About water cooled nozzles, l used them on my Seats first gasifier. If anyone is interasted the pictures are in the begining of the “charcoal powered Seat Arosa 1.0” thread.
The nozzles worked well, but the gasifier was a crossdraft so the gas was way to hot for a in the cabbin gasifier. Thats the reason l started to develop my thick steel pipe nozzle.
Bob, you mentioned a bigger pipe to hold water. Your thinking is spot on
Myne was a 4" dia with 0.5" wall. The big size did alow plenty of water to boil in the nozzle pipe, cooling it and provideing water Without water pouring in the nozzles at tilts or brakeing. The system ran great.
But why did l abandon this? The reason is idleing. When you stop from a drive, the nozzle pipe still has enough heat to boil that pool of water, killing the charbed.
A great idea for a generator, not for a car.
The information I have comes from a book in French “The vehicles with gasifier (Editions du palmier)” The Dupuy establishments have adopted a particularly original cooling mode of the zone located in the vicinity of the nozzle. This part of the generator has the form of a cylinder head with cooling fins. It has a double wall filled with lead. The latter melts when the generator heats up and ensures, under the best conditions, the transmission of heat to the fins, the efficiency of which is thus greatly increased. "
It is all that I have as information on this subject
sorry !
Thierry
Liquid lead, interesting. While it does have a low melting point, it is not a very good thermal conductor, worse than cast-iron or steel. Conductivity goes down as temperature goes up, too.
Aluminum would’ve been a better choice. It melts at slightly higher temperatures, and has a vastly higher thermal conductivity, which goes up at higher temperatures.
Lead should also volatilize if the cavity isn’t completely full, then it should act like liquid sodium used in heat pipes (I imagine). What I find interesting about using lead is the temperature range, it would only begin to effectively transfer heat somewhere above 500 F, and as you say, maybe not with great efficiency, leading to higher temperatures before the real protective effect.
I’ve never heard of lead being used like that, someone should do some Google-ing…
Edit:
The boiling point of lead is 1,750C, 3,180F, much higher than I believed. Boiling won’t be the main heat transfer means. Convection may be the intended heat transfer means? Antimony has a lower boiling point, not sure if there are other practical candidates?
Yes but it wasnt very expensive before about 1900 if l remember right. Napoleon was the only guy in europe with an aluminium fork and spoon, it was worth much more thain gold.
I iften think how nice it wuld be to send some beercans back in time and all the money they wuld be worth
Help me with your thoughts. What are the problems you see with using a double ended aluminum nozzle with water drip/flow set for a car engine under load? Would this open ended approach avoid “killing the charbed” during idle? Would adding a solonoid valve on the water line with a simple on-off switch at the throttle be helpful to keep the excess steam from overwhelming the charbed at idle?
With a double open end l see no problem except maybee a few drops might overflow from the end at lower gas demand (idle).
My nozzle was designed to always hold a bit of water on the bottom to aid cooling and ad steam.
Imagine a 4" pipe welded on each end, with a 1/2" plumbing nipple welded in one end.
Like l sayd, great for engine under load, bad for trafficlights.
I think your valve idea shuld work great.
An eaven simpler idea was presented to me by Max, to use a small carburator with throtleplates removed to precisely meter water in relation of airflow in the gasifier.
I have tried a carburettor on my system to see if I could get a way of demand amounts of water into my charcoal , it was a small carb off a generator , for some reason I could not get the velocity right to get the water spray , was a case of too much or too little and did not have time to mess too much in the end , shame because I can see it would be a good way of metering water into the system , will have to give it another try one day .
Bruce is there a reason why you want to carry on trying out the aluminium pipe ,
wouldn’t a mild steel or stainless pipe now be best to try on your system ?
Hi Bob ,
Sorry I must have missed your question about using a larger pipe , I’m pretty sure that having the bottom half of the pipe sealed so as to trap some of the water so it puddles would work ok if used on a moving vehicle .
