Ken,
Based on the data from the longer run time tests, it appears to reach
thermal equilibrium. Here's a data plot of the last full run on the
test stand:
http://www.watzlavick.com/robert/rocket/regenChamber3/tests/20130915-run1-data-regen3.png
I had two thermocouples (orange and purple traces) embedded partway in
the outer wall between cooling jacket holes.
Thrust was right around predictions using c* and Cf correction factors.
At the bottom of this page there is a link to the design spreadsheet.
http://www.watzlavick.com/robert/rocket/regenChamber3/index.html
I designed the mixture ratio quite a bit lower (1.8) than optimal to
help get the regenerative cooling solution to converge. I measured
temps about 150 degF lower than predicted so I could potentially bump it
up a bit.
The engine is 6061-T6 with drilled cooling passages. I chose an unlike
impinging injector because it seemed like a way to get good mixing with
a small number of elements. In the smaller 100 lbf version, I tried a
variant of a split triplet but the performance wasn't very good. The
250 lbf version took a few iterations to get the injector right but that
was mainly related to sealing of the LOX manifold and making room for
the igniter.
-Bob
On 8/3/20 11:34 PM, ken mason wrote:
Nice work Robert, questions, do you think your engine reached thermal equilibrium, why an unlike injector instead of like,c* efficiency and was it made out of copper?
Interesting passive sound attenuation system, the trench.
Again, nice work,
Ken
On Mon, Aug 3, 2020 at 8:09 PM Robert Watzlavick <rocket@xxxxxxxxxxxxxx <mailto:rocket@xxxxxxxxxxxxxx>> wrote:
I posted a project update covering the last 7 months of work on my
biprop liquid rocket, covering parachute and telemetry testing.
http://www.watzlavick.com/robert/rocket/index.html
-Bob
