You might have already done this, but if you do a search at uspto.gov for patent 7695242
you will find the Fuller patent for turbine pictured. Lots of tech info.
DIY Tesla Impulse Turbine
- Thread starter Toymaker
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you will find the Fuller patent for turbine pictured. Lots of tech info.
Toymaker,
I've been reading up on something else that will be of relevance, especially if you build a mk II turbine. That something is the partial admission losses.
The gist of it is that in any gas turbine the ideal flow only happens if the fluid is injected uniformly around the rotor. Unfortunately in small turbines doing that often makes for an impractically small blade height (or rotor width for a Tesla turbine), which you have solved by the sensible approach, which is injecting the fluid through small nozzles of a sensible size and letting the rotor only be in contact with the stream part of the time.
Counter-intuitively, it seems that the ideal layout for the nozzles is actually to clump them all together to simulate a sector of full flow, rather than evenly distributing them around the rotor. Apparently the reason for this is that flow in inactive parts of the rotor slows or stops, and when that bit of rotor next enters a jet of gas the gas jet has to spend some energy to get all that stationary gas moving again before it starts to do work on the rotor. So if you cluster the nozzles together only the first nozzle has to do this extra work, and the remaining nozzles get to smoothly continue a flow that is already moving.
Something to consider anyway.
I've been reading up on something else that will be of relevance, especially if you build a mk II turbine. That something is the partial admission losses.
The gist of it is that in any gas turbine the ideal flow only happens if the fluid is injected uniformly around the rotor. Unfortunately in small turbines doing that often makes for an impractically small blade height (or rotor width for a Tesla turbine), which you have solved by the sensible approach, which is injecting the fluid through small nozzles of a sensible size and letting the rotor only be in contact with the stream part of the time.
Counter-intuitively, it seems that the ideal layout for the nozzles is actually to clump them all together to simulate a sector of full flow, rather than evenly distributing them around the rotor. Apparently the reason for this is that flow in inactive parts of the rotor slows or stops, and when that bit of rotor next enters a jet of gas the gas jet has to spend some energy to get all that stationary gas moving again before it starts to do work on the rotor. So if you cluster the nozzles together only the first nozzle has to do this extra work, and the remaining nozzles get to smoothly continue a flow that is already moving.
Something to consider anyway.
That makes intuitive sense, now that you've said it. Are you thinking flat nozzles with openings that cover across all the blades to produce sheets of air like air knives, or random holes?
I think the ideal is for the flow in the active sector to be as contiguous as possible, so ideally you would make one single nozzle sized to your flow rate if you are using partial admission. There are lots of reasons not to do that however. For example having multiple nozzles allows you to control power output by turning nozzles on and off. Also you might not be able to get enough flow area from a single nozzle considering its shape. But if that is the case, you should try to design the nozzle layout so that the transition from one nozzle to the next is as smooth as practical.
I envision multiple nozzles layering the spiral flow as speed increases, would you guess the same?
Thanks for the spreadsheet Nerd!
I shall try a model in it to see what comes out!
Really appreciate you sharing this. - It may be fun...!
On the Gyrobus:
https://en.wikipedia.org/wiki/Gyrobus
Also, In case no-one noticed, Formula 1 racing cars used 2 methods of energy re-use from braking to assist "overtaking" power demands. 1 - they used batteries and motor=-generators (easily understood technology) but they also used a Torotrack transmission to power a flywheel (~16000rpm and upwards?) in a vacuum, and extract the power when required.
https://en.wikipedia.org/wiki/Kinetic_energy_recovery_system
For bearing and materials technology, the flywheel followed turbo-charger engineering... as that had been well studied and was reliable. (Hydrodynamic bearings - or something? I have no idea.). Torotrack transmissions are also in the line to become power converters from exhaust turbines on trucks, etc, to add torsional power to the main transmission, improving efficiency of road trucks.
The vacuum enclosed flywheels have been considered for cars, but simple electric hybrids do the same - simply!
K2
I shall try a model in it to see what comes out!
Really appreciate you sharing this. - It may be fun...!
On the Gyrobus:
https://en.wikipedia.org/wiki/Gyrobus
Also, In case no-one noticed, Formula 1 racing cars used 2 methods of energy re-use from braking to assist "overtaking" power demands. 1 - they used batteries and motor=-generators (easily understood technology) but they also used a Torotrack transmission to power a flywheel (~16000rpm and upwards?) in a vacuum, and extract the power when required.
https://en.wikipedia.org/wiki/Kinetic_energy_recovery_system
For bearing and materials technology, the flywheel followed turbo-charger engineering... as that had been well studied and was reliable. (Hydrodynamic bearings - or something? I have no idea.). Torotrack transmissions are also in the line to become power converters from exhaust turbines on trucks, etc, to add torsional power to the main transmission, improving efficiency of road trucks.
The vacuum enclosed flywheels have been considered for cars, but simple electric hybrids do the same - simply!
K2
With modern magnets, there may be a way to make one of these? - They cope with Tesla Turbine speeds... - Just power pick-ups have some problems of friction...
https://en.wikipedia.org/wiki/Homopolar_generator
K2.
https://en.wikipedia.org/wiki/Homopolar_generator
K2.
