petal valves in dead end ?

[rudelf]

It is widespread belief that a pulse jet must have intake in front, then chamber and after that exhaust, Not so. It is the mindsets which prevent progress, fear of contravening established customs which the small minds defend at any cost, coupled with poor resistance to brainwashing.
Examine the attached image. By machining the limiting plate in a way that the valve petals lay on and bend in slighly offset manner they overlap each other upon opening, without touching or nterfering with each other. This increases net intake area, improves filling and purging of the chamber and increases power.

If you think petals have to be attached in the middle and spread radially, you have been brainwashed by flower mafia.
In the next arrangement, filling and purging of the chamber is even better, leaving no dead gases mixed with fresh air. The valves, their roots and limiting plates are cooled effectiverly from twoo sides which should nicely prolong their life.
This one took me about one hour from conception to drawing. As you can see, I do not ef around, use any opportunity o sharpen my reflexes, even if it is not in my most favoured area..

[Mark]

If you don't have symmetry, one edge of the reed might tend to lift and one edge will smack down before the other. If you could balance the asymmetry of weight and length and flexibility, you might have something. If one reed has a proclivity to close before the other, then you will have problems. I've blown out reeds so fast by not having a retainer low enough to keep the play small enough to get the reed closed in time. Fire will attack/gate past a lagging reed or lagging edge.
Any large hole is going to indent too, it's not often seen where thicker reeds have the response, so hole size is a factor to keep in mind.
If you have air flowing over the top/sides of the reed from an adjacent flow it may interfere with the natural frequency/flutter of the reed too, at hurricane force speed. If you blow into a Dynajet, the reeds flutter and it makes this honking sound like a horn. But if you had air cross-flowing over those reeds from an angle as well as head-on, it might dampen the resonance.
That petal design is promising, but I sense there are a lot of unknowns. Believe me, when you think you have figured something out, something new, think about the millions of man-hours that have gone into reed design.
Mark

[pgup]

... It is the mindsets which prevent progress, fear of contravening established customs which the small minds defend at any cost, coupled with poor resistance to brainwashing.
Examine the attached image. ...This increases net intake area, improves filling and purging of the chamber and increases power.
In the next arrangement, filling and purging of the chamber is even better, leaving no dead gases mixed with fresh air. ...

The worth of a creative idea cannot be proved by proclamation.

Why don't you build an engine using your ideas, test it, measure the thrust and associated fuel flow, and then report the results here for all to see. Then you and everyone else will truly know the value of your new petal valve design, which appears to be very innovative.

[rudelf]

You are correct, the holes should be divided. It is also true the only way to test and refine a design is to build the engine. Computations should be done afterwards based on data , even as they are rudimentary, which were obtained practically. As you can see space agencies spent billions on computations but still no engine.
The reeds may not interfere after all, because they follow their separate paths.
I believe reeds will do crazy things only if the air is blown on them assymetrically, then they become unpredictable. Since the reeds are exactly the same, under the same conditions they should behave.
Even as it is painful, I must let others try and disprove my ideas because I am on pension , without any tools now. No friend with machine shop.
Thanks for the comments.

[Mike Everman]

Hi Rudelf,
Nice renderings. The second one is putting both torsion and bending stress into the root of the petals, rather than just bending. That seems a recipe for heartburn.

[rudelf]

Right. Bending without twisting is already big headache. The very existence of these valve is a headache.
The best I could do is to make the valve grid to mach the slant of the limiting plate. They would be clamped and twisted before they lay down on their sections of the grid and pretend nothing happened.

[dynajetjerry]

A coupla comments, if I may:
There is "grain" in the reed metal that may affect their stresses and useful life; each petal will see its unique stresses and be affected differently from the others.
The angled seats will be hell to machine and, more importantly, will be extremely difficult to sand and clean up damages caused by use.
Perhaps a flat seat can be retained but a weird "curlicue" design of the root of each petal can be devised that will induce a twisting of the petal during flexing. Of course, this, too, will lead to uneven stresses and, perhaps, early destruction.
These ideas, along with those suggested by others, might be worth investigating.
Jerry

[dynajetjerry]

Rudelf,
I'm moved to add a "philosophical" comment to your suggestion that others disprove your p-j design: The usual procedure is to come up with something novel then try it to learn if its presumed advantages are real. It ain't kosher to make claims then expect others to disprove them. I'm reminded of a long-ago acquaintance of mine who claimed he had "invented" a perpetual-motion machine but had never constucted it due to time and money problems. He invited me to prove it would not work! These days, most true scientists and researchers accept that, in our macro world, such a device is tantamount to creating energy from nothing; its operation requires energy to overcome the ever-present friction, a theoretical and practical impossibility! This includes so-called Zero-Point energy.
However, I suggest you keep investigating. Good luck.
Jerry

[Graham C. Williams]

Hi.
The first question must be: Do I want or need to admit extra air?
At speed you may need to reduce the flow through the valve!

Graham

[nsmikle]

Redelf.. Maybe you can visit a University and beg to use their machine shop and materials, or just ask them to make it for you.

I like your idea. Sure there is some slight twisting.. but Your idea about pre-twisting the petals sound good.

The tip of the petals will twist on a radius right.. so i think there will also be more opening area, So at the same time there will be a slight reduction in the bending stress.

I would really like to see this built, even just to see it work.