Viewing 15 posts - 16 through 30 (of 35 total)
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  • #5853
    Aeronaut
    Participant

    Yep, a titanium heat pipe anode is hot enough and strong enough to reduce the anode diameter, thus the cathode diameter, which should significantly increase peak field strength and hopefully significantly reduce Bremstrahlung. This approach plays naturally to the machine’s inherent desire to make heat rather than electricity.

    #5854
    AaronB
    Participant

    I like all the thinking and ideas being bounced around in this thread. Keep up the good work!

    #5855
    Henning
    Participant

    Hm, about manufacturing the onion with rapid prototyping, I don’t think that’s feasible, because that would repeat the process 2000 times for 1000 layers of conducting foil. It already takes a few hours for each process, even with speeding it up it’s unrealistic. Possibly just build the onion’s skeletal features, it’s cooling coils, and then apply the foil layers by hand. Or spray them onto it. Or more likely spray the insulator, and layer the conductor.

    #5857
    Aeronaut
    Participant

    Henning wrote: Hm, about manufacturing the onion with rapid prototyping, I don’t think that’s feasible, because that would repeat the process 2000 times for 1000 layers of conducting foil. It already takes a few hours for each process, even with speeding it up it’s unrealistic. Possibly just build the onion’s skeletal features, it’s cooling coils, and then apply the foil layers by hand. Or spray them onto it. Or more likely spray the insulator, and layer the conductor.

    Our pleasure, Aaron. Got a revised sketch at http://energymadecleanly.com/anode1.pdf

    Henning, the biggest single challenge of building onions in any quantity is going to be to get an indexing drum within a 2 powder laser sinterer or 2 material CVD machine without ‘overspray’. Given a mochine that can do that, we put several thousand of them in the 2M sq ft Government Motors plant up in Grand Rapids that Brian, Rematog, and I were discussing about a year ago. No reason not to build on the east side of that building and prove along the west side, away from housing and traffic, but closest to those 6 regional transmission lines that we could tee into 12 lines by putting transmission transformers in the west parking lot.

    Given the state of the art as I understand it, we’d need to put several thousand CVDs shoulder to shoulder, passing off in a continuous series of vacuum locks without losing registration or browning out that part of the city.

    Keep your eye on the toolmakers’ trade shows. No telling what we get for Christmas this year 😉

    #5859
    Henning
    Participant

    These laser sinterers only work with one type of material. But maybe they can be adapted to vacuum clean the dust of type one (after sinter), apply dust of type two on the same layer, sinter, vacuum clean, apply washable dust (type three), sinter, clean. And repeat that for each layer.

    So essentially add another in water-, alcohol-, or whatever-, dissoluble dust like NaCl to that process, that’s good for holes. And then wash it out afterwards.

    But those machines are not available yet.

    And maybe we don’t want water for washing – it possibly corrodes the material.

    #5860
    Henning
    Participant

    There’s another technique called “Electron Beam Melting” (EBM): http://en.wikipedia.org/wiki/Electron_beam_melting

    It’s done in vacuum, so no corrosion problem with air.

    And they already tested it with Beryllium (that is AlBeMet): http://www.arcam.com/technology/ebm-materials.aspx

    But still only one material.

    #5861
    Aeronaut
    Participant

    Henning wrote: There’s another technique called “Electron Beam Melting” (EBM): http://en.wikipedia.org/wiki/Electron_beam_melting

    It’s done in vacuum, so no corrosion problem with air.

    And they already tested it with Beryllium (that is AlBeMet): http://www.arcam.com/technology/ebm-materials.aspx

    But still only one material.

    Outstanding! Now we can optimize for both modes- thermal or electric with rapid prototyping tools to test all the ratio and geometry variations.

    The laser sintering demo flick that I looked at yesterday showed a machine that was optimized for prototyping, rather than serial production. Seems that it would be relatively easy to add robotic material feeds and masks, since its all controlled from a CAD drawing.

