Hi,
I am new to the forum, although I have read many of the posts on here, and I know the subject of thrust augmentors comes up quite alot. However I need help fairly soon as I am writing up my university dissertation.
I have dimensions of a converging-diverging augmentor however I have 2 main questions.
How can I predict the thrust increase obtained from the augmentor because I tried working from first principles assuming 1-D isentropic flow, but I don't know the temperature of exhaust gas and velocity at exhaust exit to calculate mach no.
Secondly, I have devised an experiment to investigate the optimum distance from the exhaust tip to the throat of the augmentor and I am supposed to say that students would measure peak thrust against distance from exhaust tip to the throat of the augmentor. Then compare the results they got with a theoretical calculation. But can this "optimum" distance be calculated theoretically ? Is there in fact an optimum distance or am I missing something here.
I really hope someone can help as I am stuck at this point in my write up, because I obviously need to know the maximum thrust output to safely design a clamp.
Cheers
Grant
Thrust Augmentor Calculation Help
Moderator: Mike Everman
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Al Belli
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Augmentor calculations
Hi,
See Bruno's post on thrust augmentors in the FAQ section of this site.
You can expect 1.8 to 2 times thrust augmentation.
Al Belli
See Bruno's post on thrust augmentors in the FAQ section of this site.
You can expect 1.8 to 2 times thrust augmentation.
Al Belli
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WebPilot
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V-1 exhaust gas velocity at startup ...
Hi Grant,
You are living a bit 'on the edge', eh?
F. Shultz-Grunow did the calculation for the V-1.
He did not plot this in his paper, but I did, here:
You may wish to visit my thread, Dimensionless Space and Time.
I cannot help you with the thrust augmentor, because I do not believe
in them. At startup they may help, but then they just create a lot of drag
as the vehicle accelerates to higher velocities.
Then, it's better to just 'jettison' them.
Good Luck with your defense.
You are living a bit 'on the edge', eh?
I can help you a little bit.Grant wrote: How can I predict the thrust increase obtained from the augmentor
because I tried working from first principles assuming 1-D isentropic flow,
but I don't know the temperature of exhaust gas and velocity at exhaust
exit to calculate mach no.
F. Shultz-Grunow did the calculation for the V-1.
He did not plot this in his paper, but I did, here:
You may wish to visit my thread, Dimensionless Space and Time.
I cannot help you with the thrust augmentor, because I do not believe
in them. At startup they may help, but then they just create a lot of drag
as the vehicle accelerates to higher velocities.
Then, it's better to just 'jettison' them.
Good Luck with your defense.
