Search found 47 matches

by toakreon
Thu Apr 12, 2007 4:34 pm
Forum: Valveless pulsejet forum
Topic: UFLOW1D experiments with the "Squirrel"
Replies: 19
Views: 10638

ATTACHMENT 10 - the last! (time = 0.00508) The combustion chamber pressure has peaked at about 1.3 bars right along its length, though the gas density is far less even - high right at the front of the combustion chamber but falling to a much lower value for the rest of it. From this point on the sim...
by toakreon
Thu Apr 12, 2007 4:30 pm
Forum: Valveless pulsejet forum
Topic: UFLOW1D experiments with the "Squirrel"
Replies: 19
Views: 10638

ATTACHMENT 9 (time = 0.00350)

Combustion chamber pressure is now rising and a BIG inflow from the inlet persists. The air in the inlet and the VERY FRONT of the combustion chamber is reaching quite a high density, but that high density doesn't appear to reach back far into the combustion chamber.
by toakreon
Thu Apr 12, 2007 4:27 pm
Forum: Valveless pulsejet forum
Topic: UFLOW1D experiments with the "Squirrel"
Replies: 19
Views: 10638

ATTACHMENT 8 (time = 0.00264)

Some time later there's a BIG inflow to the combustion chamber from the inlet, and also a definite inflow to the combustion chamber from the tailpipe as well (mach graph).
by toakreon
Thu Apr 12, 2007 4:24 pm
Forum: Valveless pulsejet forum
Topic: UFLOW1D experiments with the "Squirrel"
Replies: 19
Views: 10638

ATTACHMENT 7 (time = 0.00218)

The tailpipe rarefaction wave reaches the combustion chamber. By now we're getting the beginnings of a genuine inflow along the inlet (see mach graph).
by toakreon
Thu Apr 12, 2007 4:21 pm
Forum: Valveless pulsejet forum
Topic: UFLOW1D experiments with the "Squirrel"
Replies: 19
Views: 10638

ATTACHMENT 6 (time = 0.00179)

The rarefaction wave in the tailpipe is now well on the way back to the combustion chamber. It seems to be almost "deepening as it goes" - though I can't understand why.
by toakreon
Thu Apr 12, 2007 4:19 pm
Forum: Valveless pulsejet forum
Topic: UFLOW1D experiments with the "Squirrel"
Replies: 19
Views: 10638

ATTACHMENT 5 (time = 0.00102)

A rarefaction wave is obviously reflecting from the end of the tailpipe and heading back towards the combustion chamber. As mentioned before the rarefaction wave in the inlet has now almost gone.
by toakreon
Thu Apr 12, 2007 4:17 pm
Forum: Valveless pulsejet forum
Topic: UFLOW1D experiments with the "Squirrel"
Replies: 19
Views: 10638

ATTACHMENT 4 (time = 0.00065)

The rearward moving pressure wave reaches the back of the tailpipe. The vestiges of the reflected inlet rarefaction wave can still be seen, just before it disappears into the combustion chamber.
by toakreon
Thu Apr 12, 2007 4:14 pm
Forum: Valveless pulsejet forum
Topic: UFLOW1D experiments with the "Squirrel"
Replies: 19
Views: 10638

ATTACHMENT 3 (time = 0.00050)

A rarefaction wave reflects from the front of the inlet, though it's not a very potent one and "disappears" as soon as it hits the combustion chamber.
by toakreon
Thu Apr 12, 2007 4:11 pm
Forum: Valveless pulsejet forum
Topic: UFLOW1D experiments with the "Squirrel"
Replies: 19
Views: 10638

ATTACHMENT 2 (time = 0.00023)

The forward moving pressure wave reaches the front of the inlet.
by toakreon
Thu Apr 12, 2007 4:09 pm
Forum: Valveless pulsejet forum
Topic: UFLOW1D experiments with the "Squirrel"
Replies: 19
Views: 10638

UFLOW1D experiments with the "Squirrel"

As I said elsewhere, I've put my very rough-and-ready "design" for the "Squirrel" valveless pulse jet into UFLOW1D and had a look to see what happens. A LOT happens, actually! But as I am unsure about what really SHOULD happen, I am equally unsure about whether what I'm seeing is "good" or "bad". Wh...
by toakreon
Wed Apr 11, 2007 8:27 pm
Forum: Valveless pulsejet forum
Topic: New Member's Musings - Long and probably wrong! ;)
Replies: 20
Views: 12130

OK ... :) ... First a couple of BIG thank-yous. To GRAHAM Thanks for pointing me in the direction of UFLOW1D. This I have downloaded and started playing with. Great stuff - I love CFD programs! I used one (a different one, obviously) to design my "Elipso-Parabolic" air-foil sections for radio-contro...
by toakreon
Wed Apr 11, 2007 5:39 pm
Forum: Tools and Construction
Topic: NUDiS
Replies: 50
Views: 61804

Ah ... :( ... I don't have Excel ... I have Quatro Pro as my spreadsheet.

Don't think I can run NUDiS .....

John
by toakreon
Wed Apr 11, 2007 3:18 am
Forum: Valveless pulsejet forum
Topic: New Member's Musings - Long and probably wrong! ;)
Replies: 20
Views: 12130

Ah, thanks Rossco,

So you're suggesting I scale up my "Sneezing Gerbil" concept and turn it into - well - a "Sneezing Rat"? ... :)

OK - I'll go with that and have a try with something more, oh, about AFW engine sized as far as CC is concerned - and start reading about resonance tubes ... GRIN.

John
by toakreon
Tue Apr 10, 2007 6:49 pm
Forum: Valveless pulsejet forum
Topic: New Member's Musings - Long and probably wrong! ;)
Replies: 20
Views: 12130

Thanks Larry ... :) As it happens I'm just discovering the delights of UFLOW1D. I've not yet really "got to grips with it" but it's fascinating to put the dimensions of my "design" (for want of a better word - or a better design) for a very simple valveless into it and set it with an initial high pr...
by toakreon
Tue Apr 10, 2007 4:46 pm
Forum: Valveless pulsejet forum
Topic: New Member's Musings - Long and probably wrong! ;)
Replies: 20
Views: 12130

Ah - thanks, I WAS being dense (thought so ... GRIN) ... I'll have a "play".

John