    I goofed yesterday when I said using a few DPFs to make superheated steam was ridiculous. It turns out to be the most cost-effective way to deploy FF. Considering that Rematog conservatively estimated it would take 100 FFs to repower just one of his 3 boilers using 5MW FFs, the entire 1.6GW project would cost around $300M before engineering studies and structural modifications if you plan to re-use the existing building.

    Now, if as few as 2, or as many as 60 thermally-optimized FFs can make that much superheated steam, we gain at least a 5:1 price advantage over last year’s price estimates, which also risk being too cheap for credibility. Looks like I have to learn about superheated steam and once-through boilers this week.

    Update- ArCam works with many materials, although they’re still certifying the more popular metals. But if you click their auxiliary equipment tab, you’ll see what looks like a sandblast cabinet and read that the powder is blasted onto the surface. That implies a screw-type industrial air compressor and poor control over each layer. Still, it’s nice to know about. Could be a great way to build cathodes en masse.

    #5868
    Aeronaut
    Participant

    I just got initial feedback from an engineer. Seems we can design an annular (hollow core) design using titanium and lithium. Right now the dimensions are anybody’s guess- next step is ask for a NDA, and hopefully get a series of curves outlining what’s likely to be possible.

    #5873
    Aeronaut
    Participant

    I just read a Non Disclosure Agreement that would essentially give that company all rights to the anode design for 5 years. Essentially making them the sole source, thus having no control over pricing or production. Can’t fault them for asking, since I’d do the same thing from their side of the table.

    But what’s possible in a commercial R&D company vs what’s possible in the math, physics, and engineering departments of several state universities competing for Fusion Milestone Prizes and the prestige that goes with each leads me to suspect that allowing a commercial engineering company to set the limits on our cooling system components (yes, I implied that they might design in several performance stages) is not going to get us the most design and production flexibility.

    In short, I’m proceeding on the assumptions of 1.27cm titanium anode radius ~4 to 8 cm long absorbing a minimum of 500J per pulse, with frequencies as high as 1 Mhz using a pair of DPFs in switched parallel to store the cap bank’s initial pulse energy, plus ion energy gain, something like a tank circuit that may need some makeup energy as well. Fuel is back to decaborane, if not hydrogen and boron mixed in the fuel injector(s). If that can make commercial amounts of superheated steam from a handful of DPFs, we have a clear technical winner that at least resembles what the real world might be willing to invest heavily in. The political wrangling can come later, but will be required once we’re showing progress above unity.

    The tank circuit would eliminate cap bank design life as an operating consideration. I don’t think anode cooling is going to be as daunting as it looked to me last week. And I believe we can shield 2 or more units in an oval water jacket with each core (about the size, shape, and weight of a torpedo) only a few inches apart, since each would be active while the other was removing its heat. Since this is a design study with an eye towards Michigan style mass production, my major goals are ballpark parameters, rather than actual engineering.

    #5942
    Lerner
    Participant

    You have to figure that you need to get something like 2 MW heat out of the anode or it will melt, no matter what it made of. Titanium will absorb a lot of x-rays in a very small layer. It will just boil away. You can look up x-ray absorption lengths on NIST’s website. Anything other beryllium will absorb in such a small layer that it will just disappear. With Be, the x-rays mostly pass through or are absorbed in the bulk of the anode, not a thin layer. Yes it requires special conditions to machine it safely but that it possible.

    #5944
    Phil’s Dad
    Participant

    Aeronaut wrote: The political wrangling can come later, but will be required once we’re showing progress above unity.

    Finally something on this thread I can help with. ;-P Ready when you are. :coolsmirk:

    #5949
    Aeronaut
    Participant

    Lerner wrote: You have to figure that you need to get something like 2 MW heat out of the anode or it will melt, no matter what it made of. Titanium will absorb a lot of x-rays in a very small layer. It will just boil away. You can look up x-ray absorption lengths on NIST’s website. Anything other beryllium will absorb in such a small layer that it will just disappear. With Be, the x-rays mostly pass through or are absorbed in the bulk of the anode, not a thin layer. Yes it requires special conditions to machine it safely but that it possible.

