Turbulators on propane boiler

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Drprez
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Turbulators on propane boiler

Post by Drprez » Thu Mar 25, 2021 7:38 am

I recently had some custom turbulators made for my boiler on the locomotive I’m building. Made of stainless steel they fit well in the tubes and increase the heat transfer greatly.

I notice that the time to heat the boiler to steam pressure is about a 1/3 less. They also help when running as the burners don’t flame out due to the draft of the exhaust is not so drastic. The turbulators work to act to some what slow the fast sucking of the air in the tubes. I have also modified the exhaust by extending the outlet by about half way into the stack. It reduces the draft yet I still get the stack talk that is always wanted.

I had tried the zig zag style as well as stainless steel twisted flat strips. Out of all of them these by far work the best. I think a combination of surface area and the design of them help the flow have maximum turbulence in its path to the stack.

They have worked so well that I plan on installing them In my American when I take it down to rebuild it next year.
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Nicholas Kalair
Las Vegas, NV

...the best is yet to come...

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ChuckHackett-844
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Re: Turbulators on propane boiler

Post by ChuckHackett-844 » Thu Mar 25, 2021 7:55 am

Where can we get them? What do they cost?
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
Owner, MiniRail Solutions, RR Signal Systems (http://www.MiniRailSolutions.com)
"By the work, One knows the workman"

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Chris Hollands
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Re: Turbulators on propane boiler

Post by Chris Hollands » Thu Mar 25, 2021 8:08 am

I think you will have a lot of interest for these including me .

Gra2472
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Re: Turbulators on propane boiler

Post by Gra2472 » Thu Mar 25, 2021 9:25 am

Will you be offering them for sale?
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NP317
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Re: Turbulators on propane boiler

Post by NP317 » Thu Mar 25, 2021 10:44 am

Ditto, Ditto, Ditto.
RussN

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ccvstmr
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Re: Turbulators on propane boiler

Post by ccvstmr » Thu Mar 25, 2021 6:43 pm

Drprez wrote:
Thu Mar 25, 2021 7:38 am
I recently had some custom turbulators made for my boiler on the locomotive I’m building. Made of stainless steel they fit well in the tubes and increase the heat transfer greatly.

I notice that the time to heat the boiler to steam pressure is about a 1/3 less. They also help when running as the burners don’t flame out due to the draft of the exhaust is not so drastic. The turbulators work to act to some what slow the fast sucking of the air in the tubes. I have also modified the exhaust by extending the outlet by about half way into the stack. It reduces the draft yet I still get the stack talk that is always wanted.

I had tried the zig zag style as well as stainless steel twisted flat strips. Out of all of them these by far work the best. I think a combination of surface area and the design of them help the flow have maximum turbulence in its path to the stack.
Drprez...more info is needed. Some questions and comments for your consideration:

1) you noted your turbs were custom made. What were your specifications or design criteria? By who, what, where, ball park cost?
2) no flame outs? This tells me there's a potential problem somewhere else. What kind of burner baffle do you have in the firebox?
3) tried other turbs: zig-zags, twisted metal strips. How did you determine the "wire brush" turbulators were better? What kind of measurements did you take? What kind of data did you collect?

Inquiring minds would like to know. Carl B.
Life is like a sewer...what you get out of it depends on what you put into it!
I don't walk on water...I just learned where some of the stepping stones are!
I love mankind...it's some of the people I can't stand!

BillF
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Re: Turbulators on propane boiler

Post by BillF » Thu Mar 25, 2021 7:27 pm

If you do a search for "stainless steel turbulators" on Google and look at the images, you will find a number of similar designs shown. They are known as "wire matix" or "petal" designs, and seem to be manufactured mostly in Europe and India. It would still be very interesting to know what sort of manufacturing technique is needed to produce these designs.

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Chris Hollands
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Re: Turbulators on propane boiler

Post by Chris Hollands » Thu Mar 25, 2021 8:16 pm

A few pictures and suppliers .
And only in England a supplier that has been around since 1793 .
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turbulator 2.PNG

Drprez
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Re: Turbulators on propane boiler

Post by Drprez » Fri Mar 26, 2021 11:08 am

I have a supplier that make them for my commercial boilers and so I have them made.

I can get any diameter and length you would like each is custom made to spec. I just need to know the inside diameter of the tube / diameter you want them made to and the length.

Ball park cost is for example 24” long x 1/2” dia are about $18-$20 each. I guess you can save some if you just get them longer and cut them. 36” run about $22.

If you want some send me a message and I’ll get you a price. It takes about 2 weeks to produce .

As to no flame out being a problem. No I just have the airflow adjusted properly so when I open the throttle it don’t suck the flame out . I made another post about my propane burner and the arch and firebrick I use to solve this.

I think I am more than qualified to have some creditable research and numbers on the laminar heat flow and transfer. I have a masters in thermal dynamics and do research for the National Science Foundation. I have tons of spreadsheets of numbers and data more the I feel like typing here. But all the test were done scientifically with constants and parameters to make accurate judgement. Measured the heat with thermal sensors, inferred and digital scanning so we can actually see the heat flow change based on the the turbulators or the baffles etc.

