Heat issues and wall thickness
I would think, and Scott - or anyone else here -correct me if I'm wrong, that since there would be a greater area of more conductive grain on a straight up and down grained pipe that it would ...you know, I'm really not sure.
Heat naturally wants to travel up, right? So, would the up and down grain on a straight grain cunduct more heat away from the smoke? I'm not sure really, because the heat would have to travel counter to the grain to get into the wood in the first place. On the otherhand, heat would naturally have an easier time traveling into the wood of a crossgrain, but a harder time traveling up through the wood.
I guess the question is in what direction does the heat travel once its in the wood? Probably both horizontally and vertically. But which direction more?
OK, the zeroth law of thermodynamics (doesn't that sound cool? the zeroth law) states that two objects placed next to eachother will reach thermodynamic equilibrium. It doesn't talk about up or down, so one as uneducated as me can assume that heat transfers in each direction. But does it require more work to go down? I would think so. What about to the side? Probably. And is work the right term? Probably not.
Its an interesting problem. If one presumes that 75% of the heat escapes through the top of the bowl, and the other 20% goes through the wood and 5% is carried off through the smoke, what would provide the best wood allignment to disapaite the heat, i.e. have a cool bowl? What about having the smoke be as cool as possible?
Presumably, only 50% of a bowl could be birds eye. I know there are examples of more birdseye, but those seem pretty few and far inbetween. So, latterally one can expect only 50% of the pipe to have the added conductivity, while the other 50% would run accross the grain.
The more I think about it, the more I think that crossgrain will difuse the most heat, providing a cool smoke. I've a friend who's very knowledgable about thermodynamics. I think I'll pose this problem to him.
Too cool!!!
Heat naturally wants to travel up, right? So, would the up and down grain on a straight grain cunduct more heat away from the smoke? I'm not sure really, because the heat would have to travel counter to the grain to get into the wood in the first place. On the otherhand, heat would naturally have an easier time traveling into the wood of a crossgrain, but a harder time traveling up through the wood.
I guess the question is in what direction does the heat travel once its in the wood? Probably both horizontally and vertically. But which direction more?
OK, the zeroth law of thermodynamics (doesn't that sound cool? the zeroth law) states that two objects placed next to eachother will reach thermodynamic equilibrium. It doesn't talk about up or down, so one as uneducated as me can assume that heat transfers in each direction. But does it require more work to go down? I would think so. What about to the side? Probably. And is work the right term? Probably not.
Its an interesting problem. If one presumes that 75% of the heat escapes through the top of the bowl, and the other 20% goes through the wood and 5% is carried off through the smoke, what would provide the best wood allignment to disapaite the heat, i.e. have a cool bowl? What about having the smoke be as cool as possible?
Presumably, only 50% of a bowl could be birds eye. I know there are examples of more birdseye, but those seem pretty few and far inbetween. So, latterally one can expect only 50% of the pipe to have the added conductivity, while the other 50% would run accross the grain.
The more I think about it, the more I think that crossgrain will difuse the most heat, providing a cool smoke. I've a friend who's very knowledgable about thermodynamics. I think I'll pose this problem to him.
Too cool!!!
I'm not good at this but i'll try........
If we've established that heat has an easier time traveling through grain. Then the question becomes does the heat travel more efficiently from the chamber to the hand through the grain horizontaly (birds eye showing on side of chamber)? My guess would be that it would be hotter to have birds eye on the side of the chamber.
If the density (wood density and wall thickness) was the same for each example pipe, then presumably in the pipe with the straight grain on the side the heat would have to travel through the more dense wood in between grains in order to make it's way to the outside of the bowl. Whereas with a pipe with birds eye on the sides of the bowl the heat would not have to travel through as much dense wood as it would have a straight path through the softer wood in the grain.
This is OBVIOUSLY over-simplified (especialy up against Nick's posts) but I think the over-simplification gets my point accross, eh?
If we've established that heat has an easier time traveling through grain. Then the question becomes does the heat travel more efficiently from the chamber to the hand through the grain horizontaly (birds eye showing on side of chamber)? My guess would be that it would be hotter to have birds eye on the side of the chamber.
If the density (wood density and wall thickness) was the same for each example pipe, then presumably in the pipe with the straight grain on the side the heat would have to travel through the more dense wood in between grains in order to make it's way to the outside of the bowl. Whereas with a pipe with birds eye on the sides of the bowl the heat would not have to travel through as much dense wood as it would have a straight path through the softer wood in the grain.
This is OBVIOUSLY over-simplified (especialy up against Nick's posts) but I think the over-simplification gets my point accross, eh?
"Heat naturally wants to travel up, right?"
I think you may be confusing "heat" with "hot air". Hot air has the tendency to rise over cooler air because it is less dense. When you are looking at the tendecncy for heat transfer within a solid, that isn't necessarily true.
Heat transfer within a solid occurs via conduction (think of it as the thermal equivalent of diffusion - conduction is to heat transfer as diffusion is to mass transfer). The rate of conduction is a function of the thermal conductivity of the solid. Thermal conductivity of wood is higher in the direction of the grain than against the grain. So there is a tendency for heat to travel more rapidly in the direction of the grain all other things (i.e. temperature gradient) equal. From that I conclude that if you could have two pipes, exactly the same in geometry, packed with identical tobacco and smoked the same way, with one pipe covered in birdseyes and the other covered with straight grain - that the bowl of the one covered in birdseyes would feel hotter than that covered with straight grain (wow, how's that for a run-on sentence?).
