such a short time is astonishing (though not dissimilar to a scottish summer to winter transition). Must be true, it's also quoted in Wikipedia

--kiloran

tjh290633
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### Re: 1000 degC to -150degC in 0.01s

Bearing in mind that we are talking of a supersonic environment, the residence time in the heat exchanger cannot be very long. Presumably to get it that low involves slowing the air and exhaust flows down massively to achieve the required heat exchange. At Mach 5 the time in a simple tube can be seen to be miniscule. Let's say that it is 3,600mph, that is 1 mile/second, 0.01 seconds will be 17.6 yards, a bit long for an aero engine.

TJH

GoSeigen
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### Re: 1000 degC to -150degC in 0.01s

tjh290633 wrote:Bearing in mind that we are talking of a supersonic environment, the residence time in the heat exchanger cannot be very long. Presumably to get it that low involves slowing the air and exhaust flows down massively to achieve the required heat exchange. At Mach 5 the time in a simple tube can be seen to be miniscule. Let's say that it is 3,600mph, that is 1 mile/second, 0.01 seconds will be 17.6 yards, a bit long for an aero engine.

TJH

LOL, TJH was an aerospace engineer before retirement.

GS