Hi Graham,
good to know, that you are involved in current activities !
- I agree, that two motors could be used in one pump application, in
case power of a single unit won't be sufficient. (Rocket Lab is doing
the same, i.e. using one pump for LOX and Kerosene each.)
- The pump has to be for sure designed from scratch, as it is highly
unlikely, that som COTS product might even come close to the sepcific
requirements (flow rate and head pressure increase.) Due to this we are
designing and manufacturing everything ourselfes. This is feasable...but
due to the small flow rate in combination with high pressure rise
required efficiency will not be so good.
- We are working on a H2O2 / Kerosene pump. (Inlet pressure: ~ 4 bar,
exit pressure: ~ 65 bar)
- Having the chance to omit turbines and gas generators for sure is very
good in order to safe time and effort during the development: both can
be replaced by (... at least some somehow..) COTS equipment. Still
though I was not successful yet to find more powerful equipment than the
one mentioned below. (i.e. 30 KW @ 50,000 RPM).
=> do you have any other idea where to look for high-power / high-RPM
motors ?
Please keep us updated concerning your progress !
Best,
Peter
Am 04.12.2016 um 21:56 schrieb Graham Sortino (Redacted sender gnsortino
for DMARC):
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
