best way to stop this mass heater smoking?

best way to stop this mass heater smoking?
is ths barrel to big for the flue?
i know fire area needs insulating but what is best , flue linner / rockwool or bricks / rock / mortar / rubble to make it burn hotter
thanks for any help

Soley based from my applied thermodynamics class, if there is smoke then there is incomplete combustion. That means the air/fuel ratio is less than ideal so you will have to increase the air flow rate. Judging from the picture, your intake is double the size (if not more due to tube deformation at the end) of your exhaust pipe so I think there may be incomplete combustion from a choked off air supply.

From fluid dynamics, the heated air in the exhaust is less dense than the cold air so it will rise creating a drop in pressure for the intake air to fill. This creates the movement of air that feeds the combustion.

I neglected to mention the headspace distance of the inner pipe and the top of the barrel. If the top of the inner tube is to close to the top of the barrel than it will create more resistance and reduce the air flow rate.

hi thanks.
inlet and outlet are the same size. pic makes it look smaller
insulate ing the fire area must make it burn hotter

yes must measure gap between

quick check for this... lay a plate over the fire intake and slowly decrease its size and see if you start getting a hotter burn. Hard fix... increase the diameter of your exhaust and take it out the side of the burn barrel instead of going through the bottom.

Ermmm... The feed tube appears being too long, the same goes for the horizontal burn tunnel. To fix this: make the tunnel as short as possible, the feed tube half the length of the tunnel and the riser three times the tunnel, at least. Insulate all around the burn tunnel and riser, using insulating materials. Brick, rock, concrete and other dense stuff isn't insulating, at all. Rock wool, vermiculite, perlite and wood ash do. The ash will compact over time, loosing its properties. The cross sectional area should be the same everywhere, the top gap should be 2 inches high at least, more won't do any harm. Insulating the riser will close off some of the exit flue, so you have to make that wider, it's a common spot for restriction. When this is all fixed, the stove should run more, well, rockety. Burning clean is very much dependent on air speed through the system.

Edit:
The capped off end of the tunnel shouldn't be there. It's main effect is slowing down air speed because of a slight underpressure forming in that dead end. No openings in the whole thing except the vertical feed tube end.

I like your exit out the bottom of the barrel. solves a common problem. other than that, Peter knows his stuff.

Peter Berg wrote:Ermmm... The feed tube appears being too long, the same goes for the horizontal burn tunnel. To fix this: make the tunnel as short as possible, the feed tube half the length of the tunnel and the riser three times the tunnel, at least. Insulate all around the burn tunnel and riser, using insulating materials. Brick, rock, concrete and other dense stuff isn't insulating, at all. Rock wool, vermiculite, perlite and wood ash do. The ash will compact over time, loosing its properties. The cross sectional area should be the same everywhere, the top gap should be 2 inches high at least, more won't do any harm. Insulating the riser will close off some of the exit flue, so you have to make that wider, it's a common spot for restriction. When this is all fixed, the stove should run more, well, rockety. Burning clean is very much dependent on air speed through the system.

Edit:
The capped off end of the tunnel shouldn't be there. It's main effect is slowing down air speed because of a slight underpressure forming in that dead end. No openings in the whole thing except the vertical feed tube end.

thanks for help, will get on and do them mods. the riser is insulated with vermiculite by about 2 inches each side , the feed is removable to leave about a 5/6 inch , the larger feed tube has a 5 inch hole in the side about half way up coverd by foil , if i removed the foil to expose the hole would that do, will send a pic. when you say The cross sectional area should be the same everywhere, do you meen the level of the inlet and outlet should be the same level.

tel jetson wrote:I like your exit out the bottom of the barrel. solves a common problem. other than that, Peter knows his stuff.

hi yes cut a barrel off at the bottom leaving about 2 inches ov side on , cut 2 holes with grinder and jig saw to the right diamiter and pushed a 6" stainless tube in the middle one that had a thiner connecting end on it that only went in 2 inch , it sat nice and tight, then connected the burn tube to it with a jubbile clip [hose clip] then tac welded a thicker tube to the barrel over the riser and filled it with vermiculite and caped it of. then added the outlet connecter and riveted it on . then cut the other end of the barrel at about a therd where in bends in and used it as a stand , cut some holes for in/outlet then placed the bottom of the barrel on the stand and tac welded it on put another barrel over the top of it all and was going to weld it on air tight but figured that i could do it with foil and brown tape , this will melt if the fire aren is closer to it unless i could get a hold of fire prufe tap that would keep it air tight , does anybody know if there is such a thing ? thanks

rob zos wrote:the feed is removable to leave about a 5/6 inch , the larger feed tube has a 5 inch hole in the side about half way up coverd by foil , if i removed the foil to expose the hole would that do, will send a pic. when you say The cross sectional area should be the same everywhere, do you meen the level of the inlet and outlet should be the same level.

I'd think 5 inch would be just right as feed tube. Any longer and you're running into trouble, there's no reason to use such a long tube.
Don't tell me you're asking me what cross sectional area is, ask google, please. All the pipes you're using for the stove should be the same diameter, OK?

Peter Berg wrote:

rob zos wrote:the feed is removable to leave about a 5/6 inch , the larger feed tube has a 5 inch hole in the side about half way up coverd by foil , if i removed the foil to expose the hole would that do, will send a pic. when you say The cross sectional area should be the same everywhere, do you meen the level of the inlet and outlet should be the same level.

I'd think 5 inch would be just right as feed tube. Any longer and you're running into trouble, there's no reason to use such a long tube.
Don't tell me you're asking me what cross sectional area is, ask google, please. All the pipes you're using for the stove should be the same diameter, OK?

the long feed tube is so that you can put lengths of wood up to about 3 or 4 feet long in it and it keeps them upright.
i'm new to this stuff so sorry for not knowing what "the cross sectional area" is.

Long feed tube, smoking stove, your choice.
Klick this link and read.
http://wiki.answers.com/Q/How_do_you_calculate_the_cross_section_area_of_cylinder