[ExI] Space conferences

BillK pharos at gmail.com
Sat Jul 11 18:44:10 UTC 2015

On 5 July 2015 at 20:10, spike wrote:
> Hi BillK, thanks, but that still doesn't tell us anything we didn't already know.
> This notion was really hot stuff in the 80s and 90s, and we knew that to make
> a single stage to orbit notion fly, we needed to be air-breathing until way up in
> the thin air, and needed to really be hauling by the time we run out of air.
> To do that, we know our combustion chamber is downwind of some astonishing
> and mighty shock waves, which means the flow is hot and chaotic.
> To make the cycle work requires some kind of intercooler to get cold laminar flow
> to the engine.
> Then we have a chance of making the whole air-breathing to rocket hybrid scheme work.

Skylon has just revealed their intercooler.


The system chills incoming air from more than 1,000C to minus 150C in
less than 1/100th of a second before passing the pre-cooled air
through a turbo-compressor and into the rocket combustion chamber,
where it is burned with sub-cooled liquid hydrogen. But until now the
means by which the system does this without clogging up the pre-cooler
with ice has remained a closely guarded company secret.

Reaction Engines uses methanol as an antifreeze. The methanol is used
with the objective of minimizing the amount that is needed.

They use chemical process industry tricks.

* inject the methanol at one of the coldest points
* get the mix of water and methanol to flow forward in the matrix –
against the direction of the airflow
* use multiple injection and extraction points in the matrix
* Eventually you end up with a situation where you have extracted all
the water vapor as liquid from the airflow and that leaves you
essentially with dry air below 215 Kelvin. The partial pressure of the
water vapor at this point is so low that you can allow it to pass
through the heat exchanger and it does not freeze

Cool!   :)


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