I think the uni of Melbourne had a big one to drive fusion experiments. Big current at low voltage. Edit: I misremembered, it was ANU that had one.
On the topic of high rpm generators to go with turbines, another option is a flux switching alternator. They're used as electrical generators aboard guided missiles, driven by a small turbine that runs on exhaust bled from the rocket engine. Major advantage is that the rotor has no coils or magnets on it, so it can withstand very high centrifugal force. And there are no sliding contacts.
I would trade my hybrid with it's bomb, Oops I mean Li battery, for a system with a FES without even thinking about it. That would make so much more sense then a battery!
Thanks for the links to read up on. I thought the F1 just used EGR units and batteries, had no idea they used FES.
From source
"
Drum-type generatoredit
A drum-type homopolar generator has a magnetic field (B) that radiates radially from the center of the drum and induces voltage (V) down the length of the drum. A conducting drum spun from above in the field of a "loudspeaker" type of magnet that has one pole in the center of the drum and the other pole surrounding the drum could use conducting ball bearings at the top and bottom of the drum to pick up the generated current."Maybe the whole turbine could also be a generator? Each disc a "barrel"?
I found a YouTuber using the type of magnet in my sketch and drawing power from his turbine (Tesla?) by placing a single coil of wire next to the magnet: diametrically polarized magnet
I've read that Variable Frequency Spindle motors used on CNC routers use these magnets to obtain their high operating speed,....but I have no personal knowledge of this.
I've read that Variable Frequency Spindle motors used on CNC routers use these magnets to obtain their high operating speed,....but I have no personal knowledge of this.
Toymaker, as you are robably aware.... There is a curious effect that conducting but non-magnetic materials possess. They react like magnets, creating their own back EMF and thus we have AC inductance motors...
So maybe the armature needs to be non-magnetic and insulating, so only the coil sees high frequency induced current?
K2
So maybe the armature needs to be non-magnetic and insulating, so only the coil sees high frequency induced current?
K2
An easy way to demo the induced magnetic field you're talking about is to drop a magnet through a coper pipe, noticing how much slower it falls through the pipe as compared to open air
When you say, "armature", do you really mean "center shaft" ?
Yes. The armature is whatever supports the wire (centripetal forces will throw it out and foul everything outside if it is not held).
K2
K2
Ignore my comments. I had the magnet stationery and coil rotating. Confused by so many ideas appearing in this thread. My simple brain. Both cells were being used and I didn't have a 3rd...
K2
K2
Wow!! Lots of information on the Stanford.edu site you linked,....even has a C code program for calculating power output. Thanks
Another curious thread.
https://www.sciencedirect.com/science/article/abs/pii/S0894177714003100
This suggests that efficiency of the turbine as a whole is significantly increased by the use of a convergent divergent nozzle, to avoid turbulence and boundary layer separation inside the turbine disc gaps. I noted the clever design of such a rectangular nozzle in the paper by Alan Swithenbank, [email protected] noted in the previous post.
I have also read that an optimum disc spacing of 0.4mm is best for steam...
And I read somewhere that an optimum angle for highest speed and efficiency is aimed to be tangential at just a few mm inside the rim of discs. As the fluid jet expands between the nozzle(s) and gap(s) the intent is to capture all the fluid stream inside the disc gaps, so maybe keep the expanded cone just 1mm or so inside the outer rim of discs. Then let nature (Aerodynamics) take its course!
Perhaps a 9 degree internal angle cone from the nozzle outer edge to the edge of the cone is an ideal? -
Toymaker's Tesla Turbine with "paddles" can be geometrically modelled similarly perhaps for jet alignment? - But I am only guessing here.
K2
https://www.sciencedirect.com/science/article/abs/pii/S0894177714003100
This suggests that efficiency of the turbine as a whole is significantly increased by the use of a convergent divergent nozzle, to avoid turbulence and boundary layer separation inside the turbine disc gaps. I noted the clever design of such a rectangular nozzle in the paper by Alan Swithenbank, [email protected] noted in the previous post.
I have also read that an optimum disc spacing of 0.4mm is best for steam...
And I read somewhere that an optimum angle for highest speed and efficiency is aimed to be tangential at just a few mm inside the rim of discs. As the fluid jet expands between the nozzle(s) and gap(s) the intent is to capture all the fluid stream inside the disc gaps, so maybe keep the expanded cone just 1mm or so inside the outer rim of discs. Then let nature (Aerodynamics) take its course!
Perhaps a 9 degree internal angle cone from the nozzle outer edge to the edge of the cone is an ideal? -
Toymaker's Tesla Turbine with "paddles" can be geometrically modelled similarly perhaps for jet alignment? - But I am only guessing here.
K2
Toymaker, If you can get a copy of "Model Steam Turbines" by H. H. Harrison, then towards the last few pages there is a method of making a multi-stage impulse turbine where the exhaust from the first jet stream is taken and doubles-back to make a second hit of the blades, etc. up to 9 times, thus extracting real useful energy from the rotor by multi-staging a single rotor. Plus some mathematical explanation.
Any use?
K2
Any use?
K2
