Its impressive how well this works! I love the meaning behind having these designs be openly accessible. The more people that can join in on designing, the better.
Hey! I'm happy to see your progress on your wind tunnel, it's good to see another channel starting to do small scale turbine tests. Feel free to reach out, I'll be happy to help out where I can.
Anometer calibration is infact done in a larger wind tunnel like 70cm diameter vs 20-30cm anemometer size. For ensuring laminar flow the wind tunnels I hang around (through having a father with an engineering bureau with three wind tunnels from small to 4.5m nozzle size) always had a funneling nozzle with a hexagon structure of 2-3cm depth to make the airflow laminar. Also the propeller was as far away as possible.
You could use a very slight venturi tube, having the inner diameter reduce slightly (like just 1/4"-1/2" depending how big the overall inner diameter is. And at the smallest point of the venturi, you can install a piece of screen. Small pieces of window screen are available for cheap at hardware stores (use the most basic screen rather than the very tight mesh for shady screen or for "better bug resistance" because they choke off airflow too much) and that will even and smooth out the airflow for it to then expand ever so slightly to reduce airspeed slightly and bam. You now have an even, constant airflow that is equal at any point across the area of the wind tunnel.
To keep the flow “straighter” you should have the fan at the back so that it pulls air through and not pushes it in, which would create turbulence. Also the testing chamber would need a bigger ratio to the contraction so that wind can flow through it. This is because the testing chamber would increase the pressure by too much to quickly so air wouldn’t flow through. Hope this helps!
Are you planning to build an enclosure around the testing section, or is that impractical at the moment due to space constraints? I imagine any stray breezes, etc. are minimal compared to the output of the device, but it still might make it a little bit more reproducible. You'd also be able to do fun stuff like running some smoke/mist through to visualize the flow which might be more difficult in an unconstrained environment? Great work though, just thinking of possible future iterations...
I still think window screen is the easiest and cheapest option. How do you keep the straws stacked? Glue? The glue can be uneven leaving variations in the gaps. And unless you cut the straws very very short, then you must ensure they are all perfectly parallel or this will create variations in flow. And once you get them very very short, they are much harder to work with. Instead, buying a small repair patch of window screen is cheap, and all you have to do is cut it to shape with a good pair of scissors. Then you can insert it into the tunnel perpendicular to flow and thats it..
![Tesla Turbine v2.0 [3D Printed]](http://i.ytimg.com/vi/n5KmpFRSXiA/mqdefault.jpg)
Its impressive how well this works! I love the meaning behind having these designs be openly accessible. The more people that can join in on designing, the better.
Hey! I'm happy to see your progress on your wind tunnel, it's good to see another channel starting to do small scale turbine tests. Feel free to reach out, I'll be happy to help out where I can.
Anometer calibration is infact done in a larger wind tunnel like 70cm diameter vs 20-30cm anemometer size. For ensuring laminar flow the wind tunnels I hang around (through having a father with an engineering bureau with three wind tunnels from small to 4.5m nozzle size) always had a funneling nozzle with a hexagon structure of 2-3cm depth to make the airflow laminar. Also the propeller was as far away as possible.
You could use a very slight venturi tube, having the inner diameter reduce slightly (like just 1/4"-1/2" depending how big the overall inner diameter is. And at the smallest point of the venturi, you can install a piece of screen. Small pieces of window screen are available for cheap at hardware stores (use the most basic screen rather than the very tight mesh for shady screen or for "better bug resistance" because they choke off airflow too much) and that will even and smooth out the airflow for it to then expand ever so slightly to reduce airspeed slightly and bam. You now have an even, constant airflow that is equal at any point across the area of the wind tunnel.
To keep the flow “straighter” you should have the fan at the back so that it pulls air through and not pushes it in, which would create turbulence. Also the testing chamber would need a bigger ratio to the contraction so that wind can flow through it. This is because the testing chamber would increase the pressure by too much to quickly so air wouldn’t flow through. Hope this helps!
Existing stuff! Good to see you iterateing on your designs :)🎉
Hey, thanks!
Are you planning to build an enclosure around the testing section, or is that impractical at the moment due to space constraints? I imagine any stray breezes, etc. are minimal compared to the output of the device, but it still might make it a little bit more reproducible. You'd also be able to do fun stuff like running some smoke/mist through to visualize the flow which might be more difficult in an unconstrained environment? Great work though, just thinking of possible future iterations...
A stack of drinking straws is the way to equalise the flow.
I still think window screen is the easiest and cheapest option. How do you keep the straws stacked? Glue? The glue can be uneven leaving variations in the gaps. And unless you cut the straws very very short, then you must ensure they are all perfectly parallel or this will create variations in flow. And once you get them very very short, they are much harder to work with.
Instead, buying a small repair patch of window screen is cheap, and all you have to do is cut it to shape with a good pair of scissors. Then you can insert it into the tunnel perpendicular to flow and thats it..
Thingiverse Link!
www.thingiverse.com/edenia3dmodels/designs