Hello everyone,
Not exactly sure how to make a new subject in this forum, so I thought I’d
message here. At my school we’re looking at designing a new Methalox engine
with 3-4K lb of thrust and I was just wondering how I determine the what the
pressure in the combustion chamber should be?
Thanks,
Shane Cullen
Sent from my iPhone
On Jan 22, 2020, at 7:32 PM, roxanna Mason <rocketmaster.ken@xxxxxxxxx> wrote:
:)
On Wed, Jan 22, 2020 at 5:58 PM Anthony Cesaroni <anthony@xxxxxxxxxxx> wrote:
During Titan development, they ran into combustion instability frequencies
above 20Khz that literally sawed the TCAs in half. Face mounted Kistlers are
one of the best tools for the job.
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
From: arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> On Behalf
Of roxanna Mason
Sent: Wednesday, January 22, 2020 8:36 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Nozzle total conditions
Yeah Anthony, used in that TCA we about at Socorro, 40KHz facing the CC,
water cooled of course.
On Wed, Jan 22, 2020 at 4:12 PM Anthony Cesaroni <anthony@xxxxxxxxxxx> wrote:
Ken,
You just reminded me of the first time I used Kistlers. It was for a linear
pulse jet engine. Think of a pulse jet extruded in the lateral axis to form
a blade. “Blade” was the name it was actually given. We used the Kistlers to
arrange and tune septum structures in the combustion chambers to mitigate
lateral waves from forming, similar to blade type sonotrodes (ultrasonic
horns) that we used slits machined into them for the same purpose. We also
built and tested radial pulse jet motors for MHD power generation. Hydrogen
and powdered coal. Those were called “Sombreros”. Intake in the center,
exhaust all around the perimeter.
Best.
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
From: arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> On Behalf
Of roxanna Mason
Sent: Wednesday, January 22, 2020 1:18 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Nozzle total conditions
We used Kistlers at EMRTC 20K LOx/Jet-A
On Wed, Jan 22, 2020 at 8:31 AM Anthony Cesaroni <anthony@xxxxxxxxxxx> wrote:
If you want to eliminate hole effects and monitor combustion stability then
a flush mounted piezoelectric transducer is the way to go. The ones I’ve
used are heat shielded and water cooled.
https://www.kistler.com/en/products/components/pressure-sensors/?pfv_metrics=metric&pfv_pressure_applications=gas_turbine%2Ccombustion_engine
PCB in the US also makes similar versions but I’ve never used them. I’m told
the PCB units don’t offer the same temperature stability that Kistlers do
but I can’t confirm that.
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
From: arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> On Behalf
Of William Claybaugh
Sent: Tuesday, January 21, 2020 10:01 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Nozzle total conditions
Martin:
Gas velocity at the head (bulkhead) end of the combustion chamber is lowest,
thus pressure measurements at that location are little effected by this
issue.
Gas pressure at the nozzle is typically slightly higher than at the bulkhead
end, but not typically by very much. If one really wants that measurement
than the nozzle throat is the correct location where, by definition the
velocity is Mach 1. The issue then becomes the introduction of shock waves
into the gas from the presence of the pressure measuring port. I am not
aware of any sufficiently accurate simulation that would allow deducing
stagnation pressure with confidence in this case.
Alternately, one can tap pressure at the top of the nozzle (either at the
nozzle entrance or at the chamber wall) where gas velocity is typically low.
In a hybrid, in particular, the recirculation zone at the base of the grain
will typically have very low gas velocity.
Bill
On Tue, Jan 21, 2020 at 4:20 AM Martin Olde <MARTIN_OLDE@xxxxxxxxxxx> wrote:
Hey everyone,
A friend has posed me a question about hybrid propulsion (but solid or
liquid propulsion should not differ much):
How do you experimentally determine total temperature and total pressure at
the nozzle inlet if there are high port velocities? Are there standard ways
of deriving these properties from more easily measured values?
kind regards/ vriendelijke groeten,
Martin
