Talk-Polywell.org

Cool!

Choff did you mean to ruin the article like that? Spoilers!

Anyone have a decent idea how the Vortex compares to SpaceX's Merlin engines? I did a couple of searches but couldn't find any real discussion. It might be because the various sources currently seem a bit vague on the exact specs of the Vortex.

CaptainBeowulf wrote:Anyone have a decent idea how the Vortex compares to SpaceX's Merlin engines? I did a couple of searches but couldn't find any real discussion. It might be because the various sources currently seem a bit vague on the exact specs of the Vortex.

... specs for what in particular? The engine that flew in Mojave was an R&D article and not a prototype for production.

The flight was good news for the concept but it's a bit early to be trying to fit the tech to a Falcon XXX

I don't view this as something that can be compared as much as a novel idea that eliminates the need for a cooling system. I'm pretty sure most rocket engines could implement this change (providing it all pans out) with little hassle.

ScottL wrote:... I'm pretty sure most rocket engines could implement this change (providing it all pans out) with little hassle.

?

Did you mean something like "most classes of rocket engines"?

Given the rather integrated nature of regenerative cooling systems for large engines and the specialized combustion chamber geometry required for the vortex I don't think actual reuse of currently used engine designs is in the cards.

Something in the Merlin class but either lighter or more powerful for the same mass...

This style of injection and cooling would require a combustion chamber of particular geometry. In addition, it wouldn't work with certain engine cycles, such as the expander cycle, where heating the propellant in cooling passages is part of operation. But reliable, efficient engines at low cost is a good thing.

bennmann wrote:Choff did you mean to ruin the article like that? Spoilers!

Cool, as in it replaces the conventional cooling system(pun intented).

Maybe Orbitec's reversed-axial-flow vortex can be combined with a Polywell to heat air, air + onboard propellant or onboard propellant by whatever means (relativistic electron beam, alpha particles, arc discharge, ...) without thermally overloading the thrust chamber walls, which would have to contain between 0.5 to 5+ GW of power transfer to the flow stream.

viewtopic.php?t=2287&highlight=&sid=bed ... cdf0cc7a30

I remember reading about a burner that used vortex technology and they were planing to use it on water heaters or some such thing as it transferred no heat to the burner leaving more to be transferred to the water. I wonder if this is based on the same concept or something different?]

Maybe you are thinking of the work of Gutsol and others at Drexel (several types of vortex chambers were studied - no-arc, arc, inductively-coupled plasma):

http://www.pages.drexel.edu/~rpg32/diesel.htm
(looks like an unmaintained web page, copy it while you can)

Gliding arc in tornado using a reverse vortex flow

Comparative Calorimetric Study of ICP Generator with Forward-Vortex and Reverse-Vortex Stabilization






The Gliding Arc Tornado at lower right has two very desirable features for a possible Polywell-driven propulsor -
1) Very little heat transfer to cylinder wall.
2) Less wear on the lower ring and upper annulus electrodes with the gliding arc (distinct arcs are blurred in photos due to exposure time).

Getting a high-enough flow rate may be the idea killer. A few large chambers or multiple smaller ones? Mix in axial flow through the ring electrode and/or around the chamber? Fire a REB along the axis? Lot's of things to try.

https://www.space.com/sierra-nevada-vor ... video.html

SNC's upper-stage Vortex engine will be used on board the Dream Chaser spacecraft, which is expected to launch from a ULA Atlas V rocket and run cargo missions to the International Space Station as early as 2021.

Too late for them to carve a niche in the market I believe.
Their ingenious idea advantages are being eroded more and more by alloys developments and the new rocket engines generations.

CaptainBeowulf wrote:Anyone have a decent idea how the Vortex compares to SpaceX's Merlin engines? I did a couple of searches but couldn't find any real discussion. It might be because the various sources currently seem a bit vague on the exact specs of the Vortex.

One of the major benefits SpaceX is looking for in the new Raptor engine they are developing for BFR/Starship is the lower turbine temperatures of the full flow cycle it uses. Reliability of the engine over many uses is a major concern to SpaceX and apparently the ability of the turbines to hold up under the temperatures in gas generator engines like the Merlin were a potential limiting factor to engine lifespan.

I guess I would be curious to know comparatively how much of a problem heat is in the turbines vs the combustion chamber.