I think you may be confusing "heat" with "hot air". Hot air has the tendency to rise over cooler air because it is less dense. When you are looking at the tendecncy for heat transfer within a solid, that isn't necessarily true.
Heat transfer within a solid occurs via conduction (think of it as the thermal equivalent of diffusion - conduction is to heat transfer as diffusion is to mass transfer). The rate of conduction is a function of the thermal conductivity of the solid. Thermal conductivity of wood is higher in the direction of the grain than against the grain. So there is a tendency for heat to travel more rapidly in the direction of the grain all other things (i.e. temperature gradient) equal. From that I conclude that if you could have two pipes, exactly the same in geometry, packed with identical tobacco and smoked the same way, with one pipe covered in birdseyes and the other covered with straight grain - that the bowl of the one covered in birdseyes would feel hotter than that covered with straight grain (wow, how's that for a run-on sentence?).
Okay, I started a little stream of consciousness exercise today at lunch. I am up to 4 pages and I haven't even touched bowl orientation yet.
Anyone interested in reviewing this can email me at gammonus1999@yahoo.com and I will email it to you as soon as I get to completing the current line of thought (probably tomorrow's lunch hour).
When it is finished, I am submitting it as part of my application for the Nobel Pipe Smoking Prize.
:thumb:
Anyone interested in reviewing this can email me at gammonus1999@yahoo.com and I will email it to you as soon as I get to completing the current line of thought (probably tomorrow's lunch hour).
When it is finished, I am submitting it as part of my application for the Nobel Pipe Smoking Prize.
:thumb:
The term "smokes cooler" to me means that the smoke entering my mouth, and hitting my tongue in particular, is cooler. I am not so concerned with the temperature of the bowl as I am the temperature of what was hitting my tongue!
If we want the bowl itself to be cool then we would simply use the greatest amount of briar (i.e. the thickest walls) so that the heat cannot penatrate the wood enough to reach the bowls exterior surface. The outside surface of the bowl would be very cool to the touch but the smoke entering one's mouth is likely to be very hot.
Therefore, if a cross grained pipe would allow more heat to pass through it then the bowl would get hotter but the smoke (and water vapors) entering one's mouth would be cooler. Or so it stands to reason.
If we want the bowl itself to be cool then we would simply use the greatest amount of briar (i.e. the thickest walls) so that the heat cannot penatrate the wood enough to reach the bowls exterior surface. The outside surface of the bowl would be very cool to the touch but the smoke entering one's mouth is likely to be very hot.
Therefore, if a cross grained pipe would allow more heat to pass through it then the bowl would get hotter but the smoke (and water vapors) entering one's mouth would be cooler. Or so it stands to reason.
perhaps to a degree... i just didn't want the subject to be closed without discussing the bowl orientation because it sparked my interest at the beginning and I wanted to see what everyone had to say about it.Nick wrote:Well, sides of the bowl are important in this discussion in that that is one of the ways heat is removed from the smoke.
Random
There are three factors involved in fire; heat, fuel and oxygen. These three items are interdependent upon each other. when considering the heat generated by a flame if we add more oxygen to the bowl of tobacco then the tobacco will burn at a faster rate and will produce more heat (much like a turbo charger on a car engine). Someone who puffs the pipe a lot will draw more oxygen across the flame causing a greater production of heat. It is this heat that must go somewhere. Some will up and out of the borehole, some into ones mouth and the rest will go into the wood.
We must not confuse the minimum burning temperature with the actual burning temperature in an individual bowl.the ember is at the temperature it requires in order to maintain combustion
There are three factors involved in fire; heat, fuel and oxygen. These three items are interdependent upon each other. when considering the heat generated by a flame if we add more oxygen to the bowl of tobacco then the tobacco will burn at a faster rate and will produce more heat (much like a turbo charger on a car engine). Someone who puffs the pipe a lot will draw more oxygen across the flame causing a greater production of heat. It is this heat that must go somewhere. Some will up and out of the borehole, some into ones mouth and the rest will go into the wood.
I certainly agree with you here but I don't see that as a criticism of my original point. I the bore on a pipe is too large and you draw hard on it then it will smoke "hotter". The burning temperature is not fixed atI think anybody who believes they can map it out with a few equations might be confusing it though.
. That temperature is purely a minimum at which if it goes below this then we must strike another match to reintroduce more heat to the equation so that it burns.the temperature it requires in order to maintain combustion
Once this heat is produced during combustion it must "go" somewhere. The more of this heat that is dissipated into the wood then the less of it that is taken into the mouth. By understanding the basic relationship between a few main variables (wall thickness, bore diameter, shank length etc) then one can reach, to quote the Greeks, a "Golden Mean". Using that as a basis, small trade-offs can be made between the main variables while still maintaining the balance or Mean.
Facinating topic indeed!
If anyone is interested, I've constructed an MS Excel application that will calculate out the velocities and pressure profiles for a given pipe. All you have to do is enter in the dimensions, and viola. Too much fun. I have a multiple pipe thing too, but its a bit more cumbersome, and not as user friendly. One last note, I haven't been able to have it reviewed yet, so its only one man's work.
Email me at minz-elandril@lycos.com if you're interested.
If anyone is interested, I've constructed an MS Excel application that will calculate out the velocities and pressure profiles for a given pipe. All you have to do is enter in the dimensions, and viola. Too much fun. I have a multiple pipe thing too, but its a bit more cumbersome, and not as user friendly. One last note, I haven't been able to have it reviewed yet, so its only one man's work.
Email me at minz-elandril@lycos.com if you're interested.