Just a quick note, on my way out for three days of fishing, drinking and telling lies...
Could it be that the UFLOW mach numbers were "what is the speed of sound in this region?" not "how fast is the gas going?" certainly the velocity column must be telling us the gas speed with respect to the observer outside, but it may not be exceeding the internal speed of sound. I don't have time to look, but comparing the velocity column to the Mach number column will either show parity or not.
M1E Preview
Moderator: Mike Everman
-
- Posts: 5007
- Joined: Fri Oct 31, 2003 7:25 am
- Antipspambot question: 0
- Location: santa barbara, CA
- Contact:
Re: M1E Preview
Mike Often wrong, never unsure.
__________________________
__________________________
-
- Posts: 111
- Joined: Thu Mar 04, 2004 8:24 pm
- Antipspambot question: 0
- Location: Northampton, England
Re: M1E Preview
Does anybody know the speeds of sound at say 500,1000,1500 degrees centigrade?
I had thought that the pheonix b.c.v.p engine failed to run for more than a few seconds(or was it less) because the mean tube temperarture had increased making the tube effectively too short when hot.
Not so critical in other engines.
If the difference is small then I thought wrong.
Mike.
I had thought that the pheonix b.c.v.p engine failed to run for more than a few seconds(or was it less) because the mean tube temperarture had increased making the tube effectively too short when hot.
Not so critical in other engines.
If the difference is small then I thought wrong.
Mike.
-
- Posts: 557
- Joined: Thu Oct 09, 2003 10:36 pm
- Antipspambot question: 0
- Location: Pennsylvania - USA
Re: M1E Preview
Hi jmhdx,
For an online calculator, go to http://hyperphysics.phy-astr.gsu.edu/hb ... ouspe.html
Al Belli
For an online calculator, go to http://hyperphysics.phy-astr.gsu.edu/hb ... ouspe.html
Al Belli
-
- Posts: 571
- Joined: Fri Oct 03, 2003 11:33 pm
- Antipspambot question: 0
- Location: England
- Contact:
Re: M1E Preview
'I had thought that the pheonix b.c.v.p engine failed to run for more than a few seconds(or was it less) because the mean tube temperarture had increased making the tube effectively too short when hot.'
The temperature gradient does change across the motor. This tends to alter the frequency of operation. The wave form across the motor is reasonably stable over the gradient. Yes, it tends to favour one curve. The big problem is breathing.
Graham.
The temperature gradient does change across the motor. This tends to alter the frequency of operation. The wave form across the motor is reasonably stable over the gradient. Yes, it tends to favour one curve. The big problem is breathing.
Graham.
-
- Posts: 111
- Joined: Thu Mar 04, 2004 8:24 pm
- Antipspambot question: 0
- Location: Northampton, England
Re: M1E Preview
Thanks Al!. The difference is large indeed although I appreciate its not a straightforward application of the math to calculate the effect on pulse combustion.Al Belli wrote:Hi jmhdx,
For an online calculator, go to http://hyperphysics.phy-astr.gsu.edu/hb ... ouspe.html
Al Belli
I think we can conclude though, that faced with cold air at one end and hot co2 at the other the expanding gases will favour exit from the rear of the chamber. Ofcourse its a typically over-simplified thesis.
I'm thinking that a well tuned engine will be a b*stard to start cold.
Perhaps thats why mine won't run!
Mike.