I think that once Bruce can put some hours on his system we will find that with a straight through open ended pipe nozzle, and once the build up of slag around his holes will workout just fine to protect the material , and that cooling the tube with extra water wont be needed , just enough water to add a boost and not so much that condensation becomes a problem .
Still it will be fun trying out all manners of ways to improve so lets keep on playing and inventing .
Dave
Hi Max, that’s what I am trying to do with my Charcoal Gasifier, the nozzle with in a nozzle will NOT be touching the char at all. Just started working on it again after being side tracked on the WK side of Gasification.
Bob
Remember, that a furious air blast has a furious sucking from the sides and behind.
This “filles up” with return char all up to the nozzle-tip, and there you are!
The only orientation avoiding this “fill up” is the vertical down-blast, from an “artificial” cavity, as the gravity stops it to be filled; the fill-up is going on, but the blast beam sucks it down like an “ant-lion” burning it out below.
The “fill-up” cannot build up uphill, as the “ground” for it is continuously remowed downhill, by the sucking blast.
As a side phenomenon, the airbeam also sucks lots of ready made gas and uses it in the process again and again.
(Like a circulation distillery!)
You cannot get rid of the backstream; use it to your benefit!
I have my nozzles reset back into a fire brick hole about 2". The charcoal is going to be kept away by 60* slope all around the nozzle area at 3 to 4" away form the bottom of the fire brick. I was hoping the cross draft vacuum would help keep the char moving in that direction.
The char feed will not come from above but in from the sides at 60* slope. There are side walls that will keep the char away from the fire brick hole. But can see your point of the backstream from the nozzle blast. I would love to have a viewing port to look into a see what is going on. Thanks again for you input on this.
Bob
The only “doubtful” would be the gas sucked out this cavity,(bell), as per your suggestion, not passing thru a layer of glowing charcoal.
Using a “blast” effect, to keep the glowing charcoal touching the nozzle tip is , per se, a good idea, but is it feasible ?
Looking into the perspective of a piece of glowing charcoal, then the surface getting in contact with the O molecules, is way far hotter then the rest of the piece. actually it nears the 3000 degree celcius, be it short time, per molecule. The radiation heat will make the environment hot and the carbon will absorb the biggest part of it in the transition to become gas.
Carbon will stay carbon until its oxydised with O, or sublimate if its above 4000 degree’s Celcius.
I am using very high silica content materials, where as silica vitrify’s at 2800 dergree celcius or above.
looking at the clumps of molten lava inside my gasifiers, its easy to see where the blast pushes the vitrified silica.
Even having a cavity, where the nozzle is free from contact, should not change the need for the gas passing thru a layer of glowing Carbon, for the reduction, never to forget dough that the blast is created by the suction/vacuum from an engine/blower.
The vacuum point is the part where as we should avoid to get non reduced volatile matter or Co2.
having a"pool" of water in the lower part of the nozzle pipe is a damn good idea.
It will act self regulating, since at low gas demand the temperature will drop and less heat will make less steam.
A vacuum controlled solenoid does also work ( been there, does the job very fine )
remember only one thing: you have the knowledge, you have the skills… so you can build anything
“The only “doubtful” would be the gas sucked out this cavity,(bell), as per your suggestion, not passing thru a layer of glowing charcoal.”
It has passed the lower parts of the glowing “blow-bottle” walls lower down before it comes slowly up outside in the passive surrounding char. That’s unavoidable, and rational.
No, that seems vertically “compressed” and tumbelling.
A well done nozzle has about 7 degrees of diversion in its blow beam.
From the center of the cavity bottom, a narrow-throated
“bottle-cavity” reaches downwards , like an oldtime limonade bottle.
Then the gases “leak” out through the walls and flow upwards.
The nozzle tip needs not to be more than 1/2 – 1" above the actual char
level under the “upside-down” funnel. To keep its “cutting sharpness”.
Below the “bottle” some grating helps cleaning the collected ash.
And, the diameter of the upside-down funnel needs not to be more
than ~8 – 10 charbits, if you do not intend to take out the gas from
under it, coaxially with the inlet tube.
The nozzle blowing is no floppy blowing, but burn-cutting.
