Hi just read your posts
There seems to be so many variables to these vortex tubes its difficult to know where to start. I made one with 1/2 inch tube and slits simular to tuzi and it did not work well, then I read that they need a lot of air flow. A lot of web videos show the exelair one which is half the size and has a very short hot tube. One thing I did notice from the videos they make a characteristic wizzing noise, a bit like those kids toys you blow into and a wheel rotated very fast.
I am now reading a paper by Chenming Gao of Eindoven Uni which measures all the bits and tries to relate figures to various theories.
He varies length of hot tube, number of nozzles, etc. I would like to do a study (without the math).
I would start with the original spiral there may be something special about it. By the way what makes a golden spiral ? This caught my eye no-one seems to have studies the generation chamber, cylindrical spiral etc. Are yes Chenming recommends a chamfer on the edge entering the hot tube.
Regards chaps