I assume that when the fire in a steam loco is fluidized it is operating at a optmization that is ideal and everyone is in there happy place.
"Fluidized Bed" refers to a specific design, here for coal combustion: the primary air is injected under pressure and volume that levitates the particles in a (usually somewhat thick) firebed and in doing so scrubs them for full-surface combustion. Generally some of the 'clean coal' co-firing materials, dolomite being the one that springs to mind, are incorporated in the bed to implement desulfurization, ash-chemistry optimization, etc.
One of the 'canonical' references you should study if interested in this subject is the early-'80s Combustion Engineering design:
https://patents.google.com/patent/US4633818
This of course needed gimbals and some other multiplane shock mitigation to be actually useful in a railroad context ... but they were trying.
https://patents.google.com/patent/US4633818 will read this when I get some throne time in the bathroom on my new e-reader.
...speaking of fluid dynamics...
selector ...speaking of fluid dynamics...
Seriously Raymond, have you ever heard of the term "TMI" ?
Greetings from Alberta
-an Articulate Malcontent
In case he hasn't a clue Too Much Information.
No one needed to hear that.
If a poster is visibly disappointed when he gets the information he specifically asked for, is that an indication that he is a resident of caves in the Scandinavian mountains...? Maybe a Dovregubben?
Peter
M636CIf a poster is visibly disappointed when he gets the information he specifically asked for ...
I don't think he was disappointed; it's going to take a while for him to read that 'patent language' and translate it into comprehensible equivalent, and extract the parts of the patent description that refer to his original question. What better way to do that than in the bathroom? (Speaking of TMI, there are many times I've found 'throne time' the best time to peruse serial patent references... ;-} )
Note that I provided the link without much subsequent comment precisely because individual forum readers are their own best judges about what constitutes MEGO material. (And if I get started, there's likely to be tooooooooooooo much detail, but that's another story.)
I am impresssed with leval of knowledge here and yes thank you. But its been a busy summer and the only refuge is the "Seat of Knowledge". My freinds have whole offices in their throne rooms and even have teleconfernces in there.
Hey, I always bring something to read in the bathroom. Otherwise it's wasted time, don't you think?
Besides, it's a wasted day if you don't learn something new, what's it matter where you learn it?
M636CIf a poster is visibly disappointed when he gets the information he specifically asked for, is that an indication that he is a resident of caves in the Scandinavian mountains...? Maybe a Dovregubben? Peter
He's an NSB 2-8-4?
Good gawd...Overmod and Firelock!
WTE
Worst Thread Ever.
Miningman Good gawd...Overmod and Firelock! WTE Worst Thread Ever.
Heat's getting to us here "south of the border."
I don't know where Overmods's at, but here in Ol' Virginny summers are an inferno! Good thing the car knows the way home, some afternoons lately my brain's fried!
It's baking up here too, BC is burning again, just like last year. And so is northern Ontario.
Fortunately nothing like Greece's current situation has happened yet.
Not here! It was hot in Saskatoon but only 13C (55F))as the high here and the nights were 10C (50F)or less. Today was first warmer day in a week up to 22C (71F). The furnace kicked on Sunday overnight.
We get hotter days up into the high 80's but not many of those. August nights wil be real cool. Leaves start turning last week in August.
Overmod (And if I get started, there's likely to be tooooooooooooo much detail, but that's another story.)
(And if I get started, there's likely to be tooooooooooooo much detail, but that's another story.)
I'm curious as to what the CE crew were thinking on the power output of this beast. I remember another company (Rowan Co???) working on a small fluidized bed boiler in the early 80's, ISTR it was a bit bigger than the CE design.
Overmod did good job of defining fluidized combustion in the first reply.
However as David P. Morgan explained 60 years ago, in many steam locomotives the draft through the grate when working hard was strong enough to keep a lot of the finer coal particles from ever falling down onto the grate, the coal burned in suspension. You could think of that as a 'poor man's' fluidized bed combustion.
NorthWest M636C If a poster is visibly disappointed when he gets the information he specifically asked for, is that an indication that he is a resident of caves in the Scandinavian mountains...? Maybe a Dovregubben? Peter He's an NSB 2-8-4?
M636C If a poster is visibly disappointed when he gets the information he specifically asked for, is that an indication that he is a resident of caves in the Scandinavian mountains...? Maybe a Dovregubben? Peter
Would this be of interest?
https://archive.org/stream/railwaylocomotiv41newy/railwaylocomotiv41newy#page/95/mode/1up
Pulverized Coal by Edmund, on Flickr
Not exactly fluid bed but interesting just the same.
