Multiple tube Thermal Acoustic engine

[derwood]

This is just a first test of a new Engine I have designed. The heat source is small but it runs quite well with just a small pencil torch.

[youtube]https://youtu.be/5fluS_u13wI[/youtube]

[thanh-cuibap]

i like it !! Can you guide me how to make it ??

[Trevor]

Me to please Derwood - Love the concept you have done on it. That would have to be the best I have seen of late. Well done!
Trev

[derwood]

I am going to make some changes to the tail end. It uses 29 stainless steel .25 inch tubes welded on each end. The hardest part is to weld the tubes without air leaks. I tried to mig weld the tubes but could not get leak free welds. Tig welding was the key. Thanks for the interest.

[cbstirling2]

Clever. Does the heat need to be concentrated at one end of the tubes?
I wonder if a wood fire could be applied along the tube heat exchanger.
What watt output does it have?
How long can it run? (Gives clues how well it dumps heat.) I wonder how much better it would run with cooling fins (with belt driven fan) or a water jacket. Thinking CHP...

[derwood]

Clever. Does the heat need to be concentrated at one end of the tubes?
I wonder if a wood fire could be applied along the tube heat exchanger.
What watt output does it have?
How long can it run? (Gives clues how well it dumps heat.) I wonder how much better it would run with cooling fins (with belt driven fan) or a water jacket. Thinking CHP...

Yes the heat needs to be at one end. It dumps heat very well. Im still making some changes so power output is unknown. A wood fire would work well.

[cbstirling2]

What inspired the multitube design?
I thought your tube within a tube design to be very clever. Is there elements here?

I have a flame licker that doesn't run well, thinking of converting it to a thermo acoustic. Is there literature on the tube ratios and such?

[derwood]

What inspired the multitube design?
I thought your tube within a tube design to be very clever. Is there elements here?

I have a flame licker that doesn't run well, thinking of converting it to a thermo acoustic. Is there literature on the tube ratios and such?

The tube within a tube design ran well but once the inner tube heated up it suffered power loss. cooling the inner tube would be very difficult. I have found no literature on the multiple tube design. I just took an educated guess on the number of tubes which still needs to be adjusted. I have noticed a big difference in efficiency with the multiple tube and cooling is easier to achieve.

[cbstirling2]

In the far end, is there stainless wool for a regenerator? Seems a little odd that the middle space is heated...

[derwood]

Ive made some changes to the engine. It seems that the heating is so much more efficient that I have been able to greatly increase compression. approx. 1 : .75 , lowering compression does not increase stroke length. Currently Piston 3.35inch diameter, stroke 4inches, 3500 strokes per/min free piston mode. Piston and rod weight is 1.9 lbs.

[Aviator168]

That's excellent derwood. Like to see a load on it to measure the power output.

[derwood]

I noticed an error in my last post. It should read 1500 strokes per/min.