Heat exchanger design with FastTrack, FlexiScale and ReScale

[tom-rock]

Hi all,

for my Stirling engine new heat exchangers are in the planning stage using FastTrack, FlexiScale and ReScale by Dr. A. Organ for a target power of several hundred Watts.

If anybody is familar with the scaling methods of Dr. A. Organ I would be very thankful if u contact me here or via e-mail : tom-rock@web.de.

I have two questions to the gas path design:

1. What heat exchanger dead space ratio is acceptable for such a relative low-power engine?

My engine now has a dead space ratio delta=0,48
Scaled by the GPU3 as the prototype it would be delta=1,2
Scaled by the MP1002CA as the prototype it would be delta=0,51

2. Is there a way to change flow passage length Lx to fit for my design ?

Flow passage length of expansion heat exchanger scaled by GPU3 is Lxe=155 mm which is to long for my purpose (I use slots which surround the heater head) 90 mm would be the maximum I can use.

Scaled by the MP1002CA Lxe=37 mm which is to short and results in far to less external heater surface.

I would be very grateful if someone could mention something helpful to these problems.

I am always happy for comments and suggestions!

A video of my engine:

https://youtu.be/k3XNxzmMoWI

Thanks for reading

Ralf

[staska]

1. I suggest to copy Philips MP1002CA if Your engine will be air-charged. For H or He it is ok to use bigger ratio of dead-space.
2. You can do it, if you keep ratio of slot width to length, but compensate with number of slots for same purpose. In commo it is in 125-60 ratio.