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I put AR's number into the formula. The Beale number has to be much higher to make sense.

2.7 atmospheres is actually 39.7 psi, or 2052.4 mm/ 80.8 inches mercury (figures rounded).
Ian S C

Ian, your numbers are absolutely correct - in outer space. Sometimes that matters. On earth at sea level, one 14.7 psi atmosphere = a flat tire and zero psi on a gauge. And 2.7 atmospheres = 25 psi on the same gauge. Sometimes that matters.

Bumpkin

Fine. When using 2.7 bar, the Beale number still has to be 2x the maximum for AR's engine to generate that power.

Hello Ralph
This is a beautiful engine you have here! And I really envy this awesome teststand, you built around it.
Concerning the power output which is not up to your target yet i have a question: Does the hot cap of the engine get glowing red? And where and how exactly do you measure the hot end temperature? It's kind of hard to tell from the videos, but my guess is that the burner does not produce enough heat to get the engine really going.
The Shaft seal of your Engine seems to be perfect. How did you build that?

Best Regards
Plani

Hi Plani,

the hot cap glows bright red with 1 bar, with 2 or more bars it doesen´t but it isn´t tested enough because at the moment I can´t heat it up to full red heat because I have problems with intergranular corrosion at the ss-heater head due to the regular red heat, the next one will be out of 1.4541 SS.
The thermocouple is located at the upper end of the regenerator just below the burner, when I redesign the burner it will get a better position now it can´t show the right heater temperature.
You can see it in the video, its the white cable.
The shaft seal is a face seal, I have no picture of it but in the comments to the video I linked a picture of a similar one.

Best wishes
Ralf

Hello Ralph

Wow, that's a really sophisticated sealing System you devised for the Shaft sealing!! I'm currently working on a little alpha Stirling, which I intend to pressurise later on too. But I don't have enough space in the engine housing, so what i want to make is some sort of a lip seal for the shaft. It will be made from this W300 material too. Would you please post a picture of your sealing system, when you take the engine apart once again?
Did I get this right: The hot cap is finned on the inside too? My feeling is, your engine is doing great on the inside as you describe it. Once you start to pressurise the engine above a certain point, then the working gas on the inside of the heat exchanger takes more heat away than the burner can deliver. So did you consider to just improve the heat output of your burner? Or do you plan on some sort of extended surface on the outside of the hot cap?
And another question: How did you get the fins machined inside the hot cap into the stainless???
Would you share some sort of a drawing, where it can be seen how you constructed your engine (Zusammenstellungszeichnug)?
I hope, I'm not annoying you too much with all my questions, but its such an interesting engine you have here!

Best Regard
Plani

I was just reading back a bit, you say that your heater wouldn't be able to give you more than 2at, that's right, but in a pressurized engine the pressure is taken at cold, so first you must pump the internal pressure to what is required, then apply the heat, and if for example you use 10at, and double the temperature in kelvin degrees, the working pressure will double to 20at. One atmosphere = 14.7psi, international standard atmosphere.
Ian S C

Not quite Ian. That's assuming you have no dead volume. Most home builts have a bout 30% dead volume.
The correct calculate final pressure is as

3 * P1 * V1 / 2 + amount of heat added = 3 * P2 * V2 / 2

Also, when you said double the temperature, how do you really know the temperature is doubled.

Hi all,

Plani:

I think a lip seal out of W300 will not work because W300 is very brittle and hard.
When I take the sealing apart I will male a photo of the face seal.

The burner delivers more than enough heat, what I need is additional outside surface on the heater head.
It is internally slotted wit 120 slots 0,5mm wide 4mm deep.
It was very hard work slotting these on the lathe with a small chisel (grinded many of them) and feed the lathe by hand.
I think in the 2nd video on YouTube is a detailed picture of the heater head where you can see the slots.

Now I am designing the new heater head which will have more then 8 times the outside surface.
But it is still a lot of planning to do.
I asked a few professional experts about the heat exchanger design, and even Dr. A. Organ answered my questions with a kind response.
And they all said its a hard task to optimize the flow passages, maybe I must just try with the help of a 2nd order simulation as before.

Ian and Aviator:

I mean 2 atm when it is hot working and I always thought mean working pressure is the mean pressure when
it is working but I dont´t know.

Thanks for your comments

Ralf

Hi Ralf, a few things. The environmental pressure never equal the mean working pressure and some times wont equal to the low working pressure. I am more familiar with alpha. Depending where sniff value is, the low pressure can be equal or lower than the environmental pressure. In the case of no sniff value, the low pressure can be higher than the environment pressure.

About your internal slots, how long are the slots and by what method are you sure that most working fluid goes through between the slots and what is the clearance between the tip of the slot and the displacer?

Edit. There is no need to increase heater external area. Increasing flame temperature by 5 to 10 degress K goes a long way. Provided you can still maintain the same burner efficiency of cause.

Hi Ralph

This must have been a Pain in the &$$, to make all the slots into stainless steel like this!! You can be proud of your achievement! Too bad, it's not performing yet as you wish. What is your intention then with the new heater head? Does it get some sort of fins on the outside as well?
Please make sure you take some pictures when you build the new heater. That would be very interesting.

Another Question: You are pretty confident in the power of your burner and as it can be seen in the videos it lights easily as well. On the ringburner I made for my engine, it takes always some time for the burner to warm up before it produces some useful heat. I derived the size of the jet orifice and the mixer tube from the designs of Andy Ross. I have also the impression, that my burner is not very efficient. Could you give some hints how you dimensioned your burner assembly?

Thanks and best Regards
Plani

ss is the problem. Thermo conductivity 15. Go with cast iron which has thermo conductivity of 65.

Hello tom-rock,

What is you source for the rhombic drive calculations?

I've started a topic on this subject and maybe you can Help me out?

http://stirlingengineforum.com/viewtopic.php?f=1&t=1979

Thanks in advance,

JR.