    Thanx for the insights and leads, Eric. Think we could do that in PWR fashion by pumping water through a beryllium anode and controlling the steam pressure with the cooling water pressure? I hear PWRs are making a comeback these days :shut:

    PD, I was born ready. :coolsmirk:

    #5950
    jamesr
    Participant

    Aeronaut wrote: Think we could do that in PWR fashion by pumping water through a beryllium anode and controlling the steam pressure with the cooling water pressure? I hear PWRs are making a comeback these days :shut:

    There is no way a small beryllium electrode could withstand water pressurised to the 160bar or so needed to keep it liquid through the primary circuit, as they do in PWRs

    As I understand it, the plan is to use helium gas as the primary coolant. What you then do as a secondary stage largely depends on how high a temperature you can let the helium outlet be. I am guessing no more than 480C. In which case a standard boiler & small forced cooling heat sink would be enough to dump 2MW. If you have several FF units together, the secondary circuits could be linked, and make it economical to put the steam through a turbine and recover 35% or so of the heat energy.

    If the anode can cope with the helium temperature outlet being above 800C, then direct cycle options such as gas turbines become a possibility. But not probably worth it. High temperature gas turbines are being proposed and worked on for 4th Gen Fission reactors like the GT-MHR. However, even if you could operate at this temperature, I think the maximum pressure the anode can handle may be a limiting factor.

    #5954
    Aeronaut
    Participant

    jamesr wrote:

    Think we could do that in PWR fashion by pumping water through a beryllium anode and controlling the steam pressure with the cooling water pressure? I hear PWRs are making a comeback these days :shut:

    There is no way a small beryllium electrode could withstand water pressurised to the 160bar or so needed to keep it liquid through the primary circuit, as they do in PWRs

    As I understand it, the plan is to use helium gas as the primary coolant. What you then do as a secondary stage largely depends on how high a temperature you can let the helium outlet be. I am guessing no more than 480C. In which case a standard boiler & small forced cooling heat sink would be enough to dump 2MW. If you have several FF units together, the secondary circuits could be linked, and make it economical to put the steam through a turbine and recover 35% or so of the heat energy.

    If the anode can cope with the helium temperature outlet being above 800C, then direct cycle options such as gas turbines become a possibility. But not probably worth it. High temperature gas turbines are being proposed and worked on for 4th Gen Fission reactors like the GT-MHR. However, even if you could operate at this temperature, I think the maximum pressure the anode can handle may be a limiting factor.

    So much to learn, so little mind…

    What kind of cooling channel wall thickness do you think we’d need to pump water at 160bar through a beryllium anode? I’m picturing 2 coaxial cooling tubes where cool source water flows up the outer layer and hot water returns down the anode’s centerline channel. I was going to ask required flow volume in L/sec until it dawned on me that we’re trying to cool a 10- to 30 nS heat impulse.

    We can make the anode pretty much any diameter we please, as long as we don’t mind tradeoffs like required cathode diameters and cap bank size. Cap bank can be spread across many cores, so that’s not a huge issue. The payoff would be a drop-in boiler replacement that pays for itself in coal savings. I’d really like to target gas turbines, too, but that’s beginning to resemble another year.

    #6915
    JimmyT
    Participant

    Aeronaut wrote: WOW! Just the 1st para looks like the machine I’ve been looking for over in the CVD marketplace. It also gave me some ideas for the onion, since it should be able to handle a drum-shaped blank.

    I’m wondering if maybe the best way to build an onion is like orange slices. Design and build 1 slice. Repeat 40 times then fit them together. Could be sphere or cylinder, or anything in between.

    Course’ you know everyone’s thinking right now ” Just what combination of input pulse to plasmoid efficiencies, and input to plasma jet increase, and jet to electricity conversion efficiencies will allow us to forgo the x-ray conversion part of this project altogether.” At least for the early production models.

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