On Wed, 29 Jan 2003, Randall Clague wrote:
> >they were determined at: 1000 -> 0.2 psia, or 5000:1 pressure ratio...!
> >...are they within reach of practical nozzles?
>
> I don't see why not. An expansion ratio of 5000 is a diameter ratio
> of about 71...
Less than that; pressure ratio and area ratio are not the same thing. The
relationship between them is mathematically messy and depends on the ratio
of specific heats. For plausible values of the latter, getting a pressure
ratio of 5000 calls for an area ratio of 200-300, i.e. a diameter ratio of
14-18.
Sooner or later, you're going to start losing more in wall friction and
such than you gain in expansion, but the limits are quite a ways up.
In-space maneuvering engines commonly have very large expansion ratios.
Henry Spencer
[EMAIL PROTECTED]
_______________________________________________
ERPS-list mailing list
[EMAIL PROTECTED]
http://lists.erps.org/mailman/listinfo/erps-list
