I think starting as simple as possible is a good approach. To simplify
the design as much as possible, I'm proposing:
1) Assume the use of an electric motor for the first iteration.. fewer
variables, though the shaft loading is slightly different (and easier
to model).
2) Do an open bladed partial emission (barske) pump with 180* radially
opposed outlets to balance radial shaft loads
3) Have an inducer with extremely simple geometry
A pump like this will (likely) be terribly inefficient, but once there
is some hands on experience and empirical results it becomes easier to
iterate. I am going to try and dust off my CAD skills and see what I
can come up with.
Thoughts?
On Tue, Jul 14, 2015 at 8:37 AM, Monroe L. King Jr.
<monroe@xxxxxxxxxxxxxxxxxx> wrote:
I agree and it was the Merlin I was looking to for inspiration.
But the split design of the SA-2 also has it's merit and it is possible
to actually get a hold of one of those to get a good look at and take
measurements from as well as perhaps some 3D scans if nothing else. It
can also be copied.
I'm willing to cut some corners here and take advantage of a known good
design if we can.
The other thing is the SA-2's propellants and pump designs are closer to
the same for our chosen propellants.
also looks to me like the SA-2 has open impellers?
If I can find/buy one to use as a reference it should cut development in
half.
Or do you think that is mot a good way to proceed?
This is our project you tell me. You are designing a turbopump Peter.
-------- Original Message --------
Subject: [AR] Re: Arocket Pump Progress
From: Peter Fairbrother <zenadsl6186@xxxxxxxxx>
Date: Tue, July 14, 2015 8:10 am
To: arocket@xxxxxxxxxxxxx
On 14/07/15 14:36, Monroe L. King Jr. wrote:
That does help some! Thank you. I do believe working from this design is
better than trying to go with a V-2 design :)
It's not bad, but if I was designing a turbopump I'd use the Merlin
engine turbopump as an example. It's a pretty good one.
http://www.barber-nichols.com/sites/default/files/wysiwyg/images/merlin_turbopump.jpg
The picture is pretty small, but it shows most things: at the bottom,
from left to right, there is the LOX pump with integral inducer, the
shaft with fuel pump and inducer, the turbine wheel.
It is a reaction turbine, and I think a partial admission one - a
reaction turbine has less end thrust than an impulse turbine, and in
theory only a very low pressure differential across the disk - with a
single shaft with two pumps, both with screw inducers, pumping in
opposite directions to balance end thrust.
Note that the turbine gas flows to the left, creating a leftward end
thrust on the shaft, and the LOX flows to the left, creating a rightward
end thrust to balance both the turbine end thrust and the lesser
leftwards thrust of the fuel pump (fuel flows to the right).
For a smaller engine I would consider Barske style partial emission
pumps, or closed impellers; if nothing else, in order to make
construction easier. Perhaps tesla inducers too.
-- Peter Fairbrother