This practice increases the effectiveness of the available heat-transfer surface by eliminating thermal stratification and balancing the gas flow through the firetubes. Every 40°F reduction in the boiler flue gas temperature results in a 1% boiler-efficiency improvement.
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Thermal heat scan of at pressure locomotive
PLEASE NOTE THIS IS BASED ON USING Propaine. I have not tested them with any other fuel source.

Just to help with the reference there are five types turbulator:

Spring turbulator.
Soldered turbulator.
Twisted turbulator.
Hollow rod turbulator.
Flexible turbulator.

Here is examples of each.
The ones I use are closely related to the flexible turbulators since our boilers small in size are like a heat sync in ways so this is the most efficient type to use in the tubes for max results.

Flexible turbulator- is widely used in heat sinks, falling film evaporators and liquid cooled motors and static mixers.

Twisted turbulator- is very suitable for refinery transfer because its twisted appearance can offer a low pressure drop and oil can pass easily.

Soldered turbulator- is welded inside the tube of heat transfer. It offers an extended heat transfer surface and allows the manufacture of lightweight, strong compact coolers.

Spring turbulator -is containing resilience and flexibility. It is used on horizontal heat transfer.

Hollow rod turbulator- is especially useful when the liquid in the tube is very viscous and also where the viscosity varies greatly with temperature. Liquid near the tube wall develops a very high viscosity and forms a tunnel through which the hotter lower viscosity liquid passes through.

For the burner I use the rose burners that cover the bed completely without touching the sides as not to quench the flame combustion. The burners I have a supplier they run about $10 a burner and I use 11 in my boiler.
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11 burners each one produces 5000btu
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11 burner layout using 1/4 square tube
I have a brass base plate so most air comes through the burners and there is 1/8” space around each burner for air as well but it is redirected inward with grommet like rings this helps heat the air some on its path in. The burners sit on the ash pan so all air comes from the rear of the firebox.
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This is a base plate from my other locomotive but it uses the same grommet design and spacing around the burners
Once in the firebox above the burners I have a secondary stainless plate that is perforated with 1/4” holes. This plate is about 1/2” above the top of the flames of the burner. On top of this perforated plate is ceramic biscuits and the purpose of this plate and biscuits are to simulate coals constant and even burn so what happens is the stainless heats up red hot from the flame and the biscuits then heat up just like coal would. It helps retain heat so once you start going you don’t have the instant drop of temperature from the air getting sucked out when there’s a flame because the biscuits and the perforated sheet continue to create heat and make it more evenly.

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Above the flames is the stainless sheet that has ceramic biscuits. I actually use a biscuit the size of my fire box that looks like a honey comb so the air flows through it but it gets glowing red hot.
Then I have an arch that runs from the front all the way to the back of my fire box with about an inch from the rear of the fire box and about a half inch down from the top of the fire box of the crown plate.
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Arch looking up inside firebox
From there the exhaust air is now on a second journey as it goes down into the tubes but because I have the turbulators which are the pedal types. They force the air to swell backwards in itself as it’s going through you’re getting more conductIve turbulence. As exits into the smoke box and to help compensate From overdrafting and pulling the air to flame out when I’m running I extended the exhaust tube slightly into the stack just enough so that it’s not draw drafting as much an then it prevents the burn out or flame out.
Nicholas Kalair
Las Vegas, NV

...the best is yet to come...

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NP317
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Re: Turbulators on propane boiler

Post by NP317 » Fri Mar 26, 2021 3:46 pm

Very interesting firebox and burner set up.
Thanks for sharing your knowledge and experience with us.
RussN

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Chris Hollands
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Re: Turbulators on propane boiler

Post by Chris Hollands » Fri Mar 26, 2021 5:05 pm

Great info on your setup I'm very interested in getting the turbulators but also curious about the ceramic tile you are using , can you show or explain a bit more on that product also - supply / cost etc .
Thanks
Last edited by Chris Hollands on Fri Mar 26, 2021 8:02 pm, edited 1 time in total.

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NP317
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Re: Turbulators on propane boiler

Post by NP317 » Fri Mar 26, 2021 7:34 pm

Chris H:
If I remember correctly your propane burner is a slot design made by Al VonRuden. (?)
Al's designs produce heat in a flat bed simulation of a coal fire, with much radiant energy down low in the firebox.
I have one of his wonderful burners in my new Mikado.

I suspect Nicholas K. is also trying to replicate such a coal fire by using the ceramic block to produce more radiant energy than the rosebud propane burners do. Radiant heat is what works best in the firebox, where the majority of the heat energy gets transferred to the water.

It also looks like Nicholas's propane burner assembly is sitting pretty high in the firebox, increasing the need for radiant energy to heat the lower sidewalls of the firebox.
I have the same rosebud burners and manifold setup (from LocoParts) in my Ten Wheeler (without a ceramic block), but mounted low so that their rosebud flames impinge the firebox walls just above the mud ring.
This has worked quite well over my years of easy steaming this loco.

Please keep sharing, everyone.
RussN

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