HL-VAWT, Helical Lift Based Vertical Axis Wind Turbine | 3D Printed Sustainable Recycling Project

I started this project with the idea of exploring VAWT's and introducing a new design of my own suited for specific use-cases and hence happy to introduce one of the first Helical, Lift based Vertical Axis Wind Turbines (HL-VAWT), you mostly wont find any existing HL - VAWT designs as I have coined the HL part of it just now ; ) .

The best part of this project is that I have tried to design this with mostly 3d printable and easily source-able components, hence I am making the designs open source, I would love if the 3D printing community can make changes on the base idea to introduce better designs suited for small scale energy production using 3d printing and spare supplies.

I have used the following supplies.

1. 629 Bearings x2
2. 3D printed Airfoils x9
3. 3D printed Mounting Bracket to shaft x3
4. 600mm x 10mm Stainless Steel pipe x1
5. Nema 17 Stepper Motor ( Salvaged from old ender 3 printer )
6. IN4007 Diodes x4
7. 50v, 100uf Capacitor x1

Airfoil based VAWT designs have been less prevalent due to the fabrication difficulties introduced due to complex shape of these blades. However with the advent of consumer grade 3d printing, these designs are turning into a viable reality.

This HL-VAWT design is meant to harvest wind energy from the slipstream generated by high speed vehicles on highways and train along railway tracks, There is a common misconception that this induces drag on the vehicle. Here is an explanation on why it doesn't.

Since this design of my HL-VAWT has an estimated minimum starting speed of 3.5 m/s and operational speed of 5-7 m/s it is most suited for high wind speed areas ( along highways, hilly regions )

Instead of going with a standard airfoil designs like NACA 0024, I decided to use the DU 06-W-200 Airfoil which is more suited for wind turbine operation, source : https://www.sci-en-tech.com/ICCM2015/PDFs/1198-3483-1-PB.pdf

Now with the theory established, I started with designing our first prototype, while doing so I had to consider the limited bed volume of most readily available 3d printers and hence I segmented the airfoil into parts of length 150mm each. So we can stack three of such blades together to make a 450mm tall HL-VAWT for initial testing. This size should be easily printable on most 3d printers. I personally printed 3 of these 150 mm long blades at a time on my Ender 3.

The designs have been made using Fusion 360 and I have attached the stl files for you to download and print a turbine of your own.

I sliced the turbine blades in packs of 3, we will need 9 blades in total, keep in mind that there are 3 designs, and each needs to be printed thrice, using one particular design file and printing it 9 times wont do, the blades are meant to snug fit each other and hence design files are different.

Since 3d printing has been the key enabler of this type of wind turbine design for small scale, I decided to use one of my broken ender 3 printer to salvage our generator ! A Nema 17 stepper motor will act as the generator for this project. A stepper is the best suited motor to be used in low rpm settings, like with our design, we will however need to add some more components to generate a pure DC output from this stepper motor. Hence here comes our full bridge rectifier. I'll explain how to make it in the next step.

To utilize the AC output from the stepper motor, I had to convert it into DC for practical use. This can be done by constructing a full bridge rectifier using 1N4001 diodes and a smoothing capacitor.

The stepper motor generates alternating current (AC) across its two coil pairs when rotated. Each coil is connected to a separate rectifier circuit comprising four diodes, which convert the AC into pulsating DC.

The outputs of both rectifiers are combined, with a 1000 µF, 25V capacitor added across the DC terminals to smooth the voltage. At moderate rotation speeds, this setup should deliver a stable 6–12V DC output with a current range of 500–1000 mA, ready for powering or charging devices.

This step is completely optional and most modern printers wont even need it, but I observed that there was visible stringing in the 3d prints of my Ender 3, hence I used an 80 grit sanding paper to smooth the surface, this will also help a little in improving the performance of this turbine.

Now that all the components are ready, it is time for an assembly, I am first attaching the turbine wings of each stage individually to the central mount, for this I am using these 3d printed dowel's.

Once we have three such stages joint together to the main ring using the dowels we will insert the main ring in the center shaft.

Once all the three rings are on the center shaft, we will align the blades of each stage with each other and insert them for a snug tight fit. With this part complete the turbine is ready to roll, pun intended.

For the testing of this project, I currently used a standard 240mm fan at maximum speed. The output was measured using this multimeter. The project is far from over and I am actively working upon tweaking the design for better output.

This turbine has a relatively higher starting speed than most standard VAWT's and hence needs to be tested in high windspeed areas, the outdoor windspeed in Mumbai is around 2-3m/s which is not the best suited for testing it, in a upcoming instructable, I will be testing this turbine or a larger version along a highway or a high wind speed region. Please make sure to share your feedback about the design and any other suggestions. Thanks for giving a read : )