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Messages - allenmck

#1
retired2 is right. I think he is the one who introduced the subject to this forum in the first place(?), which was a really insightful modification. I was gonna ask if he was an engineer by training, or just a smart civilian. :) It was also impressive that he did his own experimental testing and shared the results. IMHO advice is worth ten times as much when it comes from first-hand observation rather than "I read somewhere."

Regarding why the vortex spinning in the same direction also causes a performance hit, I read somewhere ;D (and this is a rough paraphrase) that it is due to the impellers not being able to impart as much force to the fluid. I kind of pictured it like this: when you throw a baseball TO a batter, he can crack the h--- out of it. But if you imagine a stream of baseballs coming from behind a batter, and the batter trying to hit one hard enough to speed it up, it seems like the timing of the swing would be impossible to get right. A lot of whiffs vs. a good, solid connect.

That might be total BS, but at least I could stop wondering and use the information, because the results were pretty impressive. 19% improvement (don't know if it is a 1:1 improvement in collection, or a 19% improvement in an aspect of the process). But the two mods are such easy things to do, why not give it a shot?

I'm always open to being proved wrong (kind of the point of experimenting, after all), but the explanation about the impellers not being able to move the air at all if it is spinning in the same direction doesn't seem right. That would kind of stall the whole system, right?

Anyway, Retired2 and many others have brought in a lot of useful, creative, information. And that seems to be a big motivating factor here: building your own system that is equal to, or even better than, commercial offerings. Wringing every bit of efficiency out of the system can only help. It does make you wonder how much research the commercial manufacturers have done. Or whether other considerations get priority over what seems like cheap and simple ways to push efficiency as high as possible?

When I get a chance I want to start a thread about how the super high-end DC systems (like Felder's top line) take collection to the current highest level. I'm pretty sure I know how they do it. But there are a couple of practical aspects I'm betting guys like Retired2 can figure out no problem.  :)
#2
Thanks for fixing the link. I figured it was an anti-spam technique.

And thanks again for all the hard work it takes to maintain this site.

BTW, I forgot to mention that the research paper also experimentally validates the "bellmouth" outlet modification (referred to in the paper as "streamlined entry").

Both modifications seem to already be accepted here. But I figured it was still pretty interesting that such a specialized topic had actually been the subject of published scientific research.
#3
Hello. I recently discovered this forum while researching my own DC system. Greatly admire Mr. Thien for his invention, for sharing it, and for maintaining such a high-caliber forum.

Having read several of the threads on this forum regarding what everyone calls "air straighteners", I just wanted to offer a link to some interesting research. The paper offers both experimental validation and design guidelines for the use of Deswirl Devices in Cyclonic DCs. I am in no way connected with the researchers; I just wanted to add to the knowledge base this site offers, as well as offer kudos to whoever brought the subject of vortex straightening to the forum. Lots of smart people here!

***

Well, I tried to post a link to the PDF file of the research paper above, but the forum software said "no thanks." If a moderator wants to correct it, here's the workaround version: www.thaiscience.info/journals/Article/Application%20of%20deswirl%20device%20in%20cyclone%20dust%20separator.pdf

The two main points I took away from the paper are: 1) a three-vaned device provides the most improvement (think peace-sign-shaped cross section) and 2) a short device is quite effective (in other words, the device doesn't have to extend very far into the outlet duct).

If this paper, or similar research has already been cited here, I apologize for the repetition. If not, I hope it is useful.

Thanks again for the information and discussion this forum offers.