Apologies, Peter. I meant to send this to the whole list.
On Sunday, December 4, 2016, 3:24:24 PM EST, Graham Sortino
<gnsortino@xxxxxxxxx> wrote:Hi Peter -
I'm in the very early process of considering this... also based on Rocket Lab's
example. As was pointed out to me by someone else on this list recently is that
you could always use two motors to increase the power to the needed
requirements. I do suspect that the challenge is more in the pump design, since
likely nothing exists off the shelf that meets typical liquid rocket engine
requirements, rather than the power envelope. Just out of curiosity what sort
of change in head (pump inlet vs pump outlet pressure) are you looking to gain
based on the power requirements below?
One thing I do really like about the electric pump concept is that it
completely removes the turbine and pre-burner requirements, which are arguably
a very significant amount of work.
If I do make any progress with this I'll post updates. Good luck and keep me
posted!
Best,Graham
On Saturday, December 3, 2016, 4:34:14 PM EST, cnc-engineering@xxxxxx
<cnc-engineering@xxxxxx> wrote:
Dear all,
electric driven turbopumps did gain quite a lot of attention lately.
For sure all of you are aware of a famous example – NewZealand Rocket Lab !
http://cdn.satellitetoday.com/wp-content/uploads/2016/04/Stage-Two-Image-B.jpg
While personally I am more convinced to use classic turbine driven turbo pumps
when total power demand is larger than ~ 70 kW, below that value electric
driven pumps might become quite interesting. (For sure this is not a fixed
value and it will depend on a lot of boundary conditions as well as personal
preferences.)
When it comes to restartable engines to be used for example in upper stages,
electric propulsion to my understanding has a significant advantage over
turbine driven systems. This should be even more valid, in case engine
throttling would be involved.
Our present study in the field of upper stage propulsion shows requirements as
listed (planning stage):
- Power demand: ~ 55 kW
- RPM pf pump: 25,000 – 50,000 (pump characteristics are acceptable
within this envelope. Exact RPM number will be adapted depending on the
characteristics of available motors, electronics and batteries. )
- Total energy demand: ~ 1 kWh (= ~ 60 s operation @ 55 kW)
My questions:
- What recommendations do you have when it comes selecting electric
motors, electronics and batteries ? Any specific recommendation with respect to
the requirements mentioned above ?
(Quite interesting seems to be this motor, even though it is limited to about
30 kW @ 50,000 rpm .
http://www.lehner-shop.com/Inrunner/Series-30/3080::48.html ; ;
http://www.lehner-motoren.com/doc/man_30_series_en_11_2013.pdf ;
- Is anyone involved in electric driven turbo pump activities ?
- What are your general thoughts about the use of these kind of turbo
pumps ?
(BTW: eventually this paper might be interesting for you ('Electric feed
systems for liquid propellant rockets' :
http://www.dima.uniroma1.it:8080/STAFF2/jpp12r3.pdf ;)
Have a great weekend,
Peter
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