Good Luck, Ed
gmpullmanWould this be of interest? https://archive.org/stream/railwaylocomotiv41newy/railwaylocomotiv41newy#page/95/mode/1up
Well, yes, as would the pulverized-coal system applied to German 05 003 and the whole discussion of StuG firing in Australia (about which I hope Peter Clark will knowingly expound at length).
The thing is that, as with the situation firing Big Boys on subbituminous (or worse!) it is the antithesis of fluidized-bed firing in a critical respect: there is no bed. Most of these systems work on the general principle of replacing liquid-fuel firing, which creates a plume (ideally incandescent for radiant heat-transfer effectiveness) within the radiant section -- firebox and chamber -- with a plume of combusting solid fuel. Most of the slurry-firing schemes are similar, adding heat-recovery sections to take up the heat of condensation of the water that fluidized the slurry in the same way the TurboFire XL Donlee boiler recovered the enthalpy involved in steam injection to reduce NOx.
The point of the fluidized bed is that the primary airflow and pattern is precisely regulated so that the fuel stays within a thick firebed, roughly comparable on a locomotive to the depth used for GPCS, but is levitated so the particles don't manage to rest against each other. In the presence of ash and external vibration this is not an easy operation to manage.
As an aside: the importance of high gas speed for heat transfer in the tubes of a locomotive boiler was demonstrated very convincingly in tests conducted by the USGS, of all agencies, in 1910, which was very early for this sort of thing. Part of the advantage is in 'scrubbing' (or a bit more appropriately, using turbulent characteristics to agitate) any thin layer of gas tending to insulate the inside tube wall; I suspect a case could be made for somewhat better contact transfer from solids in the gas stream to the wall but measuring this might be intricate.
The gas plume evolved from a fluidized-bed combustor then becomes a 'once-through' effect in the radiant and convective sections, and there is a certain limit on the lb/hr that can be fired even with forced-draft enhancement because smaller combustion particles that leave the bed must combust completely within the time and path of flight up to the rear tubeplate. This implies a much lower 'grate limit' analogue for functional fluidized-bed firing on locomotives than either conventional 'forcing' of a solid-fuel boiler or high oil/PC firing can generate.
Overmod whole discussion of StuG firing in Australia
Must be an acronym for something other than the usual usage: Sturmgeschütz, i.e., various German Wehrmacht turretless assault guns/tank destroyers used in WWII?
So Fluidized Coal Combustion is only at this time feasible in stationary engineering applications? aka the Boiler in my grandfather state Hospital or School ?
charlie hebdoMust be an acronym for something other than the usual usage
It is. Here "StuG" is an abbreviation for 'Studiengesellschaft'; it refers to the group that developed the approach to PC firing, I believe in the '20s. (Associated with Henschel, but carried on as a separate 'corporation') I no longer have access to my notes on this, but we've had a number of threads on the subject that contain the information.
Here are a couple of PDFs with much of the information anyone interested in the subject will need:
https://www.advanced-steam.org/wp-content/uploads/2017/07/R707-Conversion-to-PBC-Dust-Firing.pdf
https://www.advanced-steam.org/wp-content/uploads/2017/07/Brown-Coal-Dust-Firing-for-Locomotives.pdf
Alert readers may remember the Snuff Dipper described in Trains many years ago: this was my pre-Internet introduction to the wonders of the Fuller-Lehigh pulverized-fuel system, and for those with access to the Complete Collection is still a cautionary tale worth reading.
M636CWith coupled axles on the trailing truck to maximise booster adhesion... (Although that didn't last long) No the thing that the locomotive was named after, the "Dovre Giants". These are much the same thing as other people call Trolls... I have a little statue of one, a gift from a Norwegian... (A model of the locomotive would be more useful) Peter
No the thing that the locomotive was named after, the "Dovre Giants". These are much the same thing as other people call Trolls... I have a little statue of one, a gift from a Norwegian...
(A model of the locomotive would be more useful)
I figured as much, but couldn't resist a joke like that...
Those two-axle inside bearing trailing trucks look odd to me.
NorthWestThose two-axle inside bearing trailing trucks look odd to me.
Especially if containing all the conjugation stuff to power both axles from a booster: quartered cranks or some kind of gear or belt drive, plus the usual bull gear for the disengageable rocker drive...
There were a number of European designs going right back to Golsdorf that had those inside-bearing trailing trucks.
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