turbulence needed in a liebig ?

[Tōtōchtin]

I was wondering if I should add some turbulence in a liebig condenser, I am getting ready to put a 1.5"/1" x 3' liebig condenser together. I was thinking about soldering some tabs made from 3/4" copper pipe up and down the internal pipe to increase turbulence changing directional flow a bit. I don't want to do anything that's not justified. I sometimes over think a project.
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[Salt Must Flow]

It isn't necessary. Though a lot of people like to spiral copper wire around the outside of the inner pipe prior to soldering it all together. The spiraled wire causes water to follow the spiral and can make the Liebig condenser more efficient. I've never done that, mine functioned just fine, but perhaps it would be a benefit to do. It sure couldn't hurt.

[Saltbush Bill]

IMO you will achieve more by adding some extra length.
Crimping the inner tube also helps I think, the theory is that you are killing two birds with one stone, the crimps disturb the water flow within the condensers water jacket, and also interrupt any laminar flow of vapours that may occur within the inner tube of the condenser.
Link here for more on the subject viewtopic.php?p=7706828
Different folk have different ideas plain, crimped , wound with wire, they all work....your call , your condenser.

[LWTCS]

Also, a twisted ribbon of copper (turbulator) down the length of the inner tube to promote vapor turbulence to increase vapor dwell time.

[NZChris]

There are a variety of tricks that help if you are wanting to build a short Liebig undersized for the amount of vapour it has to knock down.

If you build large enough, none of those tricks do anything, as the flow rate of the water is too slow for them to create any useful amount of turbulence.

[subbrew]

Also, a twisted ribbon of copper (turbulator) down the length of the inner tube to promote vapor turbulence to increase vapor dwell time.

Will increase turbulence but does not increase dwell time. If it increased dwell time it would be backing up the incoming vapor because the dwelling vapor would still be in the pipe. That would increase pressure, increasing velocity and shortening dwell time. Only way to increase dwell time is to cut power and thus velocity or to make the pipe longer or larger diameter..

[shadylane]

I was wondering if I should add some turbulence in a liebig condenser, I am getting ready to put a 1.5"/1" x 3' liebig condenser together.

That's a good sized liebig.
I use the same condenser without anything to add turbulence.
My thinking is causing vapor turbulence isn't needed nor good.

Dew doesn't settle on the grass if a wind is blowing.

[Tōtōchtin]

Ok well I am glad I asked first. I had meant them to increase turbulence by interfering with flow. Also to help heat transfer. Another idea you guys are blowing up of mine was putting in some spiral baffles in my shotguns condensers. I know how well these work in helping transfer heat in my absorption refers. I figured these would help if I ever cranked up my still on a hot day.

2926212602.jpg (14.11 KiB) Viewed 841 times

Again thanks a lot..

[shadylane]

Even though I think it would be counterproductive, I'd recommend giving it a try.
Measure the distillate temp before and after to see what happens.
Start with a short "turbulator" and make another one that runs the full length of the condenser.

[zach]

I have condenser with an inner copper pipe of 1.25 ID and a outer jacket of 1.5 ID jacketed condenser. I used copper reducers on each end of the jacket and wrapped the inner pipe 12 gauge wire in a spiral. I use it with a double concentric head.

This thread has good ideas on how to construct such a condenser.

viewtopic.php?t=36382&start=30

The 1.25 ID tube is 1.375 OD and fits inside a 1.5" Tri clamp with a little sanding, which makes connections easy.

[Saltbush Bill]

Another thing to consider is diameters....1 inch over 3/4 beats 3/4 over 1/2 every time IMO.

[LWTCS]

Also, a twisted ribbon of copper (turbulator) down the length of the inner tube to promote vapor turbulence to increase vapor dwell time.

Will increase turbulence but does not increase dwell time. If it increased dwell time it would be backing up the incoming vapor because the dwelling vapor would still be in the pipe. That would increase pressure, increasing velocity and shortening dwell time. Only way to increase dwell time is to cut power and thus velocity or to make the pipe longer or larger diameter..

Hmm, let me use a better word then. More turbulence will promote drag.
And rather than dwell time, I suppose I should have said more exposure to surface area contact.
Think static mixer where by the material traversing thru the tube is forced to travel just as far going east and west as it does heading north or South. So basically turbulence influenced by a partial obstruction forces the material to travel farther within the tube before being discharged.

Within the context of this discussion I don't believe that added pressure necessarily equates to added vapor speed because the thing responsible for any pressure build up is actually a partial obstruction. I visualize this as a semi clogged shower valve. The partial obstruction slows the velocity of discharge ( think shitty water pressure aka pressure drop) while no doubt increases the back pressure on the other side of the partial obstruction.

Doesn't matter. Turbulence absolutely optimizes heat transfer.

[subbrew]

Within the context of this discussion I don't believe that added pressure necessarily equates to added vapor speed because the thing responsible for any pressure build up is actually a partial obstruction. I visualize this as a semi clogged shower valve. The partial obstruction slows the velocity of discharge ( think shitty water pressure aka pressure drop) while no doubt increases the back pressure on the other side of the partial obstruction.

Doesn't matter. Turbulence absolutely optimizes heat transfer.

