The Papp engine and cavitation

One of the big mysteries of the Papp engine is understanding the Papp engine fuel preparation device. What does that device do and why is it important to the function of the Papp engine? All the Papp engine replicators have discounted the need to use this fuel prep device and try to get the Papp engine to work without prepared fuel. Papp knew that prepared fuel was critically important to getting the engine to work. Three months before his death in 1989, Papp destroyed all the fuel he had prepared so that no one could ever get his engine to work ever again. The engine laid useless inside his workshop. That engine was his alone forever and could never be shared with the world.

The cavitation theory of the Papp engine provides the reason why fuel preparation is essential. A intense shock wave is required to form the ultra dense crystal nature of the fuel in the alternate paired cylinder. Without that shockwave, active fuel cannot be formed. The fuel preparation device produced ultra dense water and latter in the fuel to act as a bootstrap or initial plasma shock wave so that cavitation could occur in the paired cylinder. Without that first shock wave, recurring fuel formation does not begin in the alternate cylinder when the compression of the water vapor/gas is underway.

Papp used this prepared fuel to disintegrate a 5/8 inch stainless steel pipe when he demoed his Papp common in the desert.

Quote from Zeus46

How does a gas, noble or otherwise, cavitate?

This phase diagram of Xenon shows that Xenon is close to liquefaction point at a pressure that could exist in the maximum gas pressure point reached by the compressing cylinder.

The pressure required to reach the liquefaction point at the operating temperature of the Papp engine is about 58 bar. Because helium is in the gas mix, helium cools the Xenon during compression because the light helium atoms moderate the kinetic energy generated in the Xenon by removing that energy through collision just like hydrogen moderates the energy of the neutron by taking its energy away through collision.

So helium brings down the temperature of the heavier noble gases so that it is easier for the liquefaction of the heavier noble gases to occur.

Droplets of the heavy noble gases condense on the walls of the cylinder at or near maximum gas compression. The Xenon liquid (and maybe even argon) is very dense and viscous. This makes this liquid very prone to cavitation when it is shocked. This cavitation is what produces the ultra dense state of the noble gas that will explode when stimulated by the electric spark during the ignition phase of the power cycle.

It looks like argon stays in the vapor state at the 50 bar pressure level.

Quote from Zeus46

58 bar is a very high compression ratio for an engine, it would have needed a beefy starter motor*... but yes, that phase diagram does imply that cavitation in that setup could be possible.

* edit: assuming the engine has valves and an exhaust cycle... which I imagine it probably doesn't. don't see on that schematic above.

The Papp engine has no valves nor an exhaust cycle. All cylinders are gas tight.

Quote from Zeus46

And what is the effect of 58:1 adiabatic compression on xenon? I assume it would raise the temperature enough to push it back into the gas phase?

Cooling the Xenon during compression is done by other lighter noble gases which move heat from the Xenon to the walls of the cylinder.

This cooling method is known and used in selected applications as follows:

Quote

Noble gas, binary mixtures for commercial gas-cooled reactor systems
El-Genk, M. S.; Tournier, J. M.ICENES 2007 Abstractshttp://www.iaea.org/inis/collection/NCLCollectionStore/_Public/38/117/38117082.pdf - 60 KB - Text Version

[en]
Commercial gas cooled reactors employ helium as a coolant and working fluid for the Closed Brayton Cycle (CBC) turbo-machines. Helium has the highest thermal conductivity and lowest dynamic viscosity of all noble gases. This paper compares the relative performance of pure helium to binary mixtures of helium and other noble gases of higher molecular weights. The comparison is for the same molecular flow rate, and same operating temperatures and geometry. Results show that although helium is a good working fluid because of its high heat transfer coefficient and significantly lower pumping requirement, a binary gas mixture of He-Xe with M = 15 gm/mole has a heat transfer coefficient that is ∼7% higher than that of helium and requires only 25% of the number stages of the turbo-machines. The binary mixture, however, requires 3.5 times the pumping requirement with helium. The second best working fluid is He-Kr binary mixture with M = 10 gm/mole. It has 4% higher heat transfer coefficient than He and requires 30% of the number of stages in the turbo-machines, but requires twice the pumping power

It seems to be rather easy to test the noble gas cavitation posit. With the advent of barbell type acoustic horns, a quantity of pressurized noble gas mix might be treated with ultrasonic stimulation from the acoustic horn and then excited with a spark. If the noble gas mix explodes then the design of a acoustic horn based cavitation engine is straightforward.

Some insights on how to build such a cavitation based reactor might come from something like this...one large acoustic driver with a pickup for each cylinder

http://www.mittoncavitation.co…n-cavitation-reactors.php

Quote from Sherlock Holmes

Isn't it a constant with inventions from the Teslas (post insanity) and the Papps of this world that, despite the incredible leaps in technology that we have seen lately, nobody can reproduce them?

I

In 1505, around the time Leonardo da Vinci was painting the Mona Lisa, he was also sketching designs for a helicopter. How's that for a Renaissance man?

The helicopter's design challenge was that the entire "air screw," as he called the flying machine, spun, not just the propeller.

He died in 1519 without resolving the engineering dilemma, which would take another four centuries to solve.

THere are mathematicians that propose conjecture that take centuries to resolve. Such is the fate of singular genius whose work takes generations to be fully integrated into the ascent of man.

Quote from Zeus46

adiabatic compression equation:

Pf = Pi(Vi / Vf)^γ

rearrange to:

Tf.Vf^(γ-1) = Ti.Vi^(γ-1)

where:

γ= spec. heat capacity / volumetric spec. heat capacity

γ(xenon)=1.65

γ(helium+xenon)=1.4

Vf=1

Vi=58

Ti=273K

so:

Tf = 273(58^0.65) = 3822K for xenon alone

Tf = 273(58^0.4) = 1385K for xenon with helium

Which is a surprisingly large effect from just adding helium... no wonder the turbines in your linked paper prefer mixed gases.

But at that temperature it's on the wrong side of the xenon phase diagram for cavitation to be happening.

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Thanks for all the effort.

The cylinder chambers were filled with a noble gas mixture of helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe).

All but xenon must have been used for cooling...similar in concept to an multi-staged rocket as the heat flows from element to element in an exchange chain.. Chlorine was in the mix too. Can you rework the numbers for this expanded list of gases?

Another complication is the formation of noble gas compounds. Chlorine catalyzed noble gas compound formation.

https://en.wikipedia.org/wiki/Noble_gas_compound