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| Dyno http://gemellocattivo.com/forum/viewtopic.php?f=11&t=332 |
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| Author: | mk e [ Sat Mar 09, 2019 7:20 pm ] | ||
| Post subject: | Re: Dyno | ||
mk e wrote: I'm thinking I need to layout the aborber...I'm pretty sure I know what to do but I've never actually seen the inside of one so there are some guesses in the equation. Score! Now I've seen most of the inside and all the really important stuff  Edit: I might call and order a replacement seal and bearing kit...it would be nice to know what they are using there
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| Author: | mk e [ Sat Mar 09, 2019 8:02 pm ] |
| Post subject: | Re: Dyno |
FSAE team dyno design https://sites.google.com/a/eng.ucsd.edu ... eam15/home |
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| Author: | cribbj [ Sat Mar 09, 2019 8:14 pm ] |
| Post subject: | Re: Dyno |
mk e wrote: If you want a dyno, here you go https://www.ebay.com/itm/800-HP-Engine- ... ctupt=true If I wasn't basically broke I'd probably buy it. I know the feeling..... |
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| Author: | mk e [ Sat Mar 09, 2019 8:21 pm ] |
| Post subject: | Re: Dyno |
cribbj wrote: mk e wrote: If you want a dyno, here you go https://www.ebay.com/itm/800-HP-Engine- ... ctupt=true If I wasn't basically broke I'd probably buy it. I know the feeling..... So I'll have to make it I guess. Found a lot of pics....the newest stuff it toroidal like the pisc I posted of the land and sea....found older pics of there stuff and they were straight blade. I found you can make a straight blade as a weldment and they work...but toroidal....ooooooooo..... |
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| Author: | mk e [ Sat Mar 09, 2019 8:32 pm ] | ||
| Post subject: | Re: Dyno | ||
The best I've found of the inside of a superflow...its supposed to be the 901. I tlooks very similar the the dynomite, but maybe better shaft attachment, this is more like I was thinking.
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| Author: | cribbj [ Sat Mar 09, 2019 11:27 pm ] |
| Post subject: | Re: Dyno |
Kinda sorta looks like turbine wheels from a big, slow speed diesel engine Or pump impellers |
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| Author: | mk e [ Sun Mar 10, 2019 8:56 am ] |
| Post subject: | Re: Dyno |
cribbj wrote: Kinda sorta looks like turbine wheels from a big, slow speed diesel engine Or pump impellers Yes. The difference is a pump is designed to efficiently rise the pressure or a flow vs a water brake the is designed to run smoothly deadheaded at 0% efficiency. A $1500-$2500 5hp well pump or pair of 2hp pool pumps in series will fully supply the water needs of a 1000hp brake by my math...if I setup nates 1200hp unit a single 2hp pool pump might be enough as the brake is bigger and doesn't need to be kep full so the system would be at lower pressure. A Big pump might work though...I know hydraulic pumps are used to build smaller dynos. This is from the dynomite site: Quote: Water brakes are similar to centrifugal water pumps. They typically have one or more vaned rotors spinning in between pocketed stator housings. Load is controlled by varying the volume of water recirculating within the brake with adjustable inlet and/or outlet valves and orifices. Raising this water level increases the rotational drag of the pump's rotor, applying more resistance to the engine turning it. Interestingly the water brake is, by design, a very inefficient pump. It uses up your engine's horsepower output by making "instant hot water"! Since the discharged hot water is clean, it can often be allowed to just run off, or air cooled and recirculated. Then they slide this in randomly elsewhere: Quote: Optional 3,000 Hp toroidal-flow absorber responds twice as quickly as ordinary vane-type brakes
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| Author: | mekilljoydammit [ Sun Mar 10, 2019 10:09 am ] |
| Post subject: | Re: Dyno |
Oh hey, water brake stuff - been a while since I've been paying attention. OK, there's two basic styles - the older vane style Stuska / etc brakes and the newer toroidal style. Basically falls down to the toroidal style flings water between the rotor and stator more quickly - centrifugal force basically forces it up a ski ramp, then the stator redirects it towards the center. So the torid style probably can respond to changes in flow faster but either way seems to work. What you need to look at is sprinkler pumps which is what they all use. The pressure requirement is one of those things where it's a "we need to get through a 1 or 1 1/2" NPT fitting" thing rather than the water brake actually needing pressure to operate. I've got an old Stuska brake I'm rehabilitating. Depac recommends "PAC-SEAL #237 from Grainger 5NC16" which have two pieces, one stays with the housing and the other stays with the rotor with a spring to press it against the housing part. The facing surfaces are ceramic and need a trickle of water (the Stuska brake uses some 1/16" hose to do so) to keep from burning up. They're called pump shaft seals. Bearings are nothing special, just shielded deep groove ball bearings - when I got it, the ones in my brake were pulled apart to have access from a zerk but I think that was a holdover from old design bearings. The big thing about flow is that the bulk water outlet temperature needs to stay relatively cool otherwise apparently it signifies there's local boiling going on and the control gets sloppy. You can do the math on water flow to absorb X amount of horsepower without too much temperature rise, I'm sure. I still have my Stuska apart, would be happy to take pictures or measurements if you need anything. |
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| Author: | mk e [ Sun Mar 10, 2019 11:27 am ] |
| Post subject: | Re: Dyno |
I saw the depac info and saved it to the project folder I will be happy for any pictures you are willing to take and go from there....rotor OD would be nice to know as a starting point. I looked quickly at sprinker pumps bu moved on when I saw they were really struggling with the 45psi min spec and 60-65 out right out. But I guess like my pool pump though, a sprinkler pump as a fist attempt and add pool/spa pre-pump if needed would work. The nice thing about a pup like that is it deadheads below system max pressure so no pressure reducer valve needed.....2 pool pumps can be setup to deadhead at 65psi or so but pool+sprinkler would be more like 75 I think. |
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| Author: | mekilljoydammit [ Sun Mar 10, 2019 3:54 pm ] |
| Post subject: | Re: Dyno |
https://imgur.com/gallery/HJysK has a few and https://i.imgur.com/xEfUm6k.jpg?1 is another. They're not great but just quick cellphone shots. I'm heading out for a work trip tomorrow but I'll measure whatever you want when I get back. Rotor is around 12" OD and 4" thick or so - cast aluminum with a stainless shaft. Again, I can measure when I get home. One of the things you'll notice is the uneven spacing of the vanes on the rotor - apparently that's to set it up so that there's not more than one vane passing its corresponding vane on the stator at a time for smoothness reasons. The point I was making on the pump is that I really don't see why 60psi is necessary; it really only cares about flow. You're introducing water closer to the eye of the rotor too so it shouldn't take much. If I were doing one from scratch I'd just use bigger fittings. I actually had parts where I was going to just fab a steel rotor but then I found that one on a bankruptcy auction. |
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