Thanks Doug. That's shorter than I expected.
If C* were less than 18" I assume C*_eff would start to drop off. Would you
expect combustion instability. I'm asking because a LOX/CH4 motor we
hot-fired a few weeks ago had a low L* and had a significant low-frequency
sound and obvious "sputtering/chugging". It had co-axial injectors which
were intended to be liquid-liquid, but were likely gas-gas (or low-quality
liquid at best), since the plumbing may not have reached thermal
equilibrium.
--- Carl Tedesco
-----Original Message-----
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On
Behalf Of Doug Jones (Redacted sender "randome" for DMARC)
Sent: Thursday, February 22, 2018 1:54 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: L* for LOX/methane
In trombone chamber testing for the 5M15, we went as low as 18" L* and saw
no dropoff in C*, with C*_eff about .96 to .98 in multiple runs.
If your injection is gas-liquid microcoaxial, the combustion is complete
about 3" from the injector face, I don't know how to make it go slower than
that.
On 2018-02-22 1:19 PM, Carl Tedesco wrote:
Anyone have know any useful values for L* for LOX/Methane? I have
searched all the common literature (Sutton, Hill & Peterson and the
www), but can’t find anything readily. I used RPA and it came up with
32.88 in.
--- Carl Tedesco