That drop is only because the pressure of the water line supplying the house remains the same. In this case as soon as you obstruct the vapor leaving the boiler, assuming power remains the same, the boiler will build pressure to the point vapor speed past the obstruction is enough to re-establish the same flow.

In this case of a condenser I don't see mechanically induced turbulence helping much. The fact is you will not get laminar flow in a condenser because the flow along the edges condenses and falls out of the stream, so vapor toward the center is pulled over to fill the void. this constant drop and fill is causing turbulence naturally with no intervention.

It is the same principle as nucleate boiling in the tubes of a boiler, of course heat flow is in the opposite direction. but the most efficient heat flow in a boiler is when you just start to get boiling. Bubbles form, move into the main stream of the tube and collapse. This induces a natural turbulence which breaks up laminar flow and increases heat transfer.

[Yummyrum]

Another thing to consider is diameters....1 inch over 3/4 beats 3/4 over 1/2 every time IMO.

I can agree with you there Salty . … especially when it comes to big ones .

My first liebig was 3/4” over 1/2” about 3’ long and it was fine for my 30 litre boiler
.

Stripping on the 80 Litre keg it just didn’t cut the mustard . I had gas to burn but little Liebig couldn’t keep up

1” over 3/4” just under 6’ long gets the job done fast .
Clocked it high 20l/h with flames lapping the sides of the boiler on stripping runs .

Oh yeah , spiral wrapped coolant jacket and crimped inner . If you can , why not

[LWTCS]

Within the context of this discussion I don't believe that added pressure necessarily equates to added vapor speed because the thing responsible for any pressure build up is actually a partial obstruction. I visualize this as a semi clogged shower valve. The partial obstruction slows the velocity of discharge ( think shitty water pressure aka pressure drop) while no doubt increases the back pressure on the other side of the partial obstruction.

Doesn't matter. Turbulence absolutely optimizes heat transfer.

That drop is only because the pressure of the water line supplying the house remains the same. Yes, precisely In this case as soon as you obstruct the vapor leaving the boiler, assuming power remains the same, the boiler will build pressure to the point vapor speed past the obstruction is enough to re-establish the same flow. Yes same flow. But with the introduction of turbulence you get a much better convection. I don't understand why is this is in question? I do admit that using added dwell time is not the correct way to characterize what is happening.

In this case of a condenser I don't see mechanically induced turbulence helping much. The fact is you will not get laminar flow in a condenser because the flow along the edges condenses and falls out of the stream, so vapor toward the center is pulled over to fill the void. this constant drop and fill is causing turbulence naturally with no intervention. Are you then saying that the use of a twisted ribbon (turbulator) doesn't work? Have you ever used one? They absolutely provide assistance.

It is the same principle as nucleate boiling in the tubes of a boiler, of course heat flow is in the opposite direction. but the most efficient heat flow in a boiler is when you just start to get boiling. Bubbles form, move into the main stream of the tube and collapse. This induces a natural turbulence which breaks up laminar flow and increases heat transfer.Yes. I'm not quite sure what we are debating here?

I definitely agree with Salty that building a properly sized condenser is the best solution. The use of a turbulator more often is an ad hoc solution for someone trying to enhance their bony little condenser performance once they realize its too small.

[subbrew]

Are you then saying that the use of a twisted ribbon (turbulator) doesn't work? Have you ever used one? They absolutely provide assistance.

I am saying that the flow rates we have and the size condensers we have that mechanically inducing turbulence will not be noticeable in the vapor flow because you are not going to get a laminar flow anyhow. I can see were adding additional copper in the tube, as long as it has good contact with the sides to provide conduction, would increase the cooling area surface and that would increase the overall cooling capacity of the condenser. My hypothesis is that if you have had good experience with a turbulator it was due to additional conduction of heat to the cooling water by the additional surface area, not turbulence.

I will say my opinions are not based on distilling units. They are based on the studies and design documents I used during my career as an engineer at various power plants. I can't see why the principles wouldn't apply but would not be the first time I was wrong. I do know we never put anything in any of the condensers at the plants where efficiency was $$ because the design studies didn't show it was worth it.

[Tōtōchtin]

I my past I worked on yachts and customer buses before I got into lighting. I have a lot of experience with absorbtion refrigerators/freezers. You take that baffle out and you don't get crap for heat transfer and loose over 20* f in the bottom half and your freezer is useless. I know it's only one example, but truth kinda flows over everything.
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[shadylane]

I think turbulence is good for a heat exchanger.
But a condenser needs slow vapor speed, not fast turbulent flow.

[squigglefunk]

I really didn't notice a difference in knock down power when I had a "turbulator" (thick twisted solid copper wire) jammed up in my liebig

I do have a thick copper wire twisted in a spiral between the inner and outer pipes of the liebig ? I dunno how much that helps Its just something I saw here

[Tōtōchtin]

Not trying to run fast just trying to plan for the worst days coming. I have time now with few parts to start, my mind wonders a lot now with me wanting to get in the game. So I have time to play, if it's just costing me time I want to make it the best I can. My shotgun PC I'm told is more then I need for 5500w. I was planning on using the baffle in my shotgun style dephlegmator/reflux condenser while the still is set up for vm. I've noticed how high the coolant is heating up there.
My Liebig I am sure most will think it as useless as tits on a boar hog...
It will be used mainly to support my column.
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