That 'Tech Brief' publication was just an outline of current projects, not
a detailed description of hardware.
But BLC was, and still is, a common method to control heat flux to the
wall. Robert Goddard used BLC coupled with off ratio O/F
to 'cool' his engines with no regenerative used at all. He paid a high
price though for this approach with an ISP in only the 150 range.
But this was OK for the kind of research he was pursuing.
Typically and generally speaking, just running the outer row of
injector elements richer than the inner ones results in a cooler boundary
which augments, not replaces thrust chamber cooling.
If you continue your research you'll find more information on
boundary layer control.
Ken
On Thu, Apr 27, 2023 at 11:16 PM Jiyansh Agarwal <jiyansh1414@xxxxxxxxx>
wrote:
Hello I'm pretty new here. Any chance you could expand on the boundary
layer control they used? Wasn't really able to find those old tech briefs.
On Mon, Oct 11, 2021 at 2:05 PM roxanna Mason <rocketmaster.ken@xxxxxxxxx>
wrote:
I just applied design rules published fifty years ago
That's the problem, people don't remember nor learn from history so
they're destined to repeat it, the bad parts.
I once read an Aerojet publication called Tech Briefs from about 40 or 50
years ago where they established thermal equilibrium at the throat of an
uncooled biprop at about 900F through BLC, Boundary Layer Control.
So yes, it can and is done, just not often enough.
Ken
On Mon, Oct 11, 2021 at 7:16 AM Doug Jones <rocketplumber@xxxxxxxxx>
wrote:
We never used film cooling at XCOR, and had 97% or more cstar with
LOX-kerosene at 2.6 O:F, no mixture ratio compromises. I've never
understood why everyone else seems to struggle with efficiency vs stability
vs cooling- they all pull together in unison. I just applied design rules
published fifty years ago.
On Mon, Oct 11, 2021, 3:20 AM roxanna Mason <rocketmaster.ken@xxxxxxxxx>
wrote:
No, it's not that difficult to build high reliability long lived
biprops, the trick is to do it with high efficiency, c* that is, not off
ratio and/or lots of film cooling as was done with that Spectre RATO engine
which BTW was derived from an earlier Aerojet RATO rocket system using
nitric acid oxidizer with variations of fuels.
Thanks Henry for mentioning Bruno, I lost all my data earlier this year
to a hard drive crash and Bruno's info was one of the casualties. I had ~
40 pics of that Spectre system with subassemblIes of the TCA showing the
cooling jacket construction which was simple enough for amature use.
If anybody has that link of Bruno's I'd love to get it back into my
archives.
Thanks,
Ken
On Sun, Oct 10, 2021 at 9:22 PM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Sun, 10 Oct 2021, roxanna Mason wrote:
engineyou get something as flaky and short-lived as a typical rocket
flights.
Enter SpaceX, particularly their Raptor which is claiming 100
SpaceX was by no means the first to build reliable, long-lived rocket
engines; citing this as another Miracle Of St. Elon :-) is silly.
See,
for example, the attached (posted by Bruno a few years ago) -- note
position of test crew in relation to 1950s rocket engine. If you want
something more recent, see assorted videos of XCOR tests.
It's not magic, it just requires different design priorities and a
different test program -- much more like those of a normal jet engine,
meant for a manned aircraft.
Henry