[AR] Re: Electric driven Turbo Pumps
- From: Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Fri, 16 Dec 2016 05:27:14 -0700
On 12/16/2016 1:45 AM, Uwe Klein wrote:
Am 15.12.2016 um 21:32 schrieb Henry Vanderbilt:
My impression is that piston pumps don't lose efficiency at lower RPMs
to the same degree turbine pumps do. This might imply that for given
performance requirements a physically larger, slower-rotating piston
pump might tend to have lower minimum required feed pressure without
impractically low efficiency.
you also see significant pulsation from any type of displacement pump.
See previous remarks - "You need to pay attention to output pressure
variations, to the extent your motor/application may be sensitive to them."
To amplify: My non-evil twin mentioned proper phasing of multiple
pistons as one way to reduce pulsations. Any given arrangement of
rocket motor and feed plumbing will likely to some testable extent
further reduce pulsations before they translate to chamber pressure
variations. The propulsion application may not care about some level of
regular chamber pressure (thrust) variations. (Extreme example: the
V-1.) And to whatever extent propellant feed-pressure pulsations do
need to be reduced, pulse-dampers are a well-established technology.
Henry
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